Eye vision system using programmable micro-optics and micro-electronics

NASA Astrophysics Data System (ADS)

Riza, Nabeel A.; Amin, M. Junaid; Riza, Mehdi N.

2014-02-01

Proposed is a novel eye vision system that combines the use of advanced micro-optic and microelectronic technologies that includes programmable micro-optic devices, pico-projectors, Radio Frequency (RF) and optical wireless communication and control links, energy harvesting and storage devices and remote wireless energy transfer capabilities. This portable light weight system can measure eye refractive powers, optimize light conditions for the eye under test, conduct color-blindness tests, and implement eye strain relief and eye muscle exercises via time sequenced imaging. Described is the basic design of the proposed system and its first stage system experimental results for vision spherical lens refractive error correction.

Design of the micro pressure multi-node measuring system for micro-fluidic chip

NASA Astrophysics Data System (ADS)

Mu, Lili; Guo, Shuheng; Rong, Li; Yin, Ke

2016-01-01

An online multi-node microfludic pressure measuring system was designed in the paper. The research focused on the design of pressure test circuit system and methods on dealing with pressure data collecting. The MPXV7002 micro-pressure sensor was selected to measure the chip inside channel pressure and installed by a silicone tube on different micro-channel measured nodes. The pressure transmission loss was estimated in the paper, and corrected by the filtering and smoothing method. The pressure test experiment was carried out and the data were analyzed. Finally, the measuring system was calibrated. The results showed that the measuring system had high testing precision.

Guiding supersonic projectiles using optically generated air density channels

NASA Astrophysics Data System (ADS)

Johnson, Luke A.; Sprangle, Phillip

2015-09-01

We investigate the feasibility of using optically generated channels of reduced air density to provide trajectory correction (guiding) for a supersonic projectile. It is shown that the projectile experiences a force perpendicular to its direction of motion as one side of the projectile passes through a channel of reduced air density. A single channel of reduced air density can be generated by the energy deposited from filamentation of an intense laser pulse. We propose changing the laser pulse energy from shot-to-shot to build longer effective channels. Current femtosecond laser systems with multi-millijoule pulses could provide trajectory correction of several meters on 5 km trajectories for sub-kilogram projectiles traveling at Mach 3.

Active phase correction of high resolution silicon photonic arrayed waveguide gratings

DOE PAGES

Gehl, M.; Trotter, D.; Starbuck, A.; ...

2017-03-10

Arrayed waveguide gratings provide flexible spectral filtering functionality for integrated photonic applications. Achieving narrow channel spacing requires long optical path lengths which can greatly increase the footprint of devices. High index contrast waveguides, such as those fabricated in silicon-on-insulator wafers, allow tight waveguide bends which can be used to create much more compact designs. Both the long optical path lengths and the high index contrast contribute to significant optical phase error as light propagates through the device. Thus, silicon photonic arrayed waveguide gratings require active or passive phase correction following fabrication. We present the design and fabrication of compact siliconmore » photonic arrayed waveguide gratings with channel spacings of 50, 10 and 1 GHz. The largest device, with 11 channels of 1 GHz spacing, has a footprint of only 1.1 cm 2. Using integrated thermo-optic phase shifters, the phase error is actively corrected. We present two methods of phase error correction and demonstrate state-of-the-art cross-talk performance for high index contrast arrayed waveguide gratings. As a demonstration of possible applications, we perform RF channelization with 1 GHz resolution. In addition, we generate unique spectral filters by applying non-zero phase offsets calculated by the Gerchberg Saxton algorithm.« less

Active phase correction of high resolution silicon photonic arrayed waveguide gratings.

PubMed

Gehl, M; Trotter, D; Starbuck, A; Pomerene, A; Lentine, A L; DeRose, C

2017-03-20

Arrayed waveguide gratings provide flexible spectral filtering functionality for integrated photonic applications. Achieving narrow channel spacing requires long optical path lengths which can greatly increase the footprint of devices. High index contrast waveguides, such as those fabricated in silicon-on-insulator wafers, allow tight waveguide bends which can be used to create much more compact designs. Both the long optical path lengths and the high index contrast contribute to significant optical phase error as light propagates through the device. Therefore, silicon photonic arrayed waveguide gratings require active or passive phase correction following fabrication. Here we present the design and fabrication of compact silicon photonic arrayed waveguide gratings with channel spacings of 50, 10 and 1 GHz. The largest device, with 11 channels of 1 GHz spacing, has a footprint of only 1.1 cm². Using integrated thermo-optic phase shifters, the phase error is actively corrected. We present two methods of phase error correction and demonstrate state-of-the-art cross-talk performance for high index contrast arrayed waveguide gratings. As a demonstration of possible applications, we perform RF channelization with 1 GHz resolution. Additionally, we generate unique spectral filters by applying non-zero phase offsets calculated by the Gerchberg Saxton algorithm.

Manufacture of micro fluidic devices by laser welding using thermal transfer printing techniques

NASA Astrophysics Data System (ADS)

Klein, R.; Klein, K. F.; Tobisch, T.; Thoelken, D.; Belz, M.

2016-03-01

Micro-fluidic devices are widely used today in the areas of medical diagnostics and drug research, as well as for applications within the process, electronics and chemical industry. Microliters of fluids or single cell to cell interactions can be conveniently analyzed with such devices using fluorescence imaging, phase contrast microscopy or spectroscopic techniques. Typical micro-fluidic devices consist of a thermoplastic base component with chambers and channels covered by a hermetic fluid and gas tight sealed lid component. Both components are usually from the same or similar thermoplastic material. Different mechanical, adhesive or thermal joining processes can be used to assemble base component and lid. Today, laser beam welding shows the potential to become a novel manufacturing opportunity for midsize and large scale production of micro-fluidic devices resulting in excellent processing quality by localized heat input and low thermal stress to the device during processing. For laser welding, optical absorption of the resin and laser wavelength has to be matched for proper joining. This paper will focus on a new approach to prepare micro-fluidic channels in such devices using a thermal transfer printing process, where an optical absorbing layer absorbs the laser energy. Advantages of this process will be discussed in combination with laser welding of optical transparent micro-fluidic devices.

Aberrations in square pore micro-channel optics used for x-ray lobster eye telescopes

NASA Astrophysics Data System (ADS)

Willingale, R.; Pearson, J. F.; Martindale, A.; Feldman, C. H.; Fairbend, R.; Schyns, E.; Petit, S.; Osborne, J. P.; O'Brien, P. T.

2016-07-01

We identify all the significant aberrations that limit the performance of square pore micro-channel plate optics (MPOs) used as an X-ray lobster eye. These include aberrations intrinsic to the geometry, intrinsic errors associated with the slumping process used to introduce a spherical form to the plates and imperfections associated with the plate manufacturing process. The aberrations are incorporated into a comprehensive software model of the X-ray response of the optics and the predicted imaging response is compared with the measured X-ray performance obtained from a breadboard lobster eye. The results reveal the manufacturing tolerances which limit the current performance of MPOs and enable us to identify particular intrinsic aberrations which will limit the ultimate performance we can expect from MPO-lobster eye telescopes.

Macro-channel cooled high power fiber coupled diode lasers exceeding 1.2kW of output power

NASA Astrophysics Data System (ADS)

Koenning, Tobias; Alegria, Kim; Wang, Zuolan; Segref, Armin; Stapleton, Dean; Faßbender, Wilhelm; Flament, Marco; Rotter, Karsten; Noeske, Axel; Biesenbach, Jens

2011-03-01

We report on a new series of fiber coupled diode laser modules exceeding 1.2kW of single wavelength optical power from a 400um / 0.2NA fiber. The units are constructed from passively cooled laser bars as opposed to other comparably powered, commercially available modules that use micro-channel heat-sinks. Micro-channel heat sinks require cooling water to meet demanding specifications and are therefore prone to failures due to contamination and increase the overall cost to operate and maintain the laser. Dilas' new series of high power fiber coupled diode lasers are designed to eliminate micro channel coolers and their associated failure mechanisms. Low-smile soldering processes were developed to maximize the brightness available from each diode laser bar. The diode laser brightness is optimally conserved using Dilas' recently developed propriety laser bar stacking geometry and optics. A total of 24 bars are coupled into a single fiber core using a polarization multiplexing scheme. The modular design permits further power scaling through wavelength multiplexing. Other customer critical features such as industrial grade fibers, pilot beams, fiber interlocks and power monitoring are standard features on these modules. The optical design and the beam parameter calculations will be presented to explain the inherit design trade offs. Results for single and dual wavelengths modules will be presented.

Integrated optical-fiber capillary electrophoresis microchips with novel spin-on-glass surface modification.

PubMed

Lin, Che-Hsin; Lee, Gwo-Bin; Fu, Lung-Ming; Chen, Shu-Hui

2004-07-30

This paper presents a novel micro-capillary electrophoresis (CE) chip with embedded optical fibers for the on-line detection of DNA samples. The optical fibers are pre-etched and then inserted directly into fiber channels incorporated within low-cost soda-lime glass substrates. The embedded optical fibers are precisely aligned with the microfluidic channels such that the induced fluorescence signals from labeled bio-samples can be detected. This arrangement avoids the requirement for delicate optical alignment procedures and equipment. Surface modification of the CE channels is accomplished by means of a simple and reliable organic-based spin-on-glass (SOG) method. The zeta potential distribution and the corresponding electroosmotic mobility of the fluid are simulated numerically for the modified and non-modified channel surfaces, and then both sets of results are verified experimentally. The present results indicate that the value of the zeta potential for a surface with an SOG coating is 19.3 times smaller than that of an untreated surface. A phiX-174 DNA marker fluid is used to evaluate the injection and separation performance of the developed micro-CE device. Furthermore, the long-term stability of the SOG-coated surface is also investigated. The experimental data reveal that the microchip device is capable of providing highly efficient separations of bio-molecules, and that the SOG layer retains its low zeta potential characteristics for at least 45 days. The present results confirm the effectiveness of the proposed micro-CE chip in performing the on-line detection of DNA samples, and indicate that the SOG process represents a simple and reliable solution for the surface modification of glass-based microchannels.

Micromachined mirrors for raster-scanning displays and optical fiber switches

NASA Astrophysics Data System (ADS)

Hagelin, Paul Merritt

Micromachines and micro-optics have the potential to shrink the size and cost of free-space optical systems, enabling a new generation of high-performance, compact projection displays and telecommunications equipment. In raster-scanning displays and optical fiber switches, a free-space optical beam can interact with multiple tilt- up micromirrors fabricated on a single substrate. The size, rotation angle, and flatness of the mirror surfaces determine the number of pixels in a raster-display or ports in an optical switch. Single-chip and two-chip optical raster display systems demonstrate static mirror curvature correction, an integrated electronic driver board, and dynamic micromirror performance. Correction for curvature caused by a stress gradient in the micromirror leads to resolution of 102 by 119 pixels in the single-chip display. The optical design of the two-chip display features in-situ mirror curvature measurement and adjustable image magnification with a single output lens. An electronic driver board synchronizes modulation of the optical source with micromirror actuation for the display of images. Dynamic off-axis mirror motion is shown to have minimal influence on resolution. The confocal switch, a free-space optical fiber cross- connect, incorporates micromirrors having a design similar to the image-refresh scanner. Two micromirror arrays redirect optical beams from an input fiber array to the output fibers. The switch architecture supports simultaneous switching of multiple wavelength channels. A 2x2 switch configuration, using single-mode optical fiber at 1550 mn, is demonstrated with insertion loss of -4.2 dB and cross-talk of -50.5 dB. The micromirrors have sufficient size and angular range for scaling to a 32x32 cross-connect switch that has low insertion-loss and low cross-talk.

Both channel coding and wavefront correction on the turbulence mitigation of optical communications using orbital angular momentum multiplexing

NASA Astrophysics Data System (ADS)

Zhao, Shengmei; Wang, Le; Zou, Li; Gong, Longyan; Cheng, Weiwen; Zheng, Baoyu; Chen, Hanwu

2016-10-01

A free-space optical (FSO) communication link with multiplexed orbital angular momentum (OAM) modes has been demonstrated to largely enhance the system capacity without a corresponding increase in spectral bandwidth, but the performance of the link is unavoidably degraded by atmospheric turbulence (AT). In this paper, we propose a turbulence mitigation scheme to improve AT tolerance of the OAM-multiplexed FSO communication link using both channel coding and wavefront correction. In the scheme, we utilize a wavefront correction method to mitigate the phase distortion first, and then we use a channel code to further correct the errors in each OAM mode. The improvement of AT tolerance is discussed over the performance of the link with or without channel coding/wavefront correction. The results show that the bit error rate performance has been improved greatly. The detrimental effect of AT on the OAM-multiplexed FSO communication link could be removed by the proposed scheme even in the relatively strong turbulence regime, such as Cn2 = 3.6 ×10-14m - 2 / 3.

Experimental study of multichromatic terahertz wave propagation through planar micro-channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Young-Min -Min; Northern Illinois Univ., Dekalb, IL; Fermi National Accelerator Lab.

2012-04-10

Previous theoretical and numerical studies [Y. M. Shin and L. R. Barnett, Appl. Phys. Lett. 92, 091501 (2008) and Y. M. Shin et al., Appl. Phys. Lett. 93, 221504 (2008)] have reported that a planar micro-channel with an asymmetric corrugation array supports strongly confined propagation of broadband THz plasmonic waves. The highly broad spectral response is experimentally demonstrated in the near-THz regime of 0.19-0.265 THz. Signal reflection and transmission tests on the three designed micro-channels including directional couplers resulted in a full-width-half-maximum bandwidth of ~ 50-60GHz with an insertion loss of approximately -5 dB, which is in good agreement withmore » simulation data. As a result, these micro-structures can be utilized for free electron beam and electronic/optic integrated devices« less

Modeling, Simulation, and Analysis of a Decoy State Enabled Quantum Key Distribution System

DTIC Science & Technology

2015-03-26

through the fiber , we assume Alice and Bob have correct basis alignment and timing control for reference frame correction and precise photon detection...optical components ( laser , polarization modulator, electronic variable optical attenuator, fixed optical attenuator, fiber channel, beamsplitter...generated by the laser in the CPG propagate through multiple optical components, each with a unique propagation delay before reaching the OPM. Timing

The wavefront compensation of free space optics utilizing micro corner-cube-reflector arrays

NASA Astrophysics Data System (ADS)

You, Shengzui; Yang, Guowei; Li, Changying; Bi, Meihua; Fan, Bing

2018-01-01

The wavefront compensation effect of micro corner-cube-reflector arrays (MCCRAs) in modulating retroreflector (MRR) free-space optical (FSO) link is investigated theoretically and experimentally. Triangular aperture of MCCRAs has been optically characterized and studied in an indoor atmospheric turbulence channel. The use of the MCCRAs instead of a single corner-cube reflector (CCR) as the reflective device is found to improve dramatically the quality of the reflected beam spot. We draw a conclusion that the MCCRAs can in principle yield a powerful wavefront compensation in MRR FSO communication links.

Micro Fluidic Channel Machining on Fused Silica Glass Using Powder Blasting

PubMed Central

Jang, Ho-Su; Cho, Myeong-Woo; Park, Dong-Sam

2008-01-01

In this study, micro fluid channels are machined on fused silica glass via powder blasting, a mechanical etching process, and the machining characteristics of the channels are experimentally evaluated. In the process, material removal is performed by the collision of micro abrasives injected by highly compressed air on to the target surface. This approach can be characterized as an integration of brittle mode machining based on micro crack propagation. Fused silica glass, a high purity synthetic amorphous silicon dioxide, is selected as a workpiece material. It has a very low thermal expansion coefficient and excellent optical qualities and exceptional transmittance over a wide spectral range, especially in the ultraviolet range. The powder blasting process parameters affecting the machined results are injection pressure, abrasive particle size and density, stand-off distance, number of nozzle scanning, and shape/size of the required patterns. In this study, the influence of the number of nozzle scanning, abrasive particle size, and pattern size on the formation of micro channels is investigated. Machined shapes and surface roughness are measured using a 3-dimensional vision profiler and the results are discussed. PMID:27879730

Limb Correction of Polar-Orbiting Imagery for the Improved Interpretation of RGB Composites

NASA Technical Reports Server (NTRS)

Jedlovec, Gary J.; Elmer, Nicholas

2016-01-01

Red-Green-Blue (RGB) composite imagery combines information from several spectral channels into one image to aid in the operational analysis of atmospheric processes. However, infrared channels are adversely affected by the limb effect, the result of an increase in optical path length of the absorbing atmosphere between the satellite and the earth as viewing zenith angle increases. This paper reviews a newly developed technique to quickly correct for limb effects in both clear and cloudy regions using latitudinally and seasonally varying limb correction coefficients for real-time applications. These limb correction coefficients account for the increase in optical path length in order to produce limb-corrected RGB composites. The improved utility of a limb-corrected Air Mass RGB composite from the application of this approach is demonstrated using Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. However, the limb correction can be applied to any polar-orbiting sensor infrared channels, provided the proper limb correction coefficients are calculated. Corrected RGB composites provide multiple advantages over uncorrected RGB composites, including increased confidence in the interpretation of RGB features, improved situational awareness for operational forecasters, and the ability to use RGB composites from multiple sensors jointly to increase the temporal frequency of observations.

Packaged integrated opto-fluidic solution for harmful fluid analysis

NASA Astrophysics Data System (ADS)

Allenet, T.; Bucci, D.; Geoffray, F.; Canto, F.; Couston, L.; Jardinier, E.; Broquin, J.-E.

2016-02-01

Advances in nuclear fuel reprocessing have led to a surging need for novel chemical analysis tools. In this paper, we present a packaged lab-on-chip approach with co-integration of optical and micro-fluidic functions on a glass substrate as a solution. A chip was built and packaged to obtain light/fluid interaction in order for the entire device to make spectral measurements using the photo spectroscopy absorption principle. The interaction between the analyte solution and light takes place at the boundary between a waveguide and a fluid micro-channel thanks to the evanescent part of the waveguide's guided mode that propagates into the fluid. The waveguide was obtained via ion exchange on a glass wafer. The input and the output of the waveguides were pigtailed with standard single mode optical fibers. The micro-scale fluid channel was elaborated with a lithography procedure and hydrofluoric acid wet etching resulting in a 150+/-8 μm deep channel. The channel was designed with fluidic accesses, in order for the chip to be compatible with commercial fluidic interfaces/chip mounts. This allows for analyte fluid in external capillaries to be pumped into the device through micro-pipes, hence resulting in a fully packaged chip. In order to produce this co-integrated structure, two substrates were bonded. A study of direct glass wafer-to-wafer molecular bonding was carried-out to improve detector sturdiness and durability and put forward a bonding protocol with a bonding surface energy of γ>2.0 J.m-2. Detector viability was shown by obtaining optical mode measurements and detecting traces of 1.2 M neodymium (Nd) solute in 12+/-1 μL of 0.01 M and pH 2 nitric acid (HNO3) solvent by obtaining an absorption peak specific to neodymium at 795 nm.

SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Circulatory fibre-optic memory loop with a built-in service channel

NASA Astrophysics Data System (ADS)

Pilipovich, V. A.; Esman, A. K.; Goncharenko, I. A.; Posed'ko, V. S.; Solonovich, I. F.

1995-10-01

A method for increasing the information capacity and enhancing the reliability of information storage in a dynamic fibre-optic memory is proposed. An additional built-in channel with counterpropagating circulation of signals is provided for this purpose. This additional channel can be used to transmit both information and service signals, such as address words, clock signals, correcting sequences, etc. The possibility of compensating the attenuation of an information signal by stimulated Raman scattering is considered.

Public classical communication in quantum cryptography: Error correction, integrity, and authentication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timofeev, A. V.; Pomozov, D. I.; Makkaveev, A. P.

2007-05-15

Quantum cryptography systems combine two communication channels: a quantum and a classical one. (They can be physically implemented in the same fiber-optic link, which is employed as a quantum channel when one-photon states are transmitted and as a classical one when it carries classical data traffic.) Both channels are supposed to be insecure and accessible to an eavesdropper. Error correction in raw keys, interferometer balancing, and other procedures are performed by using the public classical channel. A discussion of the requirements to be met by the classical channel is presented.

Shaping perfect optical vortex with amplitude modulated using a digital micro-mirror device

NASA Astrophysics Data System (ADS)

Zhang, Chonglei; Min, Changjun; Yuan, X.-C.

2016-12-01

We propose a technique to generate of perfect optical vortex (POV) via Fourier transformation of Bessel-Gauss (BG) beams through encoding of the amplitude of the optical field with binary amplitude digital micro-mirrors device (DMD). Furthermore, we confirm the correct phase patterns of the POV with the method of Mach-Zehnder interferometer. Our approach to generate the POV has the advantages that rapidly switch among the different modes, wide spectral regions and high energy tolerance. Since the POV possess propagation properties that not shape-invariant, we therefore suppose that our proposed approach will find potential applications in optical microscopy, optical fabrication, and optical communication.

No moving parts safe & arm apparatus and method with monitoring and built-in-test for optical firing of explosive systems

DOEpatents

Hendrix, J.L.

1995-04-11

A laser initiated ordnance controller apparatus which provides a safe and arm scheme with no moving parts. The safe & arm apparatus provides isolation of firing energy to explosive devices using a combination of polarization isolation and control through acousto-optical deviation of laser energy pulses. The apparatus provides constant monitoring of the systems status and performs 100% built-in-test at any time prior to ordnance ignition without the risk of premature ignition or detonation. The apparatus has a computer controller, a solid state laser, an acousto-optic deflector and RF drive circuitry, built-in-test optics and electronics, and system monitoring capabilities. The optical system is completed from the laser beam power source to the pyrotechnic ordnance through fiber optic cabling, optical splitters and optical connectors. During operation of the apparatus, a command is provided by the computer controller and, simultaneous with laser flashlamp fire, the safe & arm device is opened for approximately 200 microseconds which allows the laser pulse to transmit through the device. The arm signal also energizes the laser power supply and activates the acousto-optical deflector. When the correct fire format command is received, the acousto-optic deflector moves to the selected event channel, and the channel is verified to ensure the system is pointing to the correct position. Laser energy is transmitted through the fiber where an ignitor or detonator designed to be sensitive to optical pulses is fired at the end of the fiber channel. Simultaneous event channels may also be utilized by optically splitting a single event channel. The built-in-test may be performed anytime prior to ordnance ignition. 6 figures.

No moving parts safe & arm apparatus and method with monitoring and built-in-test for optical firing of explosive systems

DOEpatents

Hendrix, James L.

1995-01-01

A laser initiated ordnance controller apparatus which provides a safe and m scheme with no moving parts. The safe & arm apparatus provides isolation of firing energy to explosive devices using a combination of polarization isolation and control through acousto-optical deviation of laser energy pulses. The apparatus provides constant monitoring of the systems status and performs 100% built-in-test at any time prior to ordnance ignition without the risk of premature ignition or detonation. The apparatus has a computer controller, a solid state laser, an acousto-optic deflector and RF drive circuitry, built-in-test optics and electronics, and system monitoring capabilities. The optical system is completed from the laser beam power source to the pyrotechnic ordnance through fiber optic cabling, optical splitters and optical connectors. During operation of the apparatus, a command is provided by the computer controller and, simultaneous with laser flashlamp fire, the safe & arm device is opened for approximately 200 microseconds which allows the laser pulse to transmit through the device. The arm signal also energizes the laser power supply and activates the acousto-optical deflector. When the correct fire format command is received, the acousto-optic deflector moves to the selected event channel, and the channel is verified to ensure the system is pointing to the correct position. Laser energy is transmitted through the fiber where an ignitor or detonator designed to be sensitive to optical pulses is fired at the end of the fiber channel. Simultaneous event channels may also be utilized by optically splitting a single event channel. The built-in-test may be performed anytime prior to ordnance ignition.

Formation of contour optical traps using a four-channel liquid crystal focusing device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korobtsov, A V; Kotova, S P; Losevsky, N N

2014-12-31

The capabilities and specific features of the formation and dynamic control of so-called contour optical traps using a fourchannel liquid crystal modulator are studied theoretically and experimentally. Circular, elliptical and C-shaped traps are formed. Trapping and confinement of absorbing micro-objects by the formed traps are demonstrated. (optical traps)

Optofluidic refractive-index sensor in step-index fiber with parallel hollow micro-channel.

PubMed

Lee, H W; Schmidt, M A; Uebel, P; Tyagi, H; Joly, N Y; Scharrer, M; Russell, P St J

2011-04-25

We present a simple refractive index sensor based on a step-index fiber with a hollow micro-channel running parallel to its core. This channel becomes waveguiding when filled with a liquid of index greater than silica, causing sharp dips to appear in the transmission spectrum at wavelengths where the glass-core mode phase-matches to a mode of the liquid-core. The sensitivity of the dip-wavelengths to changes in liquid refractive index is quantified and the results used to study the dynamic flow characteristics of fluids in narrow channels. Potential applications of this fiber microstructure include measuring the optical properties of liquids, refractive index sensing, biophotonics and studies of fluid dynamics on the nanoscale.

Accounting for Chromatic Atmospheric Effects on Barycentric Corrections

NASA Astrophysics Data System (ADS)

Blackman, Ryan T.; Szymkowiak, Andrew E.; Fischer, Debra A.; Jurgenson, Colby A.

2017-03-01

Atmospheric effects on stellar radial velocity measurements for exoplanet discovery and characterization have not yet been fully investigated for extreme precision levels. We carry out calculations to determine the wavelength dependence of barycentric corrections across optical wavelengths, due to the ubiquitous variations in air mass during observations. We demonstrate that radial velocity errors of at least several cm s-1 can be incurred if the wavelength dependence is not included in the photon-weighted barycentric corrections. A minimum of four wavelength channels across optical spectra (380-680 nm) are required to account for this effect at the 10 cm s-1 level, with polynomial fits of the barycentric corrections applied to cover all wavelengths. Additional channels may be required in poor observing conditions or to avoid strong telluric absorption features. Furthermore, consistent flux sampling on the order of seconds throughout the observation is necessary to ensure that accurate photon weights are obtained. Finally, we describe how a multiple-channel exposure meter will be implemented in the EXtreme PREcision Spectrograph (EXPRES).

Polarization independent polymer waveguide tunable receivers incorporating a micro-optic circulator

NASA Astrophysics Data System (ADS)

Wu, Xiaoping; Park, Tae-Hyun; Park, Su-Hyun; Seo, Jun-Kyu; Oh, Min-Cheol

2018-06-01

In order to simplify the receiver configuration in a wavelength division multiplexed optical fiber network, compact wavelength tunable filters have long been expected to be used as channel selectors. Bragg reflector inherently has the most suitable reflection spectrum for filtering a single wavelength from the densely multiplexed wavelength signal. Polymer has high thermo-optic coefficient and good thermal insulation property compared to the other optical waveguide materials such as silicon and silica materials. This can be used to broadly tune the reflection spectrum of Bragg reflector using a simple micro-heater. In this work, a micro-optic circulator component and a polymeric Bragg reflector device are assembled to produce a small form factor tunable receiver. Compared to the integrated-optical versions, the micro-optics are based on well-developed manufacturing processes and can achieve competitive production yields. The device exhibits high reflectivity with a flat top passband, and a polarization dependence of 0.06 nm achieved by virtue of the low birefringence of LFR polymer, which make a significant contribution to the implementation of polarization independent tunable receiver. The wavelength tuning range of 40 nm is demonstrated by using a bottom located heater with a groove for heat isolation.

Full-field swept-source optical coherence tomography with phase-shifting techniques for skin cancer detection

NASA Astrophysics Data System (ADS)

Krauter, J.; Boettcher, T.; Körner, K.; Gronle, M.; Osten, W.; Passilly, N.; Froehly, L.; Perrin, S.; Gorecki, C.

2015-05-01

The EU-funded project VIAMOS1 proposes an optical coherence tomography system (OCT) for skin cancer detection, which combines full-field and full-range swept-source OCT in a multi-channel sensor for parallel detection. One of the project objectives is the development of new fabrication technologies for micro-optics, which makes it compatible to Micro-Opto-Electromechanical System technology (MOEMS). The basic system concept is a wafer-based Mirau interferometer array with an actuated reference mirror, which enables phase shifted interferogram detection and therefore reconstruction of the complex phase information, resulting in a higher measurement range with reduced image artifacts. This paper presents an experimental one-channel on-bench OCT system with bulk optics, which serves as a proof-of-concept setup for the final VIAMOS micro-system. It is based on a Linnik interferometer with a wavelength tuning light source and a camera for parallel A-Scan detection. Phase shifting interferometry techniques (PSI) are used for the suppression of the complex conjugate artifact, whose suppression reaches 36 dB. The sensitivity of the system is constant over the full-field with a mean value of 97 dB. OCT images are presented of a thin membrane microlens and a biological tissue (onion) as a preliminary demonstration.

Design of control system for optical fiber drawing machine driven by double motor

NASA Astrophysics Data System (ADS)

Yu, Yue Chen; Bo, Yu Ming; Wang, Jun

2018-01-01

Micro channel Plate (MCP) is a kind of large-area array electron multiplier with high two-dimensional spatial resolution, used as high-performance night vision intensifier. The high precision control of the fiber is the key technology of the micro channel plate manufacturing process, and it was achieved by the control of optical fiber drawing machine driven by dual-motor in this paper. First of all, utilizing STM32 chip, the servo motor drive and control circuit was designed to realize the dual motor synchronization. Secondly, neural network PID control algorithm was designed for controlling the fiber diameter fabricated in high precision; Finally, the hexagonal fiber was manufactured by this system and it shows that multifilament diameter accuracy of the fiber is +/- 1.5μm.

Is QR code an optimal data container in optical encryption systems from an error-correction coding perspective?

PubMed

Jiao, Shuming; Jin, Zhi; Zhou, Changyuan; Zou, Wenbin; Li, Xia

2018-01-01

Quick response (QR) code has been employed as a data carrier for optical cryptosystems in many recent research works, and the error-correction coding mechanism allows the decrypted result to be noise free. However, in this paper, we point out for the first time that the Reed-Solomon coding algorithm in QR code is not a very suitable option for the nonlocally distributed speckle noise in optical cryptosystems from an information coding perspective. The average channel capacity is proposed to measure the data storage capacity and noise-resistant capability of different encoding schemes. We design an alternative 2D barcode scheme based on Bose-Chaudhuri-Hocquenghem (BCH) coding, which demonstrates substantially better average channel capacity than QR code in numerical simulated optical cryptosystems.

A Micro-Computed Tomography Technique to Study the Quality of Fibre Optics Embedded in Composite Materials

PubMed Central

Chiesura, Gabriele; Luyckx, Geert; Voet, Eli; Lammens, Nicolas; Van Paepegem, Wim; Degrieck, Joris; Dierick, Manuel; Van Hoorebeke, Luc; Vanderniepen, Pieter; Sulejmani, Sanne; Sonnenfeld, Camille; Geernaert, Thomas; Berghmans, Francis

2015-01-01

Quality of embedment of optical fibre sensors in carbon fibre-reinforced polymers plays an important role in the resultant properties of the composite, as well as for the correct monitoring of the structure. Therefore, availability of a tool able to check the optical fibre sensor-composite interaction becomes essential. High-resolution 3D X-ray Micro-Computed Tomography, or Micro-CT, is a relatively new non-destructive inspection technique which enables investigations of the internal structure of a sample without actually compromising its integrity. In this work the feasibility of inspecting the position, the orientation and, more generally, the quality of the embedment of an optical fibre sensor in a carbon fibre reinforced laminate at unit cell level have been proven. PMID:25961383

An optical fiber-based flexible readout system for micro-pattern gas detectors

NASA Astrophysics Data System (ADS)

Li, C.; Feng, C. Q.; Zhu, D. Y.; Liu, S. B.; An, Q.

2018-04-01

This paper presents an optical fiber-based readout system that is intended to provide a general purpose multi-channel readout solution for various Micro-Pattern Gas Detectors (MPGDs). The proposed readout system is composed of several front-end cards (FECs) and a data collection module (DCM). The FEC exploits the capability of an existing 64-channel generic TPC readout ASIC chip, named AGET, to implement 256 channels readout. AGET offers FEC a large flexibility in gain range (4 options from 120 fC to 10 pC), peaking time (16 options from 50 ns to 1 us) and sampling freqency (100 MHz max.). The DCM contains multiple 1 Gbps optical fiber serial link interfaces that allow the system scaling up to 1536 channels with 6 FECs and 1 DCM. Further scaling up is possible through cascading of multiple DCMs, by configuring one DCM as a master while other DCMs in slave mode. This design offers a rapid readout solution for different application senario. Tests indicate that the nonlinearity of each channel is less than 1%, and the equivalent input noise charge is typically around 0.7 fC in RMS (root mean square), with a noise slope of about 0.01 fC/pF. The system level trigger rate limit is about 700 Hz in all channel readout mode. When in hit channel readout mode, supposing that typically 10 percent of channels are fired, trigger rate can go up to about 7 kHz. This system has been tested with Micromegas detector and GEM detector, confirming its capability in MPGD readout. Details of hardware and FPGA firmware design, as well as system performances, are described in the paper.

Comparative study on different types of segmented micro deformable mirrors

NASA Astrophysics Data System (ADS)

Qiao, Dayong; Yuan, Weizheng; Li, Kaicheng; Li, Xiaoying; Rao, Fubo

2006-02-01

In an adaptive-optical (AO) system, the wavefront of optical beam can be corrected with deformable mirror (DM). Based on MicroElectroMechanical System (MEMS) technology, segmented micro deformable mirrors can be built with denser actuator spacing than continuous face-sheet designs and have been widely researched. But the influence of the segment structure has not been thoroughly discussed until now. In this paper, the design, performance and fabrication of several micromachined, segmented deformable mirror for AO were investigated. The wavefront distorted by atmospheric turbulence was simulated in the frame of Kolmogorov turbulence model. Position function was used to describe the surfaces of the micro deformable mirrors in working state. The performances of deformable mirrors featuring square, brick, hexagonal and ring segment structures were evaluated in criteria of phase fitting error, the Strehl ratio after wavefront correction and the design considerations. Then the micro fabrication process and mask layout were designed and the fabrication of micro deformable mirrors was implemented. The results show that the micro deformable mirror with ring segments performs the best, but it is very difficult in terms of layout design. The micro deformable mirrors with square and brick segments are easy to design, but their performances are not good. The micro deformable mirror with hexagonal segments has not only good performance in terms of phase fitting error, the Strehl ratio and actuation voltage, but also no overwhelming difficulty in layout design.

Note: A portable Raman analyzer for microfluidic chips based on a dichroic beam splitter for integration of imaging and signal collection light paths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Yijia; Xu, Shuping; Xu, Weiqing, E-mail: xuwq@jlu.edu.cn

An integrated and portable Raman analyzer featuring an inverted probe fixed on a motor-driving adjustable optical module was designed for the combination of a microfluidic system. It possesses a micro-imaging function. The inverted configuration is advantageous to locate and focus microfluidic channels. Different from commercial micro-imaging Raman spectrometers using manual switchable light path, this analyzer adopts a dichroic beam splitter for both imaging and signal collection light paths, which avoids movable parts and improves the integration and stability of optics. Combined with surface-enhanced Raman scattering technique, this portable Raman micro-analyzer is promising as a powerful tool for microfluidic analytics.

A novel method for fabrication of continuous-relief optical elements

NASA Astrophysics Data System (ADS)

Guo, Xiaowei; Du, Jinglei; Chen, Mingyong; Ma, Yanqin; Zhu, Jianhua; Peng, Qinjun; Guo, Yongkang; Du, Chunlei

2005-08-01

A novel method for the fabrication of continuous micro-optical components is presented in this paper. It employs a computer controlled spatial-light-modulator (SLM) as a switchable projection mask and silver-halide sensitized gelatin (SHSG) as recording material. By etching SHSG with enzyme solution, the micro-optical components with relief modulation can be generated through special processing procedures. The principles of digital SLM-based lithography and enzyme etching SHSG are discussed in detail, and microlens arrays, micro axicon-lens arrays and gratings with good profile were achieved. This method is simple, cheap and the aberration in processing procedures can be in-situ corrected in the step of designing mask, so it is a practical method to fabricate continuous profile for low-volume production.

Accounting for Chromatic Atmospheric Effects on Barycentric Corrections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blackman, Ryan T.; Szymkowiak, Andrew E.; Fischer, Debra A.

2017-03-01

Atmospheric effects on stellar radial velocity measurements for exoplanet discovery and characterization have not yet been fully investigated for extreme precision levels. We carry out calculations to determine the wavelength dependence of barycentric corrections across optical wavelengths, due to the ubiquitous variations in air mass during observations. We demonstrate that radial velocity errors of at least several cm s{sup −1} can be incurred if the wavelength dependence is not included in the photon-weighted barycentric corrections. A minimum of four wavelength channels across optical spectra (380–680 nm) are required to account for this effect at the 10 cm s{sup −1} level,more » with polynomial fits of the barycentric corrections applied to cover all wavelengths. Additional channels may be required in poor observing conditions or to avoid strong telluric absorption features. Furthermore, consistent flux sampling on the order of seconds throughout the observation is necessary to ensure that accurate photon weights are obtained. Finally, we describe how a multiple-channel exposure meter will be implemented in the EXtreme PREcision Spectrograph (EXPRES).« less

Ultra-precision fabrication of high density micro-optical backbone interconnections for data center and mobile application

NASA Astrophysics Data System (ADS)

Lohmann, U.; Jahns, J.; Wagner, T.; Werner, C.

2012-10-01

A microoptical 3D interconnection scheme and fabricated samples of this fiberoptical multi-channel interconnec- tion with an actual capacity of 144 channels were shown. Additionally the aspects of micrometer-fabrication of such microoptical interconnection modules in the view of alignment-tolerances were considered. For the realiza- tion of the interconnection schemes, the approach of planar-integrated free space optics (PIFSO) is used with its well known advantages. This approach offers the potential for complex interconnectivity, and yet compact size.

The Lobster Mission

NASA Technical Reports Server (NTRS)

Barthelmy, Scott

2011-01-01

I will give an overview of the Goddard Lobster mission: the science goals, the two instruments, the overall instruments designs, with particular attention to the wide-field x-ray instrument (WFI) using the lobster-eye-like micro-channel optics.

Fade-resistant forward error correction method for free-space optical communications systems

DOEpatents

Johnson, Gary W.; Dowla, Farid U.; Ruggiero, Anthony J.

2007-10-02

Free-space optical (FSO) laser communication systems offer exceptionally wide-bandwidth, secure connections between platforms that cannot other wise be connected via physical means such as optical fiber or cable. However, FSO links are subject to strong channel fading due to atmospheric turbulence and beam pointing errors, limiting practical performance and reliability. We have developed a fade-tolerant architecture based on forward error correcting codes (FECs) combined with delayed, redundant, sub-channels. This redundancy is made feasible though dense wavelength division multiplexing (WDM) and/or high-order M-ary modulation. Experiments and simulations show that error-free communications is feasible even when faced with fades that are tens of milliseconds long. We describe plans for practical implementation of a complete system operating at 2.5 Gbps.

Effect of laser beam conditioning on fabrication of clean micro-channel on stainless steel 316L using second harmonic of Q-switched Nd:YAG laser

NASA Astrophysics Data System (ADS)

Singh, Sanasam Sunderlal; Baruah, Prahlad Kr; Khare, Alika; Joshi, Shrikrishna N.

2018-02-01

Laser micromachining of metals for fabrication of micro-channels generate ridge formation along the edges accompanied by ripples along the channel bed. The ridge formation is due to the formation of interference pattern formed by back reflections from the beam splitter and other optical components involved before focusing on the work piece. This problem can be curtailed by using a suitable aperture or Iris diaphragm so as to cut the unwanted portion of the laser beam before illuminating the sample. This paper reports an experimental investigation on minimizing this problem by conditioning the laser beam using an Iris diaphragm and using optimum process parameters. In this work, systematic experiments have been carried out using the second harmonic of a Q-switched Nd:YAG laser to fabricate micro-channels. Initial experiments revealed that formation of ridges along the sides of micro-channel can easily be minimized with the help of Iris diaphragm. Further it is noted that a clean micro-channel of depth 43.39 μm, width up to 64.49 μm and of good surface quality with average surface roughness (Ra) value of 370 nm can be machined on stainless steel (SS) 316L by employing optimum process condition: laser beam energy of 30 mJ/pulse, 11 number of laser scans and scan speed of 169.54 μm/s with an opening of 4 mm diameter of Iris diaphragm in the path of the laser beam.

Nanophotonics for Lab-on-Chip Applications

NASA Astrophysics Data System (ADS)

Seitz, Peter

Optical methods are the preferred measurement techniques for biosensors and lab-on-chip applications. Their key properties are sensitivity, selectivity and robustness. To simplify the systems and their operation, it is desirable to employ label-free optical methods, requiring the functionalization of interfaces. Evanescent electromagnetic waves are probing the optical proper ties near the interfaces, a few 100 nm deep into the sample fluid. The sensitivity of these measurements can be improved with optical micro-resonators, in particular whispering gallery mode devices. Q factors as high as 2x108 have been achieved in practice. The resulting narrow-linewidth resonances and an unexpected thermo-optic effect make it possible to detect single biomolecules using a label-free biosensor principle. Future generations of biosensors and labs-on-chip for point-of-care and high-troughput screening applications will require large numbers of parallel measurement channels, necessitating optical micro-resonators in array format produced very cost-effectively.

In-line photonic microcells based on the elliptical microfibers for refractive index sensors applications

NASA Astrophysics Data System (ADS)

Jin, Wa; Liu, Xuejing; Jin, Wei

2017-10-01

We report the fabrication of in-line photonic microcells (PMCs) by encapsulating tapered elliptical microfibers (MFs) inside glass tubes. The encapsulation does not change the optical property of the MF but protects the elliptical MF from external disturbance and contamination and makes the micro-laboratory robust. Such micro-laboratory can be easily integrated into standard fiber-optic circuits with low loss, making the elliptical MF-based devices more practical for real-world applications. Evanescent field sensing is realized by fabricating micro-channel on the PMC for ingress/egress of sample liquids/gas. Based on the encapsulated elliptical MF PMCs, we demonstrated RI sensitivity of 2024 nm per refractive index unit (nm/RIU) in gaseous environment and 21231 nm/RIU in water.

Laser tweezer actuated microphotonic array devices for high resolution imaging and analysis in chip-based biosystems

NASA Astrophysics Data System (ADS)

Birkbeck, Aaron L.

A new technology is developed that functionally integrates arrays of lasers and micro-optics into microfluidic systems for the purpose of imaging, analyzing, and manipulating objects and biological cells. In general, the devices and technologies emerging from this area either lack functionality through the reliance on mechanical systems or provide a serial-based, time consuming approach. As compared to the current state of art, our all-optical design methodology has several distinguishing features, such as parallelism, high efficiency, low power, auto-alignment, and high yield fabrication methods, which all contribute to minimizing the cost of the integration process. The potential use of vertical cavity surface emitting lasers (VCSELs) for the creation of two-dimensional arrays of laser optical tweezers that perform independently controlled, parallel capture, and transport of large numbers of individual objects and biological cells is investigated. One of the primary biological applications for which VCSEL array sourced laser optical tweezers are considered is the formation of engineered tissues through the manipulation and spatial arrangement of different types of cells in a co-culture. Creating devices that combine laser optical tweezers with select micro-optical components permits optical imaging and analysis functions to take place inside the microfluidic channel. One such device is a micro-optical spatial filter whose motion and alignment is controlled using a laser optical tweezer. Unlike conventional spatial filter systems, our device utilizes a refractive optical element that is directly incorporated onto the lithographically patterned spatial filter. This allows the micro-optical spatial filter to automatically align itself in three-dimensions to the focal point of the microscope objective, where it then filters out the higher frequency additive noise components present in the laser beam. As a means of performing high resolution imaging in the microfluidic channel, we developed a novel technique that integrates the capacity of a laser tweezer to optically trap and manipulate objects in three-dimensions with the resolution-enhanced imaging capabilities of a solid immersion lens (SIL). In our design, the SIL is a free-floating device whose imaging beam, motion control and alignment is provided by a laser optical tweezer, which allows the microfluidic SIL to image in areas that are inaccessible to traditional solid immersion microscopes.

Microfluidic droplet sorting using integrated bilayer micro-valves

NASA Astrophysics Data System (ADS)

Chen, Yuncong; Tian, Yang; Xu, Zhen; Wang, Xinran; Yu, Sicong; Dong, Liang

2016-10-01

This paper reports on a microfluidic device capable of sorting microfluidic droplets utilizing conventional bilayer pneumatic micro-valves as sorting controllers. The device consists of two micro-valves placed symmetrically on two sides of a sorting area, each on top of a branching channel at an inclined angle with respect to the main channel. Changes in transmitted light intensity, induced by varying light absorbance by each droplet, are used to divert the droplet from the sorting area into one of the three outlet channels. When no valve is activated, the droplet flows into the outlet channel in the direction of the main channel. When one of the valves is triggered, the flexible membrane of valve will first be deflected. Once the droplet leaves the detection point, the deflected membrane will immediately return to its default flattened position, thereby exerting a drawing pressure on the droplet and deviating it from its original streamline to the outlet on the same side as the valve. This sorting method will be particularly suitable for numerous large-scale integrated microfluidic systems, where pneumatic micro-valves are already used. Only few structural modifications are needed to achieve droplet sorting capabilities in these systems. Due to the mechanical nature of diverting energy applied to droplets, the proposed sorting method may induce only minimal interference to biological species or microorganisms encapsulated inside the droplets that may accompany electrical, optical and magnetic-based techniques.

Operational atmospheric correction of AVHRR visible and infrared data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vermote, E.; El Saleous, N.; Roger, J.C.

1995-12-31

The satellite level radiance is affected by the presence of the atmosphere between the sensor and the target. The ozone and water vapor absorption bands affect the signal recorded by the AVHRR visible and near infrared channels respectively. The Rayleigh scattering mainly affects the visible channel and is more pronounced when dealing with small sun elevations and large view angles. The aerosol scattering affects both channels and is certainly the most challenging term for atmospheric correction because of the spatial and temporal variability of both the type and amount of particles in the atmosphere. This paper presents the equation ofmore » the satellite signal, the scheme to retrieve atmospheric properties and corrections applied to AVHRR observations. The operational process uses TOMS data and a digital elevation model to correct for ozone absorption and rayleigh scattering. The water vapor content is evaluated using the split-window technique that is validated over ocean using 1988 SSM/I data. The aerosol amount retrieval over Ocean is achieved in channels 1 and 2 and compared to sun photometer observations to check consistency of the radiative transfer model and the sensor calibration. Over land, the method developed uses reflectance at 3.75 microns to deduce target reflectance in channel 1 and retrieve aerosol optical thickness that can be extrapolated in channel 2. The method to invert the reflectance at 3.75 microns is based on MODTRAN simulations and is validated by comparison to measurements performed during FIFE 87. Finally, aerosol optical thickness retrieved over Brazil and Eastern US is compared to sun photometer measurements.« less

A new XUV optical end-station to characterize compact and flexible photonic devices using synchrotron radiation

NASA Astrophysics Data System (ADS)

Marcelli, A.; Mazuritskiy, M. I.; Dabagov, S. B.; Hampai, D.; Lerer, A. M.; Izotova, E. A.; D'Elia, A.; Turchini, S.; Zema, N.; Zuccaro, F.; de Simone, M.; Javad Rezvani, S.; Coreno, M.

2018-03-01

In this contribution we present the new experimental end-station to characterize XUV diffractive optics, such as Micro Channel Plates (MCPs) and other polycapillary optics, presently under commission at the Elettra synchrotron radiation laboratory (Trieste, Italy). To show the opportunities offered by these new optical devices for 3rd and 4th generation radiation sources, in this work we present also some patterns collected at different energies of the primary XUV radiation transmitted by MCP optical devices working in the normal incidence geometry.

Modeling and measurement of electrostatic micromirror array fabricated with single-layer polysilicon micromachining technology

NASA Astrophysics Data System (ADS)

Min, Young-Hoon; Kim, Yong-Kweon

1998-09-01

A silicon based micro mirror array is a highly efficient component for use in optical applications as adaptive optical systems and optical correlators. Many types of micro mirror or micro mirror array have been studied and proposed in order to obtain the optimal performance according to their own purposes. A micro mirror array designed, fabricated and tested in this paper consists of 5 X 5 single layer polysilicon-based, electrostatically driven actuators. The micro mirror array for the optical phase modulation is made by using only two masks and can be driven independently by 25 channel circuits. About 6 (pi) phase modulation is obtained in He-Ne laser ((lambda) equals 633 nm) with 67% fill-factor. In this paper, the deflection characteristics of the actuators in controllable range were studied. The experimental results show that the deflection characteristics is much dependent upon a residual stress in flexure, the initial curvature of mirror due to stress gradient and an electrostatic force acted on other element except for mirror itself. The modeling results agree well with the experimental results. Also, it is important to fabricate a flat mirror that is not initially curved because the curved mirror brings a bad performance in optical use. Therefore, a new method to obtain the flat mirror by using the gold metallization in spite of the residual stress unbalance is proposed in this paper.

Detection system of capillary array electrophoresis microchip based on optical fiber

NASA Astrophysics Data System (ADS)

Yang, Xiaobo; Bai, Haiming; Yan, Weiping

2009-11-01

To meet the demands of the post-genomic era study and the large parallel detections of epidemic diseases and drug screening, the high throughput micro-fluidic detection system is needed urgently. A scanning laser induced fluorescence detection system based on optical fiber has been established by using a green laser diode double-pumped solid-state laser as excitation source. It includes laser induced fluorescence detection subsystem, capillary array electrophoresis micro-chip, channel identification unit and fluorescent signal processing subsystem. V-shaped detecting probe composed with two optical fibers for transmitting the excitation light and detecting induced fluorescence were constructed. Parallel four-channel signal analysis of capillary electrophoresis was performed on this system by using Rhodamine B as the sample. The distinction of different samples and separation of samples were achieved with the constructed detection system. The lowest detected concentration is 1×10-5 mol/L for Rhodamine B. The results show that the detection system possesses some advantages, such as compact structure, better stability and higher sensitivity, which are beneficial to the development of microminiaturization and integration of capillary array electrophoresis chip.

Joint channel/frequency offset estimation and correction for coherent optical FBMC/OQAM system

NASA Astrophysics Data System (ADS)

Wang, Daobin; Yuan, Lihua; Lei, Jingli; wu, Gang; Li, Suoping; Ding, Runqi; Wang, Dongye

2017-12-01

In this paper, we focus on analysis of the preamble-based joint estimation for channel and laser-frequency offset (LFO) in coherent optical filter bank multicarrier systems with offset quadrature amplitude modulation (CO-FBMC/OQAM). In order to reduce the noise impact on the estimation accuracy, we proposed an estimation method based on inter-frame averaging. This method averages the cross-correlation function of real-valued pilots within multiple FBMC frames. The laser-frequency offset is estimated according to the phase of this average. After correcting LFO, the final channel response is also acquired by averaging channel estimation results within multiple frames. The principle of the proposed method is analyzed theoretically, and the preamble structure is thoroughly designed and optimized to suppress the impact of inherent imaginary interference (IMI). The effectiveness of our method is demonstrated numerically using different fiber and LFO values. The obtained results show that the proposed method can improve transmission performance significantly.

Novel auto-correction method in a fiber-optic distributed-temperature sensor using reflected anti-Stokes Raman scattering.

PubMed

Hwang, Dusun; Yoon, Dong-Jin; Kwon, Il-Bum; Seo, Dae-Cheol; Chung, Youngjoo

2010-05-10

A novel method for auto-correction of fiber optic distributed temperature sensor using anti-Stokes Raman back-scattering and its reflected signal is presented. This method processes two parts of measured signal. One part is the normal back scattered anti-Stokes signal and the other part is the reflected signal which eliminate not only the effect of local losses due to the micro-bending or damages on fiber but also the differential attenuation. Because the beams of the same wavelength are used to cancel out the local variance in transmission medium there is no differential attenuation inherently. The auto correction concept was verified by the bending experiment on different bending points. (c) 2010 Optical Society of America.

Long distance quantum communication using quantum error correction

NASA Technical Reports Server (NTRS)

Gingrich, R. M.; Lee, H.; Dowling, J. P.

2004-01-01

We describe a quantum error correction scheme that can increase the effective absorption length of the communication channel. This device can play the role of a quantum transponder when placed in series, or a cyclic quantum memory when inserted in an optical loop.

Spectral Optical Readout of Rectangular–Miniature Hollow Glass Tubing for Refractive Index Sensing

PubMed Central

Rigamonti, Giulia; Bello, Valentina

2018-01-01

For answering the growing demand of innovative micro-fluidic devices able to measure the refractive index of samples in extremely low volumes, this paper presents an overview of the performances of a micro-opto-fluidic sensing platform that employs rectangular, miniature hollow glass tubings. The operating principle is described by showing the analytical model of the tubing, obtained as superposition of different optical cavities, and the optical readout method based on spectral reflectivity detection. We have analyzed, in particular, the theoretical and experimental optical features of rectangular tubings with asymmetrical geometry, thus with channel depth larger than the thickness of the glass walls, though all of them in the range of a few tens of micrometers. The origins of the complex line-shape of the spectral response in reflection, due to the different cavities formed by the tubing flat walls and channel, have been investigated using a Fourier transform analysis. The implemented instrumental configuration, based on standard telecom fiberoptic components and a semiconductor broadband optical source emitting in the near infrared wavelength region centered at 1.55 µm, has allowed acquisition of reflectivity spectra for experimental verification of the expected theoretical behavior. We have achieved detection of refractive index variations related to the change of concentration of glucose-water solutions flowing through the tubing by monitoring the spectral shift of the optical resonances. PMID:29462907

Spectral Optical Readout of Rectangular-Miniature Hollow Glass Tubing for Refractive Index Sensing.

PubMed

Rigamonti, Giulia; Bello, Valentina; Merlo, Sabina

2018-02-16

For answering the growing demand of innovative micro-fluidic devices able to measure the refractive index of samples in extremely low volumes, this paper presents an overview of the performances of a micro-opto-fluidic sensing platform that employs rectangular, miniature hollow glass tubings. The operating principle is described by showing the analytical model of the tubing, obtained as superposition of different optical cavities, and the optical readout method based on spectral reflectivity detection. We have analyzed, in particular, the theoretical and experimental optical features of rectangular tubings with asymmetrical geometry, thus with channel depth larger than the thickness of the glass walls, though all of them in the range of a few tens of micrometers. The origins of the complex line-shape of the spectral response in reflection, due to the different cavities formed by the tubing flat walls and channel, have been investigated using a Fourier transform analysis. The implemented instrumental configuration, based on standard telecom fiberoptic components and a semiconductor broadband optical source emitting in the near infrared wavelength region centered at 1.55 µm, has allowed acquisition of reflectivity spectra for experimental verification of the expected theoretical behavior. We have achieved detection of refractive index variations related to the change of concentration of glucose-water solutions flowing through the tubing by monitoring the spectral shift of the optical resonances.

Ultra-high throughput detection of single cell β-galactosidase activity in droplets using micro-optical lens array

NASA Astrophysics Data System (ADS)

Lim, Jiseok; Vrignon, Jérémy; Gruner, Philipp; Karamitros, Christos S.; Konrad, Manfred; Baret, Jean-Christophe

2013-11-01

We demonstrate the use of a hybrid microfluidic-micro-optical system for the screening of enzymatic activity at the single cell level. Escherichia coli β-galactosidase activity is revealed by a fluorogenic assay in 100 pl droplets. Individual droplets containing cells are screened by measuring their fluorescence signal using a high-speed camera. The measurement is parallelized over 100 channels equipped with microlenses and analyzed by image processing. A reinjection rate of 1 ml of emulsion per minute was reached corresponding to more than 105 droplets per second, an analytical throughput larger than those obtained using flow cytometry.

Tunable multiwavelength fiber laser based on a θ-shaped microfiber filter

NASA Astrophysics Data System (ADS)

Li, Yue; Xu, Zhilin; Luo, Yiyang; Xiang, Yang; Yan, Zhijun; Liu, Deming; Sun, Qizhen

2018-06-01

We propose and experimentally demonstrate a flexibly tunable multiwavelength fiber ring laser based on a θ-shaped microfiber filter in conjunction with an erbium-doped fiber amplifier. The stable operation of the multiwavelength lasing is successfully achieved at room temperature, with the peak power fluctuation less than 0.519 dB. By micro-adjusting the cavity length of the filter, the channel spacing can be independently tuned within the gain range of the optical amplifier. We have achieved 0.084 nm-spacing 48 channel, 0.147 nm-spacing 25 channel, 0.190 nm-spacing 20 channel and 0.302 nm-spacing 15 channel lasing wavelengths at room temperature.

Combining optical trapping in a microfluidic channel with simultaneous micro-Raman spectroscopy and motion detection

NASA Astrophysics Data System (ADS)

Lawton, Penelope F.; Saunter, Christopher D.; Girkin, John M.

2014-03-01

Since their invention by Ashkin optical tweezers have demonstrated their ability and versatility as a non-invasive tool for micromanipulation. One of the most useful additions to the basic optical tweezers system is micro-Raman spectroscopy, which permits highly sensitive analysis of single cells or particles. We report on the development of a dual laser system combining two spatial light modulators to holographically manipulate multiple traps (at 1064nm) whilst undertaking Raman spectroscopy using a 532nm laser. We can thus simultaneously trap multiple particles and record their Raman spectra, without perturbing the trapping system. The dual beam system is built around micro-fluidic channels where crystallisation of calcium carbonate occurs on polymethylmethacrylate (PMMA) beads. The setup is designed to simulate at a microscopic level the reactions that occur on items in a dishwasher, where permanent filming of calcium carbonate on drinking glasses is a problem. Our system allows us to monitor crystal growth on trapped particles in which the Raman spectrum and changes in movement of the bead are recorded. Due to the expected low level of crystallisation on the bead surfaces this allows us to obtain results quickly and with high sensitivity. The long term goal is to study the development of filming on samples in-situ with the microfl.uidic system acting as a model dishwasher.

A New Microstructure Device for Efficient Evaporation of Liquids

NASA Astrophysics Data System (ADS)

Brandner, Juergen J.; Maikowske, Stefan; Vittoriosi, Alice

Evaporation of liquids is of major interest for many topics in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by use of classical pool boiling and evaporation process equipment. Another possibility is creating mixtures of gases and liquids, combined with a heating of this haze. Both methods provide relatively limited performance. Due to the advantages of microstructure devices especially in chemical process engineering [1] the interest in microstructure evaporators and steam generators have been increased through the last decade. In this publication several microstructure devices used for evaporation and generation of steam as well as superheating will be described. Here, normally electrically powered devices containing micro channels as well as non-channel microstructures are used due to better controllability of the temperature level. Micro channel heat exchangers have been designed, manufactured and tested at the Institute for Micro Process Engineering of the Karlsruhe Institute of Technology for more than 15 years. Starting with the famous Karlsruhe Cube, a cross-flow micro channel heat exchanger of various dimensions, not only conventional heat transfer between liquids or gases have been theoretically and experimentally examined but also phase transition from liquids to gases (evaporation) and condensation of liquids. However, the results obtained with sealed microstructure devices have often been unsatisfying. Thus, to learn more onto the evaporation process itself, an electrically powered device for optical inspection of the microstructures and the processes inside has been designed and manufactured [2]. This was further optimized and improved for better controllability and reliable experiments [3]. Exchangeable metallic micro channel array foils as well as an optical inspection of the evaporation process by high-speed videography have been integrated into the experimental setup. Fundamental research onto the influences of the geometry and dimensions of the integrated micro channels, the inlet flow distribution system geometry as well as the surface quality and surface coatings of the micro channels have been performed. While evaporation of liquids in crossflow and counterflow or co-current flow micro channel devices is possible, it is, in many cases, not possible to obtain superheated steam due to certain boundary conditions [4]. In most cases, the residence time is not sufficiently long, or the evaporation process itself cannot be stabilized and controlled precisely enough. Thus, a new design was proposed to obtain complete evaporation and steam superheating. This microstructure evaporator consists of a concentric arrangement of semi-circular walls or semi-elliptic walls providing at least two nozzles to release the generated steam. The complete arrangement forms a row of circular blanks. An example of such geometry is shown in Figure 7. A maximum power density of 1400 kW·m-2 has been transferred using similar systems, while liquid could be completely evaporated and the generated steam superheated. This is, compared to liquid heat exchanges, a small value, but it has to be taken in account that the specific heat capacity of vapour is considerably smaller than that of liquids. It could also be shown that the arrangement in circular blanks with semi-elliptic side walls acts as a kind of micro mixer for the remaining liquid and generated steam and, therefore, enhances the evaporation.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOEpatents

Beer, Neil Reginald; Kennedy, Ian

2013-12-17

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOEpatents

Beer, Neil Reginald; Kennedy, Ian

2013-02-05

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

Induced movement of the magnetic beads and DNA-based dumbbell in a micro fluidic channel

NASA Astrophysics Data System (ADS)

Babić, B.; Ghai, R.; Dimitrov, K.

2007-12-01

We have explored controlled movement of magnetic beads and a dumbbell structure composed of DNA, a magnetic and a non-magnetic bead in a micro fluidic channel. Movement of the beads and dumbbells is simulated assuming that a net force is described as a superposition between the magnetic and hydrodynamic drag forces. Trajectories of beads and dumbbells are observed with optical light microscopy. The experimentally measured data show a good agreement with the simulations. This dynamical approach offers the prospect to stretch the DNA within the dumbbell and investigate its conformational changes. Further on, we demonstrate that short sonication can reduce multiple attachments of DNA to the beads.

Transition regime analytical solution to gas mass flow rate in a rectangular micro channel

NASA Astrophysics Data System (ADS)

Dadzie, S. Kokou; Dongari, Nishanth

2012-11-01

We present an analytical model predicting the experimentally observed gas mass flow rate in rectangular micro channels over slip and transition regimes without the use of any fitting parameter. Previously, Sone reported a class of pure continuum regime flows that requires terms of Burnett order in constitutive equations of shear stress to be predicted appropriately. The corrective terms to the conventional Navier-Stokes equation were named the ghost effect. We demonstrate in this paper similarity between Sone ghost effect model and newly so-called 'volume diffusion hydrodynamic model'. A generic analytical solution to gas mass flow rate in a rectangular micro channel is then obtained. It is shown that the volume diffusion hydrodynamics allows to accurately predict the gas mass flow rate up to Knudsen number of 5. This can be achieved without necessitating the use of adjustable parameters in boundary conditions or parametric scaling laws for constitutive relations. The present model predicts the non-linear variation of pressure profile along the axial direction and also captures the change in curvature with increase in rarefaction.

Integrated thin film Si fluorescence sensor coupled with a GaN microLED for microfluidic point-of-care testing

NASA Astrophysics Data System (ADS)

Robbins, Hannah; Sumitomo, Keiko; Tsujimura, Noriyuki; Kamei, Toshihiro

2018-02-01

An integrated fluorescence sensor consisting of a SiO2/Ta2O5 multilayer optical interference filter and hydrogenated amorphous silicon (a-Si:H) pin photodiode was coupled with a GaN microLED to construct a compact fluorescence detection module for point-of-care microfluidic biochemical analysis. The combination of the small size of the GaN microLED and asymmetric microlens resulted in a focal spot diameter of the excitation light of approximately 200 µm. The limit of detection of the sensor was as high as 36 nM for fluorescein solution flowing in a 100 µm deep microfluidic channel because of the lack of directionality of the LED light. Nevertheless, we used the GaN microLED coupled with the a-Si:H fluorescence sensor to successfully detect fluorescence from a streptavidin R-phycoerythrin conjugate that bound to biotinylated antibody-coated microbeads trapped by the barrier in the microfluidic channel.

High speed micro scanner for 3D in-volume laser micro processing

NASA Astrophysics Data System (ADS)

Schaefer, D.; Gottmann, J.; Hermans, M.; Ortmann, J.; Kelbassa, I.

2013-03-01

Using an in-house developed micro scanner three-dimensional micro components and micro fluidic devices in fused silica are realized using the ISLE process (in-volume selective laser-induced etching). With the micro scanner system the potential of high average power femtosecond lasers (P > 100 W) is exploited by the fabrication of components with micrometer precision at scan speeds of several meters per second. A commercially available galvanometer scanner is combined with an acousto-optical and/or electro-optical beam deflector and translation stages. For focusing laser radiation high numerical aperture microscope objectives (NA > 0.3) are used generating a focal volume of a few cubic micrometers. After laser exposure the materials are chemically wet etched in aqueous solution. The laser-exposed material is etched whereas the unexposed material remains nearly unchanged. Using the described technique called ISLE the fabrication of three-dimensional micro components, micro holes, cuts and channels is possible with high average power femtosecond lasers resulting in a reduced processing time for exposure. By developing the high speed micro scanner up-scaling of the ISLE process is demonstrated. The fabricated components made out of glass can be applied in various markets like biological and medical diagnostics as well as in micro mechanics.

Continuously tunable microdroplet-laser in a microfluidic channel.

PubMed

Tang, Sindy K Y; Derda, Ratmir; Quan, Qimin; Lončar, Marko; Whitesides, George M

2011-01-31

This paper describes the generation and optical characterization of a series of dye-doped droplet-based optical microcavities with continuously decreasing radius in a microfluidic channel. A flow-focusing nozzle generated the droplets (~21 μm in radius) using benzyl alcohol as the disperse phase and water as the continuous phase. As these drops moved down the channel, they dissolved, and their size decreased. The emission characteristics from the drops could be matched to the whispering gallery modes from spherical micro-cavities. The wavelength of emission from the drops changed from 700 to 620 nm as the radius of the drops decreased from 21 μm to 7 μm. This range of tunability in wavelengths was larger than that reported in previous work on droplet-based cavities.

Hard and flexible optical printed circuit board

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, Hyun Sik; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

2007-02-01

We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate micro/nano-scale photonic devices. The micro/nano-optical functional devices include lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices. For flexible boards, the optical waveguide arrays are fabricated on flexible poly-ethylen terephthalate (PET) substrates by UV embossing. Electrical layer carrying VCSEL and PD array is laminated with the optical layer carrying waveguide arrays. Both hard and flexible electrical lines are replaced with high speed optical interconnection between chips over four waveguide channels up to 10Gbps on each. We discuss uses of hard or flexible O-PCBs for telecommunication systems, computer systems, transportation systems, space/avionic systems, and bio-sensor systems.

Dissolved oxygen sensing using organometallic dyes deposited within a microfluidic environment

NASA Astrophysics Data System (ADS)

Chen, Q. L.; Ho, H. P.; Jin, L.; Chu, B. W.-K.; Li, M. J.; Yam, V. W.-W.

2008-02-01

This work primarily aims to integrate dissolved oxygen sensing capability with a microfluidic platform containing arrays of micro bio-reactors or bio-activity indicators. The measurement of oxygen concentration is of significance for a variety of bio-related applications such as cell culture and gene expression. Optical oxygen sensors based on luminescence quenching are gaining much interest in light of their low power consumption, quick response and high analyte sensitivity in comparison to similar oxygen sensing devices. In our microfluidic oxygen sensor device, a thin layer of oxygen-sensitive luminescent organometallic dye is covalently bonded to a glass slide. Micro flow channels are formed on the glass slide using patterned PDMS (Polydimethylsiloxane). Dissolved oxygen sensing is then performed by directing an optical excitation probe beam to the area of interest within the microfluidic channel. The covalent bonding approach for sensor layer formation offers many distinct advantages over the physical entrapment method including minimizing dye leaching, ensuring good stability and fabrication simplicity. Experimental results confirm the feasibility of the device.

Non-binary LDPC-coded modulation for high-speed optical metro networks with backpropagation

NASA Astrophysics Data System (ADS)

Arabaci, Murat; Djordjevic, Ivan B.; Saunders, Ross; Marcoccia, Roberto M.

2010-01-01

To simultaneously mitigate the linear and nonlinear channel impairments in high-speed optical communications, we propose the use of non-binary low-density-parity-check-coded modulation in combination with a coarse backpropagation method. By employing backpropagation, we reduce the memory in the channel and in return obtain significant reductions in the complexity of the channel equalizer which is exponentially proportional to the channel memory. We then compensate for the remaining channel distortions using forward error correction based on non-binary LDPC codes. We propose non-binary-LDPC-coded modulation scheme because, compared to bit-interleaved binary-LDPC-coded modulation scheme employing turbo equalization, the proposed scheme lowers the computational complexity and latency of the overall system while providing impressively larger coding gains.

Multi terabits/s optical access transport technologies

NASA Astrophysics Data System (ADS)

Binh, Le Nguyen; Wang Tao, Thomas; Livshits, Daniil; Gubenko, Alexey; Karinou, Fotini; Liu Ning, Gordon; Shkolnik, Alexey

2016-02-01

Tremendous efforts have been developed for multi-Tbps over ultra-long distance and metro and access optical networks. With the exponential increase demand on data transmission, storage and serving, especially the 5G wireless access scenarios, the optical Internet networking has evolved to data-center based optical networks pressuring on novel and economical access transmission systems. This paper reports (1) Experimental platforms and transmission techniques employing band-limited optical components operating at 10G for 100G based at 28G baud. Advanced modulation formats such as PAM-4, DMT, duo-binary etc are reported and their advantages and disadvantages are analyzed so as to achieve multi-Tbps optical transmission systems for access inter- and intra- data-centered-based networks; (2) Integrated multi-Tbps combining comb laser sources and micro-ring modulators meeting the required performance for access systems are reported. Ten-sub-carrier quantum dot com lasers are employed in association with wideband optical intensity modulators to demonstrate the feasibility of such sources and integrated micro-ring modulators acting as a combined function of demultiplexing/multiplexing and modulation, hence compactness and economy scale. Under the use of multi-level modulation and direct detection at 56 GBd an aggregate of higher than 2Tbps and even 3Tbps can be achieved by interleaved two comb lasers of 16 sub-carrier lines; (3) Finally the fundamental designs of ultra-compacts flexible filters and switching integrated components based on Si photonics for multi Tera-bps active interconnection are presented. Experimental results on multi-channels transmissions and performances of optical switching matrices and effects on that of data channels are proposed.

Dual-balanced detection scheme with optical hard-limiters in an optical code division multiple access system

NASA Astrophysics Data System (ADS)

Liu, Maw-Yang; Hsu, Yi-Kai

2017-03-01

Three-arm dual-balanced detection scheme is studied in an optical code division multiple access system. As the MAI and beat noise are the main deleterious source of system performance, we utilize optical hard-limiters to alleviate such channel impairment. In addition, once the channel condition is improved effectively, the proposed two-dimensional error correction code can remarkably enhance the system performance. In our proposed scheme, the optimal thresholds of optical hard-limiters and decision circuitry are fixed, and they will not change with other system parameters. Our proposed scheme can accommodate a large number of users simultaneously and is suitable for burst traffic with asynchronous transmission. Therefore, it is highly recommended as the platform for broadband optical access network.

Analysis of soft-decision FEC on non-AWGN channels.

PubMed

Cho, Junho; Xie, Chongjin; Winzer, Peter J

2012-03-26

Soft-decision forward error correction (SD-FEC) schemes are typically designed for additive white Gaussian noise (AWGN) channels. In a fiber-optic communication system, noise may be neither circularly symmetric nor Gaussian, thus violating an important assumption underlying SD-FEC design. This paper quantifies the impact of non-AWGN noise on SD-FEC performance for such optical channels. We use a conditionally bivariate Gaussian noise model (CBGN) to analyze the impact of correlations among the signal's two quadrature components, and assess the effect of CBGN on SD-FEC performance using the density evolution of low-density parity-check (LDPC) codes. On a CBGN channel generating severely elliptic noise clouds, it is shown that more than 3 dB of coding gain are attainable by utilizing correlation information. Our analyses also give insights into potential improvements of the detection performance for fiber-optic transmission systems assisted by SD-FEC.

Micron-scale channel formation by the release and bond-back of pre-stressed thin films: A finite element analysis

NASA Astrophysics Data System (ADS)

Annabattula, R. K.; Huck, W. T. S.; Onck, P. R.

2010-04-01

Buckling of thin films on a rigid substrate during use or fabrication is a well-known but unwanted phenomenon. However, this phenomenon can also be exploited to generate well-controlled patterns at the micro and nano-scale. These patterned surfaces find various technological applications such as optical gratings or micro/nano-fluidic channels. In this article, we present a numerical model that accounts for the buckling-up of pre-strained thin films by a reduction of the interface toughness and the subsequent bond-back. Channels are formed whose dimensions can be controlled by tuning the film dimensions, film thickness and stiffness, the eigenstrain in the film and the cohesive interface energy between the film and the substrate. We will show how the buckling-up and draping back processes can be captured in terms of a limited set of dimensionless parameters, providing quantitative insight on how these parameters should be tuned to generate a specified channel geometry.

Real-time optical image processing techniques

NASA Technical Reports Server (NTRS)

Liu, Hua-Kuang

1988-01-01

Nonlinear real-time optical processing on spatial pulse frequency modulation has been pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the modification of micro-channel spatial light modulators (MSLMs). Micro-channel spatial light modulators are modified via the Fabry-Perot method to achieve the high gamma operation required for non-linear operation. Real-time nonlinear processing was performed using the halftone screen and MSLM. The experiments showed the effectiveness of the thresholding and also showed the needs of higher SBP for image processing. The Hughes LCLV has been characterized and found to yield high gamma (about 1.7) when operated in low frequency and low bias mode. Cascading of two LCLVs should also provide enough gamma for nonlinear processing. In this case, the SBP of the LCLV is sufficient but the uniformity of the LCLV needs improvement. These include image correlation, computer generation of holograms, pseudo-color image encoding for image enhancement, and associative-retrieval in neural processing. The discovery of the only known optical method for dynamic range compression of an input image in real-time by using GaAs photorefractive crystals is reported. Finally, a new architecture for non-linear multiple sensory, neural processing has been suggested.

A compactly integrated laser-induced fluorescence detector for microchip electrophoresis.

PubMed

Li, Hai-Fang; Lin, Jin-Ming; Su, Rong-Guo; Uchiyama, Katsumi; Hobo, Toshiyuki

2004-06-01

A simple and easy-to-use integrated laser-induced fluorescence detector for microchip electrophoresis was constructed and evaluated. The fluid channels and optical fiber channels in the glass microchip were fabricated using standard photolithographic techniques and wet chemical etching. A 473 nm diode-pumped laser was used as the excitation source, and the collimation and collection optics and mirrors were discarded by using a multimode optical fiber to couple the excitation light straight into the microchannel and placing the microchip directly on the top of the photomultiplier tube. A combination of filter systems was incorporated into a poly(dimethylsiloxane) layer, which was reversibly sealed to the bottom of the microchip to eliminate the scattering excitation light reaching to the photomultiplier tube. Fluorescein/calcein samples were taken as model analytes to evaluate the performance with respect to design factors. The detection limits were 0.05 microM for fluorescein and 0.18 microM for calcein, respectively. The suitability of this simple detector for fluorescence detection was demonstrated by baseline separation of fluorescein isothiocyanate (FITC)-labeled arginine, phenylalanine, and glycine and FITC within 30 s at separation length of 3.8 cm and electrical field strength of 600 V/cm.

A MEMS Micro-Translation Stage with Long Linear Translation

NASA Technical Reports Server (NTRS)

Ferguson, Cynthia K.; English, J. M.; Nordin, G. P.; Ashley, P. R.; Abushagur, M. A. G.

2004-01-01

A MEMS Micro-Translation Stage (MTS) actuator concept has been developed that is capable of traveling long distances, while maintaining low power, low voltage, and accuracy as required by many applications, including optical coupling. The Micro-Translation Stage (MTS) uses capacitive electrostatic forces in a linear motor application, with stationary stators arranged linearly on both sides of a channel, and matching rotors on a moveable shuttle. This creates a force that allows the shuttle to be pulled along the channel. It is designed to carry 100 micron-sized elements on the top surface, and can travel back and forth in the channel, either in a stepping fashion allowing many interim stops, or it can maintain constant adjustable speeds for a controlled scanning motion. The MTS travel range is limited only by the size of the fabrication wafer. Analytical modeling and simulations were performed based on the fabrication process, to assure the stresses, friction and electrostatic forces were acceptable to allow successful operation of this device. The translation forces were analyzed to be near 0.5 micron N, with a 300 micron N stop-to-stop time of 11.8 ms.

Investigation of the layout and optical proximity correction effects to control the trench etching process on 4H-SiC

NASA Astrophysics Data System (ADS)

Kyoung, Sinsu; Jung, Eun-Sik; Sung, Man Young

2017-07-01

Although trench gate and super-junction technology have micro-trench problems when applied to the SiC process due to the material characteristics. In this paper, area effects are analyzed from the test element group with various patterns and optical proximity correction (OPC) methods are proposed and analyzed to reduce micro-trenches in the SiC trench etching process. First, the loading effects were analyzed from pattern samples with various trench widths (Wt). From experiments, the area must limited under a proper size for a uniform etching profile and reduced micro-trenches because a wider area accelerates the etch rate. Second, the area effects were more severely unbalanced at corner patterns because the corner pattern necessarily has an in-corner and out-corner that have different etching areas to each other. We can balance areas using OPC patterns to overcome this. Experiments with OPC represented improved micro-trench profile from when comparing differences of trench depth (Δdt) at out corner and in corner. As a result, the area effects can be used to improve the trench profile with optimized etching process conditions. Therefore, the trench gate and super-junction pillar of the SiC power MOSFET can have an improved uniform profile without micro-trenches using proper design and OPC.[Figure not available: see fulltext.

Micro-Thin Lens Final Report CRADA No. TC-0331-92

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sweeney, D.; Zhang, X.

The general objective of the CRADA was to develop ophthalmic optical elements that are so thin that they can be placed on the human eye in revolutionary new ways. More .specifically,the major accomplishment of this CRADA was to study the feasability of producing a prototype optical element in the form of a bifocal contact lens, for presbyopic vision correction.

Designing a Small-Sized Engineering Model of Solar EUV Telescopr for a Korean Satellite

NASA Astrophysics Data System (ADS)

Han, Jung-Hoon; Jang, Min-Hwan; Kim, Sang-Joon

2001-11-01

For the research of solar EUV (extreme ultraviolet) radiation, we have designed a small-sized engineering model of solar EUV telescope, which is suitable for a Korean satellite. The EUV solar telescope was designed to observe the sun at 584.3Å (He¥°) and 629.7Å (O¥´). The optical system is an f/8 Ritchey-Chrètien, and the effective diameter and focal length are 80§® and 640§®, respectively. The He¥°and O¥´ filters are loaded in a filter wheel. In the detection part, the MCP (MicroChannel Plate) type is Z-stack, and the channel-to-diameter ratio is 40:1. MCP and CCD are connected by fiber optic taper. A commercial optical design software is used for the analysis of the optical system design.

Carbon nanotube based respiratory gated micro-CT imaging of a murine model of lung tumors with optical imaging correlation

NASA Astrophysics Data System (ADS)

Burk, Laurel M.; Lee, Yueh Z.; Heathcote, Samuel; Wang, Ko-han; Kim, William Y.; Lu, Jianping; Zhou, Otto

2011-03-01

Current optical imaging techniques can successfully measure tumor load in murine models of lung carcinoma but lack structural detail. We demonstrate that respiratory gated micro-CT imaging of such models gives information about structure and correlates with tumor load measurements by optical methods. Four mice with multifocal, Kras-induced tumors expressing firefly luciferase were imaged against four controls using both optical imaging and respiratory gated micro-CT. CT images of anesthetized animals were acquired with a custom CNT-based system using 30 ms x-ray pulses during peak inspiration; respiration motion was tracked with a pressure sensor beneath each animal's abdomen. Optical imaging based on the Luc+ signal correlating with tumor load was performed on a Xenogen IVIS Kinetix. Micro-CT images were post-processed using Osirix, measuring lung volume with region growing. Diameters of the largest three tumors were measured. Relationships between tumor size, lung volumes, and optical signal were compared. CT images and optical signals were obtained for all animals at two time points. In all lobes of the Kras+ mice in all images, tumors were visible; the smallest to be readily identified measured approximately 300 microns diameter. CT-derived tumor volumes and optical signals related linearly, with r=0.94 for all animals. When derived for only tumor bearing animals, r=0.3. The trend of each individual animal's optical signal tracked correctly based on the CT volumes. Interestingly, lung volumes also correlated positively with optical imaging data and tumor volume burden, suggesting active remodeling.

Laser beam micro-milling of nickel alloy: dimensional variations and RSM optimization of laser parameters

NASA Astrophysics Data System (ADS)

Ahmed, Naveed; Alahmari, Abdulrahman M.; Darwish, Saied; Naveed, Madiha

2016-12-01

Micro-channels are considered as the integral part of several engineering devices such as micro-channel heat exchangers, micro-coolers, micro-pulsating heat pipes and micro-channels used in gas turbine blades for aerospace applications. In such applications, a fluid flow is required to pass through certain micro-passages such as micro-grooves and micro-channels. The fluid flow characteristics (flow rate, turbulence, pressure drop and fluid dynamics) are mainly established based on the size and accuracy of micro-passages. Variations (oversizing and undersizing) in micro-passage's geometry directly affect the fluid flow characteristics. In this study, the micro-channels of several sizes are fabricated in well-known aerospace nickel alloy (Inconel 718) through laser beam micro-milling. The variations in geometrical characteristics of different-sized micro-channels are studied under the influences of different parameters of Nd:YAG laser. In order to have a minimum variation in the machined geometries of each size of micro-channel, the multi-objective optimization of laser parameters has been carried out utilizing the response surface methodology approach. The objective was set to achieve the targeted top widths and depths of micro-channels with minimum degree of taperness associated with the micro-channel's sidewalls. The optimized sets of laser parameters proposed for each size of micro-channel can be used to fabricate the micro-channels in Inconel 718 with minimum amount of geometrical variations.

Brillouin micro-spectroscopy through aberrations via sensorless adaptive optics

NASA Astrophysics Data System (ADS)

Edrei, Eitan; Scarcelli, Giuliano

2018-04-01

Brillouin spectroscopy is a powerful optical technique for non-contact viscoelastic characterizations which has recently found applications in three-dimensional mapping of biological samples. Brillouin spectroscopy performances are rapidly degraded by optical aberrations and have therefore been limited to homogenous transparent samples. In this work, we developed an adaptive optics (AO) configuration designed for Brillouin scattering spectroscopy to engineer the incident wavefront and correct for aberrations. Our configuration does not require direct wavefront sensing and the injection of a "guide-star"; hence, it can be implemented without the need for sample pre-treatment. We used our AO-Brillouin spectrometer in aberrated phantoms and biological samples and obtained improved precision and resolution of Brillouin spectral analysis; we demonstrated 2.5-fold enhancement in Brillouin signal strength and 1.4-fold improvement in axial resolution because of the correction of optical aberrations.

Precision machining of optical surfaces with subaperture correction technologies MRF and IBF

NASA Astrophysics Data System (ADS)

Schmelzer, Olaf; Feldkamp, Roman

2015-10-01

Precision optical elements are used in a wide range of technical instrumentations. Many optical systems e.g. semiconductor inspection modules, laser heads for laser material processing or high end movie cameras, contain precision optics even aspherical or freeform surfaces. Critical parameters for such systems are wavefront error, image field curvature or scattered light. Following these demands the lens parameters are also critical concerning power and RMSi of the surface form error and micro roughness. How can we reach these requirements? The emphasis of this discussion is set on the application of subaperture correction technologies in the fabrication of high-end aspheres and free-forms. The presentation focuses on the technology chain necessary for the production of high-precision aspherical optical components and the characterization of the applied subaperture finishing tools MRF (magneto-rheological finishing) and IBF (ion beam figuring). These technologies open up the possibility of improving the performance of optical systems.

Aberration corrections for free-space optical communications in atmosphere turbulence using orbital angular momentum states.

PubMed

Zhao, S M; Leach, J; Gong, L Y; Ding, J; Zheng, B Y

2012-01-02

The effect of atmosphere turbulence on light's spatial structure compromises the information capacity of photons carrying the Orbital Angular Momentum (OAM) in free-space optical (FSO) communications. In this paper, we study two aberration correction methods to mitigate this effect. The first one is the Shack-Hartmann wavefront correction method, which is based on the Zernike polynomials, and the second is a phase correction method specific to OAM states. Our numerical results show that the phase correction method for OAM states outperforms the Shark-Hartmann wavefront correction method, although both methods improve significantly purity of a single OAM state and the channel capacities of FSO communication link. At the same time, our experimental results show that the values of participation functions go down at the phase correction method for OAM states, i.e., the correction method ameliorates effectively the bad effect of atmosphere turbulence.

Frequency bandwidth limitation of external pulse electric fields in cylindrical micro-channel electrophoresis with analyte velocity modulation.

PubMed

Wang, Shau-Chun; Chen, Hsiao-Ping; Lee, Chia-Yu; Yeo, Leslie Y

2005-04-15

In capillary electrophoresis, effective optical signal quality improvement is obtained when high frequency (>100 Hz) external pulse fields modulate analyte velocities with synchronous lock-in detection. However, the pulse frequency is constrained under a critical value corresponding to the time required for the bulk viscous flow, which arises due to viscous momentum diffusion from the electro-osmotic slip in the Debye layer, to reach steady-state. By solving the momentum diffusion equation for transient bulk flow in the micro-channel, we show that this set-in time to steady-state and hence, the upper limit for the pulse frequency is dependent on the characteristic diffusion length scale and therefore the channel geometry; for cylindrical capillaries, the set-in time is approximately one half of that for rectangular slot channels. From our estimation of the set-in time and hence the upper frequency modulation limit, we propose that the half width of planar channels does not exceed 100 microm and that the radii of cylindrical channels be limited to 140 microm such that there is a finite working bandwidth range above 100 Hz and below the upper limit in order for flicker noise to be effectively suppressed.

428-Gb/s single-channel coherent optical OFDM transmission over 960-km SSMF with constellation expansion and LDPC coding.

PubMed

Yang, Qi; Al Amin, Abdullah; Chen, Xi; Ma, Yiran; Chen, Simin; Shieh, William

2010-08-02

High-order modulation formats and advanced error correcting codes (ECC) are two promising techniques for improving the performance of ultrahigh-speed optical transport networks. In this paper, we present record receiver sensitivity for 107 Gb/s CO-OFDM transmission via constellation expansion to 16-QAM and rate-1/2 LDPC coding. We also show the single-channel transmission of a 428-Gb/s CO-OFDM signal over 960-km standard-single-mode-fiber (SSMF) without Raman amplification.

Noise, fluctuation, and HADAMARD-transform spectrometry

NASA Astrophysics Data System (ADS)

Nitzsche, Guenter; Riesenberg, Rainer

2003-05-01

The HADAMARD principle is known in optics as a multiplex technique. It describes the mode with the most advantageous increase of the signal-to-noise ratio (SNR) in terms of scanning (Fellget advantage). The maximum increase of SNR, we call it gain, is (n+1)/(2On), where n is the number of multiplexing. It is valid in the case of pure detector noise. The multiplex encoding Hadamard pattern in case of n = 7 is 1110100, whereby 1 stands for a switched on channel performed by a field selector. The signals of all (switched on) channels are detected by a single detector. n measurement steps with a cyclic change of the pattern is necessary to perform the Hadamard transformation and to get the result of each individual channel. In case of n = 7 the theoretical gain is 1.51. For all possible multiplex pattern (1100000, 1110000 and so on) the gain is theoretically investigated. A multiplexing advantage (gain > 1) is reached only by the Hadamard pattern, the inverse Hadamard pattern and for (0111111)-pattern (gain=1.08). Most of the multiplex pattern are disadvantageous. The reason for maximum gain of the HADAMARD transformation is analysed theoretically. Signal fluctuations during the measurement caused by fluctuations of the illumination or by the object under test, reduce the multiplex gain, too. So the limits for realizing a gain are estimated theoretically. Essential is the transformation procedure and its influence on the error propagation. The results could be verified by experiments with array spectrometeres. Requirements are derived by numerical simulation concerning the stability of the signals to be multiplexed. It is simulated the needed stability of the signals with increasing order of multiplexing. So the increase of the multiplex gain is limited by signal fluctuations. A realized 96 channel spectral reader is presented as a modern application of an optical multiplexing arrangement. ! M. Harvid, N. J. A. Sloane, Hadamard Transform Optics, Academic Press, 1979 ! R.A. De Verse, R.M. Hammaker, W. G. Fately, J.A.Graham, J.D.Tate, "Spectrometry and imaging using a digital micromirror array" American Laboratory, Vol. 30, 21, pp. 112-120, 1998 ! R. Riesenberg, A. Wuttig, B. Harnisch, "Optical MEMS Technology for Multiplexing in High-End Micro-Scpectrometers", Proc. SPIE 4928, 6-14, 2002 ! A. Wuttig, R. Riesenberg, "Hyperspectral imager with a facile MEMS", Proc. SPIE 4881A, 2002, to be published ! R. Riesenberg, G. Nitzsche, W. Voigt, 'HADAMARD Encoding and other optical Multiplexing', VDI-Berichte 1694, pp. 345-350, 2002 ! A. Wuttig, R. Riesenberg, G. Nitzsche, "Subpixel Analysis of Double Array Grating Spectrometer", Proc. SPIE 4480, pp. 334-344, 2002 ! A. Wuttig, R. Riesenberg, G. Nitzsche, "Integral Field and Multi Object Spectrometry with MEMS", Proc. SPIE 4480, pp. 367-376, 2002 ! R. Riesenberg, G. Nitzsche, A. Wuttig, B. Harnisch, "Micro Spectrometer and MEMS for Space" in "Smaller Satellites: Bigger Business?", edited by M. Rycroft, N. Crosby, Kluwer Academic Publisher, pp. 403-406, 2002 ! R. Riesenberg, A. Wuttig, "Optical sensors with MEMS, slit masks and micromechanical devices", Proc. SPIE 4561, pp. 315-322, 2001 ! R. Riesenberg, "MicroMechanical Slit Positioning System as a transmissive spatial Light Modulator", Proc. SPIE 4457, pp.197-203, 2001 ! R. Riesenberg, J. Lonschinski, "HADAMARD-Minispectrometer made by a Micro Device", Proc. "3rd Round Table on Micro/NanoTechnologies for Space", ESTEC, Noordwijk, The Netherlands, pp. 291 - 297, 2000 ! R. Riesenberg, U. Dillner, "HADAMARD Imaging Spectrometers", Proc. SPIE 3753, pp. 203-213, 1999 ! R. Riesenberg, Th. Seifert, "Design of spatial Light Modulator Microdevices - Micro Slit Arrays", Proc. SPIE 3680, Part One, pp. 406-414, 1999 ! R. Riesenberg, W. Voigt, J. Schoneich, "Compact Spectrometers made by Micro System Technology", Sensor 97, Proc. Vol. 2, pp. 145-150,1997

Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics.

PubMed

Dong, Bing; Li, Yan; Han, Xin-Li; Hu, Bin

2016-09-02

For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10(-5) in optimized correction and is 1.427 × 10(-5) in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method.

Microwave heating of aqueous samples on a micro-optical-electro-mechanical system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beer, Neil Reginald

2016-04-12

Apparatus for heating a sample includes a microchip; a microchannel flow channel in the microchip, the microchannel flow channel containing the sample; a microwave source that directs microwaves onto the sample for heating the sample; a wall section of the microchannel flow channel that receives the microwaves and enables the microwaves to pass through wall section of the microchannel flow channel, the wall section the microchannel flow channel being made of a material that is not appreciably heated by the microwaves; a carrier fluid within the microchannel flow channel for moving the sample in the microchannel flow channel, the carriermore » fluid being made of a material that is not appreciably heated by the microwaves; wherein the microwaves pass through wall section of the microchannel flow channel and heat the sample.« less

Microwave heating of aqueous samples on a micro-optical-electro-mechanical system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beer, Neil Reginald

Apparatus for heating a sample includes a microchip; a microchannel flow channel in the microchip, the microchannel flow channel containing the sample; a microwave source that directs microwaves onto the sample for heating the sample; a wall section of the microchannel flow channel that receives the microwaves and enables the microwaves to pass through wall section of the microchannel flow channel, the wall section the microchannel flow channel being made of a material that is not appreciably heated by the microwaves; a carrier fluid within the microchannel flow channel for moving the sample in the microchannel flow channel, the carriermore » fluid being made of a material that is not appreciably heated by the microwaves; wherein the microwaves pass through wall section of the microchannel flow channel and heat the sample.« less

Demonstrating Optical Aberration Correction With a Mems Micro-Mirror Device

DTIC Science & Technology

1996-12-01

intensity distributions for a corrected and uncorrected MEMS reflection. The curves have been nor- malized to the peak value of the corrected wave front...demonstration: A = 632.8 mn, f = 7 mm, and L = 203 ym. For the solid curve , s = 0, while the dashed curve shows s = 7r/L, so that the change in phase...specified for Figure 8 (see page 29), so that the figures are directly comparable. The solid curve shows an intensity distribution for 01 = 0 (no

Effects of Polymer Length and Salt Concentration on the Transport of ssDNA in Nanofluidic Channels.

PubMed

Qian, Weixin; Doi, Kentaro; Kawano, Satoyuki

2017-03-14

Electrokinetic phenomena in micro/nanofluidic channels have attracted considerable attention because precise control of molecular transport in liquids is required to optically and electrically capture the behavior of single molecules. However, the detailed mechanisms of polymer transport influenced by electroosmotic flows and electric fields in micro/nanofluidic channels have not yet been elucidated. In this study, a Langevin dynamics simulation was used to investigate the electrokinetic transport of single-stranded DNA (ssDNA) in a cylindrical nanochannel, employing a coarse-grained bead-spring model that quantitatively reproduced the radius of gyration, diffusion coefficient, and electrophoretic mobility of the polymer. Using this practical scale model, transport regimes of ssDNA with respect to the ζ-potential of the channel wall, the ion concentration, and the polymer length were successfully characterized. It was found that the relationship between the radius of gyration of ssDNA and the channel radius is critical to the formation of deformation regimes in a narrow channel. We conclude that a combination of electroosmotic flow velocity gradients and electric fields due to electrically polarized channel surfaces affects the alignment of molecular conformations, such that the ssDNA is stretched/compressed at negative/positive ζ-potentials in comparatively low-concentration solutions. Furthermore, this work suggests the possibility of controlling the center-of-mass position by tuning the salt concentration. These results should be applicable to the design of molecular manipulation techniques based on liquid flows in micro/nanofluidic devices. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beer, Neil Reginald; Kennedy, Ian

2013-12-17

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channelmore » wherein the carrier fluid is not appreciably heated by the laser beam.« less

Research on the liquid crystal adaptive optics system for human retinal imaging

NASA Astrophysics Data System (ADS)

Zhang, Lei; Tong, Shoufeng; Song, Yansong; Zhao, Xin

2013-12-01

The blood vessels only in Human eye retinal can be observed directly. Many diseases that are not obvious in their early symptom can be diagnosed through observing the changes of distal micro blood vessel. In order to obtain the high resolution human retinal images,an adaptive optical system for correcting the aberration of the human eye was designed by using the Shack-Hartmann wavefront sensor and the Liquid Crystal Spatial Light Modulator(LCLSM) .For a subject eye with 8m-1 (8D)myopia, the wavefront error is reduced to 0.084 λ PV and 0.12 λRMS after adaptive optics(AO) correction ,which has reached diffraction limit.The results show that the LCLSM based AO system has the ability of correcting the aberration of the human eye efficiently,and making the blurred photoreceptor cell to clearly image on a CCD camera.

Limb Correction of Individual Infrared Channels Used in RGB Composite Products

NASA Technical Reports Server (NTRS)

Elmer, Nicholas J.; Berndt, Emily; Jedlovec, Gary J.; Lafontaine, Frank J.

2015-01-01

This study demonstrates that limb-cooling can be removed from infrared imagery using latitudinally and seasonally dependent limb correction coefficients, which account for an increasing optical path length as scan angle increases. Furthermore, limb-corrected RGB composites provide multiple advantages over uncorrected RGB composites, including increased confidence in the interpretation of RGB features, improved situation awareness for operational forecasters, seamless transition between overlaid RGB composites, easy comparison of RGB products from different sensors, and the availability of high quality proxy products for the GOES-R era, as demonstrated by the case examples presented in Section 3. This limb correction methodology can also be applied to additional infrared channels used to create other RGB products, including those created from other satellite sensors, such as Suomi NPP Visible Infrared Imaging Radiometer Suite (VIIRS).

New multichannel kinetic spectrophotometer-fluorimeter with pulsed measuring beam for photosynthesis research.

PubMed

Bína, David; Litvín, Radek; Vácha, Frantisek; Siffel, Pavel

2006-06-01

A multichannel kinetic spectrophotometer-fluorimeter with pulsed measuring beam and differential optics has been constructed for measurements of light-induced absorbance and fluorescence yield changes in isolated chlorophyll-proteins, thylakoids and intact cells including algae and photosynthetic bacteria. The measuring beam, provided by a short (2 micros) pulse from a xenon flash lamp, is divided into a sample and reference channel by a broad band beam splitter. The spectrum in each channel is analyzed separately by a photodiode array. The use of flash measuring beam and differential detection yields high signal-to-noise ratio (noise level of 2 x 10(-4) in absorbance units per single flash) with negligible actinic effect. The instrument covers a spectral range between 300 and 1050 nm with a spectral resolution of 2.1, 6.4 or 12.8 nm dependent on the type of grating used. The optical design of the instrument enables measuring of the difference spectra during an actinic irradiation of samples with continuous light and/or saturation flashes. The time resolution of the spectrophotometer is limited by the length of Xe flash lamp pulses to 2 micros.

Hybrid acousto-optic and digital equalization for microwave digital radio channels

NASA Astrophysics Data System (ADS)

Anderson, C. S.; Vanderlugt, A.

1990-11-01

Digital radio transmission systems use complex modulation schemes that require powerful signal-processing techniques to correct channel distortions and to minimize BERs. This paper proposes combining the computation power of acoustooptic processing and the accuracy of digital processing to produce a hybrid channel equalizer that exceeds the performance of digital equalization alone. Analysis shows that a hybrid equalizer for 256-level quadrature amplitude modulation (QAM) performs better than a digital equalizer for 64-level QAM.

Sorting on the basis of deformability of single cells in a femtosecond laser fabricated optofluidic device

NASA Astrophysics Data System (ADS)

Bragheri, F.; Paiè, P.; Yang, T.; Nava, G.; Martınez Vázquez, R.; Di Tano, M.; Veglione, M.; Minzioni, P.; Mondello, C.; Cristiani, I.; Osellame, R.

2015-03-01

Optical stretching is a powerful technique for the mechanical phenotyping of single suspended cells that exploits cell deformability as an inherent functional marker. Dual-beam optical trapping and stretching of cells is a recognized tool to investigate their viscoelastic properties. The optical stretcher has the ability to deform cells through optical forces without physical contact or bead attachment. In addition, it is the only method that can be combined with microfluidic delivery, allowing for the serial, high-throughput measurement of the optical deformability and the selective sorting of single specific cells. Femtosecond laser micromachining can fabricate in the same chip both the microfluidic channel and the optical waveguides, producing a monolithic device with a very precise alignment between the components and very low sensitivity to external perturbations. Femtosecond laser irradiation in a fused silica chip followed by chemical etching in hydrofluoric acid has been used to fabricate the microfluidic channels where the cells move by pressure-driven flow. With the same femtosecond laser source two optical waveguides, orthogonal to the microfluidic channel and opposing each other, have been written inside the chip. Here we present an optimized writing process that provides improved wall roughness of the micro-channels allowing high-quality imaging. In addition, we will show results on cell sorting on the basis of mechanical properties in the same device: the different deformability exhibited by metastatic and tumorigenic cells has been exploited to obtain a metastasis-cells enriched sample. The enrichment is verified by exploiting, after cells collection, fluorescence microscopy.

Microfluidic flow rate detection based on integrated optical fiber cantilever.

PubMed

Lien, Victor; Vollmer, Frank

2007-10-01

We demonstrate an integrated microfluidic flow sensor with ultra-wide dynamic range, suitable for high throughput applications such as flow cytometry and particle sorting/counting. A fiber-tip cantilever transduces flow rates to optical signal readout, and we demonstrate a dynamic range from 0 to 1500 microL min(-1) for operation in water. Fiber-optic sensor alignment is guided by preformed microfluidic channels, and the dynamic range can be adjusted in a one-step chemical etch. An overall non-linear response is attributed to the far-field angular distribution of single-mode fiber output.

Digital Mirror Device Application in Reduction of Wave-front Phase Errors

PubMed Central

Zhang, Yaping; Liu, Yan; Wang, Shuxue

2009-01-01

In order to correct the image distortion created by the mixing/shear layer, creative and effectual correction methods are necessary. First, a method combining adaptive optics (AO) correction with a digital micro-mirror device (DMD) is presented. Second, performance of an AO system using the Phase Diverse Speckle (PDS) principle is characterized in detail. Through combining the DMD method with PDS, a significant reduction in wavefront phase error is achieved in simulations and experiments. This kind of complex correction principle can be used to recovery the degraded images caused by unforeseen error sources. PMID:22574016

Perceived image quality with simulated segmented bifocal corrections

PubMed Central

Dorronsoro, Carlos; Radhakrishnan, Aiswaryah; de Gracia, Pablo; Sawides, Lucie; Marcos, Susana

2016-01-01

Bifocal contact or intraocular lenses use the principle of simultaneous vision to correct for presbyopia. A modified two-channel simultaneous vision simulator provided with an amplitude transmission spatial light modulator was used to optically simulate 14 segmented bifocal patterns (+ 3 diopters addition) with different far/near pupillary distributions of equal energy. Five subjects with paralyzed accommodation evaluated image quality and subjective preference through the segmented bifocal corrections. There are strong and systematic perceptual differences across the patterns, subjects and observation distances: 48% of the conditions evaluated were significantly preferred or rejected. Optical simulations (in terms of through-focus Strehl ratio from Hartmann-Shack aberrometry) accurately predicted the pattern producing the highest perceived quality in 4 out of 5 patients, both for far and near vision. These perceptual differences found arise primarily from optical grounds, but have an important neural component. PMID:27895981

Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics

PubMed Central

Dong, Bing; Li, Yan; Han, Xin-li; Hu, Bin

2016-01-01

For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10−5 in optimized correction and is 1.427 × 10−5 in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method. PMID:27598161

Innovative optronics for the new PUMA tank

NASA Astrophysics Data System (ADS)

Fritze, J.; Münzberg, M.; Schlemmer, H.

2010-04-01

The new PUMA tank is equipped with a fully stabilized 360° periscope. The thermal imager in the periscope is identical to the imager in the gunner sight. All optronic images of the cameras can be fed on every electronic display within the tank. The thermal imagers operate with a long wave 384x288 MCT starring focal plane array. The high quantum efficiency of MCT provides low NETD values at short integration times. The thermal imager has an image resolution of 768x576 pixels by means of a micro scanner. The MCT detector operates at high temperatures above 75K with high stability in noise and correctibility and offers high reliability (MTTF) values for the complete camera in a very compact design. The paper discusses the principle and functionality of the optronic combination of direct view optical channel, thermal imager and visible camera and discusses in detail the performances of the subcomponents with respect to demands for new tank applications.

Blind equalization and automatic modulation classification based on subspace for subcarrier MPSK optical communications

NASA Astrophysics Data System (ADS)

Chen, Dan; Guo, Lin-yuan; Wang, Chen-hao; Ke, Xi-zheng

2017-07-01

Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind equalization algorithm is used to preprocess M-ary phase shift keying (MPSK) subcarrier modulation signal in receiver. Mountain clustering is adopted to get the clustering centers of MPSK modulation constellation diagram, and the modulation order is automatically identified through the k-nearest neighbor (KNN) classifier. The experiment has been done under four different weather conditions. Experimental results show that the convergent of constellation diagram is improved effectively after using the subspace blind equalization algorithm, which means that the accuracy of modulation recognition is increased. The correct recognition rate of 16PSK can be up to 85% in any kind of weather condition which is mentioned in paper. Meanwhile, the correct recognition rate is the highest in cloudy and the lowest in heavy rain condition.

An atlas of upper tropospheric radiances observed in the 6 to 7-micrometer water vapor band using TOVS data from the NOAA weather satellites during 1979-1991

NASA Technical Reports Server (NTRS)

Chesters, Dennis; Sharma, OM

1992-01-01

This document is a pictorial atlas of the Earth's radiance emitted in the 6 to 7 micro-m water vapor band. At these wavelengths, the infrared brightness temperature corresponds to the layer-average temperature of the top few millimeters of water vapor in the atmosphere. At low altitudes, bright regions are dry slots in the upper troposphere. The satellite observations were obtained from NOAA's cloud and angle corrected measurements made by a series of polar orbiting TOVS (TIROS Operational Vertical Sounder) instruments flown from 1979 to 1991. TOVS 6.7 micro-m and 7.2 micro-m channels were converted to a single brightness temperature that simulates a high altitude channel near '6.5' micro-m. For climatological studies, the daily '6.5' micro-m overpass data were gridded to a cartesian projection with 5 by 5 degree horizontal resolution between 40 degrees N and 40 degrees S latitude. This atlas presents greyscale images of the '6.5' micro-m brightness fields for every day in every month for 13 years. The mean brightness for each of the 12 months for 13 years is presented to display interannual variability, and the annual cycle of 12 monthly means is summarized on a single page. Statistical summaries are presented from other investigations in progress.

Adaptive optics compensation of orbital angular momentum beams with a modified Gerchberg-Saxton-based phase retrieval algorithm

NASA Astrophysics Data System (ADS)

Chang, Huan; Yin, Xiao-li; Cui, Xiao-zhou; Zhang, Zhi-chao; Ma, Jian-xin; Wu, Guo-hua; Zhang, Li-jia; Xin, Xiang-jun

2017-12-01

Practical orbital angular momentum (OAM)-based free-space optical (FSO) communications commonly experience serious performance degradation and crosstalk due to atmospheric turbulence. In this paper, we propose a wave-front sensorless adaptive optics (WSAO) system with a modified Gerchberg-Saxton (GS)-based phase retrieval algorithm to correct distorted OAM beams. We use the spatial phase perturbation (SPP) GS algorithm with a distorted probe Gaussian beam as the only input. The principle and parameter selections of the algorithm are analyzed, and the performance of the algorithm is discussed. The simulation results show that the proposed adaptive optics (AO) system can significantly compensate for distorted OAM beams in single-channel or multiplexed OAM systems, which provides new insights into adaptive correction systems using OAM beams.

Characterization and compensation of thermo-elastic instability of SWARM optical bench on micro Advanced Stellar Compass attitude observations

NASA Astrophysics Data System (ADS)

Herceg, M.; Jørgensen, P. S.; Jørgensen, J. L.

2017-08-01

Launched into orbit on November 22, 2013, the Swarm constellation of three satellites precisely measures magnetic signal of the Earth. To ensure the high accuracy of magnetic observation by vector magnetometer (VFM), its inertial attitude is precisely determined by μASC (micro Advanced Stellar Compass). Each of the three Swarm satellites is equipped with three μASC Camera Head Units (CHU) mounted on a common optical bench (OB), which has a purpose of transference of the attitude from the star trackers to the magnetometer measurements. Although substantial pre-launch analyses were made to maximize thermal and mechanical stability of the OB, significant signal with thermal signature is discovered when comparing relative attitude between the three CHU's (Inter Boresight Angle, IBA). These misalignments between CHU's, and consequently geomagnetic reference frame, are found to be correlated with the period of angle between Swarm orbital plane and the Sun (ca. 267 days), which suggests sensitivity of optical bench system on temperature variation. In this paper, we investigate the propagation of thermal effects into the μASC attitude observations and demonstrate how thermally induced attitude variation can be predicted and corrected in the Swarm data processing. The results after applying thermal corrections show decrease in IBA RMS from 6.41 to 2.58″. The model significantly improves attitude determination which, after correction, meets the requirements of Swarm satellite mission. This study demonstrates the importance of the OB pre-launch analysis to ensure minimum thermal gradient on satellite optical system and therefore maximum attitude accuracy.

Phase Adaptation and Correction by Adaptive Optics

NASA Astrophysics Data System (ADS)

Tiziani, Hans J.

2010-04-01

Adaptive optical elements and systems for imaging or laser beam propagation are used for some time in particular in astronomy, where the image quality is degraded by atmospheric turbulence. In astronomical telescopes a deformable mirror is frequently used to compensate wavefront-errors due to deformations of the large mirror, vibrations as well as turbulence and hence to increase the image quality. In the last few years interesting elements like Spatial Light Modulators, SLM's, such as photorefractive crystals, liquid crystals and micro mirrors and membrane mirrors were introduced. The development of liquid crystals and micro mirrors was driven by data projectors as consumer products. They contain typically a matrix of individually addressable pixels of liquid crystals and flip mirrors respectively or more recently piston mirrors for special applications. Pixel sizes are in the order of a few microns and therefore also appropriate as active diffractive elements in digital holography or miniature masks. Although liquid crystals are mainly optimized for intensity modulation; they can be used for phase modulation. Adaptive optics is a technology for beam shaping and wavefront adaptation. The application of spatial light modulators for wavefront adaptation and correction and defect analysis as well as sensing will be discussed. Dynamic digital holograms are generated with liquid crystal devices (LCD) and used for wavefront correction as well as for beam shaping and phase manipulation, for instance. Furthermore, adaptive optics is very useful to extend the measuring range of wavefront sensors and for the wavefront adaptation in order to measure and compare the shape of high precision aspherical surfaces.

An Optical Lever For The Metrology Of Grazing Incidence Optics

NASA Astrophysics Data System (ADS)

DeCew, Alan E.; Wagner, Robert W.

1986-11-01

Research Optics & Development, Inc. is using a slope tracing profilometer to measure the figure of optical surfaces which cannot be measured conveniently by interferometric means. As a metrological tool, the technique has its greatest advantage as an in-process easurement system. An optician can easily convert from polishing to measurement in less than a minute of time. This rapid feedback allows figure correction with minimal wasted effort and setup time. The present configuration of the slope scanner provides resolutions to 1 micro-radian. By implementing minor modifications, the resolution could be improved by an order of magnitude.

Adaptive optics in multiphoton microscopy: comparison of two, three and four photon fluorescence

PubMed Central

Sinefeld, David; Paudel, Hari P.; Ouzounov, Dimitre G.; Bifano, Thomas G.; Xu, Chris

2015-01-01

We demonstrate adaptive optics system based on nonlinear feedback from 3- and 4-photon fluorescence. The system is based on femtosecond pulses created by soliton self-frequency shift of a 1550-nm fiber-based femtosecond laser together with micro-electro-mechanical system (MEMS) phase spatial light modulator (SLM). We perturb the 1020-segment SLM using an orthogonal Walsh sequence basis set with a modified version of three-point phase shifting interferometry. We show the improvement after aberrations correction in 3-photon signal from fluorescent beads. In addition, we compare the improvement obtained in the same adaptive optical system for 2-, 3- and 4-photon fluorescence using dye pool. We show that signal improvement resulting from aberration correction grows exponentially as a function of the order of nonlinearity. PMID:26698772

Cirrus Horizontal Heterogeneity Effects on Cloud Optical Properties Retrieved from MODIS VNIR to TIR Channels as a Function of the Spatial Resolution

NASA Astrophysics Data System (ADS)

Fauchez, T.; Platnick, S. E.; Sourdeval, O.; Wang, C.; Meyer, K.; Cornet, C.; Szczap, F.

2017-12-01

Cirrus are an important part of the Earth radiation budget but an assessment of their role yet remains highly uncertain. Cirrus optical properties such as Cloud Optical Thickness (COT) and ice crystal effective particle size (Re) are often retrieved with a combination of Visible/Near InfraRed (VNIR) and ShortWave-InfraRed (SWIR) reflectance channels. Alternatively, Thermal InfraRed (TIR) techniques, such as the Split Window Technique (SWT), have demonstrated better sensitivity to thin cirrus. However, current satellite operational products for both retrieval methods assume that cloudy pixels are horizontally homogeneous (Plane Parallel and Homogeneous Approximation (PPHA)) and independent (Independent Pixel Approximation (IPA)). The impact of these approximations on cirrus retrievals needs to be understood and, as far as possible, corrected. Horizontal heterogeneity effects can be more easily estimated and corrected in the TIR range because they are mainly dominated by the PPA bias, which primarily depends on the COT subpixel heterogeneity. For solar reflectance channels, in addition to the PPHA bias, the IPA can lead to significant retrieval errors if there is large photon transport between cloudy columns in addition to brightening and shadowing effects that are more difficult to quantify.The effects of cirrus horizontal heterogeneity are here studied on COT and Re retrievals obtained using simulated MODIS reflectances at 0.86 and 2.11 μm and radiances at 8.5, 11.0 and 12.0 μm, for spatial resolutions ranging from 50 m to 10 km. For each spatial resolution, simulated TOA reflectances and radiances are combined for cloud optical property retrievals with a research-level optimal estimation retrieval method (OEM). The impact of horizontal heterogeneity on the retrieved products is assessed for different solar geometries and various combinations of the five channels.

A scalable correlator for multichannel diffuse correlation spectroscopy.

PubMed

Stapels, Christopher J; Kolodziejski, Noah J; McAdams, Daniel; Podolsky, Matthew J; Fernandez, Daniel E; Farkas, Dana; Christian, James F

2016-02-01

Diffuse correlation spectroscopy (DCS) is a technique which enables powerful and robust non-invasive optical studies of tissue micro-circulation and vascular blood flow. The technique amounts to autocorrelation analysis of coherent photons after their migration through moving scatterers and subsequent collection by single-mode optical fibers. A primary cost driver of DCS instruments are the commercial hardware-based correlators, limiting the proliferation of multi-channel instruments for validation of perfusion analysis as a clinical diagnostic metric. We present the development of a low-cost scalable correlator enabled by microchip-based time-tagging, and a software-based multi-tau data analysis method. We will discuss the capabilities of the instrument as well as the implementation and validation of 2- and 8-channel systems built for live animal and pre-clinical settings.

An Efficient Correction Algorithm for Eliminating Image Misalignment Effects on Co-Phasing Measurement Accuracy for Segmented Active Optics Systems

PubMed Central

Yue, Dan; Xu, Shuyan; Nie, Haitao; Wang, Zongyang

2016-01-01

The misalignment between recorded in-focus and out-of-focus images using the Phase Diversity (PD) algorithm leads to a dramatic decline in wavefront detection accuracy and image recovery quality for segmented active optics systems. This paper demonstrates the theoretical relationship between the image misalignment and tip-tilt terms in Zernike polynomials of the wavefront phase for the first time, and an efficient two-step alignment correction algorithm is proposed to eliminate these misalignment effects. This algorithm processes a spatial 2-D cross-correlation of the misaligned images, revising the offset to 1 or 2 pixels and narrowing the search range for alignment. Then, it eliminates the need for subpixel fine alignment to achieve adaptive correction by adding additional tip-tilt terms to the Optical Transfer Function (OTF) of the out-of-focus channel. The experimental results demonstrate the feasibility and validity of the proposed correction algorithm to improve the measurement accuracy during the co-phasing of segmented mirrors. With this alignment correction, the reconstructed wavefront is more accurate, and the recovered image is of higher quality. PMID:26934045

Statistical properties of single-mode fiber coupling of satellite-to-ground laser links partially corrected by adaptive optics.

PubMed

Canuet, Lucien; Védrenne, Nicolas; Conan, Jean-Marc; Petit, Cyril; Artaud, Geraldine; Rissons, Angelique; Lacan, Jerome

2018-01-01

In the framework of satellite-to-ground laser downlinks, an analytical model describing the variations of the instantaneous coupled flux into a single-mode fiber after correction of the incoming wavefront by partial adaptive optics (AO) is presented. Expressions for the probability density function and the cumulative distribution function as well as for the average fading duration and fading duration distribution of the corrected coupled flux are given. These results are of prime interest for the computation of metrics related to coded transmissions over correlated channels, and they are confronted by end-to-end wave-optics simulations in the case of a geosynchronous satellite (GEO)-to-ground and a low earth orbit satellite (LEO)-to-ground scenario. Eventually, the impact of different AO performances on the aforementioned fading duration distribution is analytically investigated for both scenarios.

Novel experimental technique for 3D investigation of high-speed cavitating diesel fuel flows by X-ray micro computed tomography

NASA Astrophysics Data System (ADS)

Lorenzi, M.; Mitroglou, N.; Santini, M.; Gavaises, M.

2017-03-01

An experimental technique for the estimation of the temporal-averaged vapour volume fraction within high-speed cavitating flow orifices is presented. The scientific instrument is designed to employ X-ray micro computed tomography (microCT) as a quantitative 3D measuring technique applied to custom designed, large-scale, orifice-type flow channels made from Polyether-ether-ketone (PEEK). The attenuation of the ionising electromagnetic radiation by the fluid under examination depends on its local density; the transmitted radiation through the cavitation volume is compared to the incident radiation, and combination of radiographies from sufficient number of angles leads to the reconstruction of attenuation coefficients versus the spatial position. This results to a 3D volume fraction distribution measurement of the developing multiphase flow. The experimental results obtained are compared against the high speed shadowgraph visualisation images obtained in an optically transparent nozzle with identical injection geometry; comparison between the temporal mean image and the microCT reconstruction shows excellent agreement. At the same time, the real 3D internal channel geometry (possibly eroded) has been measured and compared to the nominal manufacturing CAD drawing of the test nozzle.

Novel experimental technique for 3D investigation of high-speed cavitating diesel fuel flows by X-ray micro computed tomography.

PubMed

Lorenzi, M; Mitroglou, N; Santini, M; Gavaises, M

2017-03-01

An experimental technique for the estimation of the temporal-averaged vapour volume fraction within high-speed cavitating flow orifices is presented. The scientific instrument is designed to employ X-ray micro computed tomography (microCT) as a quantitative 3D measuring technique applied to custom designed, large-scale, orifice-type flow channels made from Polyether-ether-ketone (PEEK). The attenuation of the ionising electromagnetic radiation by the fluid under examination depends on its local density; the transmitted radiation through the cavitation volume is compared to the incident radiation, and combination of radiographies from sufficient number of angles leads to the reconstruction of attenuation coefficients versus the spatial position. This results to a 3D volume fraction distribution measurement of the developing multiphase flow. The experimental results obtained are compared against the high speed shadowgraph visualisation images obtained in an optically transparent nozzle with identical injection geometry; comparison between the temporal mean image and the microCT reconstruction shows excellent agreement. At the same time, the real 3D internal channel geometry (possibly eroded) has been measured and compared to the nominal manufacturing CAD drawing of the test nozzle.

Optimal Performance Monitoring of Hybrid Mid-Infrared Wavelength MIMO Free Space Optical and RF Wireless Networks in Fading Channels

NASA Astrophysics Data System (ADS)

Schmidt, Barnet Michael

An optimal performance monitoring metric for a hybrid free space optical and radio-frequency (RF) wireless network, the Outage Capacity Objective Function, is analytically developed and studied. Current and traditional methods of performance monitoring of both optical and RF wireless networks are centered on measurement of physical layer parameters, the most common being signal-to-noise ratio, error rate, Q factor, and eye diagrams, occasionally combined with link-layer measurements such as data throughput, retransmission rate, and/or lost packet rate. Network management systems frequently attempt to predict or forestall network failures by observing degradations of these parameters and to attempt mitigation (such as offloading traffic, increasing transmitter power, reducing the data rate, or combinations thereof) prior to the failure. These methods are limited by the frequent low sensitivity of the physical layer parameters to the atmospheric optical conditions (measured by optical signal-to-noise ratio) and the radio frequency fading channel conditions (measured by signal-to-interference ratio). As a result of low sensitivity, measurements of this type frequently are unable to predict impending failures sufficiently in advance for the network management system to take corrective action prior to the failure. We derive and apply an optimal measure of hybrid network performance based on the outage capacity of the hybrid optical and RF channel, the outage capacity objective function. The objective function provides high sensitivity and reliable failure prediction, and considers both the effects of atmospheric optical impairments on the performance of the free space optical segment as well as the effect of RF channel impairments on the radio frequency segment. The radio frequency segment analysis considers the three most common RF channel fading statistics: Rayleigh, Ricean, and Nakagami-m. The novel application of information theory to the underlying physics of the gamma-gamma optical channel and radio fading channels in determining the joint hybrid channel outage capacity provides the best performance estimate under any given set of operating conditions. It is shown that, unlike traditional physical layer performance monitoring techniques, the objective function based upon the outage capacity of the hybrid channel at any combination of OSNR and SIR, is able to predict channel degradation and failure well in advance of the actual outage. An outage in the information-theoretic definition occurs when the offered load exceeds the outage capacity under the current conditions of OSNR and SIR. The optical channel is operated at the "long" mid-infrared wavelength of 10000 nm. which provides improved resistance to scattering compared to shorter wavelengths such as 1550 nm.

Optical micro resonance based sensor schemes for detection and identification of nano particles and biological agents in situ

NASA Astrophysics Data System (ADS)

Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schweiger, Gustav; Ostendorf, Andreas

2010-05-01

A novel emerging technique for the label-free analysis of nano particles including biomolecules using optical micro cavity resonance is being developed. Various schemes based on a mechanically fixed microspheres as well as microspheres melted by laser on the tip of a standard single mode fiber have been investigated to make further development for microbial application. Water solutions of ethanol, HCl, glucose, vitamin C and biotin have been used to test refractive index changes by monitoring the magnitude of the whispering gallery modes spectral shift. Particular efforts were made for effective fixing of the micro spheres in the water flow, an optimal geometry for micro resonance observation and material of microsphere the most appropriate for microbial application. Optical resonance in free micro spheres from PMMA fixed in micro channels produced by photolithography has been observed under the laser power of less then 1 microwatt. Resonance shifts of C reactive protein water solutions as well as albumin solutions in pure water and with HCl modelling blood have been investigated. Introducing controlled amount of glass gel nano particles into sensor microsphere surrounding were accompanied by both correlative resonance shift (400 nm in diameter) and total reconstruct of resonance spectra (57 nm in diameter). Developed schemes have been demonstrated to be a promising technology platform for sensitive, lab-on-chip type sensor of diagnostic tools for different biological molecules, e.g. proteins, oligonucleotides, oligosaccharides, lipids, small molecules, viral particles, cells as well as in different experimental contexts e.g. proteomics, genomics, drug discovery, and membrane studies.

GaN-based micro-LED arrays on flexible substrates for optical cochlear implants

NASA Astrophysics Data System (ADS)

Goßler, Christian; Bierbrauer, Colin; Moser, Rüdiger; Kunzer, Michael; Holc, Katarzyna; Pletschen, Wilfried; Köhler, Klaus; Wagner, Joachim; Schwaerzle, Michael; Ruther, Patrick; Paul, Oliver; Neef, Jakob; Keppeler, Daniel; Hoch, Gerhard; Moser, Tobias; Schwarz, Ulrich T.

2014-05-01

Currently available cochlear implants are based on electrical stimulation of the spiral ganglion neurons. Optical stimulation with arrays of micro-sized light-emitting diodes (µLEDs) promises to increase the number of distinguishable frequencies. Here, the development of a flexible GaN-based micro-LED array as an optical cochlear implant is reported for application in a mouse model. The fabrication of 15 µm thin and highly flexible devices is enabled by a laser-based layer transfer process of the GaN-LEDs from sapphire to a polyimide-on-silicon carrier wafer. The fabricated 50 × 50 µm2 LEDs are contacted via conducting paths on both p- and n-sides of the LEDs. Up to three separate channels could be addressed. The probes, composed of a linear array of the said µLEDs bonded to the flexible polyimide substrate, are peeled off the carrier wafer and attached to flexible printed circuit boards. Probes with four µLEDs and a width of 230 µm are successfully implanted in the mouse cochlea both in vitro and in vivo. The LEDs emit 60 µW at 1 mA after peel-off, corresponding to a radiant emittance of 6 mW mm-2.

Optical communication for space missions

NASA Technical Reports Server (NTRS)

Firtmaurice, M.

1991-01-01

Activities performed at NASA/GSFC (Goddard Space Flight Center) related to direct detection optical communications for space applications are discussed. The following subject areas are covered: (1) requirements for optical communication systems (data rates and channel quality; spatial acquisition; fine tracking and pointing; and transmit point-ahead correction); (2) component testing and development (laser diodes performance characterization and life testing; and laser diode power combining); (3) system development and simulations (The GSFC pointing, acquisition and tracking system; hardware description; preliminary performance analysis; and high data rate transmitter/receiver systems); and (4) proposed flight demonstration of optical communications.

Aerosol anomalies in Nimbus-7 coastal zone color scanner data obtained in Japan area

NASA Technical Reports Server (NTRS)

Fukushima, Hajime; Sugimori, Yasuhiro; Toratani, Mitsuhiro; Smith, Raymond C.; Yasuda, Yoshizumi

1989-01-01

About 400 CZCS (coastal zone color scanner) scenes covering the Japan area in November 1978-May 1982 were processed to study the applicability of the Gordon-Clark atmospheric correction scheme which produces water-leaving radiances Lw at 443 nm, 520 nm, and 550 nm as well as phytoplankton pigment maps. Typical spring-fall aerosol radiance in the images was found to be 0.8-1.5 micro-W/sq cm-nm-sr, which is about 50 percent more than reported for the US eastern coastal images. The correction for about half the data resulted in negative Lw (443) values, implying overestimation of the aerosol effect for this channel. Several possible reasons for this are considered, including deviation of the aerosol optical thickness tau(a) at 443 nm from that estimated by Angstrom's exponential law, which the algorithm assumes. The analysis shows that, assuming the use of the Gordon-Clark algorithm, and for a pigment concentration of about 1 microgram/l, -40 percent to +100 percent error in satellite estimates is common. Although this does not fully explain the negative Lw (443) in the satellite data, it seems to contribute to the problem significantly, together with other error sources, including one in the sensor calibration.

A DC electrophoresis method for determining electrophoretic mobility through the pressure driven negation of electro osmosis

NASA Astrophysics Data System (ADS)

Karam, Pascal; Pennathur, Sumita

2016-11-01

Characterization of the electrophoretic mobility and zeta potential of micro and nanoparticles is important for assessing properties such as stability, charge and size. In electrophoretic techniques for such characterization, the bulk fluid motion due to the interaction between the fluid and the charged surface must be accounted for. Unlike current industrial systems which rely on DLS and oscillating potentials to mitigate electroosmotic flow (EOF), we propose a simple alternative electrophoretic method for optically determining electrophoretic mobility using a DC electric fields. Specifically, we create a system where an adverse pressure gradient counters EOF, and design the geometry of the channel so that the flow profile of the pressure driven flow matches that of the EOF in large regions of the channel (ie. where we observe particle flow). Our specific COMSOL-optimized geometry is two large cross sectional areas adjacent to a central, high aspect ratio channel. We show that this effectively removes EOF from a large region of the channel and allows for the accurate optical characterization of electrophoretic particle mobility, no matter the wall charge or particle size.

Nonlinear Phase Distortion in a Ti:Sapphire Optical Amplifier for Optical Stochastic Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andorf, Matthew; Lebedev, Valeri; Piot, Philippe

2016-06-01

Optical Stochastic Cooling (OSC) has been considered for future high-luminosity colliders as it offers much faster cooling time in comparison to the micro-wave stochastic cooling. The OSC technique relies on collecting and amplifying a broadband optical signal from a pickup undulator and feeding the amplified signal back to the beam. It creates a corrective kick in a kicker undulator. Owing to its superb gain qualities and broadband amplification features, Titanium:Sapphire medium has been considered as a gain medium for the optical amplifier (OA) needed in the OSC*. A limiting factor for any OA used in OSC is the possibility ofmore » nonlinear phase distortions. In this paper we experimentally measure phase distortions by inserting a single-pass OA into one leg of a Mach-Zehnder interferometer. The measurement results are used to estimate the reduction of the corrective kick a particle would receive due to these phase distortions in the kicker undulator.« less

Adaptive optics full-field OCT: a resolution almost insensitive to aberrations (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xiao, Peng; Fink, Mathias; Boccara, A. Claude

2016-03-01

A Full-Field OCT (FFOCT) setup coupled to a compact transmissive liquid crystal spatial light modulator (LCSLM) is used to induce or correct aberrations and simulate eye examinations. To reduce the system complexity, strict pupil conjugation was abandoned. During our work on quantifying the effect of geometrical aberrations on FFOCT images, we found that the image resolution is almost insensitive to aberrations. Indeed if the object channel PSF is distorted, its interference with the reference channel conserves the main feature of an unperturbed PSF with only a reduction of the signal level. This unique behavior is specific to the use of a spatially incoherent illumination. Based on this, the FFOCT image intensity was used as the metric for our wavefront sensorless correction. Aberration correction was first conducted on an USAF resolution target with the LSCLM as both aberration generator and corrector. A random aberration mask was induced, and the low-order Zernike Modes were corrected sequentially according to the intensity metric function optimization. A Ficus leaf and a fixed mouse brain tissue slice were also imaged to demonstrate the correction of sample self-induced wavefront distortions. After optimization, more structured information appears for the leaf imaging. And the high-signal fiber-like myelin fiber structures were resolved much more clearly after the whole correction process for mouse brain imaging. Our experiment shows the potential of this compact AO-FFOCT system for aberration correction imaging. This preliminary approach that simulates eyes aberrations correction also opens the path to a simple implementation of FFOCT adaptive optics for retinal examinations.

Experimental characterization of a 400 Gbit/s orbital angular momentum multiplexed free-space optical link over 120 m.

PubMed

Ren, Yongxiong; Wang, Zhe; Liao, Peicheng; Li, Long; Xie, Guodong; Huang, Hao; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Willner, Asher; Lavery, Martin P J; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe; Djordjevic, Ivan B; Neifeld, Mark A; Willner, Alan E

2016-02-01

We experimentally demonstrate and characterize the performance of a 400-Gbit/s orbital angular momentum (OAM) multiplexed free-space optical link over 120 m on the roof of a building. Four OAM beams, each carrying a 100-Gbit/s quadrature-phase-shift-keyed channel are multiplexed and transmitted. We investigate the influence of channel impairments on the received power, intermodal crosstalk among channels, and system power penalties. Without laser tracking and compensation systems, the measured received power and crosstalk among OAM channels fluctuate by 4.5 dB and 5 dB, respectively, over 180 s. For a beam displacement of 2 mm that corresponds to a pointing error less than 16.7 μrad, the link bit error rates are below the forward error correction threshold of 3.8×10(-3) for all channels. Both experimental and simulation results show that power penalties increase rapidly when the displacement increases.

Automatic tracking of red blood cells in micro channels using OpenCV

NASA Astrophysics Data System (ADS)

Rodrigues, Vânia; Rodrigues, Pedro J.; Pereira, Ana I.; Lima, Rui

2013-10-01

The present study aims to developan automatic method able to track red blood cells (RBCs) trajectories flowing through a microchannel using the Open Source Computer Vision (OpenCV). The developed method is based on optical flux calculation assisted by the maximization of the template-matching product. The experimental results show a good functional performance of this method.

Fundamental properties of local anesthetics: half-maximal blocking concentrations for tonic block of Na+ and K+ channels in peripheral nerve.

PubMed

Bräu, M E; Vogel, W; Hempelmann, G

1998-10-01

Local anesthetics suppress excitability by interfering with ion channel function. Ensheathment of peripheral nerve fibers, however, impedes diffusion of drugs to the ion channels and may influence the evaluation of local anesthetic potencies. Investigating ion channels in excised membrane patches avoids these diffusion barriers. We investigated the effect of local anesthetics with voltage-dependent Na+ and K+ channels in enzymatically dissociated sciatic nerve fibers of Xenopus laevis using the patch clamp method. The outside-out configuration was chosen to apply drugs to the external face of the membrane. Local anesthetics reversibly blocked the transient Na+ inward current, as well as the steady-state K+ outward current. Half-maximal tonic inhibiting concentrations (IC50), as obtained from concentration-effect curves for Na+ current block were: tetracaine 0.7 microM, etidocaine 18 microM, bupivacaine 27 microM, procaine 60 microM, mepivacaine 149 microM, and lidocaine 204 microM. The values for voltage-dependent K+ current block were: bupivacaine 92 microM, etidocaine 176 microM, tetracaine 946 microM, lidocaine 1118 microM, mepivacaine 2305 microM, and procaine 6302 microM. Correlation of potencies with octanol:buffer partition coefficients (logP0) revealed that ester-bound local anesthetics were more potent in blocking Na+ channels than amide drugs. Within these groups, lipophilicity governed local anesthetic potency. We conclude that local anesthetic action on peripheral nerve ion channels is mediated via lipophilic drug-channel interactions. Half-maximal blocking concentrations of commonly used local anesthetics for Na+ and K+ channel block were determined on small membrane patches of peripheral nerve fibers. Because drugs can directly diffuse to the ion channel in this model, these data result from direct interactions of the drugs with ion channels.

Plenoptic Imager for Automated Surface Navigation

NASA Technical Reports Server (NTRS)

Zollar, Byron; Milder, Andrew; Milder, Andrew; Mayo, Michael

2010-01-01

An electro-optical imaging device is capable of autonomously determining the range to objects in a scene without the use of active emitters or multiple apertures. The novel, automated, low-power imaging system is based on a plenoptic camera design that was constructed as a breadboard system. Nanohmics proved feasibility of the concept by designing an optical system for a prototype plenoptic camera, developing simulated plenoptic images and range-calculation algorithms, constructing a breadboard prototype plenoptic camera, and processing images (including range calculations) from the prototype system. The breadboard demonstration included an optical subsystem comprised of a main aperture lens, a mechanical structure that holds an array of micro lenses at the focal distance from the main lens, and a structure that mates a CMOS imaging sensor the correct distance from the micro lenses. The demonstrator also featured embedded electronics for camera readout, and a post-processor executing image-processing algorithms to provide ranging information.

On the quantum-channel capacity for orbital angular momentum-based free-space optical communications.

PubMed

Zhang, Yequn; Djordjevic, Ivan B; Gao, Xin

2012-08-01

Inspired by recent demonstrations of orbital angular momentum-(OAM)-based single-photon communications, we propose two quantum-channel models: (i) the multidimensional quantum-key distribution model and (ii) the quantum teleportation model. Both models employ operator-sum representation for Kraus operators derived from OAM eigenkets transition probabilities. These models are highly important for future development of quantum-error correction schemes to extend the transmission distance and improve date rates of OAM quantum communications. By using these models, we calculate corresponding quantum-channel capacities in the presence of atmospheric turbulence.

Gaussian error correction of quantum states in a correlated noisy channel.

PubMed

Lassen, Mikael; Berni, Adriano; Madsen, Lars S; Filip, Radim; Andersen, Ulrik L

2013-11-01

Noise is the main obstacle for the realization of fault-tolerant quantum information processing and secure communication over long distances. In this work, we propose a communication protocol relying on simple linear optics that optimally protects quantum states from non-Markovian or correlated noise. We implement the protocol experimentally and demonstrate the near-ideal protection of coherent and entangled states in an extremely noisy channel. Since all real-life channels are exhibiting pronounced non-Markovian behavior, the proposed protocol will have immediate implications in improving the performance of various quantum information protocols.

Design for an aberration corrected scanning electron microscope using miniature electron mirrors.

PubMed

Dohi, Hideto; Kruit, Pieter

2018-06-01

Resolution of scanning electron microscopes (SEMs) is determined by aberrations of the objective lens. It is well known that both spherical and chromatic aberrations can be compensated by placing a 90-degree bending magnet and an electron mirror in the beam path before the objective lens. Nevertheless, this approach has not led to wide use of these aberration correctors, partly because aberrations of the bending magnet can be a serious problem. A mirror corrector with two mirrors placed perpendicularly to the optic axis of an SEM and facing each other is proposed. As a result, only small-angle magnetic deflection is necessary to guide the electron beam around the top mirror to the bottom mirror and around the bottom mirror to the objective lens. The deflection angle, in the order of 50 mrad, is sufficiently small to avoid deflection aberrations. In addition, lateral dispersion at the sample plane can be avoided by making the deflection fields symmetric. Such a corrector system is only possible if the incoming beam can pass the top mirror at a distance in the order of millimeters, without being disturbed by the electric fields of electrodes of the mirror. It is proposed that condition can be satisfied with micro-scale electron optical elements fabricated by using MEMS technology. In the proposed corrector system, the micro-mirrors have to provide the exact negative spherical and chromatic aberrations for correcting the aberration of the objective lens. This exact tuning is accomplished by variable magnification between the micro-mirrors and the objective lens using an additional transfer lens. Extensive optical calculations are reported. Aberrations of the micro-mirrors were analyzed by numerical calculation. Dispersion and aberrations of the deflectors were calculated by using an analytical field model. Combination aberrations caused by the off-axis position of dispersive rays in the mirrors and objective lens were also analyzed. It is concluded that the proposed corrector system will be a promising candidate for simple and low-cost aberration correction in low-voltage SEMs. Copyright © 2018 Elsevier B.V. All rights reserved.

Propagation and switching of light in rectangular waveguiding structures

NASA Astrophysics Data System (ADS)

Sala, Anca L.

1998-10-01

In this dissertation, we investigate the conditions for the propagation and processing of temporal optical solitons in the rectangular geometry waveguides which are expected to play an important role as processing elements in optical communication systems. It is anticipated that the optical signals carrying information through optical fibers will be in the form of temporal soliton pulses, which can propagate undistorted for long distances under the condition that the dispersion is balanced by a nonlinearity in the optical fiber. An important parameter in the equation that governs temporal soliton propagation in a waveguide is the second derivative of the propagation vector with respect to the angular frequency, /omega, denoted by β/prime'. We evaluate β/prime' for rectangular waveguides using a channel model of the waveguide, which takes into account the two transverse dimensions of the rectangular channel. Significant differences are found in the values of β/prime' obtained from our model and those obtained from the more traditional, one dimensional slab model. A major additional effort in the present thesis relates to the development of a theory of temporal soliton switching in a planar geometry nonlinear directional coupler. The theory is formulated in terms of the supermodes of the total structure, and again accounts for the two transverse dimensions of the channels. To accurately determine the coupling length and switching power of the nonlinear coupler, we apply corrections to the propagation constants of the supermodes that account for the non-zero electromagnetic fields in the outer corner regions of the waveguide channels. It is shown for the case of a SiO2 based nonlinear directional coupler operating at the central wavelength of 1.55 μm, that these corrections have a significant effect on both the coupling length and the switching power. Finally, we develop the conditions under which single mode rectangular waveguides can have zero dispersion at the optical communications wavelengths 1.31 μm or 1.55 μm, and discuss the end-to-end coupling of rectangular waveguides to the standard optical fibers used in optical communications. Our results are expected to serve as a guide for the design of planar geometry based processing elements in a variety of optical communications devices.

Nonlinear response of silicon photonic crystal microresonators excited via an integrated waveguide and fiber taper.

PubMed

Barclay, Paul; Srinivasan, Kartik; Painter, Oskar

2005-02-07

A technique is demonstrated which efficiently transfers light between a tapered standard single-mode optical fiber and a high-Q, ultra-small mode volume, silicon photonic crystal resonant cavity. Cavity mode quality factors of 4.7x10(4) are measured, and a total fiber-to-cavity coupling efficiency of 44% is demonstrated. Using this efficient cavity input and output channel, the steady-state nonlinear absorption and dispersion of the photonic crystal cavity is studied. Optical bistability is observed for fiber input powers as low as 250 microW, corresponding to a dropped power of 100 microW and 3 fJ of stored cavity energy. A high-density effective free-carrier lifetime for these silicon photonic crystal resonators of ~ 0.5 ns is also estimated from power dependent loss and dispersion measurements.

Recent advances in single-molecule detection on micro- and nano-fluidic devices.

PubMed

Liu, Chang; Qu, Yueyang; Luo, Yong; Fang, Ning

2011-11-01

Single-molecule detection (SMD) allows static and dynamic heterogeneities from seemingly equal molecules to be revealed in the studies of molecular structures and intra- and inter-molecular interactions. Micro- and nanometer-sized structures, including channels, chambers, droplets, etc., in microfluidic and nanofluidic devices allow diffusion-controlled reactions to be accelerated and provide high signal-to-noise ratio for optical signals. These two active research frontiers have been combined to provide unprecedented capabilities for chemical and biological studies. This review summarizes the advances of SMD performed on microfluidic and nanofluidic devices published in the past five years. The latest developments on optical SMD methods, microfluidic SMD platforms, and on-chip SMD applications are discussed herein and future development directions are also envisioned. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Comprehensive Study of a Micro-Channel Heat Sink Using Integrated Thin-Film Temperature Sensors

PubMed Central

Wang, Tao; Wang, Jiejun; He, Jian; Wu, Chuangui; Luo, Wenbo; Shuai, Yao; Zhang, Wanli; Chen, Xiancai; Zhang, Jian; Lin, Jia

2018-01-01

A micro-channel heat sink is a promising cooling method for high power integrated circuits (IC). However, the understanding of such a micro-channel device is not sufficient, because the tools for studying it are very limited. The details inside the micro-channels are not readily available. In this letter, a micro-channel heat sink is comprehensively studied using the integrated temperature sensors. The highly sensitive thin film temperature sensors can accurately monitor the temperature change in the micro-channel in real time. The outstanding heat dissipation performance of the micro-channel heat sink is proven in terms of maximum temperature, cooling speed and heat resistance. The temperature profile along the micro-channel is extracted, and even small temperature perturbations can be detected. The heat source formed temperature peak shifts towards the flow direction with the increasing flow rate. However, the temperature non-uniformity is independent of flow rate, but solely dependent on the heating power. Specific designs for minimizing the temperature non-uniformity are necessary. In addition, the experimental results from the integrated temperature sensors match the simulation results well. This can be used to directly verify the modeling results, helping to build a convincing simulation model. The integrated sensor could be a powerful tool for studying the micro-channel based heat sink. PMID:29351248

A Comprehensive Study of a Micro-Channel Heat Sink Using Integrated Thin-Film Temperature Sensors.

PubMed

Wang, Tao; Wang, Jiejun; He, Jian; Wu, Chuangui; Luo, Wenbo; Shuai, Yao; Zhang, Wanli; Chen, Xiancai; Zhang, Jian; Lin, Jia

2018-01-19

A micro-channel heat sink is a promising cooling method for high power integrated circuits (IC). However, the understanding of such a micro-channel device is not sufficient, because the tools for studying it are very limited. The details inside the micro-channels are not readily available. In this letter, a micro-channel heat sink is comprehensively studied using the integrated temperature sensors. The highly sensitive thin film temperature sensors can accurately monitor the temperature change in the micro-channel in real time. The outstanding heat dissipation performance of the micro-channel heat sink is proven in terms of maximum temperature, cooling speed and heat resistance. The temperature profile along the micro-channel is extracted, and even small temperature perturbations can be detected. The heat source formed temperature peak shifts towards the flow direction with the increasing flow rate. However, the temperature non-uniformity is independent of flow rate, but solely dependent on the heating power. Specific designs for minimizing the temperature non-uniformity are necessary. In addition, the experimental results from the integrated temperature sensors match the simulation results well. This can be used to directly verify the modeling results, helping to build a convincing simulation model. The integrated sensor could be a powerful tool for studying the micro-channel based heat sink.

KW-4679-induced inhibition of tachykininergic contraction in the guinea-pig bronchi by prejunctional inhibition of peripheral sensory nerves.

PubMed

Ikemura, T; Okarmura, K; Sasaki, Y; Ishi, H; Ohmori, K

1996-03-01

1. Sensory mechanisms play an important role in the vagal regulation of tracheobronchial smooth muscle tone. We examined the effect of KW-4679, an anti-allergic drug, on guinea-pig tachykinin-mediated contractile responses induced by electrical field stimulation (EFS) in guinea-pig bronchial muscles. 2. EFS (8 Hz, 0.5 ms, 15 V, for 15 s) evoked biphasic contractile responses in the guinea-pig isolated main bronchus in the presence of 5 microM indomethacin. The contractions consisted of a fast phase of an atropine-sensitive transient contraction and a slow phase of a sustained contraction which was inhibited by a combination of the tachykinin NK1 receptor antagonist, (+/-)-CP-96,345 (1 microM) and the NK2 receptor antagonist, SR 48969 (0.1 microM). 3. KW-4679 preferentially inhibited the slow phase in a concentration-dependent manner by 43.2 +/- 7.7% at 10 microM, whereas the drug had no effect on the fast phase at concentrations up to 10 microM. KW-4679, at a concentration of 100 microM, inhibited not only the slow phase by 49.2 +/- 11.4%, but also the fast phase by 36.8 +/- 9.3% [corrected]. 4. KW-4679 (10 microM and 100 microM) did not affect the substance P-induced or neurokinin A-induced contraction. Against the acetylcholine-induced contractile responses, 100 microM KW-4679 had a marked effect producing a 10.2 fold shift to the right in the curve. 5. The inhibitory effect of KW-4679 (10 microM) on the slow phase contraction was not influenced by treatment with naloxone (100 nM), propranolol (1 microM), thioperamide (1 microM), saclofen (50 microM), yohimbine (1 microM), methiothepin (1 microM) or methysergide (1 microM). 6. The inhibitory effect of KW-4679 (10 microM) on the slow phase contraction was not influenced by treatment with intermediate or large conductance Ca(2+)-activated K+ channel blockers (charybdotoxin (10 nM) or iberiotoxin (10 nM)), but suppressed by treatment with small conductance Ca(2+)-activated K+ channel blockers, apamin (500 nM) or scyllatoxin (300 nM). Apamin or scyllatoxin per se did not influence the slow phase contractions. 7. The results suggest that KW-4679 preferentially inhibits the release of tachykinins from the bronchial sensory nerves through activation of small conductance Ca(2+)-activated K+ channels.

Coherent free space optics communications over the maritime atmosphere with use of adaptive optics for beam wavefront correction.

PubMed

Li, Ming; Cvijetic, Milorad

2015-02-20

We evaluate the performance of the coherent free space optics (FSO) employing quadrature array phase-shift keying (QPSK) modulation over the maritime atmosphere with atmospheric turbulence compensated by use of adaptive optics (AO). We have established a comprehensive FSO channel model for maritime conditions and also made a comprehensive comparison of performance between the maritime and terrestrial atmospheric links. The FSO links are modeled based on the intensity attenuation resulting from scattering and absorption effects, the log-amplitude fluctuations, and the phase distortions induced by turbulence. The obtained results show that the FSO system performance measured by the bit-error-rate (BER) can be significantly improved when the optimization of the AO system is achieved. Also, we find that the higher BER is observed in the maritime FSO channel with atmospheric turbulence, as compared to the terrestrial FSO systems if they experience the same turbulence strength.

Quantum dots encoded Au coated polystyrene bead arranged micro-channel for multiplex arrays.

PubMed

Cao, Yuan-Cheng; Wang, Zhan; Yang, Runyu; Zou, Linling; Zhou, Zhen; Mi, Tie; Shi, Hong

2016-01-01

This paper describes a promising micro-channel multiplex immunoassay method based on the quantum dots encoded beads which requires micro-volume sample. Briefly, Au nanoparticles coated polystyrene (PS) beads were prepared and Quantum dots (QDs) were employed to encode 4 types of the PS beads by different emission wavelength QDs and various intensities. Different coding types of the beads were immobilized with different antibodies on the surface and BSA was used to block the unsatisfied sites. The antibody linked beads were then arranged in the 150 µm diameter optical capillary where the specific reactions took place before the detections. Results showed that the antibody on the Au coated surface maintains the bioactivity for the immunoreactions. Using this system, the fluorescent intensity was linear with analyte concentration in the range of 1×10(-7)-1×10(-5) mg/mL (RSD<5%, 4 repeats) and the lower detection limit reached 5×10(-8) mg/mL. It was proved to be a promising approach for the future miniaturization analytical devices. Copyright © 2015 Elsevier B.V. All rights reserved.

Noise-immune complex correlation for vasculature imaging based on standard and Jones-matrix optical coherence tomography

NASA Astrophysics Data System (ADS)

Makita, Shuichi; Kurokawa, Kazuhiro; Hong, Young-Joo; Li, En; Miura, Masahiro; Yasuno, Yoshiaki

2016-03-01

A new optical coherence angiography (OCA) method, called correlation mapping OCA (cmOCA), is presented by using the SNR-corrected complex correlation. An SNR-correction theory for the complex correlation calculation is presented. The method also integrates a motion-artifact-removal method for the sample motion induced decorrelation artifact. The theory is further extended to compute more reliable correlation by using multi- channel OCT systems, such as Jones-matrix OCT. The high contrast vasculature imaging of in vivo human posterior eye has been obtained. Composite imaging of cmOCA and degree of polarization uniformity indicates abnormalities of vasculature and pigmented tissues simultaneously.

Shock wave attenuation in a micro-channel

NASA Astrophysics Data System (ADS)

Giordano, J.; Perrier, P.; Meister, L.; Brouillette, M.

2018-05-01

This work presents optical measurements of shock wave attenuation in a glass micro-channel. This transparent facility, with a cross section ranging from 1 mm× 150 μm to 1 mm× 500 μm, allowed for the use of high-speed schlieren videography to visualize the propagation of a shock wave within the entire micro-channel and to quantify velocity attenuation of the wave due to wall effects. In this paper, we present the experimental technique and the relevant data treatment we have used to increase the sensitivity of shock wave detection. Then, we compared our experimental results for different channel widths, lengths, and shock wave velocities with the analytical model for shock attenuation proposed by Russell (J Fluid Mech 27(2):305-314, 1967), which assumes laminar flow, and by Mirels (Attenuation in a shock tube due to unsteady-boundary-layer action, NACA Report 1333, 1957) for turbulent flow. We found that these models are inadequate to predict the observed data, owing to the presence of fully developed flow which violates the basic assumption of these models. The data are also compared with the empirical shock attenuation models proposed by Zeitoun (Phys Fluids 27(1):011701, 2015) and Deshpande and Puranik (Shock Waves 26(4):465-475, 2016), where better agreement is observed. Finally, we presented experimental data for the flow field behind the shock wave from measurements of the Mach wave angle which shows globally decreasing flow Mach numbers due to viscous wall effects.

A new method for incoherent combining of far-field laser beams based on multiple faculae recognition

NASA Astrophysics Data System (ADS)

Ye, Demao; Li, Sichao; Yan, Zhihui; Zhang, Zenan; Liu, Yuan

2018-03-01

Compared to coherent beam combining, incoherent beam combining can complete the output of high power laser beam with high efficiency, simple structure, low cost and high thermal damage resistance, and it is easy to realize in engineering. Higher target power is achieved by incoherent beam combination which using technology of multi-channel optical path correction. However, each channel forms a spot in the far field respectively, which cannot form higher laser power density with low overlap ratio of faculae. In order to improve the combat effectiveness of the system, it is necessary to overlap different faculae that improve the target energy density. Hence, a novel method for incoherent combining of far-field laser beams is present. The method compromises piezoelectric ceramic technology and evaluation algorithm of faculae coincidence degree which based on high precision multi-channel optical path correction. The results show that the faculae recognition algorithm is low-latency(less than 10ms), which can meet the needs of practical engineering. Furthermore, the real time focusing ability of far field faculae is improved which was beneficial to the engineering of high-energy laser weapon or other laser jamming systems.

Performance analysis of a full-field and full-range swept-source OCT system

NASA Astrophysics Data System (ADS)

Krauter, J.; Boettcher, T.; Körner, K.; Gronle, M.; Osten, W.; Passilly, N.; Froehly, L.; Perrin, S.; Gorecki, C.

2015-09-01

In recent years, optical coherence tomography (OCT) became gained importance in medical disciplines like ophthalmology, due to its noninvasive optical imaging technique with micrometer resolution and short measurement time. It enables e. g. the measurement and visualization of the depth structure of the retina. In other medical disciplines like dermatology, histopathological analysis is still the gold standard for skin cancer diagnosis. The EU-funded project VIAMOS (Vertically Integrated Array-type Mirau-based OCT System) proposes a new type of OCT system combined with micro-technologies to provide a hand-held, low-cost and miniaturized OCT system. The concept is a combination of full-field and full-range swept-source OCT (SS-OCT) detection in a multi-channel sensor based on a micro-optical Mirau-interferometer array, which is fabricated by means of wafer fabrication. This paper presents the study of an experimental proof-of-concept OCT system as a one-channel sensor with bulk optics. This sensor is a Linnik-interferometer type with similar optical parameters as the Mirau-interferometer array. A commercial wavelength tunable light source with a center wavelength at 845nm and 50nm spectral bandwidth is used with a camera for parallel OCT A-Scan detection. In addition, the reference microscope objective lens of the Linnik-interferometer is mounted on a piezo-actuated phase-shifter. Phase-shifting interferometry (PSI) techniques are applied for resolving the conjugate complex artifact and consequently contribute to an increase of image quality and depth range. A suppression ratio of the complex conjugate term of 36 dB is shown and a system sensitivity greater than 96 dB could be measured.

Array-type miniature interferometer as the core optical microsystem of an optical coherence tomography device for tissue inspection

NASA Astrophysics Data System (ADS)

Passilly, Nicolas; Perrin, Stéphane; Lullin, Justine; Albero, Jorge; Bargiel, Sylwester; Froehly, Luc; Gorecki, Christophe; Krauter, Johann; Osten, Wolfgang; Wang, Wei-Shan; Wiemer, Maik

2016-04-01

Some of the critical limitations for widespread use in medical applications of optical devices, such as confocal or optical coherence tomography (OCT) systems, are related to their cost and large size. Indeed, although quite efficient systems are available on the market, e.g. in dermatology, they equip only a few hospitals and hence, are far from being used as an early detection tool, for instance in screening of patients for early detection of cancers. In this framework, the VIAMOS project aims at proposing a concept of miniaturized, batch-fabricated and lower-cost, OCT system dedicated to non-invasive skin inspection. In order to image a large skin area, the system is based on a full-field approach. Moreover, since it relies on micro-fabricated devices whose fields of view are limited, 16 small interferometers are arranged in a dense array to perform multi-channel simultaneous imaging. Gaps between each channel are then filled by scanning of the system followed by stitching. This approach allows imaging a large area without the need of large optics. It also avoids the use of very fast and often expensive laser sources, since instead of a single point detector, almost 250 thousands pixels are used simultaneously. The architecture is then based on an array of Mirau interferometers which are interesting for their vertical arrangement compatible with vertical assembly at the wafer-level. Each array is consequently a local part of a stack of seven wafers. This stack includes a glass lens doublet, an out-of-plane actuated micro-mirror for phase shifting, a spacer and a planar beam-splitter. Consequently, different materials, such as silicon and glass, are bonded together and well-aligned thanks to lithographic-based fabrication processes.

Coherent random lasing from liquid waveguide gain channels with biological scatters

NASA Astrophysics Data System (ADS)

Zhang, Hong; Feng, Guoying; Wang, Shutong; Yang, Chao; Yin, Jiajia; Zhou, Shouhuan

2014-12-01

A unidirectional coherent random laser based on liquid waveguide gain channels with biological scatters is demonstrated. The optical feedback of the random laser is provided by both light scattering and waveguide confinement. This waveguide-scattering-feedback scheme not only reduces the pump threshold but also makes the output of random laser directional. The threshold of our random laser is about 11 μJ. The emission spectra can be sensitively tuned by changing pump position due to the micro/nano-scale randomness of butterfly wings. It shows the potential applications of optofluidic random lasers for bio-chemical sensors on-chip.

Numerical prediction of micro-channel LD heat sink operated with antifreeze based on CFD method

NASA Astrophysics Data System (ADS)

Liu, Gang; Liu, Yang; Wang, Chao; Wang, Wentao; Wang, Gang; Tang, Xiaojun

2014-12-01

To theoretically study the feasibility of antifreeze coolants applied as cooling fluids for high power LD heat sink, detailed Computational Fluid Dynamics (CFD) analysis of liquid cooled micro-channels heat sinks is presented. The performance operated with antifreeze coolant (ethylene glycol aqueous solution) compared with pure water are numerical calculated for the heat sinks with the same micro-channels structures. The maximum thermal resistance, total pressure loss (flow resistance), thermal resistance vs. flow-rate, and pressure loss vs. flow-rate etc. characteristics are numerical calculated. The results indicate that the type and temperature of coolants plays an important role on the performance of heat sinks. The whole thermal resistance and pressure loss of heat sinks increase significantly with antifreeze coolants compared with pure water mainly due to its relatively lower thermal conductivity and higher fluid viscosity. The thermal resistance and pressure loss are functions of the flow rate and operation temperature. Increasing of the coolant flow rate can reduce the thermal resistance of heat sinks; meanwhile increase the pressure loss significantly. The thermal resistance tends to a limit with increasing flow rate, while the pressure loss tends to increase exponentially with increasing flow rate. Low operation temperature chiefly increases the pressure loss rather than thermal resistance due to the remarkable increasing of fluid viscosity. The actual working point of the cooling circulation system can be determined on the basis of the pressure drop vs. flow rate curve for the micro-channel heat sink and that for the circulation system. In the same system, if the type or/and temperature of the coolant is changed, the working point is accordingly influenced, that is, working flow rate and pressure is changed simultaneously, due to which the heat sink performance is influenced. According to the numerical simulation results, if ethylene glycol aqueous solution is applied instead of pure water as the coolant under the same or a higher working temperature, the available output of optical power will decrease due to the worse heat sink performance; if applied under a lower working temperature(0 °C, －20 °C), although the heat sink performance become worse, however the temperature difference of heat transfer rises more significantly, the available output of optical power will increase on the contrary.

Misalignment corrections in optical interconnects

NASA Astrophysics Data System (ADS)

Song, Deqiang

Optical interconnects are considered a promising solution for long distance and high bitrate data transmissions, outperforming electrical interconnects in terms of loss and dispersion. Due to the bandwidth and distance advantage of optical interconnects, longer links have been implemented with optics. Recent studies show that optical interconnects have clear advantages even at very short distances---intra system interconnects. The biggest challenge for such optical interconnects is the alignment tolerance. Many free space optical components require very precise assembly and installation, and therefore the overall cost could be increased. This thesis studied the misalignment tolerance and possible alignment correction solutions for optical interconnects at backplane or board level. First the alignment tolerance for free space couplers was simulated and the result indicated the most critical alignments occur between the VCSEL, waveguide and microlens arrays. An in-situ microlens array fabrication method was designed and experimentally demonstrated, with no observable misalignment with the waveguide array. At the receiver side, conical lens arrays were proposed to replace simple microlens arrays for a larger angular alignment tolerance. Multilayer simulation models in CodeV were built to optimized the refractive index and shape profiles of the conical lens arrays. Conical lenses fabricated with micro injection molding machine and fiber etching were characterized. Active component VCSOA was used to correct misalignment in optical connectors between the board and backplane. The alignment correction capability were characterized for both DC and AC (1GHz) optical signal. The speed and bandwidth of the VCSOA was measured and compared with a same structure VCSEL. Based on the optical inverter being studied in our lab, an all-optical flip-flop was demonstrated using a pair of VCSOAs. This memory cell with random access ability can store one bit optical signal with set or reset beam. The operating conditions were studied to generate two stable states between the VCSOA pair. The entire functionality test was implemented with free space optical components.

Numerical analysis on a passive chaotic micromixer with helical microchannel.

PubMed

Wang, Ruijin; Lin, Jianzhong

2006-01-01

In order to improve the mixing efficiency, the diffusion and mixing of species in the helical micro-mixer are simulated numerically. The results show that the mixing efficiency in the helical micromixer is much higher than that in the straight micro-channel and obviously higher than that in the serpentine micro-channel when Reynolds number is low. At high Reynolds number, even though the mixing efficiency in the helical micro-mixer is still much higher than that in the straight micro-channel, no obvious difference of mixing efficiency in the helical micro-mixer and serpentine micro-channel is found. The conclusions are helpful to optimize the structure of the micro-mixer.

Development of 3D microwave imaging reflectometry in LHD (invited).

PubMed

Nagayama, Y; Kuwahara, D; Yoshinaga, T; Hamada, Y; Kogi, Y; Mase, A; Tsuchiya, H; Tsuji-Iio, S; Yamaguchi, S

2012-10-01

Three-dimensional (3D) microwave imaging reflectometry has been developed in the large helical device to visualize fluctuating reflection surface which is caused by the density fluctuations. The plasma is illuminated by the probe wave with four frequencies, which correspond to four radial positions. The imaging optics makes the image of cut-off surface onto the 2D (7 × 7 channels) horn antenna mixer arrays. Multi-channel receivers have been also developed using micro-strip-line technology to handle many channels at reasonable cost. This system is first applied to observe the edge harmonic oscillation (EHO), which is an MHD mode with many harmonics that appears in the edge plasma. A narrow structure along field lines is observed during EHO.

Development of 3D microwave imaging reflectometry in LHD (invited)a)

NASA Astrophysics Data System (ADS)

Nagayama, Y.; Kuwahara, D.; Yoshinaga, T.; Hamada, Y.; Kogi, Y.; Mase, A.; Tsuchiya, H.; Tsuji-Iio, S.; Yamaguchi, S.

2012-10-01

Three-dimensional (3D) microwave imaging reflectometry has been developed in the large helical device to visualize fluctuating reflection surface which is caused by the density fluctuations. The plasma is illuminated by the probe wave with four frequencies, which correspond to four radial positions. The imaging optics makes the image of cut-off surface onto the 2D (7 × 7 channels) horn antenna mixer arrays. Multi-channel receivers have been also developed using micro-strip-line technology to handle many channels at reasonable cost. This system is first applied to observe the edge harmonic oscillation (EHO), which is an MHD mode with many harmonics that appears in the edge plasma. A narrow structure along field lines is observed during EHO.

Incorporating Information of microRNAs into Pathway Analysis in a Genome-Wide Association Study of Bipolar Disorder

PubMed Central

Shih, Wei-Liang; Kao, Chung-Feng; Chuang, Li-Chung; Kuo, Po-Hsiu

2012-01-01

MicroRNAs (miRNAs) are known to be important post-transcriptional regulators that are involved in the etiology of complex psychiatric traits. The present study aimed to incorporate miRNAs information into pathway analysis using a genome-wide association dataset to identify relevant biological pathways for bipolar disorder (BPD). We selected psychiatric- and neurological-associated miRNAs (N = 157) from PhenomiR database. The miRNA target genes (miTG) predictions were obtained from microRNA.org. Canonical pathways (N = 4,051) were downloaded from the Molecule Signature Database. We employed a novel weighting scheme for miTGs in pathway analysis using methods of gene set enrichment analysis and sum-statistic. Under four statistical scenarios, 38 significantly enriched pathways (P-value < 0.01 after multiple testing correction) were identified for the risk of developing BPD, including pathways of ion channels associated (e.g., gated channel activity, ion transmembrane transporter activity, and ion channel activity) and nervous related biological processes (e.g., nervous system development, cytoskeleton, and neuroactive ligand receptor interaction). Among them, 19 were identified only when the weighting scheme was applied. Many miRNA-targeted genes were functionally related to ion channels, collagen, and axonal growth and guidance that have been suggested to be associated with BPD previously. Some of these genes are linked to the regulation of miRNA machinery in the literature. Our findings provide support for the potential involvement of miRNAs in the psychopathology of BPD. Further investigations to elucidate the functions and mechanisms of identified candidate pathways are needed. PMID:23264780

Pharmacology of the human red cell voltage-dependent cation channel; Part I. Activation by clotrimazole and analogues.

PubMed

Barksmann, Trine L; Kristensen, Berit I; Christophersen, Palle; Bennekou, Poul

2004-01-01

The activation and pharmacological modulation of the nonselective voltage-dependent cation (NSVDC) channel from human erythrocytes were studied. Basic channel activation was achieved by suspending red cells in a low Cl(-) Ringer (2 mM), where a positive membrane potential (V(m) = E(Cl)) immediately developed. Voltage- and time-dependent activation of the NSVDC channel occurred, reaching a cation conductance (g+) of 1.5-2.0 microS cm(-2). In the presence of the classical Gárdos channel blocker clotrimazole (0-50 microM), activation occurred faster, and g+ saturated dose-dependently (EC50 = 14 microM) at a value of about 4 microS cm(-2). The clotrimazole analogues TRAM-34, econazole, and miconazole also stimulated the channel, whereas the chemically more distant Gárdos channel inhibitors nitrendipine and cetiedil had no effects. Although the potency for modulation of the NSVDC channel is much lower than the IC50 value for Gárdos channel inhibition, clotrimazole (and its analogues) constitutes the first chemical class of positive modulators of the NSVDC channel. This may be an important pharmacological "fingerprint" in the identification of the cloned equivalent of the erythrocyte channel.

Integrated multi-channel nano-engineered optical hydrogen and temperature sensor detection systems for launch vehicles

NASA Astrophysics Data System (ADS)

Alam, M. Z.; Moreno, J.; Aitchison, J. S.; Mojahedi, M.; Kazemi, A. A.

2008-08-01

Launch vehicles and other satellite users need launch services that are highly reliable, less complex, easier to test, and cost effective. Being a very small molecule, hydrogen is prone to leakage through seals and micro-cracks. Hydrogen detection in space application is very challenging; public acceptance of hydrogen fuel would require the integration of a reliable hydrogen safety sensor. For detecting leakage of cryogenic fluids in spaceport facilities, launch vehicle industry and aerospace agencies are currently relying heavily on the bulky mass spectrometers, which fill one or more equipment racks, and weigh several hundred kilograms. Therefore, there is a critical need for miniaturized sensors and instruments suitable for use in space applications. This paper describes a novel multi-channel integrated nano-engineered optical sensor to detect hydrogen and monitor the temperature. The integrated optic sensor is made of multi-channel waveguide elements that measure hydrogen concentration in real Time. Our sensor is based on the use of a high index waveguide with a Ni/Pd overlay to detect hydrogen. When hydrogen is absorbed into the Ni/Pd alloy there is a change in the absorption of the material and the optical signal in the waveguide is increased. Our design uses a thin alloy (few nanometers thick) overlay which facilitates the absorption of the hydrogen and will result in a response time of approximately few seconds. Like other Pd/Pd-Ni based sensors the device response varies with temperature and hence the effects of temperature variations must be taken into account. One solution to this problem is simultaneous measurement of temperature in addition to hydrogen concentration at the same vicinity. Our approach here is to propose a temperature sensor that can easily be integrated on the same platform as the hydrogen sensor reported earlier by our group. One suitable choice of material system is silicon on insulator (SOI). Here, we propose a micro ring resonators (MRR) based temperature sensor designed on SOI that measures temperature by monitoring the output optical power.

20-meter underwater wireless optical communication link with 1.5 Gbps data rate.

PubMed

Shen, Chao; Guo, Yujian; Oubei, Hassan M; Ng, Tien Khee; Liu, Guangyu; Park, Ki-Hong; Ho, Kang-Ting; Alouini, Mohamed-Slim; Ooi, Boon S

2016-10-31

The video streaming, data transmission, and remote control in underwater call for high speed (Gbps) communication link with a long channel length (~10 meters). We present a compact and low power consumption underwater wireless optical communication (UWOC) system utilizing a 450-nm laser diode (LD) and a Si avalanche photodetector. With the LD operating at a driving current of 80 mA with an optical power of 51.3 mW, we demonstrated a high-speed UWOC link offering a data rate up to 2 Gbps over a 12-meter-long, and 1.5 Gbps over a record 20-meter-long underwater channel. The measured bit-error rate (BER) are 2.8 × 10^-5, and 3.0 × 10^-3, respectively, which pass well the forward error correction (FEC) criterion.

Design and fabrication of a multilayered polymer microfluidic chip with nanofluidic interconnects via adhesive contact printing.

PubMed

Flachsbart, Bruce R; Wong, Kachuen; Iannacone, Jamie M; Abante, Edward N; Vlach, Robert L; Rauchfuss, Peter A; Bohn, Paul W; Sweedler, Jonathan V; Shannon, Mark A

2006-05-01

The design and fabrication of a multilayered polymer micro-nanofluidic chip is described that consists of poly(methylmethacrylate) (PMMA) layers that contain microfluidic channels separated in the vertical direction by polycarbonate (PC) membranes that incorporate an array of nanometre diameter cylindrical pores. The materials are optically transparent to allow inspection of the fluids within the channels in the near UV and visible spectrum. The design architecture enables nanofluidic interconnections to be placed in the vertical direction between microfluidic channels. Such an architecture allows microchannel separations within the chip, as well as allowing unique operations that utilize nanocapillary interconnects: the separation of analytes based on molecular size, channel isolation, enhanced mixing, and sample concentration. Device fabrication is made possible by a transfer process of labile membranes and the development of a contact printing method for a thermally curable epoxy based adhesive. This adhesive is shown to have bond strengths that prevent leakage and delamination and channel rupture tests exceed 6 atm (0.6 MPa) under applied pressure. Channels 100 microm in width and 20 microm in depth are contact printed without the adhesive entering the microchannel. The chip is characterized in terms of resistivity measurements along the microfluidic channels, electroosmotic flow (EOF) measurements at different pH values and laser-induced-fluorescence (LIF) detection of green-fluorescent protein (GFP) plugs injected across the nanocapillary membrane and into a microfluidic channel. The results indicate that the mixed polymer micro-nanofluidic multilayer chip has electrical characteristics needed for use in microanalytical systems.

All-optical phase discrimination using SOA.

PubMed

Power, Mark J; Webb, Roderick P; Manning, Robert J

2013-11-04

We describe the first experimental demonstration of a novel all-optical phase discrimination technique, which can separate the two orthogonal phase components of a signal onto different frequencies. This method exploits nonlinear mixing in a semiconductor optical amplifier (SOA) to separate a 10.65 Gbaud QPSK signal into two 10.65 Gb/s BPSK signals which are then demodulated using a delay interferometer (DI). Eye diagrams and spectral measurements verify correct operation and a conversion efficiency greater than 9 dB is observed on both output BPSK channels when compared with the input QPSK signal.

Optical fiber Fabry-Perot interferometer cavity fabricated by femtosecond laser micromachining and fusion splicing for refractive index sensing.

PubMed

Liao, C R; Hu, T Y; Wang, D N

2012-09-24

We demonstrate a fiber in-line Fabry-Perot interferometer cavity sensor for refractive index measurement. The interferometer cavity is formed by drilling a micro-hole at the cleaved fiber end facet, followed by fusion splicing. A micro-channel is inscribed by femtosecond laser micromachining to vertically cross the cavity to allow liquid to flow in. The refractive index sensitivity obtained is ~994 nm/RIU (refractive index unit). Such a device is simple in configuration, easy for fabrication and reliable in operation due to extremely low temperature cross sensitivity of ~4.8 × 10(-6) RIU/°C.

An experimental analysis of process parameters to manufacture micro-channels in AISI H13 tempered steel by laser micro-milling

NASA Astrophysics Data System (ADS)

Teixidor, D.; Ferrer, I.; Ciurana, J.

2012-04-01

This paper reports the characterization of laser machining (milling) process to manufacture micro-channels in order to understand the incidence of process parameters on the final features. Selection of process operational parameters is highly critical for successful laser micromachining. A set of designed experiments is carried out in a pulsed Nd:YAG laser system using AISI H13 hardened tool steel as work material. Several micro-channels have been manufactured as micro-mold cavities varying parameters such as scanning speed (SS), pulse intensity (PI) and pulse frequency (PF). Results are obtained by evaluating the dimensions and the surface finish of the micro-channel. The dimensions and shape of the micro-channels produced with laser-micro-milling process exhibit variations. In general the use of low scanning speeds increases the quality of the feature in both surface finishing and dimensional.

Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips

PubMed Central

Jung, Woo-Chul; Heo, Young-Moo; Yoon, Gil-Sang; Shin, Kwang-Ho; Chang, Sung-Ho; Kim, Gun-Hee; Cho, Myeong-Woo

2007-01-01

Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip), has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for microfluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

Investigation on adaptive optics performance from propagation channel characterization with the small optical transponder

NASA Astrophysics Data System (ADS)

Petit, Cyril; Védrenne, Nicolas; Velluet, Marie Therese; Michau, Vincent; Artaud, Geraldine; Samain, Etienne; Toyoshima, Morio

2016-11-01

In order to address the high throughput requested for both downlink and uplink satellite to ground laser links, adaptive optics (AO) has become a key technology. While maturing, application of this technology for satellite to ground telecommunication, however, faces difficulties, such as higher bandwidth and optimal operation for a wide variety of atmospheric conditions (daytime and nighttime) with potentially low elevations that might severely affect wavefront sensing because of scintillation. To address these specificities, an accurate understanding of the origin of the perturbations is required, as well as operational validation of AO on real laser links. We report here on a low Earth orbiting (LEO) microsatellite to ground downlink with AO correction. We discuss propagation channel characterization based on Shack-Hartmann wavefront sensor (WFS) measurements. Fine modeling of the propagation channel is proposed based on multi-Gaussian model of turbulence profile. This model is then used to estimate the AO performance and validate the experimental results. While AO performance is limited by the experimental set-up, it proves to comply with expected performance and further interesting information on propagation channel is extracted. These results shall help dimensioning and operating AO systems for LEO to ground downlinks.

Development and characterisation of FPGA modems using forward error correction for FSOC

NASA Astrophysics Data System (ADS)

Mudge, Kerry A.; Grant, Kenneth J.; Clare, Bradley A.; Biggs, Colin L.; Cowley, William G.; Manning, Sean; Lechner, Gottfried

2016-05-01

In this paper we report on the performance of a free-space optical communications (FSOC) modem implemented in FPGA, with data rate variable up to 60 Mbps. To combat the effects of atmospheric scintillation, a 7/8 rate low density parity check (LDPC) forward error correction is implemented along with custom bit and frame synchronisation and a variable length interleaver. We report on the systematic performance evaluation of an optical communications link employing the FPGA modems using a laboratory test-bed to simulate the effects of atmospheric turbulence. Log-normal fading is imposed onto the transmitted free-space beam using a custom LabVIEW program and an acoustic-optic modulator. The scintillation index, transmitted optical power and the scintillation bandwidth can all be independently varied allowing testing over a wide range of optical channel conditions. In particular, bit-error-ratio (BER) performance for different interleaver lengths is investigated as a function of the scintillation bandwidth. The laboratory results are compared to field measurements over 1.5km.

Imaging model for the scintillator and its application to digital radiography image enhancement.

PubMed

Wang, Qian; Zhu, Yining; Li, Hongwei

2015-12-28

Digital Radiography (DR) images obtained by OCD-based (optical coupling detector) Micro-CT system usually suffer from low contrast. In this paper, a mathematical model is proposed to describe the image formation process in scintillator. By solving the correlative inverse problem, the quality of DR images is improved, i.e. higher contrast and spatial resolution. By analyzing the radiative transfer process of visible light in scintillator, scattering is recognized as the main factor leading to low contrast. Moreover, involved blurring effect is also concerned and described as point spread function (PSF). Based on these physical processes, the scintillator imaging model is then established. When solving the inverse problem, pre-correction to the intensity of x-rays, dark channel prior based haze removing technique, and an effective blind deblurring approach are employed. Experiments on a variety of DR images show that the proposed approach could improve the contrast of DR images dramatically as well as eliminate the blurring vision effectively. Compared with traditional contrast enhancement methods, such as CLAHE, our method could preserve the relative absorption values well.

Direct simulation Monte Carlo method for gas flows in micro-channels with bends with added curvature

NASA Astrophysics Data System (ADS)

Tisovský, Tomáš; Vít, Tomáš

Gas flows in micro-channels are simulated using an open source Direct Simulation Monte Carlo (DSMC) code dsmcFOAM for general application to rarefied gas flow written within the framework of the open source C++ toolbox called OpenFOAM. Aim of this paper is to investigate the flow in micro-channel with bend with added curvature. Results are compared with flows in channel without added curvature and equivalent straight channel. Effects of micro-channel bend was already thoroughly investigated by White et al. Geometry proposed by White is also used here for refference.

On-field measurement trial of 4×128 Gbps PDM-QPSK signals by linear optical sampling

NASA Astrophysics Data System (ADS)

Bin Liu; Wu, Zhichao; Fu, Songnian; Feng, Yonghua; Liu, Deming

2017-02-01

Linear optical sampling is a promising characterization technique for advanced modulation formats, together with digital signal processing (DSP) and software-synchronized algorithm. We theoretically investigate the acquisition of optical sampling, when the high-speed signal under test is either periodic or random. Especially, when the profile of optical sampling pulse is asymmetrical, the repetition frequency of sampling pulse needs careful adjustment in order to obtain correct waveform. Then, we demonstrate on-field measurement trial of commercial four-channel 128 Gbps polarization division multiplexing quadrature phase shift keying (PDM-QPSK) signals with truly random characteristics by self-developed equipment. A passively mode-locked fiber laser (PMFL) with a repetition frequency of 95.984 MHz is used as optical sampling source, meanwhile four balanced photo detectors (BPDs) with 400 MHz bandwidth and four-channel analog-to-digital convertor (ADC) with 1.25 GS/s sampling rate are used for data acquisition. The performance comparison with conventional optical modulation analyzer (OMA) verifies that the self-developed equipment has the advantages of low cost, easy implementation, and fast response.

Spectrally Shaped DP-16QAM Super-Channel Transmission with Multi-Channel Digital Back-Propagation

PubMed Central

Maher, Robert; Xu, Tianhua; Galdino, Lidia; Sato, Masaki; Alvarado, Alex; Shi, Kai; Savory, Seb J.; Thomsen, Benn C.; Killey, Robert I.; Bayvel, Polina

2015-01-01

The achievable transmission capacity of conventional optical fibre communication systems is limited by nonlinear distortions due to the Kerr effect and the difficulty in modulating the optical field to effectively use the available fibre bandwidth. In order to achieve a high information spectral density (ISD), while simultaneously maintaining transmission reach, multi-channel fibre nonlinearity compensation and spectrally efficient data encoding must be utilised. In this work, we use a single coherent super-receiver to simultaneously receive a DP-16QAM super-channel, consisting of seven spectrally shaped 10GBd sub-carriers spaced at the Nyquist frequency. Effective nonlinearity mitigation is achieved using multi-channel digital back-propagation (MC-DBP) and this technique is combined with an optimised forward error correction implementation to demonstrate a record gain in transmission reach of 85%; increasing the maximum transmission distance from 3190 km to 5890 km, with an ISD of 6.60 b/s/Hz. In addition, this report outlines for the first time, the sensitivity of MC-DBP gain to linear transmission line impairments and defines a trade-off between performance and complexity. PMID:25645457

MEMS deformable mirror for wavefront correction of large telescopes

NASA Astrophysics Data System (ADS)

Manhart, Sigmund; Vdovin, Gleb; Collings, Neil; Sodnik, Zoran; Nikolov, Susanne; Hupfer, Werner

2017-11-01

A 50 mm diameter membrane mirror was designed and manufactured at TU Delft. It is made from bulk silicon by micromachining - a technology primarily used for micro-electromechanical systems (MEMS). The mirror unit is equipped with 39 actuator electrodes and can be electrostatically deformed to correct wavefront errors in optical imaging systems. Performance tests on the deformable mirror were carried out at Astrium GmbH using a breadboard setup with a wavefront sensor and a closed-loop control system. It was found that the deformable membrane mirror is well suited for correction of low order wavefront errors as they must be expected in lightweighted space telescopes.

Micro system comprising 96 micro valves on a titer plate

NASA Astrophysics Data System (ADS)

Krabbe, S.; Flitsch, D.; Büchs, J.; Schomburg, W. K.

2016-10-01

A system of 96 micro valves has been developed and mounted on top of a 48-well micro titer plate providing two valves for each well controlling its air inlet and outlet. Testing of the valve system showed that all valves are working and are opened and closed reliably. A pneumatic system is switching inlet and outlet valves independently of each other. The geometry of the feed channels ensures an equal air flow through all wells, when the valves are open. Between the micro valves, one optical fibre was inserted through the lid of each well allowing measuring the oxygen partial pressure in the enclosed air volume by fluorescence sensor spots. Escherichia coli bacteria were grown inside the wells and their metabolism was observed by the oxygen partial pressure change due to respiration. In all 48 wells, the same oxygen transfer rate was observed within an averaged standard deviation of 1 mmol/L/h. The oxygen transfer rate differences compared to a macroscopic standard shake flask system were overall compatible within their uncertainties.

Secure communications using nonlinear silicon photonic keys.

PubMed

Grubel, Brian C; Bosworth, Bryan T; Kossey, Michael R; Cooper, A Brinton; Foster, Mark A; Foster, Amy C

2018-02-19

We present a secure communication system constructed using pairs of nonlinear photonic physical unclonable functions (PUFs) that harness physical chaos in integrated silicon micro-cavities. Compared to a large, electronically stored one-time pad, our method provisions large amounts of information within the intrinsically complex nanostructure of the micro-cavities. By probing a micro-cavity with a rapid sequence of spectrally-encoded ultrafast optical pulses and measuring the lightwave responses, we experimentally demonstrate the ability to extract 2.4 Gb of key material from a single micro-cavity device. Subsequently, in a secure communication experiment with pairs of devices, we achieve bit error rates below 10 -5 at code rates of up to 0.1. The PUFs' responses are never transmitted over the channel or stored in digital memory, thus enhancing the security of the system. Additionally, the micro-cavity PUFs are extremely small, inexpensive, robust, and fully compatible with telecommunications infrastructure, components, and electronic fabrication. This approach can serve one-time pad or public key exchange applications where high security is required.

MEMS for optical switching: technologies, applications, and perspectives

NASA Astrophysics Data System (ADS)

Lin, Lih-Y.; Goldstein, Evan L.

1999-09-01

Micro-electro-mechanical-systems (MEMS), due to their unique ability to integrate electrical, mechanical, and optical elements on a single chip, have recently begun to exhibit great potential for realizing optical components and subsystems in compact, lowcost form. Recently, this technology has been applied to wavelength-division-multiplexed (WDM) networks, and resulted in advances in several network elements, including switches, filters, modulators, and wavelength-add/drop multiplexers. Due largely to the exploding capacity demand arising from data traffic, the transmission capacity demanded of and available from WDM networks is anticipated to increase rapidly. For managing such networks, optical switching is of particular interest due to the fact that its complexity is essentially immune to steady advances in the per-channel bit-rate. We will review various micromachined optical-switching technologies, emphasizing studies of their reliability. We then summarizing recent progress in the free-space MEMS optical switch we have demonstrated.

MEMS for optical switching: technologies, applications, and perspectives

NASA Astrophysics Data System (ADS)

Lin, Lih-Yuan; Goldstein, Evan L.

1999-09-01

Micro-electro-mechanical-systems (MEMS), due to their unique ability to integrate electrical, mechanical, and optical elements on a single chip, have recently begun to exhibit great potential for realizing optical components and subsystems in compact, low-cost form. Recently, this technology has been applied to wavelength-division-multiplexed (WDM) networks, and resulted in advances in several network elements, including switches, filters, modulators, and wavelength-add/drop multiplexers. Due largely to the exploding capacity demand arising from data traffic, the transmission capacity demanded of and available from WDM networks is anticipated to increase rapidly. For managing such networks, optical switching is of particular interest due to the fact that its complexity is essentially immune to steady advances in the per-channel bit-rate. We will review various micromachined optical-switching technologies, emphasizing studies of their reliability. We then summarizing recent progress in the free-space MEMS optical switch we have demonstrated.

Development and test of photon counting lidar

NASA Astrophysics Data System (ADS)

Wang, Chun-hui; Wang, Ao-you; Tao, Yu-liang; Li, Xu; Peng, Huan; Meng, Pei-bei

2018-02-01

In order to satisfy the application requirements of spaceborne three dimensional imaging lidar , a prototype of nonscanning multi-channel lidar based on receiver field of view segmentation was designed and developed. High repetition frequency micro-pulse lasers, optics fiber array and Geiger-mode APD, combination with time-correlated single photon counting technology, were adopted to achieve multi-channel detection. Ranging experiments were carried out outdoors. In low echo photon condition, target photon counting showed time correlated and noise photon counting were random. Detection probability and range precision versus threshold were described and range precision increased from 0.44 to 0.11 when threshold increased from 4 to 8.

Adaptive software-defined coded modulation for ultra-high-speed optical transport

NASA Astrophysics Data System (ADS)

Djordjevic, Ivan B.; Zhang, Yequn

2013-10-01

In optically-routed networks, different wavelength channels carrying the traffic to different destinations can have quite different optical signal-to-noise ratios (OSNRs) and signal is differently impacted by various channel impairments. Regardless of the data destination, an optical transport system (OTS) must provide the target bit-error rate (BER) performance. To provide target BER regardless of the data destination we adjust the forward error correction (FEC) strength. Depending on the information obtained from the monitoring channels, we select the appropriate code rate matching to the OSNR range that current channel OSNR falls into. To avoid frame synchronization issues, we keep the codeword length fixed independent of the FEC code being employed. The common denominator is the employment of quasi-cyclic (QC-) LDPC codes in FEC. For high-speed implementation, low-complexity LDPC decoding algorithms are needed, and some of them will be described in this invited paper. Instead of conventional QAM based modulation schemes, we employ the signal constellations obtained by optimum signal constellation design (OSCD) algorithm. To improve the spectral efficiency, we perform the simultaneous rate adaptation and signal constellation size selection so that the product of number of bits per symbol × code rate is closest to the channel capacity. Further, we describe the advantages of using 4D signaling instead of polarization-division multiplexed (PDM) QAM, by using the 4D MAP detection, combined with LDPC coding, in a turbo equalization fashion. Finally, to solve the problems related to the limited bandwidth of information infrastructure, high energy consumption, and heterogeneity of optical networks, we describe an adaptive energy-efficient hybrid coded-modulation scheme, which in addition to amplitude, phase, and polarization state employs the spatial modes as additional basis functions for multidimensional coded-modulation.

Investigation of Overlap Correction Techniques for Application in the Micro-Pulse Lidar Network (MPLNET)

NASA Technical Reports Server (NTRS)

Berkoff, Timothy A.; Welton, Ellsworth J.; Campbell, James R.; Scott, Vibart S.; Spinhirne, James D.

2003-01-01

The Micro-Pulse Lidar NETwork (MPLNET) is comprised of micro-pulse lidars (MPL) stationed around the globe to provide measurements of aerosol and cloud vertical distribution on a continuous basis. MPLNET sites are co-located with sunphotometers in the AErosol Robotic NETwork (AERONET) to provide joint measurements of aerosol optical depth, size, and other inherent optical properties. The IPCC 2001 report discusses . the importance of obtaining routine measurements of aerosol vertical structure, especially for absorbing aerosols. MPLNET provides exactly this sort of measurement, including calculation of aerosol extinction profiles, in a near real-time basis for all sites in the network. In order to obtain aerosol profiles, near range signal returns (0-6 km) must be accurately measured by the MPL. This measurement is complicated by the instrument s overlap range: Le., the minimum distance at which returning signals are completely in the instrument s field-of-view (FOV). Typical MPL overlap distances are large, between 5 - 6 km, due to the narrow FOV of the MPL receiver. A function describing the MPL overlap must be determined and used to correct signals in this range. Currently, overlap functions for MPLNET are determined using horizontal MPL measurements along a path with 10-1 5 km clear line-of-sight and a homogenous atmosphere. These conditions limit the location and ease in which successful overlaps can be obtained. Furthermore, the current MPLNET process of correcting for overlap increases the uncertainty and bias error for the near range signals and the resulting aerosol extinction profiles. To address these issues, an alternative overlap correction method using a small-diameter, wide FOV receiver is being considered for potential use in MPLNET. The wide FOV receiver has a much shorter overlap distance and will be used to calculate the overlap function of the MPL receiver. This approach has a significant benefit in that overlap corrections could be obtained without the need for horizontal measurements. A review of both overlap methods is presented, including a discussion of the impact on reducing the uncertainty and bias error in MPLNET aerosol profiles.

DPD simulation on the dynamics of a healthy and infected red blood cell in flow through a constricted channel

NASA Astrophysics Data System (ADS)

Hoque, Sazid Zamal; Anand, D. Vijay; Patnaik, B. S. V.

2017-11-01

The state of the red blood cell (either healthy or infected RBC) will influence its deformation dynamics. Since the pathological condition related to RBC, primarily originates from a single cell infection, therefore, it is important to relate the deformation dynamics to the mechanical properties (such as, bending rigidity and membrane elasticity). In the present study, numerical simulation of a healthy and malaria infected RBC in a constricted channel is analyzed. The flow simulations are carried out using finite sized dissipative particle dynamics (FDPD) method in conjunction with a discrete model that represents the membrane of the RBC. The numerical equivalent of optical tweezers test is validated against the experimental studies. Two different types of constrictions, viz., a converging-diverging type tapered channel and a stenosed microchannel are considered for the simulation. The effect of degree of constriction and the flow rate effect on the RBC is investigated. It was observed that, as the flow rate decreases, the infected RBC completely blocks the micro vessel. The transit time for infected cell drastically increases compared to healthy RBC. Our simulations indicate that, there is a critical flow rate below which infected RBC cannot pass through the micro capillary.

Research on the Micro Sheet Stamping Process Using Plasticine as Soft Punch

PubMed Central

Wang, Xiao; Zhang, Di; Gu, Chunxing; Shen, Zongbao; Liu, Huixia

2014-01-01

Plasticine is widely used in the analysis of metal forming processes, due to its excellent material flow ability. In this study, plasticine is used as the soft punch to fabricate array micro-channels on metal sheet in the micro sheet stamping process. This is because plasticine can produce a large material flow after being subjected to force and through the material flow, the plasticine can cause the sheet to fill into the micro-channels of the rigid die, leading to the generation of micro-channels in the sheet. The distribution of array micro-channels was investigated as well as the influence of load forces on the sheet deformations. It was found that the depth of micro-channels increases as the load force increases. When the load force reaches a certain level, a crack can be observed. The micro sheet stamping process was also investigated by the method of numerical simulation. The obtained experimental and numerical results for the stamping process showed that they were in good agreement. Additionally, from the simulation results, it can be seen that the corner region of the micro-channel-shape work piece has a risk to crack due to the existence of maximum von Mises stress and significant thinning. PMID:28788668

Optically controlled electrophoresis with a photoconductive substrate

NASA Astrophysics Data System (ADS)

Inami, Wataru; Nagashima, Taiki; Kawata, Yoshimasa

2018-05-01

A photoconductive substrate is used to perform electrophoresis. Light-induced micro-particle flow manipulation is demonstrated without using a fabricated flow channel. The path along which the particles were moved was formed by an illuminated light pattern on the substrate. Because the substrate conductivity and electric field distribution can be modified by light illumination, the forces acting on the particles can be controlled. This technique has potential applications as a high functionality analytical device.

MEMS deformable mirror embedded wavefront sensing and control system

NASA Astrophysics Data System (ADS)

Owens, Donald; Schoen, Michael; Bush, Keith

2006-01-01

Electrostatic Membrane Deformable Mirror (MDM) technology developed using silicon bulk micro-machining techniques offers the potential of providing low-cost, compact wavefront control systems for diverse optical system applications. Electrostatic mirror construction using bulk micro-machining allows for custom designs to satisfy wavefront control requirements for most optical systems. An electrostatic MDM consists of a thin membrane, generally with a thin metal or multi-layer high-reflectivity coating, suspended over an actuator pad array that is connected to a high-voltage driver. Voltages applied to the array elements deflect the membrane to provide an optical surface capable of correcting for measured optical aberrations in a given system. Electrostatic membrane DM designs are derived from well-known principles of membrane mechanics and electrostatics, the desired optical wavefront control requirements, and the current limitations of mirror fabrication and actuator drive electronics. MDM performance is strongly dependent on mirror diameter and air damping in meeting desired spatial and temporal frequency requirements. In this paper, we present wavefront control results from an embedded wavefront control system developed around a commercially available high-speed camera and an AgilOptics Unifi MDM driver using USB 2.0 communications and the Linux development environment. This new product, ClariFast TM, combines our previous Clarifi TM product offering into a faster more streamlined version dedicated strictly to Hartmann Wavefront sensing.

Study of condensation of refrigerants in a micro-channel for development of future compact micro-channel condensers

NASA Astrophysics Data System (ADS)

Chowdhury, Sourav

2009-12-01

Mini- and micro-channel technology has gained considerable ground in the recent years in industry and is favored due to its several advantages stemming from its high surface to volume ratio and high values of proof pressure it can withstand. Micro-channel technology has paved the way to development of highly compact heat exchangers with low cost and mass penalties. In the present work, the issues related to the sizing of compact micro-channel condensers have been explored. The considered designs encompass both the conventional and MEMS fabrication techniques. In case of MEMS-fabricated micro-channel condenser, wet etching of the micro-channel structures, followed by bonding of two such wafers with silicon nitride layers at the interface was attempted. It was concluded that the silicon nitride bonding requires great care in terms of high degree of surface flatness and absence of roughness and also high degree of surface purity and thus cannot be recommended for mass fabrication. Following this investigation, a carefully prepared experimental setup and test micro-channel with hydraulic diameter 700 mum and aspect ratio 7:1 was fabricated and overall heat transfer and pressure drop aspects of two condensing refrigerants, R134a and R245fa were studied at a variety of test conditions. To the best of author's knowledge, so far no data has been reported in the literature on condensation in such high aspect ratio micro-channels. Most of the published experimental works on condensation of refrigerants are concerning conventional hydraulic diameter channels (> 3mm) and only recently some experimental data has been reported in the sub-millimeter scale channels for which the surface tension and viscosity effects play a dominant role and the effect of gravity is diminished. It is found that both experimental data and empirically-derived correlations tend to under-predict the present data by an average of 25%. The reason for this deviation could be because a high aspect ratio channel tends to collect the condensate in the corners of its cross-section leaving only a thin liquid film on the flat side surfaces for better heat transfer than in circular or low aspect ratio channels.

Experimental purification of single qubits.

PubMed

Ricci, M; De Martini, F; Cerf, N J; Filip, R; Fiurásek, J; Macchiavello, C

2004-10-22

We report the experimental realization of the purification protocol for single qubits sent through a depolarizing channel. The qubits are associated with polarization states of single photons and the protocol is achieved by means of passive linear optical elements. The present approach may represent a convenient alternative to the distillation and error correction protocols of quantum information.

Niamey Aerosol Optical Depths

DOE Data Explorer

Flynn, Connor

2008-10-01

MFRSR irradiance data collected during the ACRF AMF deployment in Niamey, Niger have been used to derive AOD for five wavelength channels of the MFRSR. These data have been corrected to adjust for filter drift over the course of the campaign and contamination due to forward scattering as a result of large dust particles in the atmosphere around Niamey.

Calculated Coupling Efficiency Between an Elliptical-Core Optical Fiber and a Silicon Oxynitride Rib Waveguide [Corrected Copy

NASA Technical Reports Server (NTRS)

Tuma, Margaret L.; Beheim, Glenn

1995-01-01

The effective-index method and Marcatili's technique were utilized independently to calculate the electric field profile of a rib channel waveguide. Using the electric field profile calculated from each method, the theoretical coupling efficiency between a single-mode optical fiber and a rib waveguide was calculated using the overlap integral. Perfect alignment was assumed and the coupling efficiency calculated. The coupling efficiency calculation was then repeated for a range of transverse offsets.

Protecting the entanglement of twisted photons by adaptive optics

NASA Astrophysics Data System (ADS)

Leonhard, Nina; Sorelli, Giacomo; Shatokhin, Vyacheslav N.; Reinlein, Claudia; Buchleitner, Andreas

2018-01-01

We study the efficiency of adaptive optics (AO) correction for the free-space propagation of entangled photonic orbital-angular-momentum (OAM) qubit states to reverse moderate atmospheric turbulence distortions. We show that AO can significantly reduce crosstalk to modes within and outside the encoding subspace and thereby stabilize entanglement against turbulence. This method establishes a reliable quantum channel for OAM photons in turbulence, and it enhances the threshold turbulence strength for secure quantum communication by at least a factor 2.

Modeling and Reconstruction of Micro-structured 3D Chitosan/Gelatin Porous Scaffolds Using Micro-CT

NASA Astrophysics Data System (ADS)

Gong, Haibo; Li, Dichen; He, Jiankang; Liu, Yaxiong; Lian, Qin; Zhao, Jinna

2008-09-01

Three dimensional (3D) channel networks are the key to promise the uniform distribution of nutrients inside 3D hepatic tissue engineering scaffolds and prompt elimination of metabolic products out of the scaffolds. 3D chitosan/gelatin porous scaffolds with predefined internal channels were fabricated and a combination of light microscope, laser confocal microscopy and micro-CT were employed to characterize the structure of porous scaffolds. In order to evaluate the flow field distribution inside the micro-structured 3D scaffolds, a computer reconstructing method based on Micro-CT was proposed. According to this evaluating method, a contrast between 3D porous scaffolds with and without predefined internal channels was also performed to assess scaffolds' fluid characters. Results showed that the internal channel of the 3D scaffolds formed the 3D fluid channel network; the uniformity of flow field distribution of the scaffolds fabricated in this paper was better than the simple porous scaffold without micro-fluid channels.

Microoptical System And Fabrication Method Therefor

DOEpatents

Sweatt, William C.; Christenson, Todd R.

2005-03-15

Microoptical systems with clear aperture of about one millimeter or less are fabricated from a layer of photoresist using a lithographic process to define the optical elements. A deep X-ray source is typically used to expose the photoresist. Exposure and development of the photoresist layer can produce planar, cylindrical, and radially symmetric micro-scale optical elements, comprising lenses, mirrors, apertures, diffractive elements, and prisms, monolithically formed on a common substrate with the mutual optical alignment required to provide the desired system functionality. Optical alignment can be controlled to better than one micron accuracy. Appropriate combinations of structure and materials enable optical designs that include corrections for chromatic and other optical aberrations. The developed photoresist can be used as the basis for a molding operation to produce microoptical systems made of a range of optical materials. Finally, very complex microoptical systems can be made with as few as three lithographic exposures.

Microoptical system and fabrication method therefor

DOEpatents

Sweatt, William C.; Christenson, Todd R.

2003-07-08

Microoptical systems with clear aperture of about one millimeter or less are fabricated from a layer of photoresist using a lithographic process to define the optical elements. A deep X-ray source is typically used to expose the photoresist. Exposure and development of the photoresist layer can produce planar, cylindrical, and radially symmetric micro-scale optical elements, comprising lenses, mirrors, apertures, diffractive elements, and prisms, monolithically formed on a common substrate with the mutual optical alignment required to provide the desired system functionality. Optical alignment can be controlled to better than one micron accuracy. Appropriate combinations of structure and materials enable optical designs that include corrections for chromatic and other optical aberrations. The developed photoresist can be used as the basis for a molding operation to produce microoptical systems made of a range of optical materials. Finally, very complex microoptical systems can be made with as few as three lithographic exposures.

Hot gas path component having near wall cooling features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miranda, Carlos Miguel; Kottilingam, Srikanth Chandrudu; Lacy, Benjamin Paul

A method for providing micro-channels in a hot gas path component includes forming a first micro-channel in an exterior surface of a substrate of the hot gas path component. A second micro-channel is formed in the exterior surface of the hot gas path component such that it is separated from the first micro-channel by a surface gap having a first width. The method also includes disposing a braze sheet onto the exterior surface of the hot gas path component such that the braze sheet covers at least of portion of the first and second micro-channels, and heating the braze sheetmore » to bond it to at least a portion of the exterior surface of the hot gas path component.« less

Lymphocyte migration in the micro-channel of splenic sheathed capillaries in Chinese soft-shelled turtles, Pelodiscus sinensis.

PubMed

Zhang, Qian; Ullah, Shakeeb; Liu, Yi; Yang, Ping; Chen, Bing; Waqas, Yasir; Bao, Huijun; Hu, Lisi; Li, Quanfu; Chen, Qiusheng

2016-01-01

The structural characteristics of the splenic sheathed capillary were investigated using light microscopy and transmission electron microscopy (TEM). This study mainly focused on lymphocyte migration to the splenic white pulp via micro-channels in Chinese soft-shelled turtles, Pelodiscus sinensis. The results showed that the sheathed capillaries in the turtle spleen were high endothelial venule (HEV)-like vessels. These capillaries consist of micro-channels that facilitate lymphocyte migration to the splenic white pulp. The micro-channel is a dynamic structure comprising processes of endothelial cells, supporting cells, and ellipsoid-associated cells (EACs), which provides a microenvironment for lymphocyte migration. The pattern of lymphocyte migration in the micro-channel of the turtle spleen includes the following steps: (i) lymphocyte first adheres to the endothelium of the sheathed capillary, passes through the endothelial cells, and traverses through the basement membrane of the sheathed capillary; (ii) it then enters into the ellipsoid combined with supporting cells and EACs; and (iii) lymphocyte migrates from the ellipsoid to the periellipsoidal lymphatic sheath (PELS) via the micro-channel. This study provides morphological evidence for lymphocyte migration in the micro-channels of turtle spleens and also an insight into the mechanism of lymphocyte homing to the splenic white pulp of reptiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of microfabricated deformable mirror systems

NASA Astrophysics Data System (ADS)

Cowan, William D.; Lee, Max K.; Bright, Victor M.; Welsh, Byron M.

1998-09-01

This paper presents recent result for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages, thus eliminating high voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203 micrometers 12 by 12 square grid. The overall array size is 2.4 mm square. The arrays were fabricated in the commercially available DARPA supported MUMPs surface micromachining foundry process. The cost per mirror array in this prototyping process is less than 200 dollars. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror which requires no digital to analog converters, further reducing the cost of adaptive optics system.

Improved performance of the laser guide star adaptive optics system at Lick Observatory

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, J R; Avicola, K; Bauman, B J

1999-07-20

Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2 {micro}m were corrected to over 40% of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to {approx}10% of the theoretical peak intensity limit. After a campaign to improve the beam quality of the laser system, and to improve calibration accuracy and stability of the adaptive optics systemmore » using new techniques for phase retrieval and phase-shifting diffraction interferometry, the system performance has been substantially increased. The next step will be to use the Lick system for astronomical science observations, and to demonstrate this level of performance with the new system being installed on the 10-meter Keck II telescope.« less

Analog and digital transport of RF channels over converged 5G wireless-optical networks

NASA Astrophysics Data System (ADS)

Binh, Le Nguyen

2016-02-01

Under the exponential increase demand by the emerging 5G wireless access networking and thus data-center based Internet, novel and economical transport of RF channels to and from wireless access systems. This paper presents the transport technologies of RF channels over the analog and digital domain so as to meet the demands of the transport capacity reaching multi-Tbps, in the followings: (i) The convergence of 5G broadband wireless and optical networks and its demands on capacity delivery and network structures; (ii) Analog optical technologies for delivery of both the information and RF carriers to and from multiple-input multiple-output (MIMO) antenna sites so as to control the beam steering of MIMO antenna in the mmW at either 28.6 GHz and 56.8 GHz RF carrier and delivery of channels of aggregate capacity reaching several Tbps; (ii) Transceiver employing advanced digital modulation formats and digital signal processing (DSP) so as to provide 100G and beyond transmission rate to meet the ultra-high capacity demands with flexible spectral grids, hence pay-on-demand services. The interplay between DSP-based and analog transport techniques is examined; (iii) Transport technologies for 5G cloud access networks and associate modulation and digital processing techniques for capacity efficiency; and (iv) Finally the integrated optic technologies with novel lasers, comb generators and simultaneous dual function photonic devices for both demultiplexing/multiplexing and modulation are proposed, hence a system on chip structure can be structured. Quantum dot lasers and matrixes of micro ring resonators are integrated on the same Si-on-Silica substrate are proposed and described.

Calibration schemes of a field-compatible optical spectroscopic system to quantify neovascular changes in the dysplastic cervix

NASA Astrophysics Data System (ADS)

Chang, Vivide Tuan-Chyan; Merisier, Delson; Yu, Bing; Walmer, David K.; Ramanujam, Nirmala

2011-03-01

A significant challenge in detecting cervical pre-cancer in low-resource settings is the lack of effective screening facilities and trained personnel to detect the disease before it is advanced. Light based technologies, particularly quantitative optical spectroscopy, have the potential to provide an effective, low cost, and portable solution for cervical pre-cancer screening in these communities. We have developed and characterized a portable USB-powered optical spectroscopic system to quantify total hemoglobin content, hemoglobin saturation, and reduced scattering coefficient of cervical tissue in vivo. The system consists of a high-power LED as light source, a bifurcated fiber optic assembly, and two USB spectrometers for sample and calibration spectra acquisitions. The system was subsequently tested in Leogane, Haiti, where diffuse reflectance spectra from 33 colposcopically normal sites in 21 patients were acquired. Two different calibration methods, i.e., a post-study diffuse reflectance standard measurement and a real time self-calibration channel were studied. Our results suggest that a self-calibration channel enabled more accurate extraction of scattering contrast through simultaneous real-time correction of intensity drifts in the system. A self-calibration system also minimizes operator bias and required training. Hence, future contact spectroscopy or imaging systems should incorporate a selfcalibration channel to reliably extract scattering contrast.

Correction of phase-shifting error in wavelength scanning digital holographic microscopy

NASA Astrophysics Data System (ADS)

Zhang, Xiaolei; Wang, Jie; Zhang, Xiangchao; Xu, Min; Zhang, Hao; Jiang, Xiangqian

2018-05-01

Digital holographic microscopy is a promising method for measuring complex micro-structures with high slopes. A quasi-common path interferometric apparatus is adopted to overcome environmental disturbances, and an acousto-optic tunable filter is used to obtain multi-wavelength holograms. However, the phase shifting error caused by the acousto-optic tunable filter reduces the measurement accuracy and, in turn, the reconstructed topographies are erroneous. In this paper, an accurate reconstruction approach is proposed. It corrects the phase-shifting errors by minimizing the difference between the ideal interferograms and the recorded ones. The restriction on the step number and uniformity of the phase shifting is relaxed in the interferometry, and the measurement accuracy for complex surfaces can also be improved. The universality and superiority of the proposed method are demonstrated by practical experiments and comparison to other measurement methods.

Fluorescence imaging spectrometer optical design

NASA Astrophysics Data System (ADS)

Taiti, A.; Coppo, P.; Battistelli, E.

2015-09-01

The optical design of the FLuORescence Imaging Spectrometer (FLORIS) studied for the Fluorescence Explorer (FLEX) mission is discussed. FLEX is a candidate for the ESA's 8th Earth Explorer opportunity mission. FLORIS is a pushbroom hyperspectral imager foreseen to be embarked on board of a medium size satellite, flying in tandem with Sentinel-3 in a Sun synchronous orbit at a height of about 815 km. FLORIS will observe the vegetation fluorescence and reflectance within a spectral range between 500 and 780 nm. Multi-frames acquisitions on matrix detectors during the satellite movement will allow the production of 2D Earth scene images in two different spectral channels, called HR and LR with spectral resolution of 0.3 and 2 nm respectively. A common fore optics is foreseen to enhance by design the spatial co-registration between the two spectral channels, which have the same ground spatial sampling (300 m) and swath (150 km). An overlapped spectral range between the two channels is also introduced to simplify the spectral coregistration. A compact opto-mechanical solution with all spherical and plane optical elements is proposed, and the most significant design rationales are described. The instrument optical architecture foresees a dual Babinet scrambler, a dioptric telescope and two grating spectrometers (HR and LR), each consisting of a modified Offner configuration. The developed design is robust, stable vs temperature, easy to align, showing very high optical quality along the whole field of view. The system gives also excellent correction for transverse chromatic aberration and distortions (keystone and smile).

Characterization of electrokinetic gating valve in microfluidic channels.

PubMed

Zhang, Guiseng; Du, Wei; Liu, Bi-Feng; Hisamoto, Hideaki; Terabe, Shigeru

2007-02-12

Electrokinetic gating, functioning as a micro-valve, has been widely employed in microfluidic chips for sample injection and flow switch. Investigating its valving performance is fundamentally vital for microfluidics and microfluidics-based chemical analysis. In this paper, electrokinetic gating valve in microchannels was evaluated using optical imaging technique. Microflow profiles at channels junction were examined, revealing that molecular diffusion played a significant role in the valving disable; which could cause analyte leakage in sample injection. Due to diffusion, the analyte crossed the interface of the analyte flow and gating flow, and then formed a cometic tail-like diffusion area at channels junction. From theoretical calculation and some experimental evidences, the size of the area was related to the diffusion coefficient and the velocity of analytes. Additionally, molecular diffusion was also believed to be another reason of sampling bias in gated injection.

Characterizing quantum channels with non-separable states of classical light

NASA Astrophysics Data System (ADS)

Ndagano, Bienvenu; Perez-Garcia, Benjamin; Roux, Filippus S.; McLaren, Melanie; Rosales-Guzman, Carmelo; Zhang, Yingwen; Mouane, Othmane; Hernandez-Aranda, Raul I.; Konrad, Thomas; Forbes, Andrew

2017-04-01

High-dimensional entanglement with spatial modes of light promises increased security and information capacity over quantum channels. Unfortunately, entanglement decays due to perturbations, corrupting quantum links that cannot be repaired without performing quantum tomography on the channel. Paradoxically, the channel tomography itself is not possible without a working link. Here we overcome this problem with a robust approach to characterize quantum channels by means of classical light. Using free-space communication in a turbulent atmosphere as an example, we show that the state evolution of classically entangled degrees of freedom is equivalent to that of quantum entangled photons, thus providing new physical insights into the notion of classical entanglement. The analysis of quantum channels by means of classical light in real time unravels stochastic dynamics in terms of pure state trajectories, and thus enables precise quantum error correction in short- and long-haul optical communication, in both free space and fibre.

Toward a Role of Light Absorption in Initiation Chemistry of Shocked HMX single Crystals and Crystalline High Explosives

NASA Astrophysics Data System (ADS)

Plaksin, Igor; Rodrigues, L.

2013-06-01

Question which mechanism is driving radiation-induced reactions, thermal or athermal becomes a subject of conflicting discussions. Major challenge of this work is to identify at micro- (sub-granular), meso- (grain level) and macro-scale roles of these two mechanisms in triggering initiation chemistry in HMX-based HEs. Four acceptor-patterns were tested at 20 GPa input pressure: single HMX crystal-in-water, HMX/water-slurry, PBX(HMX/HTPB) & inert PBX-simulant (HMX-particles replaced by crystalline sucrose). Scenario of reaction onset-localizations-dissipation was spatially resolved using Multi-Channel Optical Analyzer MCOA-UC (96 channels, 100um-spatial accuracy, 0.2ns-timeresolution, 450-850 nm-spectral range) through real-time panoramic recording emitted reaction light and shock field in standard optic monitor. Experiments reveal a dual nature of initiation chemistry: athermal and thermal. Single-crystal tests disclose origination of photo-induced reactions downstream of emitting reaction spot due to intensified radiation absorption in surface micro-defects. Polycrystalline samples reveal cyclic reproducibility of radiation-induced thermal precursors in which radiation absorption causes thermal expansion/phase-changes of HMX-grains resulting in oscillating detonation. Work was supported by the Office of Naval Research under the ONR and ONR Global Grants N00014-12-1-0477 and N62909-12-1-7131 with Drs. Cliff Bedford and Shawn Thorne Program Managers.

THz photonic wireless links with 16-QAM modulation in the 375-450 GHz band.

PubMed

Jia, Shi; Yu, Xianbin; Hu, Hao; Yu, Jinlong; Guan, Pengyu; Da Ros, Francesco; Galili, Michael; Morioka, Toshio; Oxenløwe, Leif K

2016-10-17

We propose and experimentally demonstrate THz photonic wireless communication systems with 16-QAM modulation in the 375-450 GHz band. The overall throughput reaches as high as 80 Gbit/s by exploiting four THz channels with 5 Gbaud 16-QAM baseband modulation per channel. We create a coherent optical frequency comb (OFC) for photonic generation of multiple THz carriers based on photo-mixing in a uni-travelling carrier photodiode (UTC-PD). The OFC configuration also allows us to generate reconfigurable THz carriers with low phase noise. The multiple-channel THz radiation is received by using a Schottky mixer based electrical receiver after 0.5 m free-space wireless propagation. 2-channel (40 Gbit/s) and 4-channel (80 Gbit/s) THz photonic wireless links with 16-QAM modulation are reported in this paper, and the bit error rate (BER) performance for all channels in both cases is below the hard decision forward error correction (HD-FEC) threshold of 3.8e-3 with 7% overhead. In addition, we also successfully demonstrate hybrid photonic wireless transmission of 40 Gbit/s 16-QAM signal at carrier frequencies of 400 GHz and 425 GHz over 30 km standard single mode fiber (SSMF) between the optical baseband signal transmitter and the THz wireless transmitter with negligible induced power penalty.

Three-dimension imaging lidar

NASA Technical Reports Server (NTRS)

Degnan, John J. (Inventor)

2007-01-01

This invention is directed to a 3-dimensional imaging lidar, which utilizes modest power kHz rate lasers, array detectors, photon-counting multi-channel timing receivers, and dual wedge optical scanners with transmitter point-ahead correction to provide contiguous high spatial resolution mapping of surface features including ground, water, man-made objects, vegetation and submerged surfaces from an aircraft or a spacecraft.

On a Road to "Soft" Optical MEMS

NASA Astrophysics Data System (ADS)

Yang, Shu; Mach, Peter; Krupenkin, Tom

2003-03-01

A phenomenon of electrowetting has been applied to the actuation of micro-optical devices. The devices use small droplets of transparent conductive liquids to manipulate light in a useful way. The form and position of these droplets is controlled by the applied voltage. Both fiber based and open space optical devices are demonstrated. As an example of an open space optical device, a tunable liquid microlens capable of adjusting its focal length and lateral position is discussed. The microlens consists of a droplet of a transparent conductive liquid placed on a dielectric substrate with underlying electrodes. By varying the voltage applied to the structure, both the position and curvature of microlens can be reversibly changed. Similarly, electrowetting actuation of fluids in micro channels is employed to provide dynamic and reversible tuning of the optical fiber structures. When combined with in-fiber gratings or etched fibers this approach yields tunable broadband and narrowband filters with a large dynamic range. Both the surface and bulk properties of the materials are found important to control the device performance. Fundamental problems, such as stick-slip behavior and contact angle hysteresis associated with the surface roughness and surface contamination, are studied to optimize the choice of dielectric materials and their coatings. Some of the possible ways to control these phenomena are outlined. Several potential applications of the proposed approach are also discussed.

Custom ceramic microchannel-cooled array for high-power fiber-coupled application

NASA Astrophysics Data System (ADS)

Junghans, Jeremy; Feeler, Ryan; Stephens, Ed

2018-03-01

A low-SWaP (Size, Weight and Power) diode array has been developed for a high-power fiber-coupled application. High efficiency ( 65%) diodes enable high optical powers while minimizing thermal losses. A large amount of waste heat is still generated and must be extracted. Custom ceramic microchannel-coolers (MCCs) are used to dissipate the waste heat. The custom ceramic MCC was designed to accommodate long cavity length diodes and micro-lenses. The coolers provide similar thermal performance as copper MCCs however they are not susceptible to erosion and can be cooled with standard filtered water. The custom ceramic micro-channel cooled array was designed to be a form/fit replacement for an existing copperbased solution. Each array consisted of three-vertically stacked MCCs with 4 mm CL, 976 nm diodes and beamshaping micro-optics. The erosion and corrosion resistance of ceramic array is intended to mitigate the risk of copperbased MCC corrosion failures. Elimination of the water delivery requirements (pH, resistivity and dissolved oxygen control) further reduces the system SWaP while maintaining reliability. The arrays were fabricated and fully characterized. This work discusses the advantages of the ceramic MCC technology and describes the design parameters that were tailored for the fiber-coupled application. Additional configuration options (form/fit, micro-lensing, alternate coolants, etc.) and on-going design improvements are also discussed.

Inhibitory action of ICI-182,780, an estrogen receptor antagonist, on BK(Ca) channel activity in cultured endothelial cells of human coronary artery.

PubMed

Liu, Yen-Chin; Lo, Yi-Ching; Huang, Chin-Wei; Wu, Sheng-Nan

2003-11-15

ICI-182,780 is known to be a selective inhibitor of the intracellular estrogen receptors. The effect of ICI-182,780 on ion currents was studied in cultured endothelial cells of human coronary artery. In whole-cell current recordings, ICI-182,780 reversibly decreased the amplitude of K(+) outward currents. The decrease in outward current caused by ICI-182,780 could be counteracted by further application of magnolol or nordihydroguaiaretic acid, yet not by 17beta-estradiol. Under current-clamp condition, ICI-182,780 (3microM) depolarized the membrane potentials of the cells, and magnolol (10 microM) or nordihydroguaiaretic acid (10 microM) reversed ICI-182,780-induced depolarization. In inside-out patches, ICI-182,780 added to the bath did not alter single-channel conductance of large-conductance Ca(2+)-activated K(+) channels (BK(Ca) channels), but decreased their open probability. ICI-182,780 reduced channel activity in a concentration-dependent manner with an IC(50) value of 3 microM. After BK(Ca) channel activity was suppressed by 2-methoxyestradiol (3 microM), subsequent application of ICI-182,780 (3 microM) did not further reduce the channel activity. The application of ICI-182,780 shifted the activation curve of BK(Ca) channels to positive potentials. Its decrease in the open probability primarily involved a reduction in channel open duration. ICI-182,780 also suppressed the proliferation of these endothelial cells with an IC(50) value of 2 microM. However, in coronary smooth muscle cells, a bell-shaped concentration-response curve for the ICI-182,780 effect on BK(Ca) channel activity was observed. This study provides evidence that ICI-182,780 can inhibit BK(Ca) channels in vascular endothelial cells in a mechanism unlikely to be linked to its anti-estrogen activity. The inhibitory effects on these channels may partly contribute to the underlying mechanisms by which ICI-182,780 affects endothelial function.

An Experimental Study of a Micro-Projection Enabled Optical Terminal for Short-Range Bidirectional Multi-Wavelength Visible Light Communications

PubMed Central

Tsai, Cheng-Yu; Jiang, Jhih-Shan

2018-01-01

A micro-projection enabled short-range communication (SRC) approach using red-, green- and blue-based light-emitting diodes (RGB-LEDs) has experimentally demonstrated recently that micro-projection and high-speed data transmission can be performed simultaneously. In this research, a reconfigurable design of a polarization modulated image system based on the use of a Liquid Crystal on Silicon based Spatial Light Modulator (LCoS-based SLM) serving as a portable optical terminal capable of micro-projection and bidirectional multi-wavelength communications is proposed and experimentally demonstrated. For the proof of concept, the system performance was evaluated through a bidirectional communication link at a transmission distance over 0.65 m. In order to make the proposed communication system architecture compatible with the data modulation format of future possible wireless communication system, baseband modulation scheme, i.e., Non-Return-to-Zero On-Off-Keying (NRZ_OOK), M-ary Phase Shift Keying (M-PSK) and M-ary Quadrature Amplitude Modulation (M-QAM) were used to investigate the system transmission performance. The experimental results shown that an acceptable BER (satisfying the limitation of Forward Error Correction, FEC standard) and crosstalk can all be achieved in the bidirectional multi-wavelength communication scenario. PMID:29587457

Calibrated Link Budget of a Silicon Photonics WDM Transceiver with SOA and Semiconductor Mode-Locked Laser.

PubMed

Moscoso-Mártir, Alvaro; Müller, Juliana; Islamova, Elmira; Merget, Florian; Witzens, Jeremy

2017-09-20

Based on the single channel characterization of a Silicon Photonics (SiP) transceiver with Semiconductor Optical Amplifier (SOA) and semiconductor Mode-Locked Laser (MLL), we evaluate the optical power budget of a corresponding Wavelength Division Multiplexed (WDM) link in which penalties associated to multi-channel operation and the management of polarization diversity are introduced. In particular, channel cross-talk as well as Cross Gain Modulation (XGM) and Four Wave Mixing (FWM) inside the SOA are taken into account. Based on these link budget models, the technology is expected to support up to 12 multiplexed channels without channel pre-emphasis or equalization. Forward Error Correction (FEC) does not appear to be required at 14 Gbps if the SOA is maintained at 25 °C and MLL-to-SiP as well as SiP-to-SOA interface losses can be maintained below 3 dB. In semi-cooled operation with an SOA temperature below 55 °C, multi-channel operation is expected to be compatible with standard 802.3bj Reed-Solomon FEC at 14 Gbps provided interface losses are maintained below 4.5 dB. With these interface losses and some improvements to the Transmitter (Tx) and Receiver (Rx) electronics, 25 Gbps multi-channel operation is expected to be compatible with 7% overhead hard decision FEC.

Simulation of micro/nano electroporation for cell transfection

NASA Astrophysics Data System (ADS)

Zhang, Guocheng; Fan, Na; Jiang, Hai; Guo, Jian; Peng, Bei

2018-03-01

The 3D micro/nano electroporation for transfection has become a powerful biological cell research technique with the development of micro-nano manufacturing technology. The micro channels connected the cells with transfection reagents on the chip were important to the transmemnbrane potentical, which directly influences the electroporation efficiency. In this study, a two-dimensional model for electroporation of cells was designed to address the effects of channels’ sizes and number on transmembrane potential. The simulation results indicated that the transmembrane potential increased with increasing size of channels’ entrances. Moreover, compared with single channel entrance, the transmembrane potential was higher when the cells located at multiple channels entrances. These results suggest that it IS required to develop higher micro manufacturing technology to create channels as we expected size.

Optical design for CETUS: a wide-field 1.5m aperture UV payload being studied for a NASA probe class mission study

NASA Astrophysics Data System (ADS)

Woodruff, Robert A.; Hull, Tony; Heap, Sara R.; Danchi, William; Kendrick, Stephen E.; Purves, Lloyd

2017-09-01

We are developing a NASA Headquarters selected Probe-class mission concept called the Cosmic Evolution Through UV Spectroscopy (CETUS) mission, which includes a 1.5-m aperture diameter large field-of-view (FOV) telescope optimized for UV imaging, multi-object spectroscopy, and point-source spectroscopy. The optical system includes a Three Mirror Anastigmatic (TMA) telescope that simultaneously feeds three separate scientific instruments: the near-UV (NUV) Multi-Object Spectrograph (MOS) with a next-generation Micro-Shutter Array (MSA); the two-channel camera covering the far-UV (FUV) and NUV spectrum; and the point-source spectrograph covering the FUV and NUV region with selectable R 40,000 echelle modes and R 2,000 first order modes. The optical system includes fine guidance sensors, wavefront sensing, and spectral and flat-field in-flight calibration sources. This paper will describe the current optical design of CETUS.

Optical design for CETUS: a wide-field 1.5m aperture UV payload being studied for a NASA probe class mission study

NASA Astrophysics Data System (ADS)

Woodruff, Robert; Robert Woodruff, Goddard Space Flight Center, Kendrick Optical Consulting

2018-01-01

We are developing a NASA Headquarters selected Probe-class mission concept called the Cosmic Evolution Through UV Spectroscopy (CETUS) mission, which includes a 1.5-m aperture diameter large field-of-view (FOV) telescope optimized for UV imaging, multi-object spectroscopy, and point-source spectroscopy. The optical system includes a Three Mirror Anastigmatic (TMA) telescope that simultaneously feeds three separate scientific instruments: the near-UV (NUV) Multi-Object Spectrograph (MOS) with a next-generation Micro-Shutter Array (MSA); the two-channel camera covering the far-UV (FUV) and NUV spectrum; and the point-source spectrograph covering the FUV and NUV region with selectable R~ 40,000 echelle modes and R~ 2,000 first order modes. The optical system includes fine guidance sensors, wavefront sensing, and spectral and flat-field in-flight calibration sources. This paper will describe the current optical design of CETUS.

Information content of OCO-2 oxygen A-band channels for retrieving marine liquid cloud properties

NASA Astrophysics Data System (ADS)

Richardson, Mark; Stephens, Graeme L.

2018-03-01

Information content analysis is used to select channels for a marine liquid cloud retrieval using the high-spectral-resolution oxygen A-band instrument on NASA's Orbiting Carbon Observatory-2 (OCO-2). Desired retrieval properties are cloud optical depth, cloud-top pressure and cloud pressure thickness, which is the geometric thickness expressed in hectopascals. Based on information content criteria we select a micro-window of 75 of the 853 functioning OCO-2 channels spanning 763.5-764.6 nm and perform a series of synthetic retrievals with perturbed initial conditions. We estimate posterior errors from the sample standard deviations and obtain ±0.75 in optical depth and ±12.9 hPa in both cloud-top pressure and cloud pressure thickness, although removing the 10 % of samples with the highest χ2 reduces posterior error in cloud-top pressure to ±2.9 hPa and cloud pressure thickness to ±2.5 hPa. The application of this retrieval to real OCO-2 measurements is briefly discussed, along with limitations and the greatest caution is urged regarding the assumption of a single homogeneous cloud layer, which is often, but not always, a reasonable approximation for marine boundary layer clouds.

Crosstalk eliminating and low-density parity-check codes for photochromic dual-wavelength storage

NASA Astrophysics Data System (ADS)

Wang, Meicong; Xiong, Jianping; Jian, Jiqi; Jia, Huibo

2005-01-01

Multi-wavelength storage is an approach to increase the memory density with the problem of crosstalk to be deal with. We apply Low Density Parity Check (LDPC) codes as error-correcting codes in photochromic dual-wavelength optical storage based on the investigation of LDPC codes in optical data storage. A proper method is applied to reduce the crosstalk and simulation results show that this operation is useful to improve Bit Error Rate (BER) performance. At the same time we can conclude that LDPC codes outperform RS codes in crosstalk channel.

Micro-Organ Device

NASA Technical Reports Server (NTRS)

Sun, Wei (Inventor); Chang, Robert C. (Inventor); Starly, Binil (Inventor); Holtorf, Heidi L. (Inventor); Leslie, Julia (Inventor); Culbertson, Christopher (Inventor); Gonda, Steve R. (Inventor)

2013-01-01

A method for fabricating a micro-organ device comprises providing a microscale support having one or more microfluidic channels and one or more micro-chambers for housing a micro-organ and printing a micro-organ on the microscale support using a cell suspension in a syringe controlled by a computer-aided tissue engineering system, wherein the cell suspension comprises cells suspended in a solution containing a material that functions as a three-dimensional scaffold. The printing is performed with the computer-aided tissue engineering system according to a particular pattern. The micro-organ device comprises at least one micro-chamber each housing a micro-organ; and at least one microfluidic channel connected to the micro-chamber, wherein the micro-organ comprises cells arranged in a configuration that includes microscale spacing between portions of the cells to facilitate diffusion exchange between the cells and a medium supplied from the at least one microfluidic channel.

Micro-organ device

NASA Technical Reports Server (NTRS)

von Gustedt-Gonda, legal representative, Iris (Inventor); Holtorf, Heidi L. (Inventor); Gonda, Steve R. (Inventor); Leslie, Julia (Inventor); Chang, Robert C. (Inventor); Sun, Wei (Inventor); Starly, Binil (Inventor); Culbertson, Christopher (Inventor)

2013-01-01

A method for fabricating a micro-organ device comprises providing a microscale support having one or more microfluidic channels and one or more micro-chambers for housing a micro-organ and printing a micro-organ on the microscale support using a cell suspension in a syringe controlled by a computer-aided tissue engineering system, wherein the cell suspension comprises cells suspended in a solution containing a material that functions as a three-dimensional scaffold. The printing is performed with the computer-aided tissue engineering system according to a particular pattern. The micro-organ device comprises at least one micro-chamber each housing a micro-organ; and at least one microfluidic channel connected to the micro-chamber, wherein the micro-organ comprises cells arranged in a configuration that includes microscale spacing between portions of the cells to facilitate diffusion exchange between the cells and a medium supplied from the at least one microfluidic channel.

Analytical approach for modeling and performance analysis of microring resonators as optical filters with multiple output bus waveguides

NASA Astrophysics Data System (ADS)

Lakra, Suchita; Mandal, Sanjoy

2017-06-01

A quadruple micro-optical ring resonator (QMORR) with multiple output bus waveguides is mathematically modeled and analyzed by making use of the delay-line signal processing approach in Z-domain and Mason's gain formula. The performances of QMORR with two output bus waveguides with vertical coupling are analyzed. This proposed structure is capable of providing wider free spectral response from both the output buses with appreciable cross talk. Thus, this configuration could provide increased capacity to insert a large number of communication channels. The simulated frequency response characteristic and its dispersion and group delay characteristics are graphically presented using the MATLAB environment.

Flow-cytometric identification of vinegars using a multi-parameter analysis optical detection module

NASA Astrophysics Data System (ADS)

Verschooten, T.; Ottevaere, H.; Vervaeke, M.; Van Erps, J.; Callewaert, M.; De Malsche, W.; Thienpont, H.

2015-09-01

We show a proof-of-concept demonstration of a multi-parameter analysis low-cost optical detection system for the flowcytometric identification of vinegars. This multi-parameter analysis system can simultaneously measure laser induced fluorescence, absorption and scattering excited by two time-multiplexed lasers of different wavelengths. To our knowledge no other polymer optofluidic chip based system offers more simultaneous measurements. The design of the optofluidic channels is aimed at countering the effects that viscous fingering, air bubbles, and emulsion samples can have on the correct operation of such a detection system. Unpredictable variations in viscosity and refractive index of the channel content can be turned into a source of information. The sample is excited by two laser diodes that are driven by custom made low-cost laser drivers. The optofluidic chip is built to be robust and easy to handle and is reproducible using hot embossing. We show a custom optomechanical holder for the optofluidic chip that ensures correct alignment and automatic connection to the external fluidic system. We show an experiment in which 92 samples of vinegar are measured. We are able to identify 9 different kinds of vinegar with an accuracy of 94%. Thus we show an alternative approach to the classic optical spectroscopy solution at a lowered. Furthermore, we have shown the possibility of predicting the viscosity and turbidity of vinegars with a goodness-of-fit R2 over 0.947.

An analysis of haze effects on LANDSAT multispectral scanner data

NASA Technical Reports Server (NTRS)

Johnson, W. R.; Sestak, M. L. (Principal Investigator)

1981-01-01

Early season changes in optical depth change brightness, primarily along the soil line; and during crop development, changes in optical depth change both greenness and brightness. Thus, the existence of haze in the imagery could cause an unsuspecting analyst to interpret the spectral appearance as indicating an episodal event when, in fact, haze was present. The techniques for converting LANDSAT-3 data to simulate LANDSAT-2 data are in error. The yellowness and none such computations are affected primarily. Yellowness appears well correlated to optical depth. Experimental evidence with variable background and variable optical depth is needed, however. The variance of picture elements within a spring wheat field is related to its equivalent in optical depth changes caused by haze. This establishes the sensitivity of channel 1 (greenness) pixels to changes in haze levels. The between field picture element means and variances were determined for the spring wheat fields. This shows the variability of channel data on two specific dates, emphasizing that crop development can be influenced by many factors. The atmospheric correction program ATCOR reduces segment data from LANDSAT acquisitions to a common haze level and improves the results of analysis.

SCSI Communication Test Bus

NASA Technical Reports Server (NTRS)

Hua, Chanh V.; D'Ambrose, John J.; Jaworski, Richard C.; Halula, Elaine M.; Thornton, David N.; Heligman, Robert L.; Turner, Michael R.

1990-01-01

Small Computer System Interface (SCSI) communication test bus provides high-data-rate, standard interconnection enabling communication among International Business Machines (IBM) Personal System/2 Micro Channel, other devices connected to Micro Channel, test equipment, and host computer. Serves primarily as nonintrusive input/output attachment to PS/2 Micro Channel bus, providing rapid communication for debugger. Opens up possibility of using debugger in real-time applications.

Laser figuring for the generation of analog micro-optics and kineform surfaces

NASA Technical Reports Server (NTRS)

Gratrix, Edward J.

1993-01-01

To date, there have been many techniques used to generate micro-optic structures in glass or other materials. Using methods common to the lithographic industry, the manufacturing technique known as 'binary optics,' has demonstrated the use of diffractive optics in a variety of micro-optic applications. It is well established that diffractive structures have limited capability when applied in a design more suited for a refractive element. For applications that demand fast, highly efficient, broadband designs, we have developed a technique which uses laser figuring to generate the refractive micro-optical surface. This paper describes the technique used to fabricate refractive micro-optics. Recent results of micro-optics in CdZnTe focal planes are shown.

Energy efficient rateless codes for high speed data transfer over free space optical channels

NASA Astrophysics Data System (ADS)

Prakash, Geetha; Kulkarni, Muralidhar; Acharya, U. S.

2015-03-01

Terrestrial Free Space Optical (FSO) links transmit information by using the atmosphere (free space) as a medium. In this paper, we have investigated the use of Luby Transform (LT) codes as a means to mitigate the effects of data corruption induced by imperfect channel which usually takes the form of lost or corrupted packets. LT codes, which are a class of Fountain codes, can be used independent of the channel rate and as many code words as required can be generated to recover all the message bits irrespective of the channel performance. Achieving error free high data rates with limited energy resources is possible with FSO systems if error correction codes with minimal overheads on the power can be used. We also employ a combination of Binary Phase Shift Keying (BPSK) with provision for modification of threshold and optimized LT codes with belief propagation for decoding. These techniques provide additional protection even under strong turbulence regimes. Automatic Repeat Request (ARQ) is another method of improving link reliability. Performance of ARQ is limited by the number of retransmissions and the corresponding time delay. We prove through theoretical computations and simulations that LT codes consume less energy per bit. We validate the feasibility of using energy efficient LT codes over ARQ for FSO links to be used in optical wireless sensor networks within the eye safety limits.

Effect of nano-scale morphology on micro-channel wall surface and electrical characterization in lead silicate glass micro-channel plate

NASA Astrophysics Data System (ADS)

Cai, Hua; Li, Fangjun; Xu, Yanglei; Bo, Tiezhu; Zhou, Dongzhan; Lian, Jiao; Li, Qing; Cao, Zhenbo; Xu, Tao; Wang, Caili; Liu, Hui; Li, Guoen; Jia, Jinsheng

2017-10-01

Micro-channel plate (MCP) is a two dimensional arrays of microscopic channel charge particle multiplier. Silicate composition and hydrogen reduction are keys to determine surface morphology of micro-channel wall in MCP. In this paper, lead silicate glass micro-channel plates in two different cesium contents (0at%, 0.5at%) and two different hydrogen reduction temperatures (400°C,450°C) were present. The nano-scale morphology, elements content and chemical states of microporous wall surface treated under different alkaline compositions and reduction conditions was investigated by Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS), respectively. Meanwhile, the electrical characterizations of MCP, including the bulk resistance, electron gain and the density of dark current, were measured in a Vacuum Photoelectron Imaging Test Facility (VPIT).The results indicated that the granular phase occurred on the surface of microporous wall and diffuses in bulk glass is an aggregate of Pb atom derived from the reduction of Pb2+. In micro-channel plate, the electron gain and bulk resistance were mainly correlated to particle size and distribution, the density of dark current (DDC) went up with the increasing root-mean-square roughness (RMS) on the microporous wall surface. Adding cesiums improved the size of Pb atomic aggregation, lowered the relative concentration of [Pb] reduced from Pb2+ and decreased the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a less dark current. Increasing hydrogen reduction temperature also improved the size of Pb atomic aggregation, but enhanced the relative concentration of [Pb] and enlarged the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a larger dark current. The reasons for the difference of electrical characteristics were discussed.

Thermal and hydrodynamic studies for micro-channel cooling for large area silicon sensors in high energy physics experiments

NASA Astrophysics Data System (ADS)

Flaschel, Nils; Ariza, Dario; Díez, Sergio; Gerboles, Marta; Gregor, Ingrid-Maria; Jorda, Xavier; Mas, Roser; Quirion, David; Tackmann, Kerstin; Ullan, Miguel

2017-08-01

Micro-channel cooling initially aiming at small-sized high-power integrated circuits is being transferred to the field of high energy physics. Today's prospects of micro-fabricating silicon opens a door to a more direct cooling of detector modules. The challenge in high energy physics is to save material in the detector construction and to cool large areas. In this paper, we are investigating micro-channel cooling as a candidate for a future cooling system for silicon detectors in a generic research and development approach. The work presented in this paper includes the production and the hydrodynamic and thermal testing of a micro-channel equipped prototype optimized to achieve a homogeneous flow distribution. Furthermore, the device was simulated using finite element methods.

Micro-droplet formation via 3D printed micro channel

NASA Astrophysics Data System (ADS)

Jian, Zhen; Zhang, Jiaming; Li, Erqiang; Thoroddsen, Sigurdur T.

2016-11-01

Low cost, fast-designed and fast-fabricated 3D micro channel was used to create micro-droplets. Capillary with an outer diameter of 1.5 mm and an inner diameter of 150 μm was inserted into a 3D printed cylindrical channel with a diameter of 2 mm . Flow rate of the two inlets, insert depth, liquid (density, viscosity and surface tension) and solid (roughness, contact angle) properties all play a role in the droplet formation. Different regimes - dripping, jetting, unstable state - were observed in the micro-channel on varying these parameters. With certain parameter combinations, successive formation of micro-droplets with equal size was observed and its size can be much smaller than the smallest channel size. Based on our experimental results, the droplet formation via 3D printed micro T-junction was investigated through direct numerical simulations with a code called Gerris. Reynolds numbers Re = ρUL / μ and Weber numbers We = ρU2 L / σ of the two liquids were introduced to measure the liquid effect. The parameter regime where different physical dynamics occur was studied and the regime transition was observed with certain threshold values. Qualitative and quantitative analysis were performed as well between simulations and experiments.

Free-space high data rate communications technologies for near terrestrial space

NASA Astrophysics Data System (ADS)

Edwards, C. L.; Bruzzi, J. R.; Boone, B. G.

2008-08-01

Recent progress at the Applied Physics Laboratory in high data rate communications technology development is described in this paper. System issues for developing and implementing high data rate downlinks from geosynchronous earth orbit to the ground, either for CONUS or in-theater users is considered. Technology is described that supports a viable dual-band multi-channel system concept. Modeling and simulation of micro-electro-mechanical systems (MEMS) beamsteering mirrors has been accomplished to evaluate the potential for this technology to support multi-channel optical links with pointing accuracies approaching 10 microradians. These models were validated experimentally down to levels in which Brownian motion was detected and characterized for single mirror devices only 500 microns across. This multi-channel beamsteering technology can be designed to address environmental compromises to free-space optical links, which derive from turbulence, clouds, as well as spacecraft vibration. Another technology concept is being pursued that is designed to mitigate the adverse effects of weather. It consists of a dual-band (RF/optical) antenna that is optimally designed in both bands simultaneously (e.g., Ku-band and near infrared). This technology would enable optical communications hardware to be seamlessly integrated with existing RF communications hardware on spacecraft platforms, while saving on mass and power, and improving overall system performance. These technology initiatives have been pursued principally because of potential sponsor interest in upgrading existing systems to accommodate quick data recovery and decision support, particularly for the warfighter in future conflicts where the exchange of large data sets such as high resolution imagery would have significant tactical benefits.

Wafer-scale micro-optics fabrication

NASA Astrophysics Data System (ADS)

Voelkel, Reinhard

2012-07-01

Micro-optics is an indispensable key enabling technology for many products and applications today. Probably the most prestigious examples are the diffractive light shaping elements used in high-end DUV lithography steppers. Highly-efficient refractive and diffractive micro-optical elements are used for precise beam and pupil shaping. Micro-optics had a major impact on the reduction of aberrations and diffraction effects in projection lithography, allowing a resolution enhancement from 250 nm to 45 nm within the past decade. Micro-optics also plays a decisive role in medical devices (endoscopes, ophthalmology), in all laser-based devices and fiber communication networks, bringing high-speed internet to our homes. Even our modern smart phones contain a variety of micro-optical elements. For example, LED flash light shaping elements, the secondary camera, ambient light and proximity sensors. Wherever light is involved, micro-optics offers the chance to further miniaturize a device, to improve its performance, or to reduce manufacturing and packaging costs. Wafer-scale micro-optics fabrication is based on technology established by the semiconductor industry. Thousands of components are fabricated in parallel on a wafer. This review paper recapitulates major steps and inventions in wafer-scale micro-optics technology. The state-of-the-art of fabrication, testing and packaging technology is summarized.

Limb Correction of Infrared Imagery in Cloudy Regions for the Improved Interpretation of RGB Composites

NASA Technical Reports Server (NTRS)

Elmer, Nicholas J.; Berndt, Emily; Jedlovec, Gary J.

2016-01-01

Red-Green-Blue (RGB) composites (EUMETSAT User Services 2009) combine information from several channels into a single composite image. RGB composites contain the same information as the original channels, but presents the information in a more efficient manner. However, RGB composites derived from infrared imagery of both polar-orbiting and geostationary sensors are adversely affected by the limb effect, which interferes with the qualitative interpretation of RGB composites at large viewing zenith angles. The limb effect, or limb-cooling, is a result of an increase in optical path length of the absorbing atmosphere as viewing zenith angle increases (Goldberg et al. 2001; Joyce et al. 2001; Liu and Weng 2007). As a result, greater atmospheric absorption occurs at the limb, causing the sensor to observe anomalously cooler brightness temperatures. Figure 1 illustrates this effect. In general, limb-cooling results in a 4-11 K decrease in measured brightness temperature (Liu and Weng 2007) depending on the infrared band. For example, water vapor and ozone absorption channels display much larger limb-cooling than infrared window channels. Consequently, RGB composites created from infrared imagery not corrected for limb effects can only be reliably interpreted close to nadir, which reduces the spatial coverage of the available imagery. Elmer (2015) developed a reliable, operational limb correction technique for clear regions. However, many RGB composites are intended to be used and interpreted in cloudy regions, so a limb correction methodology valid for both clear and cloudy regions is needed. This paper presents a limb correction technique valid for both clear and cloudy regions, which is described in Section 2. Section 3 presents several RGB case studies demonstrating the improved functionality of limb-corrected RGBs in both clear and cloudy regions, and Section 4 summarizes and presents the key conclusions of this work.

The theoretical simulation on electrostatic distribution of 1st proximity region in proximity focusing low-light-level image intensifier

NASA Astrophysics Data System (ADS)

Zhang, Liandong; Bai, Xiaofeng; Song, De; Fu, Shencheng; Li, Ye; Duanmu, Qingduo

2015-03-01

Low-light-level night vision technology is magnifying low light level signal large enough to be seen by naked eye, which uses the photons - photoelectron as information carrier. Until the micro-channel plate was invented, it has been possibility for the realization of high performance and miniaturization of low-light-level night vision device. The device is double-proximity focusing low-light-level image intensifier which places a micro-channel plate close to photocathode and phosphor screen. The advantages of proximity focusing low-light-level night vision are small size, light weight, small power consumption, no distortion, fast response speed, wide dynamic range and so on. It is placed parallel to each other for Micro-channel plate (both sides of it with metal electrode), the photocathode and the phosphor screen are placed parallel to each other. The voltage is applied between photocathode and the input of micro-channel plate when image intensifier works. The emission electron excited by photo on the photocathode move towards to micro-channel plate under the electric field in 1st proximity focusing region, and then it is multiplied through the micro-channel. The movement locus of emission electrons can be calculated and simulated when the distributions of electrostatic field equipotential lines are determined in the 1st proximity focusing region. Furthermore the resolution of image tube can be determined. However the distributions of electrostatic fields and equipotential lines are complex due to a lot of micro-channel existing in the micro channel plate. This paper simulates electrostatic distribution of 1st proximity region in double-proximity focusing low-light-level image intensifier with the finite element simulation analysis software Ansoft maxwell 3D. The electrostatic field distributions of 1st proximity region are compared when the micro-channel plates' pore size, spacing and inclination angle ranged. We believe that the electron beam movement trajectory in 1st proximity region will be better simulated when the electronic electrostatic fields are simulated.

Nano-stepper-driven optical shutter for applications in free-space micro-optics

NASA Astrophysics Data System (ADS)

Zawadzka, Justyna; Li, Lijie; Unamuno, Anartz; Uttamchandani, Deepak G.

2002-09-01

In this paper we report a simple design of a micro-optical shutter/attenuator. The standard MUMPS process was used to fabricate the device. A vertically erected, gold-coated, 200x300 mm side length micro-mirror was precisely placed between the end faces of two closely spaced optical fibers. The position of the micro-mirror with respect to the optical fiber end face was controlled by a nano-stepping motor array. Optical and mechanical tests were performed on the device. A 1.55 mm laser beam was sent along the optical fiber. When the micro-mirror was removed from the front of the fiber, the coupling efficiency between two fibers was -10 dBm. Once the micro-mirror was placed in the optical path the coupling efficiency dropped to -51.5 dBm. The best attenuation was obtained when the micro-mirror blocked the whole cross-section of the laser beam diameter. It is evident that the device can operate as a high precision fiber optic attenuator or shutter.

Three-dimensional holographic optical manipulation through a high-numerical-aperture soft-glass multimode fibre

NASA Astrophysics Data System (ADS)

Leite, Ivo T.; Turtaev, Sergey; Jiang, Xin; Šiler, Martin; Cuschieri, Alfred; Russell, Philip St. J.; Čižmár, Tomáš

2018-01-01

Holographic optical tweezers (HOT) hold great promise for many applications in biophotonics, allowing the creation and measurement of minuscule forces on biomolecules, molecular motors and cells. Geometries used in HOT currently rely on bulk optics, and their exploitation in vivo is compromised by the optically turbid nature of tissues. We present an alternative HOT approach in which multiple three-dimensional (3D) traps are introduced through a high-numerical-aperture multimode optical fibre, thus enabling an equally versatile means of manipulation through channels having cross-section comparable to the size of a single cell. Our work demonstrates real-time manipulation of 3D arrangements of micro-objects, as well as manipulation inside otherwise inaccessible cavities. We show that the traps can be formed over fibre lengths exceeding 100 mm and positioned with nanometric resolution. The results provide the basis for holographic manipulation and other high-numerical-aperture techniques, including advanced microscopy, through single-core-fibre endoscopes deep inside living tissues and other complex environments.

Safe Laser Beam Propagation for Interplanetary Links

NASA Technical Reports Server (NTRS)

Wilson, Keith E.

2011-01-01

Ground-to-space laser uplinks to Earth–orbiting satellites and deep space probes serve both as a beacon and an uplink command channel for deep space probes and Earth-orbiting satellites. An acquisition and tracking point design to support a high bandwidth downlink from a 20-cm optical terminal on an orbiting Mars spacecraft typically calls for 2.5 kW of 1030-nm uplink optical power in 40 micro-radians divergent beams.2 The NOHD (nominal ocular hazard distance) of the 1030nm uplink is in excess of 2E5 km, approximately half the distance to the moon. Recognizing the possible threat of high power laser uplinks to the flying public and to sensitive Earth-orbiting satellites, JPL developed a three-tiered system at its Optical Communications Telescope Laboratory (OCTL) to ensure safe laser beam propagation through navigational and near-Earth space.

Micro-endoscopy of the human vas deferens: a feasibility study of a novel device in several ex vivo models.

PubMed

Trottmann, M; Sroka, R; Braun, C; Liedl, B; Schaaf, H; Graw, M; Becker, A J; Stief, C G; Khoder, W Y

2017-01-01

The aim of this study was to show limitation as well as potential of micro-endoscopy techniques as an innovative diagnostic and therapeutic approach in andrology. Two kinds of custom-made micro-endoscopes (ME) were tested in ex vivo vas deferens specimen and in post-mortem whole body. The semi-rigid ME included a micro-optic (0.9 mm outer diameter [OD], 10.000 pixels, 120° vision angle [VE], 3-20 mm field depth [FD]) and an integrated fibre-optic light source. The flexible ME was composed of a micro-optic (OD = 0.6 mm, 6.000 pixels, 120° VE, 3-20 mm FD). The ex vivo study included retrograde investigation of the vas deferens (surgical specimen n = 9, radical prostatectomy n = 3). The post-mortem investigation (n = 4) included the inspection of the vas deferens via both approaches. The results showed that antegrade and retrograde rigid endoscopy of the vas deferens were achieved as a diagnostic tool. The working channel enabled therapeutic use including biopsies or baskets. Using the flexible ME, the orifices of the ejaculatory ducts were identified. In vivo cadaveric retrograde cannulation of the orifices was successful. Post-mortem changes of verumontanum hindered the examinations beyond. Orifices were identified shaded behind a thin transparent membrane. Antegrade vasoscopy using flexible ME was possible up to the internal inguinal ring. Further advancement was impossible because of anatomical angle and lack adequate vision guidance. The vas deferens interior was clearly visible and was documented by pictures and movies. Altogether, the described ME techniques were feasible and effective, offering the potential of innovative diagnostic and therapeutic approaches for use in the genital tract. Several innovative indications could be expected. © 2016 American Society of Andrology and European Academy of Andrology.

Micro benchtop optics by bulk silicon micromachining

DOEpatents

Lee, Abraham P.; Pocha, Michael D.; McConaghy, Charles F.; Deri, Robert J.

2000-01-01

Micromachining of bulk silicon utilizing the parallel etching characteristics of bulk silicon and integrating the parallel etch planes of silicon with silicon wafer bonding and impurity doping, enables the fabrication of on-chip optics with in situ aligned etched grooves for optical fibers, micro-lenses, photodiodes, and laser diodes. Other optical components that can be microfabricated and integrated include semi-transparent beam splitters, micro-optical scanners, pinholes, optical gratings, micro-optical filters, etc. Micromachining of bulk silicon utilizing the parallel etching characteristics thereof can be utilized to develop miniaturization of bio-instrumentation such as wavelength monitoring by fluorescence spectrometers, and other miniaturized optical systems such as Fabry-Perot interferometry for filtering of wavelengths, tunable cavity lasers, micro-holography modules, and wavelength splitters for optical communication systems.

Electroosmotically Driven Liquid Flows in Complex Micro-Geometries

NASA Astrophysics Data System (ADS)

Dutta, Prashanta; Warburton, Timothy C.; Beskok, Ali

1999-11-01

Electroosmotically driven flows in micro-channels are analyzed analytically and numerically by using a high-order h/p type spectral element simulation suite, Nektar. The high-resolution characteristic of the spectral element method enables us to resolve the sharp electric double layers with successive p-type mesh refinements. For electric double layers that are much smaller than the channel height, the Helmholtz Smoluchowski velocity is used to develop semi-analytical relations for the velocity and the pressure distributions in micro channels. Analytical relations for wall shear stress and pressure distributions are also obtained. These relations show amplification of the normal and shear stresses on the micro-channel walls. Finally, flow through a step-channel is analyzed to document the interaction of the electroosmotic forces with the adverse pressure gradients. Depending on the direction and the magnitude of the electroosmotic force, enhancement or elimination of the separation bubble is observed. These findings can be used to develop innovative strategies for flow control with no moving components and for promotion of mixing in micro-scale geometries.

Comparison of heat transfer coefficients of open micro-channels and plain micro-fins

NASA Astrophysics Data System (ADS)

Kaniowski, Robert; Pastuszko, Robert

2018-06-01

The paper describes results of analysis of pool boiling heat transfer on enhanced surfaces. Two types of structural surfaces were used: open microchannel surfaces consisting of a system of parallel micro-channels 0.3 mm wide, from 0.2 to 0.5 mm deep and with a pitch of 0.6 mm, and plain micro-fins 0.5 mm in height, uniformly spaced on the base surface with a spacing from 0.6 to1.5 mm. Pool boiling data at atmospheric pressure were obtained for saturated water, ethanol and FC-72. The effects of micro-channel/micro-fin dimensions on heat transfer coefficient in nucleate pool boiling were examined. Substantial enhancement of heat transfer coefficient was observed.

Multimode entanglement assisted QKD through a free-space maritime channel

NASA Astrophysics Data System (ADS)

Gariano, John; Djordjevic, Ivan B.

2017-10-01

When using quantum key distribution (QKD), one of the trade-offs for security is that the generation rate of a secret key is typically very low. Recent works have shown that using a weak coherent source allows for higher secret key generation rates compared to an entangled photon source, when a channel with low loss is considered. In most cases, the system that is being studied is over a fiber-optic communication channel. Here a theoretical QKD system using the BB92 protocol and entangled photons over a free-space maritime channel with multiple spatial modes is presented. The entangled photons are generated from a spontaneous parametric down conversion (SPDC) source of type II. To employ multiple spatial modes, the transmit apparatus will contain multiple SPDC sources, all driven by the pump lasers assumed to have the same intensity. The receive apparatuses will contain avalanche photo diodes (APD), modeled based on the NuCrypt CPDS-1000 detector, and located at the focal point of the receive aperture lens. The transmitter is assumed to be located at Alice and Bob will be located 30 km away, implying no channel crosstalk will be introduced in the measurements at Alice's side due to turbulence. To help mitigate the effects of atmospheric turbulence, adaptive optics will be considered at the transmitter and the receiver. An eavesdropper, Eve, is located 15 km from Alice and has no control over the devices at Alice or Bob. Eve is performing the intercept resend attack and listening to the communication over the public channel. Additionally, it is assumed that Eve can correct any aberrations caused by the atmospheric turbulence to determine which source the photon was transmitted from. One, four and nine spatial modes are considered with and without applying adaptive optics and compared to one another.

Calibration of the High Energy Replicated Optics to Explore the Sun (HEROES) Hard X-ray Telescope

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.; Gaskin, Jessica; Christe, Steven; Shih, Albert; Tennant, Allyn; Swartz, Doug; Kilaru, Kiranmayee; Elsner, Ron; Kolodziejczak, Jeff; Ramsey, Brian

2014-01-01

On September 21-22, 2013, the High Energy Replicated Optics to Explore the Sun (HEROES) hard X-ray telescope, flew as a balloon payload from Ft. Sumner, N.M. HEROES observed the Sun, the black hole binary GRS 1915+105, and the Crab Nebula during its 27 hour flight. In this paper we describe laboratory calibration measurements of the HEROES detectors using line and continuum sources, applications of these measurements to define channel to energy (gain) corrections for observed events and to define detector response matrices. We characterize the HEROES X-ray grazing incidence optics using measurements taken in the Stray-Light (SLF) Facility in Huntsville, AL, and using ray traces.

Performance analysis of optical wireless communication system based on two-fold turbo code

NASA Astrophysics Data System (ADS)

Chen, Jun; Huang, Dexiu; Yuan, Xiuhua

2005-11-01

Optical wireless communication (OWC) is beginning to emerge in the telecommunications market as a strategy to meet last-mile demand owing to its unique combination of features. Turbo codes have an impressive near Shannon-limit error correcting performance. Twofold turbo codes have been recently introduced as the least complex member of the multifold turbo code family. In this paper, at first, we present the mathematical model of signal and optical wireless channel with fading and bit error rate model with scintillation, then we provide a new turbo code method to use in OWC system, we can obtain a better BER curse of OWC system with twofold turbo code than with common turbo code.

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, Raoul; Tan, Weihong; Shi, Zhong-You

1997-01-01

This invention relates generally to the development of and a method of fabricating a fiber optic micro-light source and sensor (50). An optical fiber micro-light source (50) is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors (22) in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material (60). This process allows significant control of the size of the micro light source (50). Furthermore, photo-chemically attaching an optically active material (60) enables the implementation of the micro-light source in a variety of sensor applications.

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, Raoul; Tan, Weihong; Shi, Zhong-You

1994-01-01

This invention relates generally to the development of and a method of fabricating a micro optical fiber light source. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications.

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, R.; Tan, W.; Shi, Z.Y.

1997-05-06

This invention relates generally to the development of and a method of fabricating a fiber optic micro-light source and sensor. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications. 10 figs.

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, R.; Tan, W.; Shi, Z.Y.

1994-11-01

This invention relates generally to the development of and a method of fabricating a micro optical fiber light source. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications. 4 figs.

Wafer-level micro-optics: trends in manufacturing, testing, packaging, and applications

NASA Astrophysics Data System (ADS)

Voelkel, Reinhard; Gong, Li; Rieck, Juergen; Zheng, Alan

2012-11-01

Micro-optics is an indispensable key enabling technology (KET) for many products and applications today. Probably the most prestigious examples are the diffractive light shaping elements used in high-end DUV lithography steppers. Highly efficient refractive and diffractive micro-optical elements are used for precise beam and pupil shaping. Micro-optics had a major impact on the reduction of aberrations and diffraction effects in projection lithography, allowing a resolution enhancement from 250 nm to 45 nm within the last decade. Micro-optics also plays a decisive role in medical devices (endoscopes, ophthalmology), in all laser-based devices and fiber communication networks (supercomputer, ROADM), bringing high-speed internet to our homes (FTTH). Even our modern smart phones contain a variety of micro-optical elements. For example, LED flashlight shaping elements, the secondary camera, and ambient light and proximity sensors. Wherever light is involved, micro-optics offers the chance to further miniaturize a device, to improve its performance, or to reduce manufacturing and packaging costs. Wafer-scale micro-optics fabrication is based on technology established by semiconductor industry. Thousands of components are fabricated in parallel on a wafer. We report on the state of the art in wafer-based manufacturing, testing, packaging and present examples and applications for micro-optical components and systems.

Development of a standardized differential-reflective bioassay for microbial pathogens

NASA Astrophysics Data System (ADS)

Wilhelm, Jay; Auld, J. R. X.; Smith, James E.

2008-04-01

This research examines standardizing a method for the rapid/semi-automated identification of microbial contaminates. It introduces a method suited to test for food/water contamination, serology, urinalysis and saliva testing for any >1 micron sized molecule that can be effectively bound to an identifying marker with exclusivity. This optical biosensor method seeks to integrate the semi-manual distribution of a collected sample onto a "transparent" substrate array of binding sites that will then be applied to a standard optical data disk and run for analysis. The detection of most microbe species is possible in this platform because the relative scale is greater than the resolution of the standard-scale digital information on a standard CD or DVD. This paper explains the critical first stage in the advance of this detection concept. This work has concentrated on developing the necessary software component needed to perform highly sensitive small-scale recognition using the standard optical disk as a detection platform. Physical testing has made significant progress in demonstrating the ability to utilize a standard optical drive for the purposes of micro-scale detection through the exploitation of CIRC error correction. Testing has also shown a definable trend in the optimum scale and geometry of micro-arrayed attachment sites for the technology's concept to reach achievement.

Magnetic Tethering of Microswimmers in Microfluidic Devices

NASA Astrophysics Data System (ADS)

Chawan, Aschvin; Jana, Saikat; Ghosh, Suvojit; Jung, Sunghwan; Puri, Ishwar

2013-03-01

Exercising control over animal locomotion is well known in the macro world. In the micro-scale world, such methods require more sophistication. We magnetize Paramecium multimicronucleatum by internalization of magnetite nanoparticles coated with bovine serum albumin (BSA). This enables control of their motion in a microfluidic device using a magnetic field. Miniature permanent magnets embedded within the device are used to tether the magnetized organisms to specific locations along a micro-channel. Ciliary beatings of the microswimmer generate shear flows nearby. We apply this setup to enhance cross-stream mixing in a microfluidic device by supplementing molecular diffusion. The device is similar to an active micromixer but requires no external power sources or artificial actuators. We optically characterize the effectiveness of the mechanism in a variety of flow situations.

A multiscale method for modeling high-aspect-ratio micro/nano flows

NASA Astrophysics Data System (ADS)

Lockerby, Duncan; Borg, Matthew; Reese, Jason

2012-11-01

In this paper we present a new multiscale scheme for simulating micro/nano flows of high aspect ratio in the flow direction, e.g. within long ducts, tubes, or channels, of varying section. The scheme consists of applying a simple hydrodynamic description over the entire domain, and allocating micro sub-domains in very small ``slices'' of the channel. Every micro element is a molecular dynamics simulation (or other appropriate model, e.g., a direct simulation Monte Carlo method for micro-channel gas flows) over the local height of the channel/tube. The number of micro elements as well as their streamwise position is chosen to resolve the geometrical features of the macro channel. While there is no direct communication between individual micro elements, coupling occurs via an iterative imposition of mass and momentum-flux conservation on the macro scale. The greater the streamwise scale of the geometry, the more significant is the computational speed-up when compared to a full MD simulation. We test our new multiscale method on the case of a converging/diverging nanochannel conveying a simple Lennard-Jones liquid. We validate the results from our simulations by comparing them to a full MD simulation of the same test case. Supported by EPSRC Programme Grant, EP/I011927/1.

LDPC-PPM Coding Scheme for Optical Communication

NASA Technical Reports Server (NTRS)

Barsoum, Maged; Moision, Bruce; Divsalar, Dariush; Fitz, Michael

2009-01-01

In a proposed coding-and-modulation/demodulation-and-decoding scheme for a free-space optical communication system, an error-correcting code of the low-density parity-check (LDPC) type would be concatenated with a modulation code that consists of a mapping of bits to pulse-position-modulation (PPM) symbols. Hence, the scheme is denoted LDPC-PPM. This scheme could be considered a competitor of a related prior scheme in which an outer convolutional error-correcting code is concatenated with an interleaving operation, a bit-accumulation operation, and a PPM inner code. Both the prior and present schemes can be characterized as serially concatenated pulse-position modulation (SCPPM) coding schemes. Figure 1 represents a free-space optical communication system based on either the present LDPC-PPM scheme or the prior SCPPM scheme. At the transmitting terminal, the original data (u) are processed by an encoder into blocks of bits (a), and the encoded data are mapped to PPM of an optical signal (c). For the purpose of design and analysis, the optical channel in which the PPM signal propagates is modeled as a Poisson point process. At the receiving terminal, the arriving optical signal (y) is demodulated to obtain an estimate (a^) of the coded data, which is then processed by a decoder to obtain an estimate (u^) of the original data.

3D MOEMS-based optical micro-bench platform for the miniaturization of sensing devices

NASA Astrophysics Data System (ADS)

Garcia-Blanco, Sonia; Caron, Jean-Sol; Leclair, Sébastien; Topart, Patrice A.; Jerominek, Hubert

2008-02-01

As we enter into the 21st century, the need for miniaturized portable diagnostic devices is increasing continuously. Portable devices find important applications for point-of-care diagnostics, patient self-monitoring and in remote areas, such as unpopulated regions where the cost of large laboratory facilities is not justifiable, underdeveloped countries and other remote locations such as space missions. The advantage of miniaturized sensing optical systems includes not only the reduced weight and size but also reduced cost, decreased time to results and robustness (e.g. no need for frequent re-alignments). Recent advances in micro-fabrication and assembly technologies have enabled important developments in the field of miniaturized sensing systems. INO has developed a technology platform for the three dimensional integration of MOEMS on an optical microbench. Building blocks of the platform include microlenses, micromirrors, dichroic beamsplitters, filters and optical fibers, which can be positioned using passive alignment structures to build the desired miniaturised system. The technology involves standard microfabrication, thick resist UV-lithography, thick metal electroplating, soldering, replication in sol-gel materials and flip-chip bonding processes. The technology is compatible with wafer-to-wafer bonding. A placement accuracy of +/- 5 μm has been demonstrated thanks to the integration of alignment marks co registered with other optical elements fabricated on different wafers. In this paper, the building blocks of the technology will be detailed. The design and fabrication of a 5x5 channels light processing unit including optical fibers, mirrors and collimating microlenses will be described. Application of the technology to various kinds of sensing devices will be discussed.

Micro-optics technology and sensor systems applications

NASA Technical Reports Server (NTRS)

Gal, George; Herman, B.; Anderson, W.; Whitney, R.; Morrow, H.

1993-01-01

The current generation of electro-optical sensors utilizing refractive and reflective optical elements require sophisticated, complex, and expensive designs. Advanced-technology-based electro-optical sensors of minimum size and weight require miniaturization of optical, electrical, and mechanical devices with an increasing trend toward integration of various components. Micro-optics technology has the potential in a number of areas to simplify optical design with improved performance. This includes internally cooled apertures, hybrid optical design, microlenses, dispersive multicolor microlenses, active dither, electronically controlled optical beam steer, and microscopic integration of micro-optics, detectors, and signal processing layers. This paper describes our approach to the development of micro-optics technology with our main emphasis for sensors applications.

Physically secured orthogonal frequency division multiplexing-passive optical network employing noise-based encryption and signal recovery process

NASA Astrophysics Data System (ADS)

Jin, Wei; Zhang, Chongfu; Yuan, Weicheng

2016-02-01

We propose a physically enhanced secure scheme for direct detection-orthogonal frequency division multiplexing-passive optical network (DD-OFDM-PON) and long reach coherent detection-orthogonal frequency division multiplexing-passive optical network (LRCO-OFDM-PON), by employing noise-based encryption and channel/phase estimation. The noise data generated by chaos mapping are used to substitute training sequences in preamble to realize channel estimation and frame synchronization, and also to be embedded on variable number of key-selected randomly spaced pilot subcarriers to implement phase estimation. Consequently, the information used for signal recovery is totally hidden as unpredictable noise information in OFDM frames to mask useful information and to prevent illegal users from correctly realizing OFDM demodulation, and thereby enhancing resistance to attackers. The levels of illegal-decryption complexity and implementation complexity are theoretically discussed. Through extensive simulations, the performances of the proposed channel/phase estimation and the security introduced by encrypted pilot carriers have been investigated in both DD-OFDM and LRCO-OFDM systems. In addition, in the proposed secure DD-OFDM/LRCO-OFDM PON models, both legal and illegal receiving scenarios have been considered. These results show that, by utilizing the proposed scheme, the resistance to attackers can be significantly enhanced in DD-OFDM-PON and LRCO-OFDM-PON systems without performance degradations.

A full-duplex optical access system with hybrid 64/16/4QAM-OFDM downlink

NASA Astrophysics Data System (ADS)

He, Chao; Tan, Ze-fu; Shao, Yu-feng; Cai, Li; Pu, He-sheng; Zhu, Yun-le; Huang, Si-si; Liu, Yu

2016-09-01

A full-duplex optical passive access scheme is proposed and verified by simulation, in which hybrid 64/16/4-quadrature amplitude modulation (64/16/4QAM) orthogonal frequency division multiplexing (OFDM) optical signal is for downstream transmission and non-return-to-zero (NRZ) optical signal is for upstream transmission. In view of the transmitting and receiving process for downlink optical signal, in-phase/quadrature-phase (I/Q) modulation based on Mach-Zehnder modulator (MZM) and homodyne coherent detection technology are employed, respectively. The simulation results show that the bit error ratio ( BER) less than hardware decision forward error correction (HD-FEC) threshold is successfully obtained over transmission path with 20-km-long standard single mode fiber (SSMF) for hybrid downlink modulation OFDM optical signal. In addition, by dividing the system bandwidth into several subchannels consisting of some continuous subcarriers, it is convenient for users to select different channels depending on requirements of communication.

On-Chip Photothermal Analyte Detection Using Integrated Luminescent Temperature Sensors.

PubMed

Pfeiffer, Simon A; Nagl, Stefan

2017-09-05

Optical absorbance detection based on attenuated light transmission is limited in sensitivity due to short path lengths in microfluidic and other miniaturized platforms. An alternative is detection using the photothermal effect. Herein we introduce a new kind of photothermal absorbance measurement using integrated luminescent temperature sensor spots inside microfluidic channels. The temperature sensors were photopolymerized inside the channels from NOA 81 UV-curable thiolene prepolymer doped with a tris(1,10-phenanthroline)ruthenium(II) temperature probe. The polymerized sensing structures were as small as 26 ± 3 μm in diameter and displayed a temperature resolution of better than 0.3 K between 20 and 50 °C. The absorbance from 532 nm laser excitation of the food dye Amaranth as a model analyte was quantified using these spots, and the influence of the flow rate, laser power, and concentration was investigated. Calibration yielded a linear relationship between analyte concentration and the temperature signal in the channels. The limit of detection for the azo-dye Amaranth (E123) in this setup was 13 μM. A minimal detectable absorbance of 3.2 × 10 -3 AU was obtained using an optical path length of 125 μm in this initial study. A microreactor with integrated temperature sensors was then employed for an absorbance-based miniaturized nitrite analysis, yielding a detection limit of 26 μM at a total assay time of only 75 s. This technique is very promising for sensitive, and potentially spatially resolved, optical absorbance detection on the micro- and nanoscale.

Free-space optical communications using orbital-angular-momentum multiplexing combined with MIMO-based spatial multiplexing.

PubMed

Ren, Yongxiong; Wang, Zhe; Xie, Guodong; Li, Long; Cao, Yinwen; Liu, Cong; Liao, Peicheng; Yan, Yan; Ahmed, Nisar; Zhao, Zhe; Willner, Asher; Ashrafi, Nima; Ashrafi, Solyman; Linquist, Roger D; Bock, Robert; Tur, Moshe; Molisch, Andreas F; Willner, Alan E

2015-09-15

We explore the potential of combining the advantages of multiple-input multiple-output (MIMO)-based spatial multiplexing with those of orbital angular momentum (OAM) multiplexing to increase the capacity of free-space optical (FSO) communications. We experimentally demonstrate an 80 Gbit/s FSO system with a 2×2 aperture architecture, in which each transmitter aperture contains two multiplexed data-carrying OAM modes. Inter-channel crosstalk effects are minimized by the OAM beams' inherent orthogonality and by the use of 4×4 MIMO signal processing. Our experimental results show that the bit-error rates can reach below the forward error correction limit of 3.8×10(-3) and the power penalties are less than 3.6 dB for all channels after MIMO processing. This indicates that OAM and MIMO-based spatial multiplexing could be simultaneously utilized, thereby providing the potential to enhance system performance.

Flow-through micro-capillary refractive index sensor based on T/R spectral shift monitoring.

PubMed

Rigamonti, Giulia; Guardamagna, Marco; Bello, Valentina; Marconi, Stefania; Auricchio, Ferdinando; Merlo, Sabina

2017-10-01

We present a flow-through refractive index sensor for measuring the concentration of glucose solutions based on the application of rectangular glass micro-capillaries, with channel depth of 50 µm and 30 µm. A custom designed and 3D printed polymeric shell protects the tiny capillaries, ensuring an easier handling and interconnection with the macro-fluidic path. By illuminating the capillary with broadband radiation centered at λ~1.55 µm, both the transmitted (T) and reflected (R) optical spectrum from the capillary are detected with an optical spectrum analyzer, exploiting an all-fiber setup. Monitoring the spectral shift of the ratio T/R in response to increasing concentration of glucose solutions in water we have obtained sensitivities up to 530.9 nm/RIU and limit of detection in the range of 10 -5 -10 -4 RIU. Experimental results are in agreement with the theoretically predicted principle of operation. After the demonstration of amplitude detection at a single wavelength, we finally discuss the impact of the capillary parameters on the sensitivity.

CCD imaging system for the EUV solar telescope

NASA Astrophysics Data System (ADS)

Gong, Yan; Song, Qian; Ye, Bing-Xun

2006-01-01

In order to develop the detector adapted to the space solar telescope, we have built a CCD camera system capable of working in the extra ultraviolet (EUV) band, which is composed of one phosphor screen, one intensified system using a photocathode/micro-channel plate(MCP)/ phosphor, one optical taper and one chip of front-illuminated (FI) CCD without screen windows. All of them were stuck one by one with optical glue. The working principle of the camera system is presented; moreover we have employed the mesh experiment to calibrate and test the CCD camera system in 15~24nm, the position resolution of about 19 μm is obtained at the wavelength of 17.1nm and 19.5nm.

Parallel multipoint recording of aligned and cultured neurons on corresponding Micro Channel Array toward on-chip cell analysis.

PubMed

Tonomura, W; Moriguchi, H; Jimbo, Y; Konishi, S

2008-01-01

This paper describes an advanced Micro Channel Array (MCA) so as to record neuronal network at multiple points simultaneously. Developed MCA is designed for neuronal network analysis which has been studied by co-authors using MEA (Micro Electrode Arrays) system. The MCA employs the principle of the extracellular recording. Presented MCA has the following advantages. First of all, the electrodes integrated around individual micro channels are electrically isolated for parallel multipoint recording. Sucking and clamping of cells through micro channels is expected to improve the cellular selectivity and S/N ratio. In this study, hippocampal neurons were cultured on the developed MCA. As a result, the spontaneous and evoked spike potential could be recorded by sucking and clamping the cells at multiple points. Herein, we describe the successful experimental results together with the design and fabrication of the advanced MCA toward on-chip analysis of neuronal network.

Two-Phase Flow in High-Heat-Flux Micro-Channel Heat Sink for Refrigeration Cooling Applications. Part 2: Low Temperature Hybrid Micro-Channel/Micro-Jet Impingement Cooling

DTIC Science & Technology

2008-09-01

TWO-PHASE FLOW IN HIGH-HEAT-FLUX MICRO-CHANNEL HEAT SINK FOR REFRIGERATION COOLING APPLICATIONS (Contract No. N00014-05-1-0408) by Issam Mudawar ...Refrigeration Cooling Applications 5b. GRANT NUMBER N00014-04-1-0408 5c. PROGRAM ELEMENT NUMBER NA 6. AUTHOR(S) 5d. PROJECT NUMBER Mudawar , Issam NA...ABSTRACT OF Mudawar , Issam PAGES U U U UU 465 19b. TELEPHONE NUMBER (Include area code) 765-494-5705 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std

Multi-angle lensless digital holography for depth resolved imaging on a chip.

PubMed

Su, Ting-Wei; Isikman, Serhan O; Bishara, Waheb; Tseng, Derek; Erlinger, Anthony; Ozcan, Aydogan

2010-04-26

A multi-angle lensfree holographic imaging platform that can accurately characterize both the axial and lateral positions of cells located within multi-layered micro-channels is introduced. In this platform, lensfree digital holograms of the micro-objects on the chip are recorded at different illumination angles using partially coherent illumination. These digital holograms start to shift laterally on the sensor plane as the illumination angle of the source is tilted. Since the exact amount of this lateral shift of each object hologram can be calculated with an accuracy that beats the diffraction limit of light, the height of each cell from the substrate can be determined over a large field of view without the use of any lenses. We demonstrate the proof of concept of this multi-angle lensless imaging platform by using light emitting diodes to characterize various sized microparticles located on a chip with sub-micron axial and lateral localization over approximately 60 mm(2) field of view. Furthermore, we successfully apply this lensless imaging approach to simultaneously characterize blood samples located at multi-layered micro-channels in terms of the counts, individual thicknesses and the volumes of the cells at each layer. Because this platform does not require any lenses, lasers or other bulky optical/mechanical components, it provides a compact and high-throughput alternative to conventional approaches for cytometry and diagnostics applications involving lab on a chip systems.

Interplay between topological phase and self-acceleration in a vortex symmetric Airy beam.

PubMed

Fang, Zhao-Xiang; Chen, Yue; Ren, Yu-Xuan; Gong, Lei; Lu, Rong-De; Zhang, An-Qi; Zhao, Hong-Ze; Wang, Pei

2018-03-19

Photons in an optical vortex usually carry orbital angular momentum, which boosts the application of the micro-rotation of absorbing particles and quantum information encoding. Such photons propagate along a straight line in free space or follow a curved trace once guided by an optical fiber. Teleportation of an optical vortex using a beam with non-diffraction and self-healing is quite challenging. We demonstrate the manipulation of the propagation trace of an optical vortex with a symmetric Airy beam (SAB) and found that the SAB experiences self-rotation with the implementation of a topological phase structure of coaxial vortex. Slight misalignment of the vortex and the SAB enables the guiding of the vortex into one of the self-accelerating channels. Multiple off-axis vortices embedded in SAB are also demonstrated to follow the trajectory of the major lobe for the SAB beam. The Poynting vector for the beams proves the direction of the energy flow corresponding to the intensity distribution. Hence, we anticipate that the proposed vortex symmetric Airy beam (VSAB) will provide new possibilities for optical manipulation and optical communication.

INSAT-3D: an advanced meteorological mission over Indian Ocean

NASA Astrophysics Data System (ADS)

Katti, V. R.; Pratap, V. R.; Dave, R. K.; Mankad, K. N.

2006-12-01

This paper presents the salient features of INSAT 3D mission and its Met Payloads. INSAT-3D, the next ISRO meteorological satellite aims for a significant technological improvement in sensor capabilities as compared to earlier INSAT missions. It is an exclusive mission designed for enhanced meteorological observations and monitoring of land and ocean surfaces for weather forecasting and disaster warning. The three-axis stabilized geostationary satellite is to carry two meteorological instruments: a six channel Imager and an IR Sounder. Along with the channels in Visible, Middle Infrared, Water Vapor and Thermal Infrared bands, the Imager includes a SWIR channel for wider applications. The Sounder will have eighteen narrow spectral channels in three IR bands in addition to a channel in visible band. INSAT-3D is configured around standard 2000 kg I2K spacecraft bus with 7-year life. Several innovative technologies like on-the-fly correction of scan mirror pointing errors, biannual yaw rotation of the spacecraft, micro-stepping SADA, star sensors and integrated bus management unit have been incorporated to meet the stringent payload requirements like pointing accuracies, thermal management of IR detectors and concurrent operation of both instruments.

PDT dose dosimetry for Photofrin-mediated pleural photodynamic therapy (pPDT)

NASA Astrophysics Data System (ADS)

Ong, Yi Hong; Kim, Michele M.; Finlay, Jarod C.; Dimofte, Andreea; Singhal, Sunil; Glatstein, Eli; Cengel, Keith A.; Zhu, Timothy C.

2018-01-01

Photosensitizer fluorescence excited by photodynamic therapy (PDT) treatment light can be used to monitor the in vivo concentration of the photosensitizer and its photobleaching. The temporal integral of the product of in vivo photosensitizer concentration and light fluence is called PDT dose, which is an important dosimetry quantity for PDT. However, the detected photosensitizer fluorescence may be distorted by variations in the absorption and scattering of both excitation and fluorescence light in tissue. Therefore, correction of the measured fluorescence for distortion due to variable optical properties is required for absolute quantification of photosensitizer concentration. In this study, we have developed a four-channel PDT dose dosimetry system to simultaneously acquire light dosimetry and photosensitizer fluorescence data. We measured PDT dose at four sites in the pleural cavity during pleural PDT. We have determined an empirical optical property correction function using Monte Carlo simulations of fluorescence for a range of physiologically relevant tissue optical properties. Parameters of the optical property correction function for Photofrin fluorescence were determined experimentally using tissue-simulating phantoms. In vivo measurements of photosensitizer fluorescence showed negligible photobleaching of Photofrin during the PDT treatment, but large intra- and inter-patient heterogeneities of in vivo Photofrin concentration are observed. PDT doses delivered to 22 sites in the pleural cavity of 8 patients were different by 2.9 times intra-patient and 8.3 times inter-patient.

Correction of large amplitude wavefront aberrations

NASA Astrophysics Data System (ADS)

Cornelissen, S. A.; Bierden, P. A.; Bifano, T. G.; Webb, R. H.; Burns, S.; Pappas, S.

2005-12-01

Recently, a number of research groups around the world have developed ophthalmic instruments capable of in vivo diffraction limited imaging of the human retina. Adaptive optics was used in these systems to compensate for the optical aberrations of the eye and provide high contrast, high resolution images. Such compensation uses a wavefront sensor and a wavefront corrector (usually a deformable mirror) coordinated in a closed- loop control system that continuously works to counteract aberrations. While those experiments produced promising results, the deformable mirrors have had insufficient range of motion to permit full correction of the large amplitude aberrations of the eye expected in a normal population of human subjects. Other retinal imaging systems developed to date with MEMS (micro-electromechanical systems) DMs suffer similar limitations. This paper describes the design, manufacture and testing of a 6um stroke polysilicon surface micromachined deformable mirror that, coupled with an new optical method to double the effective stroke of the MEMS-DM, will permit diffraction-limited retinal imaging through dilated pupils in at least 90% of the human population. A novel optical design using spherical mirrors provides a double pass of the wavefront over the deformable mirror such that a 6um mirror displacement results in 12um of wavefront compensation which could correct for 24um of wavefront error. Details of this design are discussed. Testing of the effective wavefront modification was performed using a commercial wavefront sensor. Results are presented demonstrating improvement in the amplitude of wavefront control using an existing high degree of freedom MEMS deformable mirror.

Power Considerations for Micro-Autonomous Systems

DTIC Science & Technology

2012-07-30

PV cell APPROVED FOR PUBLIC RELEASE 15 Micro-Thermo- Photovoltaics POC: Ivan Celanovic low- power MPPT micro channel Silicon MEMs reactor Ill...max power density 150 W/kg (3000 mW, 500 sec) APPROVED FOR PUBLIC RELEASE 29 Micro-Thermo- Photovoltaics low- power MPPT micro channel Silicon MEMs...Secondary used as a Primary *Contour  4g (220Whr/kg, 750W/kg), 15g (400 Whr/kg, 1000W/kg) *Sion Power ??? •Lithium-Sulfur: promising rechargeable

Modeling Microscale Electro-thermally Induced Vortex Flows

NASA Astrophysics Data System (ADS)

Paul, Rajorshi; Tang, Tian; Kumar, Aloke

2017-11-01

In presence of a high frequency alternating electric field and a laser induced heat source, vortex flows are generated inside micro-channels. Such electro-thermally influenced micro-vortices can be used for manipulating nano-particles, programming colloidal assemblies, trapping biological cells as well as for fabricating designed bacterial biofilms. In this study, a theoretical model is developed for microscale electro-thermally induced vortex flows with multiple heat sources. Semi-analytical solutions are obtained, using Hankel transformation and linear superposition, for the temperature, pressure and velocity fields. The effect of material properties such as electrical and thermal conductivities, as well as experimental parameters such as the frequency and strength of the alternating electric field, and the intensity and heating profile of the laser source, are systematically investigated. Resolution for a pair of laser sources is determined by analyzing the strength of the micro-vortices under the influence of two heating sources. Results from this work will provide useful insights into the design of efficient optical tweezers and Rapid Electrokinetic Patterning techniques.

Electrokinetically driven active micro-mixers utilizing zeta potential variation induced by field effect

NASA Astrophysics Data System (ADS)

Lee, Chia-Yen; Lee, Gwo-Bin; Fu, Lung-Ming; Lee, Kuo-Hoong; Yang, Ruey-Jen

2004-10-01

This paper presents a new electrokinetically driven active micro-mixer which uses localized capacitance effects to induce zeta potential variations along the surface of silica-based microchannels. The mixer is fabricated by etching bulk flow and shielding electrode channels into glass substrates and then depositing Au/Cr thin films within the latter to form capacitor electrodes, which establish localized zeta potential variations near the electrical double layer (EDL) region of the electroosmotic flow (EOF) within the microchannels. The potential variations induce flow velocity changes within a homogeneous fluid and a rapid mixing effect if an alternating electric field is provided. The current experimental data confirm that the fluid velocity can be actively controlled by using the capacitance effect of the buried shielding electrodes to vary the zeta potential along the channel walls. While compared with commonly used planar electrodes across the microchannels, the buried shielding electrodes prevent current leakage caused by bad bonding and allow direct optical observation during operation. It also shows that the buried shielding electrodes can significantly induce the field effect, resulting in higher variations of zeta potential. Computational fluid dynamic simulations are also used to study the fluid characteristics of the developed active mixers. The numerical and experimental results demonstrate that the developed microfluidic device permits a high degree of control over the fluid flow and an efficient mixing effect. Moreover, the developed device could be used as a pumping device as well. The development of the active electrokinetically driven micro-mixer could be crucial for micro-total-analysis-systems.

Domain imaging in ferroelectric thin films via channeling-contrast backscattered electron microscopy

DOE PAGES

Ihlefeld, Jon F.; Michael, Joseph R.; McKenzie, Bonnie B.; ...

2016-09-16

We report that ferroelastic domain walls provide opportunities for deterministically controlling mechanical, optical, electrical, and thermal energy. Domain wall characterization in micro- and nanoscale systems, where their spacing may be of the order of 100 nm or less is presently limited to only a few techniques, such as piezoresponse force microscopy and transmission electron microscopy. These respective techniques cannot, however, independently characterize domain polarization orientation and domain wall motion in technologically relevant capacitor structures or in a non-destructive manner, thus presenting a limitation of their utility. In this work, we show how backscatter scanning electron microscopy utilizing channeling contrast yieldmore » can image the ferroelastic domain structure of ferroelectric films with domain wall spacing as narrow as 10 nm.« less

Flexible micro-OCT endobronchial probe for imaging of mucociliary transport (Conference Presentation)

NASA Astrophysics Data System (ADS)

Cui, Dongyao; Chu, Kengyeh K.; Unglert, Carolin I.; Ford, Tim N.; Carruth, Robert W.; Hyun, Daryl; Singh, Kanwarpal; Birket, Susan E.; Solomon, George M.; Rowe, Steve M.; Tearney, Guillermo J.

2016-03-01

Mucociliary clearance (MCC) plays a significant role in maintaining the health of human respiratory system by eliminating foreign particles trapped within mucus. Failure of this mechanism in diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD) leads to airway blockage and lung infection, causing morbidity and mortality. The volume of airway mucus and the periciliary liquid encapsulating the cilia, in addition to ciliary beat frequency and velocity of mucociliary transport, are vital parameters of airway health. However, the diagnosis of disease pathogenesis and advances of novel therapeutics are hindered by the lack of tools for visualization of ciliary function in vivo. Our laboratory has previously developed a 1-µm resolution optical coherence tomography method, termed Micro-OCT, which is capable of visualizing mucociliary transport and quantitatively capturing epithelial functional metrics. We have also miniaturized Micro-OCT optics in a first-generation rigid 4mm Micro-OCT endoscope utilizing a common-path design and an apodizing prism configuration to produce an annular profile sample beam, and reported the first in vivo visualization of mucociliary transport in swine. We now demonstrate a flexible 2.5 mm Micro-OCT probe that can be inserted through the instrument channel of standard flexible bronchoscopes, allowing bronchoscopic navigation to smaller airways and greatly improving clinical utility. Longitudinal scanning over a field of view of more than 400 µm at a frame rate of 40 Hz was accomplished with a driveshaft transduced by a piezo-electric stack motor. We present characterization and imaging results from the flexible micro-OCT probe and progress towards clinical translation. The ability of the bronchoscope-compatible micro-OCT probe to image mucus clearance and epithelial function will enable studies of cystic fibrosis pathogenesis in small airways, provide diagnosis of mucociliary clearance disorders, and allow individual responses to treatments to be monitored.

Spreading of a ferrofluid core in three-stream micromixer channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhaomeng; Varma, V. B.; Ramanujan, R. V., E-mail: ramanujan@ntu.edu.sg

2015-05-15

Spreading of a water based ferrofluid core, cladded by a diamagnetic fluid, in three-stream micromixer channels was studied. This spreading, induced by an external magnetic field, is known as magnetofluidic spreading (MFS). MFS is useful for various novel applications where control of fluid-fluid interface is desired, such as micromixers or micro-chemical reactors. However, fundamental aspects of MFS are still unclear, and a model without correction factors is lacking. Hence, in this work, both experimental and numerical analyses were undertaken to study MFS. We show that MFS increased for higher applied magnetic fields, slower flow speed of both fluids, smaller flowmore » rate of ferrofluid relative to cladding, and higher initial magnetic particle concentration. Spreading, mainly due to connective diffusion, was observed mostly near the channel walls. Our multi-physics model, which combines magnetic and fluidic analyses, showed, for the first time, excellent agreement between theory and experiment. These results can be useful for lab-on-a-chip devices.« less

Spreading of a ferrofluid core in three-stream micromixer channels

NASA Astrophysics Data System (ADS)

Wang, Zhaomeng; Varma, V. B.; Xia, Huan Ming; Wang, Z. P.; Ramanujan, R. V.

2015-05-01

Spreading of a water based ferrofluid core, cladded by a diamagnetic fluid, in three-stream micromixer channels was studied. This spreading, induced by an external magnetic field, is known as magnetofluidic spreading (MFS). MFS is useful for various novel applications where control of fluid-fluid interface is desired, such as micromixers or micro-chemical reactors. However, fundamental aspects of MFS are still unclear, and a model without correction factors is lacking. Hence, in this work, both experimental and numerical analyses were undertaken to study MFS. We show that MFS increased for higher applied magnetic fields, slower flow speed of both fluids, smaller flow rate of ferrofluid relative to cladding, and higher initial magnetic particle concentration. Spreading, mainly due to connective diffusion, was observed mostly near the channel walls. Our multi-physics model, which combines magnetic and fluidic analyses, showed, for the first time, excellent agreement between theory and experiment. These results can be useful for lab-on-a-chip devices.

Deep Proton Writing for the rapid prototyping of polymer micro-components for optical interconnects and optofluidics

NASA Astrophysics Data System (ADS)

Van Erps, Jürgen; Vervaeke, Michael; Ottevaere, Heidi; Hermanne, Alex; Thienpont, Hugo

2013-07-01

The use of photonics in data communication and numerous other industrial applications brought plenty of prospects for innovation and opened up different unexplored market opportunities. This is a major driving force for the fabrication of micro-optical and micro-mechanical structures and their accurate alignment and integration into opto-mechanical modules and systems. To this end, we present Deep Proton Writing (DPW) as a powerful rapid prototyping technology for such micro-components. The DPW process consists of bombarding polymer samples (PMMA or SU-8) with swift protons, which results after chemical processing steps in high-quality micro-optical components. One of the strengths of the DPW micro-fabrication technology is the ability to fabricate monolithic building blocks that include micro-optical and mechanical functionalities which can be precisely integrated into more complex photonic systems. In this paper we comment on how we shifted from using 8.3 to 16.5 MeV protons for DPW and give some examples of micro-optical and micro-mechanical components recently fabricated through DPW, targeting applications in optical interconnections and in optofluidics.

Potential Scientific Output from the Visible Channels of EPIC Spectroradiometer as Part of the DSCOVR L1 Mission

NASA Technical Reports Server (NTRS)

Marshak, Alexander; Herman, Jay

2011-01-01

In addition to 4 UV channels, the EPIC spectroradiometer will provide measurements at 6 visible (and near IR) channels (443,551,680,687.75, 764 and 779.9 nm) at roughly 10 km spatial resolution. The scattering angles are near backscattering and vary between 165 and 176 degree. Two pairs {680 and 687.75 nm} and {764 and 779.9 nm} represent 02 B- and A-bands (and their references) channels; they will be used for cloud height measurements over land and ocean. The B-band channel will contribute to the more absorbing A-band measurements over bright vegetation. A pair {680 and 779.9 nm} will be used for retrieving vegetation properties. Due to the special EPIC geometry, the illuminated part of the leaves will be always observed. As a result, in additional to the traditional Leaf Area Index (LAI), these observations for the first time will provide the sunlit fraction of LAI. Since the sunlit and shaded leaves exhibit different photosynthetic response to incident radiation, these measurements will help to improve global ecological and biogeochemistry models. Finally, a pair {443 and 551 nm} will be used for atmospheric correction. As a by-product of the atmospheric correction algorithm, we also expect to get aerosol optical thickness (AOT) and surface bidirectional reflection function (BRF). The presentation will briefly overview the proposed science algorithms.

Performance of an untethered micro-optical pressure sensor

NASA Astrophysics Data System (ADS)

Ioppolo, Tindaro; Manzo, Maurizio; Krueger, Paul

2012-11-01

We present analytical and computational studies of the performance of a novel untethered micro-optical pressure sensor for fluid dynamics measurements. In particular, resolution and dynamic range will be presented. The sensor concept is based on the whispering galley mode (WGM) shifts that are observed in micro-scale dielectric optical cavities. A micro-spherical optical cavity (liquid or solid) is embedded in a thin polymeric sheet. The applied external pressure perturbs the morphology of the optical cavity leading to a shift in its optical resonances. The optical sensors are interrogated remotely, by embedding quantum dots or fluorescent dye in the micro-optical cavity. This allows a free space coupling of excitation and monitoring of the optical modes without the need of optical fibers or other cabling. With appropriate excitation and monitoring equipment, the micro-scale sensors can be distributed over a surface (e.g., including flexible biological surfaces) to monitor the local pressure field. We acknowledge the financial support from the National Science Foundation through grant CBET-1133876 with Dr. Horst Henning Winter as the program director.

Incorporation of sodium channel blocking and free radical scavenging activities into a single drug, AM-36, results in profound inhibition of neuronal apoptosis.

PubMed

Callaway, J K; Beart, P M; Jarrott, B; Giardina, S F

2001-04-01

AM-36 is a novel neuroprotective agent incorporating both antioxidant and Na(+) channel blocking actions. In cerebral ischaemia, loss of cellular ion homeostasis due to Na(+) channel activation, together with increased reactive oxygen species (ROS) production, are thought to contribute to neuronal death. Since neuronal death in the penumbra of the ischaemic lesion is suggested to occur by apoptosis, we investigated the ability of AM-36, antioxidants and Na(+) channel antagonists to inhibit toxicity induced by the neurotoxin, veratridine in cultured cerebellar granule cells (CGC's). Veratridine (10 - 300 microM) concentration-dependently reduced cell viability of cultured CGC's. Under the experimental conditions employed, cell death induced by veratridine (100 microM) possessed the characteristics of apoptosis as assessed by morphology, TUNEL staining and DNA laddering on agarose gels. Neurotoxicity and apoptosis induced by veratridine (100 microM) were inhibited to a maximum of 50% by the antioxidants, U74500A (0.1 - 10 microM) and U83836E (0.03 - 10 microM), and to a maximum of 30% by the Na(+) channel blocker, dibucaine (0.1 - 100 microM). In contrast, AM-36 (0.01 - 10 microM) completely inhibited veratridine-induced toxicity ( IC(50) 1.7 (1.5 - 1.9) microM, 95% confidence intervals (CI) in parentheses) and concentration-dependently inhibited apoptosis. These findings suggest veratridine-induced toxicity and apoptosis are partially mediated by generation of ROS. AM-36, which combines both Na(+) channel blocking and antioxidant activity, provided superior neuroprotection compared with agents possessing only one of these actions. This bifunctional profile of activity may underlie the potent neuroprotective effects of AM-36 recently found in a stroke model in conscious rats.

Anisotropic Janus Si nanopillar arrays as a microfluidic one-way valve for gas-liquid separation

NASA Astrophysics Data System (ADS)

Wang, Tieqiang; Chen, Hongxu; Liu, Kun; Li, Yang; Xue, Peihong; Yu, Ye; Wang, Shuli; Zhang, Junhu; Kumacheva, Eugenia; Yang, Bai

2014-03-01

In this paper, we demonstrate a facile strategy for the fabrication of a one-way valve for microfluidic (MF) systems. The micro-valve was fabricated by embedding arrays of Janus Si elliptical pillars (Si-EPAs) with anisotropic wettability into a MF channel fabricated in poly(dimethylsiloxane) (PDMS). Two sides of the Janus pillar are functionalized with molecules with distinct surface energies. The ability of the Janus pillar array to act as a valve was proved by investigating the flow behaviour of water in a T-shaped microchannel at different flow rates and pressures. In addition, the one-way valve was used to achieve gas-liquid separation. We believe that the Janus Si-EPAs modified by specific surface functionalization provide a new strategy to control the flow and motion of fluids in MF channels.In this paper, we demonstrate a facile strategy for the fabrication of a one-way valve for microfluidic (MF) systems. The micro-valve was fabricated by embedding arrays of Janus Si elliptical pillars (Si-EPAs) with anisotropic wettability into a MF channel fabricated in poly(dimethylsiloxane) (PDMS). Two sides of the Janus pillar are functionalized with molecules with distinct surface energies. The ability of the Janus pillar array to act as a valve was proved by investigating the flow behaviour of water in a T-shaped microchannel at different flow rates and pressures. In addition, the one-way valve was used to achieve gas-liquid separation. We believe that the Janus Si-EPAs modified by specific surface functionalization provide a new strategy to control the flow and motion of fluids in MF channels. Electronic supplementary information (ESI) available: The XPS spectrum of the as-prepared Janus arrays after the MHA modification; the SEM images of the PFS-MHA Janus Si pillar arrays fabricated through oblique evaporation of gold along the short axis of the elliptical pillars; images of the cross-shaped MF channel and Rhodamine aqueous solution injecting in a cross-shaped MF channel taken at different times; the plot data of DPFS/DMHA against the flow rate of the aqueous solution; the plot data of failure pressure against the bottom size of the channel; optical microscopy images of the Janus pillar array with less density of pillars; optical microscopy images of the T junction with higher magnification; the video of Rhodamine solution running in the T-shaped microchannel integrated with the Janus Si-EPAs; the video of the entire gas-liquid separation process. See DOI: 10.1039/c3nr05865d

Linearisation of λDNA molecules by instantaneous variation of the trapping electrode voltage inside a micro-channel

NASA Astrophysics Data System (ADS)

Hanasaki, Itsuo; Yukimoto, Naoya; Uehara, Satoshi; Shintaku, Hirofumi; Kawano, Satoyuki

2015-04-01

Because long DNA molecules usually exist in random coil states due to the entropic effect, linearisation is required for devices equipped with nanopores where electrical sequencing is necessary during single-file translocation. We present a novel technique for linearising DNA molecules in a micro-channel. In our device, electrodes are embedded in the bottom surface of the channel. The application of a voltage induces the trapping of λDNA molecules on the positive electrode. An instantaneous voltage drop is used to put the λDNA molecules in a partly released state and the hydrodynamic force of the solution induces linearisation. Phenomena were directly observed using an optical microscopy system equipped with a high-speed camera and the linearisation principle was explored in detail. Furthermore, we estimate the tensile characteristics produced by the flow of the solution through a numerical model of a tethered polymer subject to a Poiseuille flow. The mean tensile force is in the range of 0.1-1 pN. This is sufficiently smaller than the structural transition point of λDNA but counterbalances the entropic elasticity that causes the random coil shape of λDNA molecules in solution. We show the important role of thermal fluctuation in the manipulation of molecules in solution and clarify the tensile conditions required for DNA linearisation using a combination of solution flow and voltage variation in a microchannel.

Ocean Observations with EOS/MODIS: Algorithm Development and Post Launch Studies

NASA Technical Reports Server (NTRS)

Gordon, Howard R.

1997-01-01

The following accomplishments were made during the present reporting period: (1) We expanded our new method, for identifying the presence of absorbing aerosols and simultaneously performing atmospheric correction, to the point where it could be added as a subroutine to the MODIS water-leaving radiance algorithm; (2) We successfully acquired micro pulse lidar (MPL) data at sea during a cruise in February; (3) We developed a water-leaving radiance algorithm module for an approximate correction of the MODIS instrument polarization sensitivity; and (4) We participated in one cruise to the Gulf of Maine, a well known region for mesoscale coccolithophore blooms. We measured coccolithophore abundance, production and optical properties.

Novel optical interconnect devices applying mask-transfer self-written method

NASA Astrophysics Data System (ADS)

Ishizawa, Nobuhiko; Matsuzawa, Yusuke; Tokiwa, Yu; Nakama, Kenichi; Mikami, Osamu

2012-01-01

The introduction of optical interconnect technology is expected to solve problems of conventional electric wiring. One of the promising technologies realizing optical interconnect is the self-written waveguide (SWW) technology with lightcurable resin. We have developed a new technology of the "Mask-Transfer Self-Written (MTSW)" method. This new method enables fabrication of arrayed M x N optical channels at one shot of UV-light. Using this technology, several new optical interconnect devices and connection technologies have been proposed and investigated. In this paper, first, we introduce MTSW method briefly. Next, we show plug-in alignment approach using optical waveguide plugs (OWP) and a micro-hole array (MHA) which are made of the light-curable resin. Easy and high efficiency plug-in alignment between fibers and an optoelectronic-printed wiring board (OE-PWB), between a fiber and a VCSEL, so on will be feasible. Then, we propose a new three-dimensional (3D) branch waveguide. By controlling the irradiating angle through the photomask aperture, it will be possible to fabricate 2-branch and 4-branch waveguides with a certain branch angle. The 3D branch waveguide will be very promising in the future optical interconnects and coupler devices of the multicore optical fiber.

High-speed real-time OFDM transmission based on FPGA

NASA Astrophysics Data System (ADS)

Xiao, Xin; Li, Fan; Yu, Jianjun

2016-02-01

In this paper, we review our recent research progresses on real-time orthogonal frequency division multiplexing (OFDM) transmission based on FPGA. We successfully demonstrated four-channel wavelength-division multiplexing (WDM) 256.51Gb/s 16-ary quadrature amplitude modulation (16QAM)-OFDM signal transmission system for short-reach optical amplifier free inter-connection with real-time reception. Four optical carriers are modulated by four different 16QAM-OFDM signals via 10G-class direct modulation lasers (DMLs). We achieved highest capacity real-time reception optical OFDM signal transmission over 2.4-km SMF with the bit-error ratio (BER) under soft-decision forward error correction (SD-FEC) limitation of 2.4×10-2. In order to achieve higher spectrum efficiency (SE), we demonstrate 4-channel high level QAM-OFDM transmission over 20-km SMF-28 with real-time reception. 58.72-Gb/s 256QAM-OFDM and 56.4-Gb/s 128QAM-OFDM signal transmission within 25-GHz grid is achieved with the BER under 2.4×10-2 and real-time reception.

Rapid prototyping of 2D glass microfluidic devices based on femtosecond laser assisted selective etching process

NASA Astrophysics Data System (ADS)

Kim, Sung-Il; Kim, Jeongtae; Koo, Chiwan; Joung, Yeun-Ho; Choi, Jiyeon

2018-02-01

Microfluidics technology which deals with small liquid samples and reagents within micro-scale channels has been widely applied in various aspects of biological, chemical, and life-scientific research. For fabricating microfluidic devices, a silicon-based polymer, PDMS (Polydimethylsiloxane), is widely used in soft lithography, but it has several drawbacks for microfluidic applications. Glass has many advantages over PDMS due to its excellent optical, chemical, and mechanical properties. However, difficulties in fabrication of glass microfluidic devices that requires multiple skilled steps such as MEMS technology taking several hours to days, impedes broad application of glass based devices. Here, we demonstrate a rapid and optical prototyping of a glass microfluidic device by using femtosecond laser assisted selective etching (LASE) and femtosecond laser welding. A microfluidic droplet generator was fabricated as a demonstration of a microfluidic device using our proposed prototyping. The fabrication time of a single glass chip containing few centimeter long and complex-shaped microfluidic channels was drastically reduced in an hour with the proposed laser based rapid and simple glass micromachining and hermetic packaging technique.

Micro-optics for microfluidic analytical applications.

PubMed

Yang, Hui; Gijs, Martin A M

2018-02-19

This critical review summarizes the developments in the integration of micro-optical elements with microfluidic platforms for facilitating detection and automation of bio-analytical applications. Micro-optical elements, made by a variety of microfabrication techniques, advantageously contribute to the performance of an analytical system, especially when the latter has microfluidic features. Indeed the easy integration of optical control and detection modules with microfluidic technology helps to bridge the gap between the macroscopic world and chip-based analysis, paving the way for automated and high-throughput applications. In our review, we start the discussion with an introduction of microfluidic systems and micro-optical components, as well as aspects of their integration. We continue with a detailed description of different microfluidic and micro-optics technologies and their applications, with an emphasis on the realization of optical waveguides and microlenses. The review continues with specific sections highlighting the advantages of integrated micro-optical components in microfluidic systems for tackling a variety of analytical problems, like cytometry, nucleic acid and protein detection, cell biology, and chemical analysis applications.

Transient Flow Dynamics in Optical Micro Well Involving Gas Bubbles

NASA Technical Reports Server (NTRS)

Johnson, B.; Chen, C. P.; Jenkins, A.; Spearing, S.; Monaco, L. A.; Steele, A.; Flores, G.

2006-01-01

The Lab-On-a-Chip Application Development (LOCAD) team at NASA s Marshall Space Flight Center is utilizing Lab-On-a-Chip to support technology development specifically for Space Exploration. In this paper, we investigate the transient two-phase flow patterns in an optic well configuration with an entrapped bubble through numerical simulation. Specifically, the filling processes of a liquid inside an expanded chamber that has bubbles entrapped. Due to the back flow created by channel expansion, the entrapped bubbles tend to stay stationary at the immediate downstream of the expansion. Due to the huge difference between the gas and liquid densities, mass conservation issues associated with numerical diffusion need to be specially addressed. The results are presented in terms of the movement of the bubble through the optic well. Bubble removal strategies are developed that involve only pressure gradients across the optic well. Results show that for the bubble to be moved through the well, pressure pulsations must be utilized in order to create pressure gradients across the bubble itself.

Local heterogeneities in early batches of EBT2 film: a suggested solution.

PubMed

Kairn, T; Aland, T; Kenny, J

2010-08-07

To enhance the utility of radiochromic films for high-resolution dosimetry of small and modulated radiotherapy fields, we propose a means to negate the effects of heterogeneities in EBT2 (and other) films. The results of using our simple procedure for evaluating radiation dose in EBT2 film are compared with the results of using the manufacturer's recommended procedure as well as a procedure previously established for evaluating dose in older EBT film. It is shown that Newton's ring-like scanning artefacts can be avoided through the use of a plastic frame, to elevate the film above the scanner's surface. The effects of film heterogeneity can be minimized by evaluating net optical density, pixelwise, as the logarithm of the ratio of the red-channel pixel value in each pixel of each irradiated film to the red-channel pixel value in the same pixel in the same film prior to irradiation. The application of a blue-channel correction was found to result in increased noise. It is recommended that, when using EBT2 film for radiotherapy quality assurance, the films should be scanned before and after irradiation and analysed using the method proposed herein, without the use of the blue-channel correction, in order to produce dose images with minimal film heterogeneity effects.

Wirelessly powered micro-tracer enabled by miniaturized antenna and microfluidic channel

NASA Astrophysics Data System (ADS)

Duan, G.; Zhao, X.; Seren, H. R.; Chen, C.; Zhang, X.

2015-12-01

A miniaturized antenna, 380μm by 380μm in size, was fabricated and integrated with a commercialized passive RFID chip to form a micro-tracer, whose size was 2mm by 1mm in total. The micro-tracer was wirelessly powered and interrogated by a single layer spiral reader antenna through near field coupling. To maximize the working distance, the resonant frequency of micro-tracer and reader antenna were matched at 840MHz. Due to the ultra small size of the tracer antenna, power transfer efficiency decreased dramatically as the distance between tracer antenna and reader antenna increased, thus the working distance of the microtracer was limited within 1mm. To achieve massive operation of the micro-tracer, a microfluidic platform was fabricated with in channel focusing and separation. Acrylic sheets were laser cut to define the channel and cover structure, then bonded together layer by layer with a glass substrate, on which reader antenna was integrated. Pump oil was used as the fluidic media carrying the micro-tracer flowing inside the microfluidic channel. The wireless power transfer and real-time communication was demonstrated with the micro-tracer flowing above the reader antenna, as the ID of the micro-tracer was retrieved and displayed on a computer screen.

Design of micro-ring optical sensors and circuits for integration on optical printed circuit boards (O-PCBs)

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, Hyun S.; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

2007-05-01

We report on the design of micro-ring resonator optical sensors for integration on what we call optical printed circuit boards (O-PCBs). The objective is to realize application-specific O-PCBs, either on hard board or on flexible board, by integrating micro/nano-scale optical sensors for compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly processing of information. The O-PCBs consist of two-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing and then storing, transporting, processing, switching, routing and distributing optical signals that have been collected by means of sensors. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate sensors and other micro/ nano-scale photonic devices. Here, in our study, we focus on the sensors based on the micro-ring structures. We designed bio-sensors using silicon based micro-ring resonator. We investigate the characteristics such as sensitivity and selectivity (or quality factor) of micro-ring resonator for their use in bio-sensing application. We performed simulation studies on the quality factor of micro-ring resonators by varying the radius of the ring resonators and the separation between adjacent waveguides. We introduce the effective coupling coefficient as a realistic value to describe the strength of the coupling in micro-ring resonators.

Uncertainty of Passive Imager Cloud Optical Property Retrievals to Instrument Radiometry and Model Assumptions: Examples from MODIS

NASA Technical Reports Server (NTRS)

Platnick, Steven; Wind, Galina; Meyer, Kerry; Amarasinghe, Nandana; Arnold, G. Thomas; Zhang, Zhibo; King, Michael D.

2013-01-01

The optical and microphysical structure of clouds is of fundamental importance for understanding a variety of cloud radiation and precipitation processes. With the advent of MODIS on the NASA EOS Terra and Aqua platforms, simultaneous global-daily 1 km retrievals of cloud optical thickness (COT) and effective particle radius (CER) are provided, as well as the derived water path (WP). The cloud product (MOD06/MYD06 for MODIS Terra and Aqua, respectively) provides separate retrieval datasets for various two-channel retrievals, typically a VISNIR channel paired with a 1.6, 2.1, and 3.7 m spectral channel. The MOD06 forward model is derived from on a homogeneous plane-parallel cloud. In Collection 5 processing (completed in 2007 with a modified Collection 5.1 completed in 2010), pixel-level retrieval uncertainties were calculated for the following non-3-D error sources: radiometry, surface spectral albedo, and atmospheric corrections associated with model analysis uncertainties (water vapor only). The latter error source includes error correlation across the retrieval spectral channels. Estimates of uncertainty in 1 aggregated (Level-3) means were also provided assuming unity correlation between error sources for all pixels in a grid for a single day, and zero correlation of error sources from one day to the next. I n Collection 6 (expected to begin in late summer 2013) we expanded the uncertainty analysis to include: (a) scene-dependent calibration uncertainty that depends on new band and detector-specific Level 1B uncertainties, (b) new model error sources derived from the look-up tables which includes sensitivities associated with wind direction over the ocean and uncertainties in liquid water and ice effective variance, (c) thermal emission uncertainties in the 3.7 m band associated with cloud and surface temperatures that are needed to extract reflected solar radiation from the total radiance signal, (d) uncertainty in the solar spectral irradiance at 3.7 m, and (e) addition of stratospheric ozone uncertainty in visible atmospheric corrections. A summary of the approach and example Collection 6 results will be shown.

How flatbed scanners upset accurate film dosimetry

NASA Astrophysics Data System (ADS)

van Battum, L. J.; Huizenga, H.; Verdaasdonk, R. M.; Heukelom, S.

2016-01-01

Film is an excellent dosimeter for verification of dose distributions due to its high spatial resolution. Irradiated film can be digitized with low-cost, transmission, flatbed scanners. However, a disadvantage is their lateral scan effect (LSE): a scanner readout change over its lateral scan axis. Although anisotropic light scattering was presented as the origin of the LSE, this paper presents an alternative cause. Hereto, LSE for two flatbed scanners (Epson 1680 Expression Pro and Epson 10000XL), and Gafchromic film (EBT, EBT2, EBT3) was investigated, focused on three effects: cross talk, optical path length and polarization. Cross talk was examined using triangular sheets of various optical densities. The optical path length effect was studied using absorptive and reflective neutral density filters with well-defined optical characteristics (OD range 0.2-2.0). Linear polarizer sheets were used to investigate light polarization on the CCD signal in absence and presence of (un)irradiated Gafchromic film. Film dose values ranged between 0.2 to 9 Gy, i.e. an optical density range between 0.25 to 1.1. Measurements were performed in the scanner’s transmission mode, with red-green-blue channels. LSE was found to depend on scanner construction and film type. Its magnitude depends on dose: for 9 Gy increasing up to 14% at maximum lateral position. Cross talk was only significant in high contrast regions, up to 2% for very small fields. The optical path length effect introduced by film on the scanner causes 3% for pixels in the extreme lateral position. Light polarization due to film and the scanner’s optical mirror system is the main contributor, different in magnitude for the red, green and blue channel. We concluded that any Gafchromic EBT type film scanned with a flatbed scanner will face these optical effects. Accurate dosimetry requires correction of LSE, therefore, determination of the LSE per color channel and dose delivered to the film.

Analytical Modelling of a Refractive Index Sensor Based on an Intrinsic Micro Fabry-Perot Interferometer

PubMed Central

Vargas-Rodriguez, Everardo; Guzman-Chavez, Ana D.; Cano-Contreras, Martin; Gallegos-Arellano, Eloisa; Jauregui-Vazquez, Daniel; Hernández-García, Juan C.; Estudillo-Ayala, Julian M.; Rojas-Laguna, Roberto

2015-01-01

In this work a refractive index sensor based on a combination of the non-dispersive sensing (NDS) and the Tunable Laser Spectroscopy (TLS) principles is presented. Here, in order to have one reference and one measurement channel a single-beam dual-path configuration is used for implementing the NDS principle. These channels are monitored with a couple of identical optical detectors which are correlated to calculate the overall sensor response, called here the depth of modulation. It is shown that this is useful to minimize drifting errors due to source power variations. Furthermore, a comprehensive analysis of a refractive index sensing setup, based on an intrinsic micro Fabry-Perot Interferometer (FPI) is described. Here, the changes over the FPI pattern as the exit refractive index is varied are analytically modelled by using the characteristic matrix method. Additionally, our simulated results are supported by experimental measurements which are also provided. Finally it is shown that by using this principle a simple refractive index sensor with a resolution in the order of 2.15 × 10−4 RIU can be implemented by using a couple of standard and low cost photodetectors. PMID:26501277

Analytical modelling of a refractive index sensor based on an intrinsic micro Fabry-Perot interferometer.

PubMed

Vargas-Rodriguez, Everardo; Guzman-Chavez, Ana D; Cano-Contreras, Martin; Gallegos-Arellano, Eloisa; Jauregui-Vazquez, Daniel; Hernández-García, Juan C; Estudillo-Ayala, Julian M; Rojas-Laguna, Roberto

2015-10-15

In this work a refractive index sensor based on a combination of the non-dispersive sensing (NDS) and the Tunable Laser Spectroscopy (TLS) principles is presented. Here, in order to have one reference and one measurement channel a single-beam dual-path configuration is used for implementing the NDS principle. These channels are monitored with a couple of identical optical detectors which are correlated to calculate the overall sensor response, called here the depth of modulation. It is shown that this is useful to minimize drifting errors due to source power variations. Furthermore, a comprehensive analysis of a refractive index sensing setup, based on an intrinsic micro Fabry-Perot Interferometer (FPI) is described. Here, the changes over the FPI pattern as the exit refractive index is varied are analytically modelled by using the characteristic matrix method. Additionally, our simulated results are supported by experimental measurements which are also provided. Finally it is shown that by using this principle a simple refractive index sensor with a resolution in the order of 2.15 × 10(-4) RIU can be implemented by using a couple of standard and low cost photodetectors.

Algorithms and uncertainties for the determination of multispectral irradiance components and aerosol optical depth from a shipborne rotating shadowband radiometer

NASA Astrophysics Data System (ADS)

Witthuhn, Jonas; Deneke, Hartwig; Macke, Andreas; Bernhard, Germar

2017-03-01

The 19-channel rotating shadowband radiometer GUVis-3511 built by Biospherical Instruments provides automated shipborne measurements of the direct, diffuse and global spectral irradiance components without a requirement for platform stabilization. Several direct sun products, including spectral direct beam transmittance, aerosol optical depth, Ångström exponent and precipitable water, can be derived from these observations. The individual steps of the data analysis are described, and the different sources of uncertainty are discussed. The total uncertainty of the observed direct beam transmittances is estimated to be about 4 % for most channels within a 95 % confidence interval for shipborne operation. The calibration is identified as the dominating contribution to the total uncertainty. A comparison of direct beam transmittance with those obtained from a Cimel sunphotometer at a land site and a manually operated Microtops II sunphotometer on a ship is presented. Measurements deviate by less than 3 and 4 % on land and on ship, respectively, for most channels and in agreement with our previous uncertainty estimate. These numbers demonstrate that the instrument is well suited for shipborne operation, and the applied methods for motion correction work accurately. Based on spectral direct beam transmittance, aerosol optical depth can be retrieved with an uncertainty of 0.02 for all channels within a 95 % confidence interval. The different methods to account for Rayleigh scattering and gas absorption in our scheme and in the Aerosol Robotic Network processing for Cimel sunphotometers lead to minor deviations. Relying on the cross calibration of the 940 nm water vapor channel with the Cimel sunphotometer, the column amount of precipitable water can be estimated with an uncertainty of ±0.034 cm.

Impact of large field angles on the requirements for deformable mirror in imaging satellites

NASA Astrophysics Data System (ADS)

Kim, Jae Jun; Mueller, Mark; Martinez, Ty; Agrawal, Brij

2018-04-01

For certain imaging satellite missions, a large aperture with wide field-of-view is needed. In order to achieve diffraction limited performance, the mirror surface Root Mean Square (RMS) error has to be less than 0.05 waves. In the case of visible light, it has to be less than 30 nm. This requirement is difficult to meet as the large aperture will need to be segmented in order to fit inside a launch vehicle shroud. To reduce this requirement and to compensate for the residual wavefront error, Micro-Electro-Mechanical System (MEMS) deformable mirrors can be considered in the aft optics of the optical system. MEMS deformable mirrors are affordable and consume low power, but are small in size. Due to the major reduction in pupil size for the deformable mirror, the effective field angle is magnified by the diameter ratio of the primary and deformable mirror. For wide field of view imaging, the required deformable mirror correction is field angle dependant, impacting the required parameters of a deformable mirror such as size, number of actuators, and actuator stroke. In this paper, a representative telescope and deformable mirror system model is developed and the deformable mirror correction is simulated to study the impact of the large field angles in correcting a wavefront error using a deformable mirror in the aft optics.

Anaesthetic modulation of nicotinic ion channel kinetics in bovine chromaffin cells.

PubMed Central

Charlesworth, P; Richards, C D

1995-01-01

1. We have investigated the action of the anaesthetics methoxyflurane, methohexitone and etomidate on the nicotinic acetylcholine receptor channel of bovine adrenal chromaffin cells using the whole cell patch clamp technique. 2. Spectral analysis of macroscopic currents evoked by 25 microM carbachol revealed that each of the agents tested reduced the lifetime of the channel open state in a dose-dependent manner. The whole cell current was inhibited in a concentration-dependent fashion by each agent. 3. Channel gating parameters were calculated from single channel studies and the results used to test models explaining the modulation of nicotinic acetylcholine receptor channels by anaesthetics. 4. Each of the agents studied reduced the mean channel open time in a concentration-dependent manner. Anaesthetic concentrations reducing mean open time by 50% were: 370 microM methoxyflurane, 30 microM methohexitone or 23 microM etomidate. 5. Methohexitone and etomidate produced an increase in the number of brief closures within bursts, while no such increase was observed with methoxyflurane. Despite these inter-burst gaps, mean burst length was reduced by each of the agents tested. 6. It is concluded that a simple sequential blocking model fails to account for the action of these anaesthetics. An extended model, in which blocked channels can close, may be applicable. PMID:7773553

Spacecraft Applications of Compact Optical and Mass Spectrometers

NASA Technical Reports Server (NTRS)

Davinic, N. M.; Nagel, D. J.

1995-01-01

Optical spectrometers, and mass spectrometers to a lesser extent, have a long and rich history of use aboard spacecraft. Space mission applications include deep space science spacecraft, earth orbiting satellites, atmospheric probes, and surface landers, rovers, and penetrators. The large size of capable instruments limited their use to large, expensive spacecraft. Because of the novel application of micro-fabrication technologies, compact optical and mass spectrometers are now available. The new compact devices are especially attractive for spacecraft because of their small mass and volume, as well as their low power consumption. Dispersive optical multi-channel analyzers which cover the 0.4-1.1 micrometer wavelength are now commercially available in packages as small as 3 x 6 x 18 mm exclusive of drive and recording electronics. Mass spectrometers as small as 3 x 3 mm, again without electronics, are under development. A variety of compact optical and mass spectrometers are reviewed in this paper. A number of past space applications are described, along with some upcoming opportunities that are likely candidate missions to fly this new class of compact spectrometers.

A micro-vibration generated method for testing the imaging quality on ground of space remote sensing

NASA Astrophysics Data System (ADS)

Gu, Yingying; Wang, Li; Wu, Qingwen

2018-03-01

In this paper, a novel method is proposed, which can simulate satellite platform micro-vibration and test the impact of satellite micro-vibration on imaging quality of space optical remote sensor on ground. The method can generate micro-vibration of satellite platform in orbit from vibrational degrees of freedom, spectrum, magnitude, and coupling path. Experiment results show that the relative error of acceleration control is within 7%, in frequencies from 7Hz to 40Hz. Utilizing this method, the system level test about the micro-vibration impact on imaging quality of space optical remote sensor can be realized. This method will have an important applications in testing micro-vibration tolerance margin of optical remote sensor, verifying vibration isolation and suppression performance of optical remote sensor, exploring the principle of micro-vibration impact on imaging quality of optical remote sensor.

Fabrication of micro/nano optical fiber by mechano-electrospinning

NASA Astrophysics Data System (ADS)

Chen, Qinnan; Wu, Dezhi; Yu, Zhe; Mei, Xuecui; Fang, Ke; Sun, Daoheng

2017-10-01

We study a novel fabrication method of micro/nano optical fiber by mechano-electrospinning (MES) direct-written technology. MES process is able to precisely manipulate the position and diameter of the electro-spun micro/nano fiber by adjusting the mechanical drawing force, which through changing the speed of motion stage (substrate). By adjusting the substrate speed, the nozzle-to-substrate distance and the applied voltage, the poly(methyl methacrylate) (PMMA) micro/nano optical fibers (MNOF) with controlled diameter are obtained and the tapered MNOF are fabricated by continuously changing the substrate speed. The transmission characteristics of PMMA micro/nano fiber is experimentally demonstrated, and a PMMA micro/nano fiber based refractive index sensor is designed. Our works shows the new fabrication method of MNOF by MES has the potential in the field of light mode conversion, optical waveguide coupling, refractive index detection and new micro/nano optical fiber components.

Single-File Escape of Colloidal Particles from Microfluidic Channels

NASA Astrophysics Data System (ADS)

Locatelli, Emanuele; Pierno, Matteo; Baldovin, Fulvio; Orlandini, Enzo; Tan, Yizhou; Pagliara, Stefano

2016-07-01

Single-file diffusion is a ubiquitous physical process exploited by living and synthetic systems to exchange molecules with their environment. It is paramount to quantify the escape time needed for single files of particles to exit from constraining synthetic channels and biological pores. This quantity depends on complex cooperative effects, whose predominance can only be established through a strict comparison between theory and experiments. By using colloidal particles, optical manipulation, microfluidics, digital microscopy, and theoretical analysis we uncover the self-similar character of the escape process and provide closed-formula evaluations of the escape time. We find that the escape time scales inversely with the diffusion coefficient of the last particle to leave the channel. Importantly, we find that at the investigated microscale, bias forces as tiny as 10-15 N determine the magnitude of the escape time by drastically reducing interparticle collisions. Our findings provide crucial guidelines to optimize the design of micro- and nanodevices for a variety of applications including drug delivery, particle filtering, and transport in geometrical constrictions.

A Krill's Eye View: Sea Ice Microstructure and Microchemistry

NASA Astrophysics Data System (ADS)

Obbard, R. W.; Lieb-Lappen, R.

2015-12-01

Sea ice plays important roles in the marine ecosystem and our environment, and a detailed understanding of all aspects of its microstructure is especially important in this time of changing climate. For many months of the year, the ice forms a permeable barrier between Polar oceans and the atmosphere, and as it freezes and melts, its microstructure evolves and changes in ways that affect other parts of that system. Sea ice also provides a microhabitat that is an important part of the marine ecosystem, but much remains to be learned about it on this scale. In material terms, sea ice is multiphase and very close to its melting point, and these properties make its microstructure particularly complex and dynamic, as well as challenging and interesting to study. We use a combination of analytical methods to achieve a very detailed understanding of sea ice microstructure - specifically the morphology and distribution of ice crystals and brine channels. Overall porosity affects freeboard, emissivity, and optical and mechanical properties, but pore connectivity is critical to gas and fluid transport, salt flux to polar oceans, the transfer of halogens to the boundary layer troposphere, and the transport of nutrients and pollutants to microorganisms. When sea ice forms, salts are expelled from newly formed ice crystals and concentrated on grain boundaries and in brine pockets and channels. We use synchrotron-based X-ray fluorescence spectroscopy (SXRF) and scanning electron microscope-based energy dispersive spectroscopy (EDS) to map the location in two dimensions of several important salt components in sea ice: SXRF for bromine, chlorine, potassium, calcium and iron, EDS for these as well as some lighter elements such as sodium, magnesium, and silicon. We use X-ray microcomputed tomography (microCT) to produce three-dimensional models of brine channels and to study changes in brine network topology due to warming and cooling. Both microCT and optical thin sections provide necessary structural reference points in the analysis of microchemical data from SXRF and EDS.

Small volume low mechanical stress cytometry using computer-controlled Braille display microfluidics.

PubMed

Tung, Yi-Chung; Torisawa, Yu-suke; Futai, Nobuyuki; Takayama, Shuichi

2007-11-01

This paper describes a micro flow cytometer system designed for efficient and non-damaging analysis of samples with small numbers of precious cells. The system utilizes actuation of Braille-display pins for micro-scale fluid manipulation and a fluorescence microscope with a CCD camera for optical detection. The microfluidic chip is fully disposable and is composed of a polydimethylsiloxane (PDMS) slab with microchannel features sealed against a thin deformable PDMS membrane. The channels are designed with diffusers to alleviate pulsatile flow behaviors inherent in pin actuator-based peristaltic pumping schemes to maximize hydrodynamic focusing of samples with minimal disturbances in the laminar streams within the channel. A funnel connected to the microfluidic channel is designed for efficient loading of samples with small number of cells and is also positioned on the chip to prevent physical damages of the samples by the squeezing actions of Braille pins during actuation. The sample loading scheme was characterized by both computational fluidic dynamics (CFD) simulation and experimental observation. A fluorescein solution was first used for flow field investigation, followed by use of fluorescence beads with known relative intensities for optical detection performance calibration. Murine myoblast cells (C2C12) were exploited to investigate cell viability for the sample loading scheme of the device. Furthermore, human promyelocytic leukemia (HL60) cells stained by hypotonic DNA staining buffer were also tested in the system for cell cycle analysis. The ability to efficiently analyze cellular samples where the number of cells is small was demonstrated by analyzing cells from a single embryoid body derived from mouse embryonic stem cells. Consequently, the designed microfluidic device reported in this paper is promising for easy-to-use, small sample size flow cytometric analysis, and has potential to be further integrated with other Braille display-based microfluidic devices to facilitate a multi-functional lab-on-a-chip for mammalian cell manipulations.

Simulation and experimental research on micro-channel for detecting cell status in bio-artificial liver.

PubMed

Wu, Changzhe; Cao, Yue; Huo, Xiaolin; Li, Ming

2015-01-01

Bioartificial liver support system (BALSS) based on culturing hepatocytes is an important research field for the treatment of acute liver failure. It is necessary to monitor the state of liver cell functions during the treatment of BALSS in order to guide clinical treatment. To design a micro-channel chip to achieve flash mixing for timely detection of liver cell status in bioreactors and improving liver cells growth environment to ensure the efficacy of the bio-artificial liver support system. Alanine aminotransferase (ALT) and Urea are chosen as detection indicators to reflect the degree of liver cell injury and the detoxification function. A diamond tandem structure micro-channel is designed and optimized to achieve the efficient mixing of serum and ALT or Urea reagent. The simulation and experimental results show that the diamond tandem structure micro-channel can significantly improve the mixing efficiency and meet the online detecting requirements. The easily controllable diamond tandem structure micro-channel combines the advantages of active and passive mixer and can effectively mix the serum and ALT or Urea reagent. It lays the foundation for online monitoring of liver cells and will help to improve the viability of liver cell in the bioreactor.

Microsystem enabled photovoltaic modules and systems

DOEpatents

Nielson, Gregory N; Sweatt, William C; Okandan, Murat

2015-05-12

A microsystem enabled photovoltaic (MEPV) module including: an absorber layer; a fixed optic layer coupled to the absorber layer; a translatable optic layer; a translation stage coupled between the fixed and translatable optic layers; and a motion processor electrically coupled to the translation stage to controls motion of the translatable optic layer relative to the fixed optic layer. The absorber layer includes an array of photovoltaic (PV) elements. The fixed optic layer includes an array of quasi-collimating (QC) micro-optical elements designed and arranged to couple incident radiation from an intermediate image formed by the translatable optic layer into one of the PV elements such that it is quasi-collimated. The translatable optic layer includes an array of focusing micro-optical elements corresponding to the QC micro-optical element array. Each focusing micro-optical element is designed to produce a quasi-telecentric intermediate image from substantially collimated radiation incident within a predetermined field of view.

Acoustic trapping in bubble-bounded micro-cavities

NASA Astrophysics Data System (ADS)

O'Mahoney, P.; McDougall, C.; Glynne-Jones, P.; MacDonald, M. P.

2016-12-01

We present a method for controllably producing longitudinal acoustic trapping sites inside microfluidic channels. Air bubbles are injected into a micro-capillary to create bubble-bounded `micro-cavities'. A cavity mode is formed that shows controlled longitudinal acoustic trapping between the two air/water interfaces along with the levitation to the centre of the channel that one would expect from a lower order lateral mode. 7 μm and 10 μm microspheres are trapped at the discrete acoustic trapping sites in these micro-cavities.We show this for several lengths of micro-cavity.

Micro-optical design of a three-dimensional microlens scanner for vertically integrated micro-opto-electro-mechanical systems.

PubMed

Baranski, Maciej; Bargiel, Sylwester; Passilly, Nicolas; Gorecki, Christophe; Jia, Chenping; Frömel, Jörg; Wiemer, Maik

2015-08-01

This paper presents the optical design of a miniature 3D scanning system, which is fully compatible with the vertical integration technology of micro-opto-electro-mechanical systems (MOEMS). The constraints related to this integration strategy are considered, resulting in a simple three-element micro-optical setup based on an afocal scanning microlens doublet and a focusing microlens, which is tolerant to axial position inaccuracy. The 3D scanning is achieved by axial and lateral displacement of microlenses of the scanning doublet, realized by micro-electro-mechanical systems microactuators (the transmission scanning approach). Optical scanning performance of the system is determined analytically by use of the extended ray transfer matrix method, leading to two different optical configurations, relying either on a ball lens or plano-convex microlenses. The presented system is aimed to be a core component of miniature MOEMS-based optical devices, which require a 3D optical scanning function, e.g., miniature imaging systems (confocal or optical coherence microscopes) or optical tweezers.

Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

NASA Technical Reports Server (NTRS)

Defrere, D.; Hinz, P.; Downey, E.; Boehm, M.; Danchi, W. C.; Durney, O.; Ertel, S.; Hill, J. M.; Hoffmann, W. F.; Mennesson, B.;

Development of an Operational Multi-sensor and Multi-channel Aerosol Assimilation Package

DTIC Science & Technology

2011-08-18

2010, EGU General Assembly 2010. Shi, Y., J. Zhang, J. S. Reid, E. Hyer, Evaluation of MISR Aerosol Optical Depth Product for Aerosol Data...empirical correction procedures for generating data-assimilation-friendly over-water MODIS aerosol products. This study has been published (Shi et al...type as large r\\ values are generally related to fine mode aerosols, such as sulfate and smoke aerosols, and small r\\ values typically indicate sea

An Experimental Device for Real Time Determination of Slant Path Atmospheric Contrast Transmittance.

DTIC Science & Technology

1982-03-01

copies ftom th Defense Technical Information Caster. AN others ioM apply to the National Technical Information Service. UNCLASSIFIED SECURITV...EXPERIMENTAL DEVICE FOR REAL TIME DETERMINATION OF SLANT PATH ATMOSPHERIC CONTRAST TRANSMITTANCE Richard W. Johnson 1. INTRODUCTION 2. BASIC CONCEPTS As...and z is an altitude parameter. primary optical channel uses a cosine corrected and PE- ASSIG SYSTM DEPIS1ttt STAGE I DSIN STAGEM Pgormiy TES

New ultraportable display technology and applications

NASA Astrophysics Data System (ADS)

Alvelda, Phillip; Lewis, Nancy D.

1998-08-01

MicroDisplay devices are based on a combination of technologies rooted in the extreme integration capability of conventionally fabricated CMOS active-matrix liquid crystal display substrates. Customized diffraction grating and optical distortion correction technology for lens-system compensation allow the elimination of many lenses and systems-level components. The MicroDisplay Corporation's miniature integrated information display technology is rapidly leading to many new defense and commercial applications. There are no moving parts in MicroDisplay substrates, and the fabrication of the color generating gratings, already part of the CMOS circuit fabrication process, is effectively cost and manufacturing process-free. The entire suite of the MicroDisplay Corporation's technologies was devised to create a line of application- specific integrated circuit single-chip display systems with integrated computing, memory, and communication circuitry. Next-generation portable communication, computer, and consumer electronic devices such as truly portable monitor and TV projectors, eyeglass and head mounted displays, pagers and Personal Communication Services hand-sets, and wristwatch-mounted video phones are among the may target commercial markets for MicroDisplay technology. Defense applications range from Maintenance and Repair support, to night-vision systems, to portable projectors for mobile command and control centers.

Front-surface fabrication of moderate aspect ratio micro-channels in fused silica by single picosecond Gaussian-Bessel laser pulse

NASA Astrophysics Data System (ADS)

Liu, Xin; Sanner, Nicolas; Sentis, Marc; Stoian, Razvan; Zhao, Wei; Cheng, Guanghua; Utéza, Olivier

2018-02-01

Single-shot Gaussian-Bessel laser beams of 1 ps pulse duration and of 0.9 μm core size and 60 μm depth of focus are used for drilling micro-channels on front side of fused silica in ambient condition. Channels ablated at different pulse energies are fully characterized by AFM and post-processing polishing procedures. We identify experimental energy conditions (typically 1.5 µJ) suitable to fabricate non-tapered channels with mean diameter of 1.2 µm and length of 40 μm while maintaining an utmost quality of the front opening of the channels. In addition, by further applying accurate post-polishing procedure, channels with high surface quality and moderate aspect ratio down to a few units are accessible, which would find interest in the surface micro-structuring of materials, with perspective of further scalability to meta-material specifications.

Indoleamines and calcium channels influence morphogenesis in in vitro cultures of Mimosa pudica L.

PubMed

Ramakrishna, Akula; Giridhar, Parvatam; Ravishankar, G A

2009-12-01

The present article reports the interplay of indoleamine neurohormones viz. serotonin, melatonin and calcium channels on shoot organogenesis in Mimosa pudica L. In vitro grown nodal segments were cultured on MS medium with B5 vitamins containing Serotonin (SER) and Melatonin (MEL) at 100 microM and indoleamine inhibitors viz. serotonin to melatonin conversion inhibitor p-chlorophenylalanine (p-CPA) at 40 microM, serotonin reuptake inhibitor (Prozac) 20 microM. In another set of experiment, calcium at 5 mM, calcium ionophore (A23187) 100 microM, and calcium channel blocker varapamil hydrochloride (1 mM) a calcium chelator EGTA (100 microM) were administered to the culture medium. The percentage of shoot multiplication, endogenous MEL and SER were monitored during shoot organogenesis. At 100 microM SER and MEL treatment 60% and 70% explants responded for shoot multiplication respectively. Medium supplemented with either SER or MEL along with calcium (5 mM) 75%-80% explants responded for organogenesis. SER or MEL along with calcium ionophore (A23187) at 100 microM 70% explants responded for shoot multiplication. p-CPA, prozac, verapamil and EGTA, shoot multiplication was reduced and endogenous pools of SER, MEL decreased by 40-70%. The results clearly demonstrated that indoleamines and calcium channels positively influenced shoot organogenesis in M. pudica L.

Hardware-efficient bosonic quantum error-correcting codes based on symmetry operators

NASA Astrophysics Data System (ADS)

Niu, Murphy Yuezhen; Chuang, Isaac L.; Shapiro, Jeffrey H.

2018-03-01

We establish a symmetry-operator framework for designing quantum error-correcting (QEC) codes based on fundamental properties of the underlying system dynamics. Based on this framework, we propose three hardware-efficient bosonic QEC codes that are suitable for χ(2 )-interaction based quantum computation in multimode Fock bases: the χ(2 ) parity-check code, the χ(2 ) embedded error-correcting code, and the χ(2 ) binomial code. All of these QEC codes detect photon-loss or photon-gain errors by means of photon-number parity measurements, and then correct them via χ(2 ) Hamiltonian evolutions and linear-optics transformations. Our symmetry-operator framework provides a systematic procedure for finding QEC codes that are not stabilizer codes, and it enables convenient extension of a given encoding to higher-dimensional qudit bases. The χ(2 ) binomial code is of special interest because, with m ≤N identified from channel monitoring, it can correct m -photon-loss errors, or m -photon-gain errors, or (m -1 )th -order dephasing errors using logical qudits that are encoded in O (N ) photons. In comparison, other bosonic QEC codes require O (N2) photons to correct the same degree of bosonic errors. Such improved photon efficiency underscores the additional error-correction power that can be provided by channel monitoring. We develop quantum Hamming bounds for photon-loss errors in the code subspaces associated with the χ(2 ) parity-check code and the χ(2 ) embedded error-correcting code, and we prove that these codes saturate their respective bounds. Our χ(2 ) QEC codes exhibit hardware efficiency in that they address the principal error mechanisms and exploit the available physical interactions of the underlying hardware, thus reducing the physical resources required for implementing their encoding, decoding, and error-correction operations, and their universal encoded-basis gate sets.

Coalescence of liquid droplets in micro fluidic device

NASA Astrophysics Data System (ADS)

Wu, Mingming; Cubaud, Thomas; Ho, Chih-Ming; Chiou, Peiyu; Wu, Ming C.

2003-11-01

We study experimentally the initial dynamic process when two droplets (diameter range 100μm -1000μm) merge in micro fluidic device. It is known that passive mixing in micro fluidic device relies mostly on a time consuming process - diffusion. In digital fluidic platform,(S.K. Cho, H. Moon, and C.J. Kim, J. of Microelectromechanical Systems, Vol 12, No 1, 70(2003).) we find that the surface-tension-driven flow at the initial stage of the merging can be used to enhance mixing. In our experiments, the droplets are manipulated by two different methods, and results are compared. In one method, the droplet is manipulated by pressure driven flow in micro channels, and in the other, the droplet is moved using an optical electro-wetting device. The droplet is seeded with 4 μm diameter latex particles for visualizing the mixing process. The outlines of the droplets as well as the flow patterns marked by the latex particles inside the droplets are recorded using a high speed imaging system. This work is supported by the National Science Foundation (CTS-0121340), Institute for CMISE (a NASA URETI), DARPA MPG program, and DARPA Optoelectronics Center Program (CHIPS).

Direct writing of micro/nano-scale patterns by means of particle lens arrays scanned by a focused diode pumped Nd:YVO4 laser

NASA Astrophysics Data System (ADS)

Pena, Ana; Wang, Zengbo; Whitehead, David; Li, Lin

2010-11-01

A practical approach to a well-known technique of laser micro/nano-patterning by optical near fields is presented. It is based on surface patterning by scanning a Gaussian laser beam through a self-assembled monolayer of silica micro-spheres on a single-crystalline silicon (Si) substrate. So far, the outcome of this kind of near-field patterning has been related to the simultaneous, parallel surface-structuring of large areas either by top hat or Gaussian laser intensity distributions. We attempt to explore the possibility of using the same technique in order to produce single, direct writing of features. This could be of advantage for applications in which only some areas need to be patterned (i.e. local area selective patterning) or single lines are required (e.g. a particular micro/nano-fluidic channel). A diode pumped Nd:YVO4 laser system (wavelength of 532 nm, pulse duration of 8 ns, repetition rate of 30 kHz) with a computer-controlled 3 axis galvanometer beam scanner was employed to write user-defined patterns through the particle lens array on the Si substrate. After laser irradiation, the obtained patterns which are in the micro-scale were composed of sub-micro/micro-holes or bumps. The micro-pattern resolution depends on the dimension of both the micro-sphere’s diameter and the beam’s spot size. The developed technique could potentially be employed to fabricate photonic crystal structures mimicking nature’s butterfly wings and anti-reflective “moth eye” arrays for photovoltaic cells.

Dual-channel in-line digital holographic double random phase encryption

PubMed Central

Das, Bhargab; Yelleswarapu, Chandra S; Rao, D V G L N

2012-01-01

We present a robust encryption method for the encoding of 2D/3D objects using digital holography and virtual optics. Using our recently developed dual-plane in-line digital holography technique, two in-line digital holograms are recorded at two different planes and are encrypted using two different double random phase encryption configurations, independently. The process of using two mutually exclusive encryption channels makes the system more robust against attacks since both the channels should be decrypted accurately in order to get a recognizable reconstruction. Results show that the reconstructed object is unrecognizable even when the portion of the correct phase keys used during decryption is close to 75%. The system is verified against blind decryptions by evaluating the SNR and MSE. Validation of the proposed method and sensitivities of the associated parameters are quantitatively analyzed and illustrated. PMID:23471012

NEMO educational kit on micro-optics at the secondary school

NASA Astrophysics Data System (ADS)

Flores-Arias, M. T.; Bao-Varela, Carmen

2014-07-01

NEMO was the "Network of Excellence in Micro-Optics" granted in the "Sixth Framework Program" of the European Union. It aimed at providing Europe with a complete Micro-Optics food-chain, by setting up centers for optical modeling and design; measurement and instrumentation; mastering, prototyping and replication; integration and packaging and reliability and standardization. More than 300 researchers from 30 groups in 12 countries participated in the project. One of the objectives of NEMO was to spread excellence and disseminate knowledge on micro-optics and micro-photonics. To convince pupils, already from secondary school level on, about the crucial role of light and micro-optics and the opportunities this combination holds, several partners of NEMO had collaborate to create this Educational Kit. In Spain the partner involved in this aim was the "Microoptics and GRIN Optics Group" at the University of Santiago of Compostela (USC). The educational kits provided to the Secondary School were composed by two plastic cards with the following microoptical element: different kinds of diffractive optical elements or DOES and refractive optical elements or ROEs namely arrays of micro-lenses. The kit also included a DVD with a handbook for performing the experiments as well as a laser pointer source. This kit was distributed free of charge in the countries with partners in NEMO. In particular in Spain was offered to around 200 Secondary School Centers and only 80 answered accepting evaluate the kit.

Blood-mimicking delivery in polygonal structure of inner quadrupletip microneedle with valveless micro-pump

NASA Astrophysics Data System (ADS)

Ibrahim, M. D.; Yunos, Y. S.; Rigit, A. R. H.; Mohtadzar, N. A. A.; Watanabe, N.; Sunami, Y.; Rahman, M. R. A.; Wong, L. K.; Mohtar, M. Z.

2017-04-01

This paper presents a titanium quadrupletip micro-needle integrated with a micro-pump with different inner designs, length and diameter of the micro-channels to measure and maximize the velocity flow in the micro-needle as blood delivered into human body. Titanium is used as the material of the micro-needle which are also the common material in manufacturing of micro-needle. The advancement of micro-needle technologies is improved in penetrating human outermost skin, stratum corneum and further to human blood vessels. The micro-needles with channel inner design of circular, square, hexagon, and dodecagon with quadruple tip designs are drawn with inner diameter parameter of 150μm and 100μm with two different channel length which are 10mm and 25mm. The characteristics of blood delivery in geometrically changed inner designs affect the output velocity in microneedle when the micropump is operating. The results showed that, when it is pumped at 0.04m/s, the blood velocity improved by 5.6% than when the pump is increased by 30% of its capacity. This is due to the backflow generated in the micropump.

Simultaneous measurement of temperature, stress, and electric field in GaN HEMTs with micro-Raman spectroscopy.

PubMed

Bagnall, Kevin R; Moore, Elizabeth A; Badescu, Stefan C; Zhang, Lenan; Wang, Evelyn N

2017-11-01

As semiconductor devices based on silicon reach their intrinsic material limits, compound semiconductors, such as gallium nitride (GaN), are gaining increasing interest for high performance, solid-state transistor applications. Unfortunately, higher voltage, current, and/or power levels in GaN high electron mobility transistors (HEMTs) often result in elevated device temperatures, degraded performance, and shorter lifetimes. Although micro-Raman spectroscopy has become one of the most popular techniques for measuring localized temperature rise in GaN HEMTs for reliability assessment, decoupling the effects of temperature, mechanical stress, and electric field on the optical phonon frequencies measured by micro-Raman spectroscopy is challenging. In this work, we demonstrate the simultaneous measurement of temperature rise, inverse piezoelectric stress, thermoelastic stress, and vertical electric field via micro-Raman spectroscopy from the shifts of the E 2 (high), A 1 longitudinal optical (LO), and E 2 (low) optical phonon frequencies in wurtzite GaN. We also validate experimentally that the pinched OFF state as the unpowered reference accurately measures the temperature rise by removing the effect of the vertical electric field on the Raman spectrum and that the vertical electric field is approximately the same whether the channel is open or closed. Our experimental results are in good quantitative agreement with a 3D electro-thermo-mechanical model of the HEMT we tested and indicate that the GaN buffer acts as a semi-insulating, p-type material due to the presence of deep acceptors in the lower half of the bandgap. This implementation of micro-Raman spectroscopy offers an exciting opportunity to simultaneously probe thermal, mechanical, and electrical phenomena in semiconductor devices under bias, providing unique insight into the complex physics that describes device behavior and reliability. Although GaN HEMTs have been specifically used in this study to demonstrate its viability, this technique is applicable to any solid-state material with a suitable Raman response and will likely enable new measurement capabilities in a wide variety of scientific and engineering applications.

Simultaneous measurement of temperature, stress, and electric field in GaN HEMTs with micro-Raman spectroscopy

NASA Astrophysics Data System (ADS)

Bagnall, Kevin R.; Moore, Elizabeth A.; Badescu, Stefan C.; Zhang, Lenan; Wang, Evelyn N.

2017-11-01

As semiconductor devices based on silicon reach their intrinsic material limits, compound semiconductors, such as gallium nitride (GaN), are gaining increasing interest for high performance, solid-state transistor applications. Unfortunately, higher voltage, current, and/or power levels in GaN high electron mobility transistors (HEMTs) often result in elevated device temperatures, degraded performance, and shorter lifetimes. Although micro-Raman spectroscopy has become one of the most popular techniques for measuring localized temperature rise in GaN HEMTs for reliability assessment, decoupling the effects of temperature, mechanical stress, and electric field on the optical phonon frequencies measured by micro-Raman spectroscopy is challenging. In this work, we demonstrate the simultaneous measurement of temperature rise, inverse piezoelectric stress, thermoelastic stress, and vertical electric field via micro-Raman spectroscopy from the shifts of the E2 (high), A1 longitudinal optical (LO), and E2 (low) optical phonon frequencies in wurtzite GaN. We also validate experimentally that the pinched OFF state as the unpowered reference accurately measures the temperature rise by removing the effect of the vertical electric field on the Raman spectrum and that the vertical electric field is approximately the same whether the channel is open or closed. Our experimental results are in good quantitative agreement with a 3D electro-thermo-mechanical model of the HEMT we tested and indicate that the GaN buffer acts as a semi-insulating, p-type material due to the presence of deep acceptors in the lower half of the bandgap. This implementation of micro-Raman spectroscopy offers an exciting opportunity to simultaneously probe thermal, mechanical, and electrical phenomena in semiconductor devices under bias, providing unique insight into the complex physics that describes device behavior and reliability. Although GaN HEMTs have been specifically used in this study to demonstrate its viability, this technique is applicable to any solid-state material with a suitable Raman response and will likely enable new measurement capabilities in a wide variety of scientific and engineering applications.

Refractive microlensarray made of silver-halide sensitized gelatin (SHSG) etched by enzyme with SLM-based lithography

NASA Astrophysics Data System (ADS)

Guo, Xiaowei; Chen, Mingyong; Zhu, Jianhua; Ma, Yanqin; Du, Jinglei; Guo, Yongkang; Du, Chunlei

2006-01-01

A novel method for the fabrication of continuous micro-optical components is presented in this paper. It employs a computer controlled digital-micromirror-device(DMD TM) as a switchable projection mask and silver-halide sensitized gelatin (SHSG) as recording material. By etching SHSG with enzyme solution, the micro-optical components with relief modulation can be generated through special processing procedures. The principles of etching SHSG with enzyme and theoretical analysis for deep etching are also discussed in detail, and the detailed quantitative experiments on the processing procedures are conducted to determine optimum technique parameters. A good linear relationship within a depth range of 4μm was experimentally obtained between exposure dose and relief depth. At last, the microlensarray with 256.8μm radius and 2.572μm depth was achieved. This method is simple, cheap and the aberration in processing procedures can be corrected in the step of designing mask, so it is a practical method to fabricate good continuous profile for low-volume production.

In-situ and elementally resolved determination of the thickness uniformity of multi-ply films by confocal micro XRF.

PubMed

Peng, Song; Liu, Zhiguo; Sun, Tianxi; Wang, Guangfu; Ma, Yongzhong; Ding, Xunliang

2014-08-01

Confocal micro X-ray fluorescence (CM-XRF) with quasi-monochromatic excitation based on polycapillary X-ray optics was used to measure the thickness of multi-ply films. The relative errors of measuring an Fe film with a thickness of 16.3 μm and a Cu film with a thickness of 24.5 μm were 7.3% and 0.4%, respectively. The non-destructive and in-situ measurement of the thickness and uniformity of multi-ply films of Cu, Fe and Ni on a silicon surface was performed. CM-XRF was convenient in in-situ and elementally resolved analysis of the thickness of multi-ply films without a cumbersome theoretical correction model. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optical bias selector based on a multilayer a-SiC:H optical filter

NASA Astrophysics Data System (ADS)

Vieira, M.; Vieira, M. A.; Louro, P.

2017-08-01

In this paper we present a MUX/DEMUX device based on a multilayer a-SiC:H optical filter that requires nearultraviolet steady state optical switches to select desired wavelengths in the visible range. Spectral response and transmittance measurements are presented and show the feasibility of tailoring the wavelength and bandwidth of a polychromatic mixture of different wavelengths. The selector filter is realized by using a two terminal double pi'n/pin a-SiC:H photodetector. Five visible communication channels are transmitted together, each one with a specific bit sequence. The combined optical signal is analyzed by reading out the photocurrent, under near-UV front steady state background. Data shows that 25 current levels are detected and corresponds to the thirty-two on/off possible states. The proximity of the magnitude of consecutive levels causes occasional errors in the decoded information. To minimize the errors, four parity bit are generated and stored along with the data word. The parity of the word is checked after reading the word to detect and correct the transmitted data. Results show that the background works as a selector in the visible range, shifting the sensor sensitivity and together with the parity check bits allows the identification and decoding of the different input channels. A transmission capability of 60 kbps using the generated codeword was achieved. An optoeletronic model gives insight on the system physics.

Optical Design of COATLI: A Diffraction-Limited Visible Imager with Fast Guiding and Active Optics Correction

NASA Astrophysics Data System (ADS)

Fuentes-Fernández, J.; Cuevas, S.; Watson, A. M.

2018-04-01

We present the optical design of COATLI, a two channel visible imager for a comercial 50 cm robotic telescope. COATLI will deliver diffraction-limited images (approximately 0.3 arcsec FWHM) in the riz bands, inside a 4.2 arcmin field, and seeing limited images (approximately 0.6 arcsec FWHM) in the B and g bands, inside a 5 arcmin field, by means of a tip-tilt mirror for fast guiding, and a deformable mirror for active optics, both located on two optically transferred pupil planes. The optical design is based on two collimator-camera systems plus a pupil transfer relay, using achromatic doublets of CaF2 and S-FTM16 and one triplet of N-BK7 and CaF2. We discuss the effciency, tolerancing, thermal behavior and ghosts. COATLI will be installed at the Observatorio Astronómico Nacional in Sierra San Pedro Mártir, Baja California, Mexico, in 2018.

Retinoic acid induction of calcium channel expression in human NT2N neurons.

PubMed

Gao, Z Y; Xu, G; Stwora-Wojczyk, M M; Matschinsky, F M; Lee, V M; Wolf, B A

1998-06-18

Ca2+ channel expression and regulation of intracellular Ca2+ homeostasis were studied during retinoic acid (RA)-induced differentiation of the human teratocarcinoma cell line Ntera 2/C1.D1 (NT2- cells) into NT2N neurons, a unique model of human neurons in culture. The cytosolic Ca2+ level of undifferentiated NT2- cells was low (75 +/- 5 nM) and stable under basal conditions, and it was only marginally decreased (by 9%) upon removal of extracellular Ca2+. After 10 microM RA treatment, NT2- cells were irreversibly differentiated into a phenotype of neuron-like NT2N cells. Cytosolic Ca2+ level of NT2N neurons was higher (106 +/- 14 nM) than that of NT2- cells and spontaneously fluctuated (0.208 +/- 0.038 transients/min) under basal conditions. Although K+ increased 86Rb fluxes in both NT2- cells and NT2N neurons, it only increased cytosolic Ca2+ level in NT2N neurons. The K+-induced increase in cytosolic Ca2+ in NT2N neurons was antagonized by 0.1-10 microM nifedipine or verapamil, 5 microM omega-CgTx GVIA, but not by 1 microM omega-agatoxin IVA, 1 microM omega-agatoxin TK, 1 microM FTX-3.3, or 100 microM Ni+ implicating L- and N-type voltage-dependent Ca2+ channels. In L- and N-type channels, but not in P- and Q-types, mRNAs were expressed in NT2N neurons as well as NT2- cells. Quantitative analysis of L- and N-type Ca2+ protein levels showed major differences between NT2- cells and NT2N neurons. In NT2- cells, N-type Ca2+ channels were undetectable while L-type channels levels were fivefold lower compared to NT2N neurons. Our findings show that L- and N-type channels are expressed during differentiation of NT2- cells into neurons, and that these voltage-dependent Ca2+ channels have a major role in regulating intracellular Ca2+ homeostasis and neuronal excitability. Copyright 1998 Academic Press.

Superior spatial resolution in confocal X-ray techniques using collimating channel array optics: elemental mapping and speciation in archaeological human bone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhury, S.; Agyeman-Budu, D. N.; Woll, A. R.

Confocal X-ray fluorescence imaging (CXFI) and confocal X-ray absorption spectroscopy (CXAS) respectively enable the study of three dimensionally resolved localization and speciation of elements. Applied to a thick sample, essentially any volume element of interest within the X-ray fluorescence escape depth can be examined without the need for physical thin sectioning. To date, X-ray confocal detection generally has employed a polycapillary optic in front of the detector to collect fluorescence from the probe volume formed at the intersection of its focus with the incident microfocus beam. This work demonstrates the capability of a novel Collimating Channel Array (CCA) optic inmore » providing an improved and essentially energy independent depth resolution approaching 2 μm. By presenting a comparison of elemental maps of archaeological bone collected without confocal detection, and with polycapillary- and CCA-based confocal detection, this study highlights the strengths and limitations of each mode. Unlike the polycapillary, the CCA shows similar spatial resolution in maps for both low (Ca) and high (Pb and Sr) energy X-ray fluorescence, thus illustrating the energy independent nature of the CCA optic resolution. While superior spatial resolution is demonstrated for all of these elements, the most significant improvement is observed for Ca, demonstrating the advantage of employing the CCA optic in examining light elements. In addition to CXFI, this configuration also enables the collection of Pb L3 CXAS data from micro-volumes with dimensions comparable to bone microstructures of interest. Our CXAS result, which represents the first CCA-based biological CXAS, demonstrates the ability of CCA optics to collect site specific spectroscopic information. The demonstrated combination of site-specific elemental localization and speciation data will be useful in diverse fields.« less

[New type distributed optical fiber temperature sensor (DTS) based on Raman scattering and its' application].

PubMed

Wang, Jian-Feng; Liu, Hong-Lin; Zhang, Shu-Qin; Yu, Xiang-Dong; Sun, Zhong-Zhou; Jin, Shang-Zhong; Zhang, Zai-Xuan

2013-04-01

Basic principles, development trends and applications status of distributed optical fiber Raman temperature sensor (DTS) are introduced. Performance parameters of DTS system include the sensing optical fiber length, temperature measurement uncertainty, spatial resolution and measurement time. These parameters have a certain correlation and it is difficult to improve them at the same time by single technology. So a variety of key techniques such as Raman amplification, pulse coding technique, Raman related dual-wavelength self-correction technique and embedding optical switching technique are researched to improve the performance of the DTS system. A 1 467 nm continuous laser is used as pump laser and the light source of DTS system (1 550 nm pulse laser) is amplified. When the length of sensing optical fiber is 50 km the Raman gain is about 17 dB. Raman gain can partially compensate the transmission loss of optical fiber, so that the sensing length can reach 50 km. In DTS system using pulse coding technique, pulse laser is coded by 211 bits loop encoder and correlation calculation is used to demodulate temperature. The encoded laser signal is related, whereas the noise is not relevant. So that signal-to-noise ratio (SNR) of DTS system can be improved significantly. The experiments are carried out in DTS system with single mode optical fiber and multimode optical fiber respectively. Temperature measurement uncertainty can all reach 1 degrees C. In DTS system using Raman related dual-wavelength self-correction technique, the wavelength difference of the two light sources must be one Raman frequency shift in optical fiber. For example, wavelength of the main laser is 1 550 nm and wavelength of the second laser must be 1 450 nm. Spatial resolution of DTS system is improved to 2 m by using dual-wavelength self-correction technique. Optical switch is embedded in DTS system, so that the temperature measurement channel multiply extended and the total length of the sensing optical fiber effectively extended. Optical fiber sensor network is composed.

Impact of Adsorption on Gas Transport in Nanopores.

PubMed

Wu, Tianhao; Zhang, Dongxiao

2016-03-29

Given the complex nature of the interaction between gas and solid atoms, the development of nanoscale science and technology has engendered a need for further understanding of gas transport behavior through nanopores and more tractable models for large-scale simulations. In the present paper, we utilize molecular dynamic simulations to demonstrate the behavior of gas flow under the influence of adsorption in nano-channels consisting of illite and graphene, respectively. The results indicate that velocity oscillation exists along the cross-section of the nano-channel, and the total mass flow could be either enhanced or reduced depending on variations in adsorption under different conditions. The mechanisms can be explained by the extra average perturbation stress arising from density oscillation via the novel perturbation model for micro-scale simulation, and approximated via the novel dual-region model for macro-scale simulation, which leads to a more accurate permeability correction model for industrial applications than is currently available.

Implementation of real-time nonuniformity correction with multiple NUC tables using FPGA in an uncooled imaging system

NASA Astrophysics Data System (ADS)

Oh, Gyong Jin; Kim, Lyang-June; Sheen, Sue-Ho; Koo, Gyou-Phyo; Jin, Sang-Hun; Yeo, Bo-Yeon; Lee, Jong-Ho

2009-05-01

This paper presents a real time implementation of Non Uniformity Correction (NUC). Two point correction and one point correction with shutter were carried out in an uncooled imaging system which will be applied to a missile application. To design a small, light weight and high speed imaging system for a missile system, SoPC (System On a Programmable Chip) which comprises of FPGA and soft core (Micro-blaze) was used. Real time NUC and generation of control signals are implemented using FPGA. Also, three different NUC tables were made to make the operating time shorter and to reduce the power consumption in a large range of environment temperature. The imaging system consists of optics and four electronics boards which are detector interface board, Analog to Digital converter board, Detector signal generation board and Power supply board. To evaluate the imaging system, NETD was measured. The NETD was less than 160mK in three different environment temperatures.

Calibration of the High Energy Replicated Optics to Explore the Sun (HEROES) Hard X-ray Telescope

NASA Astrophysics Data System (ADS)

Wilson-Hodge, Colleen A.; Gaskin, Jessica; Christe, Steven; Shih, Albert; Tennant, Allyn; Swartz, Doug; Kilaru, Kiranmayee; Elsner, Ron; Kolodziejczak, Jeff; Ramsey, Brian

On 2013 September 21-22, the High Energy Replicated Optics to Explore the Sun (HEROES) hard X-ray telescope flew as a balloon payload from Ft. Sumner, NM. HEROES observed the Sun, the black hole binary GRS 1915+105, and the Crab Nebula during its 27 h flight. In this paper, we describe laboratory calibration measurements of the HEROES detectors using line and continuum sources and applications of these measurements to define channel to energy (gain) corrections for observed events and to define detector response matrices. We characterize the HEROES X-ray grazing incidence optics using measurements taken in the Stray Light Facility (SLF) in Huntsville, AL, and using ray traces. We describe the application of our calibration measurements to in-flight observations of the Crab Nebula.

Facile fabrication of microfluidic surface-enhanced Raman scattering devices via lift-up lithography

NASA Astrophysics Data System (ADS)

Wu, Yuanzi; Jiang, Ye; Zheng, Xiaoshan; Jia, Shasha; Zhu, Zhi; Ren, Bin; Ma, Hongwei

2018-04-01

We describe a facile and low-cost approach for a flexibly integrated surface-enhanced Raman scattering (SERS) substrate in microfluidic chips. Briefly, a SERS substrate was fabricated by the electrostatic assembling of gold nanoparticles, and shaped into designed patterns by subsequent lift-up soft lithography. The SERS micro-pattern could be further integrated within microfluidic channels conveniently. The resulting microfluidic SERS chip allowed ultrasensitive in situ SERS monitoring from the transparent glass window. With its advantages in simplicity, functionality and cost-effectiveness, this method could be readily expanded into optical microfluidic fabrication for biochemical applications.

Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braun, T.; Schneider, C.; Maier, S.

In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches.

Simple method based on intensity measurements for characterization of aberrations from micro-optical components.

PubMed

Perrin, Stephane; Baranski, Maciej; Froehly, Luc; Albero, Jorge; Passilly, Nicolas; Gorecki, Christophe

2015-11-01

We report a simple method, based on intensity measurements, for the characterization of the wavefront and aberrations produced by micro-optical focusing elements. This method employs the setup presented earlier in [Opt. Express 22, 13202 (2014)] for measurements of the 3D point spread function, on which a basic phase-retrieval algorithm is applied. This combination allows for retrieval of the wavefront generated by the micro-optical element and, in addition, quantification of the optical aberrations through the wavefront decomposition with Zernike polynomials. The optical setup requires only an in-motion imaging system. The technique, adapted for the optimization of micro-optical component fabrication, is demonstrated by characterizing a planoconvex microlens.

Modulation of nucleotide sensitivity of ATP-sensitive potassium channels by phosphatidylinositol-4-phosphate 5-kinase.

PubMed

Shyng, S L; Barbieri, A; Gumusboga, A; Cukras, C; Pike, L; Davis, J N; Stahl, P D; Nichols, C G

2000-01-18

ATP-sensitive potassium channels (K(ATP) channels) regulate cell excitability in response to metabolic changes. K(ATP) channels are formed as a complex of a sulfonylurea receptor (SURx), a member of the ATP-binding cassette protein family, and an inward rectifier K(+) channel subunit (Kir6.x). Membrane phospholipids, in particular phosphatidylinositol (PI) 4,5-bisphosphate (PIP(2)), activate K(ATP) channels and antagonize ATP inhibition of K(ATP) channels when applied to inside-out membrane patches. To examine the physiological relevance of this regulatory mechanism, we manipulated membrane PIP(2) levels by expressing either the wild-type or an inactive form of PI-4-phosphate 5-kinase (PIP5K) in COSm6 cells and examined the ATP sensitivity of coexpressed K(ATP) channels. Channels from cells expressing the wild-type PIP5K have a 6-fold lower ATP sensitivity (K(1/2), the half maximal inhibitory concentration, approximately 60 microM) than the sensitivities from control cells (K(1/2) approximately 10 microM). An inactive form of the PIP5K had little effect on the K(1/2) of wild-type channels but increased the ATP-sensitivity of a mutant K(ATP) channel that has an intrinsically lower ATP sensitivity (from K(1/2) approximately 450 microM to K(1/2) approximately 100 microM), suggesting a decrease in membrane PIP(2) levels as a consequence of a dominant-negative effect of the inactive PIP5K. These results show that PIP5K activity, which regulates PIP(2) and PI-3,4,5-P(3) levels, is a significant determinant of the physiological nucleotide sensitivity of K(ATP) channels.

Analysis of Poiseuille Flow Property in Two-Dimensional Mi-cro Channels of Microfluidic Pneumatic Micro-Valve

NASA Astrophysics Data System (ADS)

Yang, Shaohua; Long, Wei; Chen, Yajun

2018-03-01

In this paper, the control mechanism and mathematical description of the microfluidic flow in the microfluidic process of the PDMS membrane type pneumatic micro-valve were studied. The velocity and pressure variation law of the velocity field inside micro valve was analyzed by numerical simulation method. The influence of the two kinds of inlet drive modes on the working effect and the pressure flow characteristics of the pneumatic micro-valve was studied. The structure of the elastic solid valve diaphragm under the dual action of the airway and the liquid channel was analyzed. Deformation and stress distribution. The results show that the gas flow in the gas flow channel under the diaphragm by the vacuum part of the role of the formation of a suction gas vortex, pressure-driven mode was easier under the diaphragm to produce a strong gas vortex, resulting in internal and external pressure to promote diaphragm cut-off liquid channel; In the pressure pneumatic mode, the stress at both ends of the diaphragm was smaller, the membrane was not easy to tear failure.

Parallel multipoint recording of aligned and cultured neurons on micro channel array toward cellular network analysis.

PubMed

Tonomura, Wataru; Moriguchi, Hiroyuki; Jimbo, Yasuhiko; Konishi, Satoshi

2010-08-01

This paper describes an advanced Micro Channel Array (MCA) for recording electrophysiological signals of neuronal networks at multiple points simultaneously. The developed MCA is designed for neuronal network analysis which has been studied by the co-authors using the Micro Electrode Arrays (MEA) system, and employs the principles of extracellular recordings. A prerequisite for extracellular recordings with good signal-to-noise ratio is a tight contact between cells and electrodes. The MCA described herein has the following advantages. The electrodes integrated around individual micro channels are electrically isolated to enable parallel multipoint recording. Reliable clamping of a targeted cell through micro channels is expected to improve the cellular selectivity and the attachment between the cell and the electrode toward steady electrophysiological recordings. We cultured hippocampal neurons on the developed MCA. As a result, the spontaneous and evoked spike potentials could be recorded by sucking and clamping the cells at multiple points. In this paper, we describe the design and fabrication of the MCA and the successful electrophysiological recordings leading to the development of an effective cellular network analysis device.

Detection of Multiple Innervation Zones from Multi-Channel Surface EMG Recordings with Low Signal-to-Noise Ratio Using Graph-Cut Segmentation.

PubMed

Marateb, Hamid Reza; Farahi, Morteza; Rojas, Monica; Mañanas, Miguel Angel; Farina, Dario

2016-01-01

Knowledge of the location of muscle Innervation Zones (IZs) is important in many applications, e.g. for minimizing the quantity of injected botulinum toxin for the treatment of spasticity or for deciding on the type of episiotomy during child delivery. Surface EMG (sEMG) can be noninvasively recorded to assess physiological and morphological characteristics of contracting muscles. However, it is not often possible to record signals of high quality. Moreover, muscles could have multiple IZs, which should all be identified. We designed a fully-automatic algorithm based on the enhanced image Graph-Cut segmentation and morphological image processing methods to identify up to five IZs in 60-ms intervals of very-low to moderate quality sEMG signal detected with multi-channel electrodes (20 bipolar channels with Inter Electrode Distance (IED) of 5 mm). An anisotropic multilayered cylinder model was used to simulate 750 sEMG signals with signal-to-noise ratio ranging from -5 to 15 dB (using Gaussian noise) and in each 60-ms signal frame, 1 to 5 IZs were included. The micro- and macro- averaged performance indices were then reported for the proposed IZ detection algorithm. In the micro-averaging procedure, the number of True Positives, False Positives and False Negatives in each frame were summed up to generate cumulative measures. In the macro-averaging, on the other hand, precision and recall were calculated for each frame and their averages are used to determine F1-score. Overall, the micro (macro)-averaged sensitivity, precision and F1-score of the algorithm for IZ channel identification were 82.7% (87.5%), 92.9% (94.0%) and 87.5% (90.6%), respectively. For the correctly identified IZ locations, the average bias error was of 0.02±0.10 IED ratio. Also, the average absolute conduction velocity estimation error was 0.41±0.40 m/s for such frames. The sensitivity analysis including increasing IED and reducing interpolation coefficient for time samples was performed. Meanwhile, the effect of adding power-line interference and using other image interpolation methods on the deterioration of the performance of the proposed algorithm was investigated. The average running time of the proposed algorithm on each 60-ms sEMG frame was 25.5±8.9 (s) on an Intel dual-core 1.83 GHz CPU with 2 GB of RAM. The proposed algorithm correctly and precisely identified multiple IZs in each signal epoch in a wide range of signal quality and is thus a promising new offline tool for electrophysiological studies.

Detection of Multiple Innervation Zones from Multi-Channel Surface EMG Recordings with Low Signal-to-Noise Ratio Using Graph-Cut Segmentation

PubMed Central

Farahi, Morteza; Rojas, Monica; Mañanas, Miguel Angel; Farina, Dario

2016-01-01

Knowledge of the location of muscle Innervation Zones (IZs) is important in many applications, e.g. for minimizing the quantity of injected botulinum toxin for the treatment of spasticity or for deciding on the type of episiotomy during child delivery. Surface EMG (sEMG) can be noninvasively recorded to assess physiological and morphological characteristics of contracting muscles. However, it is not often possible to record signals of high quality. Moreover, muscles could have multiple IZs, which should all be identified. We designed a fully-automatic algorithm based on the enhanced image Graph-Cut segmentation and morphological image processing methods to identify up to five IZs in 60-ms intervals of very-low to moderate quality sEMG signal detected with multi-channel electrodes (20 bipolar channels with Inter Electrode Distance (IED) of 5 mm). An anisotropic multilayered cylinder model was used to simulate 750 sEMG signals with signal-to-noise ratio ranging from -5 to 15 dB (using Gaussian noise) and in each 60-ms signal frame, 1 to 5 IZs were included. The micro- and macro- averaged performance indices were then reported for the proposed IZ detection algorithm. In the micro-averaging procedure, the number of True Positives, False Positives and False Negatives in each frame were summed up to generate cumulative measures. In the macro-averaging, on the other hand, precision and recall were calculated for each frame and their averages are used to determine F1-score. Overall, the micro (macro)-averaged sensitivity, precision and F1-score of the algorithm for IZ channel identification were 82.7% (87.5%), 92.9% (94.0%) and 87.5% (90.6%), respectively. For the correctly identified IZ locations, the average bias error was of 0.02±0.10 IED ratio. Also, the average absolute conduction velocity estimation error was 0.41±0.40 m/s for such frames. The sensitivity analysis including increasing IED and reducing interpolation coefficient for time samples was performed. Meanwhile, the effect of adding power-line interference and using other image interpolation methods on the deterioration of the performance of the proposed algorithm was investigated. The average running time of the proposed algorithm on each 60-ms sEMG frame was 25.5±8.9 (s) on an Intel dual-core 1.83 GHz CPU with 2 GB of RAM. The proposed algorithm correctly and precisely identified multiple IZs in each signal epoch in a wide range of signal quality and is thus a promising new offline tool for electrophysiological studies. PMID:27978535

Initial data from a new High Spectral Resolution Lidar. Appendix A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eloranta, E.W.; Piironen, P.K.

1993-12-31

The University of Wisconsin High Spectral Resolution Lidar (HSRL) has been recently redesigned for operation in an electronics semitrailer van. The HSRL can now be deployed in support of field experiments. This paper presents initial observations with the new configuration along with an analysis of measurement accuracy. New measurement capabilities have been added. These include: observation of the signal variation with angular field of view, and observation of depolarization in all data channels. Depolarization measurements have been implemented by transmitting orthogonal linear polarizations on alternate laser pulses. Pulses are transmitted at 250 {micro}s intervals such that the lidar observes themore » same ensemble of particles for both polarizations. Orthogonal polarizations are measured with a single detector per channel. Since the optical components and detector gains are identical for the two polarizations the measured depolarization ratios are independent of these factors and the system delivers very precise depolarizations. A new data channel with a computer controlled aperture allows measurements of multiple scattering as a function of receiver field of view. Since the field of view variation is dependent on the size of the scattering particles it is expected that this will allow remote measurements of cloud particle size. Other technical improvements in the new system include active control of spectrometer temperatures, greatly increased mechanical stability, an increased receiver aperture, injection of calibration signals into the signal profiles to allow continuous monitoring of system calibration drifts, and extensive computer control of system operations.« less

The mechanism of gentisic acid-induced relaxation of the guinea pig isolated trachea: the role of potassium channels and vasoactive intestinal peptide receptors.

PubMed

Cunha, J F; Campestrini, F D; Calixto, J B; Scremin, A; Paulino, N

2001-03-01

We examined some of the mechanisms by which the aspirin metabolite and the naturally occurring metabolite gentisic acid induced relaxation of the guinea pig trachea in vitro. In preparations with or without epithelium and contracted by histamine, gentisic acid caused concentration-dependent and reproducible relaxation, with mean EC(50) values of 18 microM and E(max) of 100% (N = 10) or 20 microM and E(max) of 92% (N = 10), respectively. The relaxation caused by gentisic acid was of slow onset in comparison to that caused by norepinephrine, theophylline or vasoactive intestinal peptide (VIP). The relative rank order of potency was: salbutamol 7.9 > VIP 7.0 > gentisic acid 4.7 > theophylline 3.7. Gentisic acid-induced relaxation was markedly reduced (24 +/- 7.0, 43 +/- 3.9 and 78 +/- 5.6%) in preparations with elevated potassium concentration in the medium (20, 40 or 80 mM, respectively). Tetraethylammonium (100 microM), a nonselective blocker of the potassium channels, partially inhibited the relaxation response to gentisic acid, while 4-AP (10 microM), a blocker of the voltage potassium channel, inhibited gentisic acid-induced relaxation by 41 +/- 12%. Glibenclamide (1 or 3 microM), at a concentration which markedly inhibited the relaxation induced by the opener of ATP-sensitive K(+) channels, levcromakalim, had no effect on the relaxation induced by gentisic acid. Charybdotoxin (0.1 or 0.3 microM), a selective blocker of the large-conductance Ca(2+)-activated K(+) channels, caused rightward shifts (6- and 7-fold) of the gentisic acid concentration-relaxation curve. L-N(G)-nitroarginine (100 microM), a NO synthase inhibitor, had no effect on the relaxant effect of gentisic acid, and caused a slight displacement to the right in the relaxant effect of the gentisic acid curve at 300 microM, while methylene blue (10 or 30 microM) or ODQ (1 microM), the inhibitors of soluble guanylate cyclase, all failed to affect gentisic acid-induced relaxation. D-(P)-Cl-Phe(6),Leu(17)[VIP] (0.1 microM), a VIP receptor antagonist, significantly inhibited (37 +/- 7%) relaxation induced by gentisic acid, whereas CGRP (8-37) (0.1 microM), a CGRP antagonist, only slightly enhanced the action of gentisic acid. Taken together, these results provide functional evidence for the direct activation of voltage and large-conductance Ca(+2)-activated K(+) channels, or indirect modulation of potassium channels induced by VIP receptors and accounts for the predominant relaxation response caused by gentisic acid in the guinea pig trachea.

Enhanced Evaporation and Condensation in Tubes

NASA Astrophysics Data System (ADS)

Honda, Hiroshi

A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

Optics design for J-TEXT ECE imaging with field curvature adjustment lens.

PubMed

Zhu, Y; Zhao, Z; Liu, W D; Xie, J; Hu, X; Muscatello, C M; Domier, C W; Luhmann, N C; Chen, M; Ren, X; Tobias, B J; Zhuang, G; Yang, Z

2014-11-01

Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas. Of particular importance has been microwave electron cyclotron emission imaging (ECEI) for imaging Te fluctuations. Key to the success of ECEI is a large Gaussian optics system constituting a major portion of the focusing of the microwave radiation from the plasma to the detector array. Both the spatial resolution and observation range are dependent upon the imaging optics system performance. In particular, it is critical that the field curvature on the image plane is reduced to decrease crosstalk between vertical channels. The receiver optics systems for two ECEI on the J-TEXT device have been designed to ameliorate these problems and provide good performance with additional field curvature adjustment lenses with a meniscus shape to correct the aberrations from several spherical surfaces.

Research on the compensation of laser launch optics to improve the performance of the LGS spot.

PubMed

Liu, Jie; Wang, Jianli; Wang, Yuning; Tian, Donghe; Zheng, Quan; Lin, Xudong; Wang, Liang; Yang, Qingyun

2018-02-01

To improve the beam quality of the uplink laser, a 37 channel piezo-ceramic deformable mirror was inserted into the laser launch optics to compensate the static aberrations. An interferometer was used as the calibration light source as well as the wavefront sensor to perform closed-loop correction for the moment. About 0.38λ root mean square (rms) aberrations, including the deformable mirror's initial figure error, were compensated, and the residual error was less than 0.07λ rms. Field observations with a 2 m optical telescope demonstrated that the peak intensity value of the laser guide star (LGS) spot increased from 5650 to 7658, and the full width at half-maximum (FWHM) size reduced from 4.07 arcseconds to 3.52 arcseconds. With the compensation, an improved guide star spot can be obtained, which is crucial for the adaptive optics systems of ground-based large telescopes.

Double-helix micro-channels on microfluidic chips for enhanced continuous on-chip derivatization followed by electrophoretic separation.

PubMed

Peng, Xianglu; Zhao, Lei; Guo, Jinxiu; Yang, Shenghong; Ding, Hui; Wang, Xiayan; Pu, Qiaosheng

2015-10-15

Micro-channels that contain a special inner structure are critical for efficient mixing and chemical reactions. In this paper, we described the facile fabrication of an integrated microchip with double-helix type micro-channels to improve mixing efficiency and to facilitate multi-step derivatization reactions prior to electrophoretic separation. With a prepared microchip, reagents, samples and reaction products could be driven through micro-channels by siphon, and no other pumping device was necessary. To test its performance, reductive amination of aldehydes with 8-aminonaphthalene-1,3,6-trisulfonate acid disodium (ANTS) was attempted via microchip electrophoresis with laser induced fluorescence (LIF). The effect of the geometry of the reaction micro-channel on the reaction's efficiency was evaluated. Under the selected conditions, successful derivatization of five aldehydes was realized for highly reproducible analysis. The relative standard deviations of the peak areas for 30 consecutive injections were in the range of 0.28-1.61%. The method was applied for the determination of aldehydes in real samples with standard addition recoveries of 87.8-102.8%. Good tolerance of organic solvents was achieved, and the proposed method can potentially be employed for rapid screening of excessively added aldehyde food flavoring. Copyright © 2015 Elsevier B.V. All rights reserved.

Cellular defibrillation: interaction of micro-scale electric fields with voltage-gated ion channels.

PubMed

Kargol, Armin; Malkinski, Leszek; Eskandari, Rahmatollah; Carter, Maya; Livingston, Daniel

2015-09-01

We study the effect of micro-scale electric fields on voltage-gated ion channels in mammalian cell membranes. Such micro- and nano-scale electric fields mimic the effects of multiferroic nanoparticles that were recently proposed [1] as a novel way of controlling the function of voltage-sensing biomolecules such as ion channels. This article describes experimental procedures and initial results that reveal the effect of the electric field, in close proximity of cells, on the ion transport through voltage-gated ion channels. We present two configurations of the whole-cell patch-clamping apparatus that were used to detect the effect of external stimulation on ionic currents and discuss preliminary results that indicate modulation of the ionic currents consistent with the applied stimulus.

Design and Fabrication of a PDMS Microchip Based Immunoassay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao, Guocheng; Wang, Wanjun; Wang, Jun

2010-07-01

In this paper, we describe the design and fabrication process of a polydimethylsiloxane (PDMS) microchip for on-chip multiplex immunoassay application. The microchip consists of a PDMS microfluidic channel layer and a micro pneumatic valve control layer. By selectively pressurizing the pneumatic microvalves, immuno reagents were controlled to flow and react in certain fluidic channel sites. Cross contamination was prevented by tightly closed valves. Our design was proposed to utilize PDMS micro channel surface as the solid phase immunoassay substrate and simultaneously detect four targets antigens on chip. Experiment result shows that 20psi valve pressure is sufficient to tightly close amore » 200µm wide micro channel with flow rate up to 20µl/min.« less

Bidirectional optical subassembly-shaped 20-Gbit/s compact single-mode four-channel wavelength-division multiplexing optical modules for optical multimedia interfaces

NASA Astrophysics Data System (ADS)

Lim, Kwon-Seob; Yu, Hong-Yeon; Park, Hyoung-Jun; Kang, Hyun Seo; Jang, Jae-Hyung

2016-06-01

Low-cost single-mode four-channel optical transmitter and receiver modules using the wavelength-division multiplexing (WDM) method have been developed for long-reach fiber optic applications. The single-mode four-channel WDM optical transmitter and receiver modules consist of two dual-wavelength optical transmitter and receiver submodules, respectively. The integration of two channels in a glass-sealed transistor outline-can package is an effective way to reduce cost and size and to extend the number of channels. The clear eye diagrams with more than about 6 dB of the extinction ratio and the minimum receiver sensitivity of lower than -16 dBm at a bit error rate of 10-12 have been obtained for the transmitter and receiver modules, respectively, at 5 Gbps/channel. The 4K ultrahigh definition contents have been transmitted over a 1-km-long single-mode fiber using a pair of proposed four-channel transmitter optical subassembly and receiver optical subassembly.

Dual Telecentric Lens System For Projection Onto Tilted Toroidal Screen

NASA Technical Reports Server (NTRS)

Gold, Ronald S.; Hudyma, Russell M.

1995-01-01

System of two optical assemblies for projecting image onto tilted toroidal screen. One projection lens optimized for red and green spectral region; other for blue. Dual-channel approach offers several advantages which include: simplified color filtering, simplified chromatic aberration corrections, less complex polarizing prism arrangement, and increased throughput of blue light energy. Used in conjunction with any source of imagery, designed especially to project images formed by reflection of light from liquid-crystal light valve (LCLV).

Self-assembly micro optical filter

NASA Astrophysics Data System (ADS)

Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

2006-01-01

Optical communication and sensor industry face critical challenges in manufacturing for system integration. Due to the assembly complexity and integration platform variety, micro optical components require costly alignment and assembly procedures, in which many required manual efforts. Consequently, self-assembly device architectures have become a great interest and could provide major advantages over the conventional optical devices. In this paper, we discussed a self-assembly integration platform for micro optical components. To demonstrate the adaptability and flexibility of the proposed optical device architectures, we chose a commercially available MEMS fabrication foundry service - MUMPs (Multi-User MEMS Process). In this work, polysilicon layers of MUMPS are used as the 3-D structural material for construction of micro component framework and actuators. However, because the polysilicon has high absorption in the visible and near infrared wavelength ranges, it is not suitable for optical interaction. To demonstrate the required optical performance, hybrid integration of materials was proposed and implemented. Organic compound materials were applied on the silicon-based framework to form the required optical interfaces. Organic compounds provide good optical transparency, flexibility to form filters or lens and inexpensive manufacturing procedures. In this paper, we have demonstrated a micro optical filter integrated with self-assembly structures. We will discuss the self-assembly mechanism, optical filter designs, fabrication issues and results.

Marker-Based Multi-Sensor Fusion Indoor Localization System for Micro Air Vehicles.

PubMed

Xing, Boyang; Zhu, Quanmin; Pan, Feng; Feng, Xiaoxue

2018-05-25

A novel multi-sensor fusion indoor localization algorithm based on ArUco marker is designed in this paper. The proposed ArUco mapping algorithm can build and correct the map of markers online with Grubbs criterion and K-mean clustering, which avoids the map distortion due to lack of correction. Based on the conception of multi-sensor information fusion, the federated Kalman filter is utilized to synthesize the multi-source information from markers, optical flow, ultrasonic and the inertial sensor, which can obtain a continuous localization result and effectively reduce the position drift due to the long-term loss of markers in pure marker localization. The proposed algorithm can be easily implemented in a hardware of one Raspberry Pi Zero and two STM32 micro controllers produced by STMicroelectronics (Geneva, Switzerland). Thus, a small-size and low-cost marker-based localization system is presented. The experimental results show that the speed estimation result of the proposed system is better than Px4flow, and it has the centimeter accuracy of mapping and positioning. The presented system not only gives satisfying localization precision, but also has the potential to expand other sensors (such as visual odometry, ultra wideband (UWB) beacon and lidar) to further improve the localization performance. The proposed system can be reliably employed in Micro Aerial Vehicle (MAV) visual localization and robotics control.

Porous silicon based micro-opto-electro-mechanical-systems (MOEMS) components for free space optical interconnects

NASA Astrophysics Data System (ADS)

Song, Da

2008-02-01

One of the major challenges confronting the current integrated circuits (IC) industry is the metal "interconnect bottleneck". To overcome this obstacle, free space optical interconnects (FSOIs) can be used to address the demand for high speed data transmission, multi-functionality and multi-dimensional integration for the next generation IC. One of the crucial elements in FSOIs system is to develop a high performance and flexible optical network to transform the incoming optical signal into a distributed set of optical signals whose direction, alignment and power can be independently controlled. Among all the optical materials for the realization of FSOI components, porous silicon (PSi) is one of the most promising candidates because of its unique optical properties, flexible fabrication methods and integration with conventional IC material sets. PSi-based Distributed Bragg Reflector (DBR) and Fabry-Perot (F-P) structures with unique optical properties are realized by electrochemical etching of silicon. By incorporating PSi optical structures with Micro-Opto-Electro-Mechanical-Systems (MOEMS), several components required for FSOI have been developed. The first type of component is the out-of-plane freestanding optical switch. Implementing a PSi DBR structure as an optically active region, the device can realize channel selection by changing the tilting angle of the micromirror supported by the thermal bimorph actuator. All the fabricated optical switches have reached kHz working frequency and life time of millions of cycles. The second type of component is the in-plane tunable optical filter. By introducing PSi F-P structure into the in-plane PSi film, a thermally tunable optical filter with a sensitivity of 7.9nm/V has been realized for add/drop optical signal selection. Also, for the first time, a new type of PSi based reconfigurable diffractive optical element (DOE) has been developed. By using patterned photoresist as a protective mask for electrochemical etching, the freestanding PSi-based MOEMS DOE has been created as a beam splitter to redistribute the incoming optical signal with onto desired detector arrays. All the developed devices are realized in array fashion and can be addressed and controlled individually. The combination of PSi and MOEMS opens the door for a new generation of silicon compatible optical interconnects.

Optical design of the SuMIRe/PFS spectrograph

NASA Astrophysics Data System (ADS)

Pascal, Sandrine; Vives, Sébastien; Barkhouser, Robert; Gunn, James E.

2014-07-01

The SuMIRe Prime Focus Spectrograph (PFS), developed for the 8-m class SUBARU telescope, will consist of four identical spectrographs, each receiving 600 fibers from a 2394 fiber robotic positioner at the telescope prime focus. Each spectrograph includes three spectral channels to cover the wavelength range [0.38-1.26] um with a resolving power ranging between 2000 and 4000. A medium resolution mode is also implemented to reach a resolving power of 5000 at 0.8 um. Each spectrograph is made of 4 optical units: the entrance unit which produces three corrected collimated beams and three camera units (one per spectral channel: "blue, "red", and "NIR"). The beam is split by using two large dichroics; and in each arm, the light is dispersed by large VPH gratings (about 280x280mm). The proposed optical design was optimized to achieve the requested image quality while simplifying the manufacturing of the whole optical system. The camera design consists in an innovative Schmidt camera observing a large field-of-view (10 degrees) with a very fast beam (F/1.09). To achieve such a performance, the classical spherical mirror is replaced by a catadioptric mirror (i.e meniscus lens with a reflective surface on the rear side of the glass, like a Mangin mirror). This article focuses on the optical architecture of the PFS spectrograph and the perfornance achieved. We will first described the global optical design of the spectrograph. Then, we will focus on the Mangin-Schmidt camera design. The analysis of the optical performance and the results obtained are presented in the last section.

MEMS-based beam-steerable free-space optical communication link for reconfigurable wireless data center

NASA Astrophysics Data System (ADS)

Deng, Peng; Kavehrad, Mohsen; Lou, Yan

2017-01-01

Flexible wireless datacenter networks based on free space optical communication (FSO) links are being considered as promising solutions to meet the future datacenter demands of high throughput, robustness to dynamic traffic patterns, cabling complexity and energy efficiency. Robust and precise steerable FSO links over dynamic traffic play a key role in the reconfigurable optical wireless datacenter inter-rack network. In this work, we propose and demonstrate a reconfigurable 10Gbps FSO system incorporated with smart beam acquisition and tracking mechanism based on gimballess two-axis MEMS micro-mirror and retro-reflective film marked aperture. The fast MEMS-based beam acquisition switches laser beam of FSO terminal from one rack to the next for reconfigurable networks, and the precise beam tracking makes FSO device auto-correct the misalignment in real-time. We evaluate the optical power loss and bit error rate performance of steerable FSO links at various directions. Experimental results suggest that the MEMS based beam steerable FSO links hold considerable promise for the future reconfigurable wireless datacenter networks.

Optical Micromachining

NASA Technical Reports Server (NTRS)

1998-01-01

Under an SBIR (Small Business Innovative Research) with Marshall Space Flight Center, Potomac Photonics, Inc., constructed and demonstrated a unique tool that fills a need in the area of diffractive and refractive micro-optics. It is an integrated computer-aided design and computer-aided micro-machining workstation that will extend the benefits of diffractive and micro-optic technology to optical designers. Applications of diffractive optics include sensors and monitoring equipment, analytical instruments, and fiber optic distribution and communication. The company has been making diffractive elements with the system as a commercial service for the last year.

The new Heavy-ion MCP-based Ancillary Detector DANTE for the CLARA-PRISMA Setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valiente-Dobon, J. J.; Gadea, A.; Corradi, L.

2006-08-14

The CLARA-PRISMA setup is a powerful tool for spectroscopic studies of neutron-rich nuclei produced in multi-nucleon transfer and deep-inelastic reactions. It combines the large acceptance spectrometer PRISMA with the {gamma}-ray array CLARA. At present, the ancillary heavy-ion detector DANTE, based on Micro-Channel Plates to be installed at the CLARA-PRISMA setup, is being constructed at LNL. DANTE will open the possibility of measuring {gamma}-{gamma} Doppler-corrected coincidences for the events outside the acceptance of PRISMA. In this presentation, it is described the heavy-ion detector DANTE, as well as the performances of the first prototype.

Rapid prototyping of interfacing microcomponents for printed circuit board-level optical interconnects

NASA Astrophysics Data System (ADS)

Van Erps, Jürgen; Vervaeke, Michael; Thienpont, Hugo

2012-01-01

One of the important challenges for the deployment of the emerging breed of nanotechnology components is interfacing them with the external world, preferably accomplished with low-cost micro-optical devices. For the fabrication of this kind of micro-optical components, we make use of deep proton writing (DPW) as a generic rapid prototyping technology. DPW consists of bombarding polymer samples with swift protons, which results after chemical processing steps in high quality micro-optical components. The strength of the DPW micro-machining technology is the ability to fabricate monolithic building blocks that include micro-optical and mechanical functionalities which can be precisely integrated into more complex photonic systems. In this paper we give an overview of the process steps of the technology and we present several examples of micro-optical and micro-mechanical components, fabricated through DPW, targeting applications in printed circuit baordlevel optical interconnections. These include: high-precision 2-D fiber connectors, discrete out-of-plane coupling structures featuring high-quality 45° and curved micro-mirrors, arrays of high aspect ratio micro-pillars and backplane connectors. While DPW is clearly not a mass fabrication technique as such, one of its assets is that once the master component has been prototyped, a metal mould can be generated from the DPW master by applying electroplating. After removal of the plastic master, this metal mould can be used as a shim in a final microinjection moulding or hot embossing step. This way, the master component can be mass-produced at low cost in a wide variety of high-tech plastics.

Femtosecond laser direct-write of optofluidics in polymer-coated optical fiber

NASA Astrophysics Data System (ADS)

Joseph, Kevin A. J.; Haque, Moez; Ho, Stephen; Aitchison, J. Stewart; Herman, Peter R.

2017-03-01

Multifunctional lab in fiber technology seeks to translate the accomplishments of optofluidic, lab on chip devices into silica fibers. a robust, flexible, and ubiquitous optical communication platform that can underpin the `Internet of Things' with distributed sensors, or enable lab on chip functions deep inside our bodies. Femtosecond lasers have driven significant advances in three-dimensional processing, enabling optical circuits, microfluidics, and micro-mechanical structures to be formed around the core of the fiber. However, such processing typically requires the stripping and recoating of the polymer buffer or jacket, increasing processing time and mechanically weakening the device. This paper reports on a comprehensive assessment of laser damage in urethane-acrylate-coated fiber. The results show a sufficient processing window is available for femtosecond laser processing of the fiber without damaging the polymer jacket. The fiber core, cladding, and buffer could be simultaneously processed without removal of the buffer jacket. Three-dimensional lab in fiber devices were successfully fabricated by distortion-free immersionlens focusing, presenting fiber-cladding optical circuits and progress towards chemically-etched channels, microfluidic cavities, and MEMS structure inside buffer-coated fiber.

Infrared Hollow Optical Fiber Probe for Localized Carbon Dioxide Measurement in Respiratory Tracts.

PubMed

Katagiri, Takashi; Shibayama, Kyosuke; Iida, Takeru; Matsuura, Yuji

2018-03-27

A real-time gas monitoring system based on optical absorption spectroscopy is proposed for localized carbon dioxide (CO₂) measurement in respiratory tracts. In this system, a small gas cell is attached to the end of a hollow optical fiber that delivers mid-infrared light with small transmission loss. The diameters of the fiber and the gas cell are smaller than 1.2 mm so that the probe can be inserted into a working channel of common bronchoscopes. The dimensions of the gas cell are designed based on absorption spectra of CO₂ standard gases in the 4.2 μm wavelength region, which are measured using a Fourier-transform infrared spectrometer. A miniature gas cell that is comprised of a stainless-steel tube with slots for gas inlet and a micro-mirror is fabricated. A compact probing system with a quantum cascade laser (QCL) light source is built using a gas cell with a hollow optical fiber for monitoring CO₂ concentration. Experimental results using human breaths show the feasibility of the system for in-situ measurement of localized CO₂ concentration in human airways.

Characterizing relationship between optical microangiography signals and capillary flow using microfluidic channels.

PubMed

Choi, Woo June; Qin, Wan; Chen, Chieh-Li; Wang, Jingang; Zhang, Qinqin; Yang, Xiaoqi; Gao, Bruce Z; Wang, Ruikang K

2016-07-01

Optical microangiography (OMAG) is a powerful optical angio-graphic tool to visualize micro-vascular flow in vivo. Despite numerous demonstrations for the past several years of the qualitative relationship between OMAG and flow, no convincing quantitative relationship has been proven. In this paper, we attempt to quantitatively correlate the OMAG signal with flow. Specifically, we develop a simplified analytical model of the complex OMAG, suggesting that the OMAG signal is a product of the number of particles in an imaging voxel and the decorrelation of OCT (optical coherence tomography) signal, determined by flow velocity, inter-frame time interval, and wavelength of the light source. Numerical simulation with the proposed model reveals that if the OCT amplitudes are correlated, the OMAG signal is related to a total number of particles across the imaging voxel cross-section per unit time (flux); otherwise it would be saturated but its strength is proportional to the number of particles in the imaging voxel (concentration). The relationship is validated using microfluidic flow phantoms with various preset flow metrics. This work suggests OMAG is a promising quantitative tool for the assessment of vascular flow.

Spectral atmospheric observations at Nantucket Island, May 7-14, 1981

NASA Technical Reports Server (NTRS)

Talay, T. A.; Poole, L. R.

1981-01-01

An experiment was conducted by the National Langley Research Center to measure atmospheric optical conditions using a 10-channel solar spectral photometer system. This experiment was part of a larger series of multidisciplinary experiments performed in the area of Nantucket Shoals aimed at studying the dynamics of phytoplankton production processes. Analysis of the collected atmospheric data yield total and aerosol optical depths, transmittances, normalized sky radiance distributions, and total and sky irradiances. Results of this analysis may aid in atmospheric corrections of remote sensor data obtained by several sensors overflying the Nantucket Shoals area. Recommendations are presented concerning future experiments using the described solar photometer system and calibration and operational deficiencies uncovered during the experiment.

Ideal form of optical plasma lenses

NASA Astrophysics Data System (ADS)

Gordon, D. F.; Stamm, A. B.; Hafizi, B.; Johnson, L. A.; Kaganovich, D.; Hubbard, R. F.; Richardson, A. S.; Zhigunov, D.

2018-06-01

The canonical form of an optical plasma lens is a parabolic density channel. This form suffers from spherical aberrations, among others. Spherical aberration is partially corrected by adding a quartic term to the radial density profile. Ideal forms which lead to perfect focusing or imaging are obtained. The fields at the focus of a strong lens are computed with high accuracy and efficiency using a combination of eikonal and full Maxwell descriptions of the radiation propagation. The calculations are performed using a new computer propagation code, SeaRay, which is designed to transition between various solution methods as the beam propagates through different spatial regions. The calculations produce the full Maxwell vector fields in the focal region.

Formation Flying and Deformable Instruments

NASA Astrophysics Data System (ADS)

Rio, Yvon

2009-05-01

Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.

Determination of small field synthetic single-crystal diamond detector correction factors for CyberKnife, Leksell Gamma Knife Perfexion and linear accelerator.

PubMed

Veselsky, T; Novotny, J; Pastykova, V; Koniarova, I

2017-12-01

The aim of this study was to determine small field correction factors for a synthetic single-crystal diamond detector (PTW microDiamond) for routine use in clinical dosimetric measurements. Correction factors following small field Alfonso formalism were calculated by comparison of PTW microDiamond measured ratio M Qclin fclin /M Qmsr fmsr with Monte Carlo (MC) based field output factors Ω Qclin,Qmsr fclin,fmsr determined using Dosimetry Diode E or with MC simulation itself. Diode measurements were used for the CyberKnife and Varian Clinac 2100C/D linear accelerator. PTW microDiamond correction factors for Leksell Gamma Knife (LGK) were derived using MC simulated reference values from the manufacturer. PTW microDiamond correction factors for CyberKnife field sizes 25-5 mm were mostly smaller than 1% (except for 2.9% for 5 mm Iris field and 1.4% for 7.5 mm fixed cone field). The correction of 0.1% and 2.0% for 8 mm and 4 mm collimators, respectively, needed to be applied to PTW microDiamond measurements for LGK Perfexion. Finally, PTW microDiamond M Qclin fclin /M Qmsr fmsr for the linear accelerator varied from MC corrected Dosimetry Diode data by less than 0.5% (except for 1 × 1 cm 2 field size with 1.3% deviation). Regarding low resulting correction factor values, the PTW microDiamond detector may be considered an almost ideal tool for relative small field dosimetry in a large variety of stereotactic and radiosurgery treatment devices. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Improvements in brain activation detection using time-resolved diffuse optical means

NASA Astrophysics Data System (ADS)

Montcel, Bruno; Chabrier, Renee; Poulet, Patrick

2005-08-01

An experimental method based on time-resolved absorbance difference is described. The absorbance difference is calculated over each temporal step of the optical signal with the time-resolved Beer-Lambert law. Finite element simulations show that each step corresponds to a different scanned zone and that cerebral contribution increases with the arrival time of photons. Experiments are conducted at 690 and 830 nm with a time-resolved system consisting of picosecond laser diodes, micro-channel plate photo-multiplier tube and photon counting modules. The hemodynamic response to a short finger tapping stimulus is measured over the motor cortex. Time-resolved absorbance difference maps show that variations in the optical signals are not localized in superficial regions of the head, which testify for their cerebral origin. Furthermore improvements in the detection of cerebral activation is achieved through the increase of variations in absorbance by a factor of almost 5 for time-resolved measurements as compared to non-time-resolved measurements.

Analysis of Active Sensor Discrimination Requirements for Various Defense Missile Defense Scenarios Final Report 1999(99-ERD-080)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ledebuhr, A.G.; Ng, L.C.; Gaughan, R.J.

2000-02-15

During FY99, we have explored and analyzed a combined passive/active sensor concept to support the advanced discrimination requirements for various missile defense scenario. The idea is to combine multiple IR spectral channels with an imaging LIDAR (Light Detection and Ranging) behind a common optical system. The imaging LIDAR would itself consist of at least two channels; one at the fundamental laser wavelength (e.g., the 1.064 {micro}m for Nd:YAG) and one channel at the frequency doubled (at 532 nm for Nd:YAG). two-color laser output would, for example, allow the longer wavelength for a direct detection time of flight ranger and anmore » active imaging channel at the shorter wavelength. The LIDAR can function as a high-resolution 2D spatial image either passively or actively with laser illumination. Advances in laser design also offer three color (frequency tripled) systems, high rep-rate operation, better pumping efficiencies that can provide longer distance acquisition, and ranging for enhanced discrimination phenomenology. New detector developments can enhance the performance and operation of both LIDAR channels. A real time data fusion approach that combines multi-spectral IR phenomenology with LIDAR imagery can improve both discrimination and aim-point selection capability.« less

Fabrication of PDMS architecture

NASA Astrophysics Data System (ADS)

Adam, Tijjani; Hashim, U.

2017-03-01

The study report novel, yet simple and flexible fabrication method for micro channel patterning PDMS thin mold on glass surfaces, the method allows microstructures with critical dimensions to be formed using PDMS. Micro channel production is a two-step process. First, soft photolithography methods are implemented to fabricate a reusable mold. The mold is then used to create the micro channel, which consists of SU8, PDMS and glass. The micro channel design was performed using AutoCAD and the fabrication begins by creating a replicable mold. The mold is created on a glass slide. by spin-coating speed between 500 to 1250rpm with an acceleration of 100 rpm/s for 100 and 15 second ramp up and down speed respectively. Channel flow rate based on concentration were measured by analyzing the recorded flow profiles which was collected from the high powered microscope at. 80µ, 70µm, 50µm for inlet channel 1, 2, 3 respectively the channel flow were compared for flow efficiency at different concentrations and Re. Thus, the simplicity of device structure and fabrication makes it feasible to miniaturize it for the development of point-of-care kits, facilitating its use in both clinical and non-clinical environments. With its simple geometric structure and potential for mass commercial fabrication, the device can be developed to become a portable photo detection sensor that can be use for both environmental and diagnostic application.

Vertical comb-drive microscanner with 4x4 array of micromirrors for phase-shifting Mirau microinterferometry

NASA Astrophysics Data System (ADS)

Bargiel, Sylwester; Lullin, Justine; Lemoal, Patrice; Perrin, Stéphane; Passilly, Nicolas; Albero, Jorge; Froehly, Luc; Lardet-Vieudrin, Franck; Gorecki, Christophe

2016-04-01

In this paper, we present construction, fabrication and characterization of an electrostatic MOEMS vertical microscanner for generation of an optical phase shift in array-type interferometric microsystems. The microscanner employs asymmetric comb-drives for a vertical displacement of a large 4x4 array of reference micromirrors and for in-situ position sensing. The device is designed to be fully compatible with Mirau configuration and with vertical integration strategy. This enables further integration of the device within an "active" multi-channel Mirau micro-interferometer and implementation of the phase shifting interferometry (PSI) technique for imaging applications. The combination of micro-interferometer and PSI is particularly interesting in the swept-source optical coherence tomography, since it allows not only strong size reduction of a system but also improvement of its performance (sensitivity, removal of the image artefacts). The technology of device is based on double-side DRIE of SOI wafer and vapor HF releasing of the suspended platform. In the static mode, the device provides vertical displacement of micromirrors up to 2.8μm (0 - 40V), whereas at resonance (fo=500 Hz), it reaches 0.7 μm for only 1VDC+1VAC. In both operation modes, the measured displacement is much more than required for PSI implementation (352nm peak-to-peak). The presented device is a key component of array-type Mirau micro-interferometer that enables the construction of portable, low-cost interferometric systems, e.g. for in vivo medical diagnostics.

Modeling of a heat sink and high heat flux vapor chamber

NASA Astrophysics Data System (ADS)

Vadnjal, Aleksander

An increasing demand for a higher heat flux removal capability within a smaller volume for high power electronics led us to focus on a novel cold plate design. A high heat flux evaporator and micro channel heat sink are the main components of a cold plate which is capable of removing couple of 100 W/cm2. In order to describe performance of such porous media device a proper modeling has to be addressed. A universal approach based on the volume average theory (VAT) to transport phenomena in porous media is shown. An approach on how to treat the closure for momentum and energy equations is addressed and a proper definition for friction factors and heat transfer coefficients are discussed. A numerical scheme using a solution to Navier-Stokes equations over a representative elementary volume (REV) and the use of VAT is developed to show how to compute friction factors and heat transfer coefficients. The calculation show good agreement with the experimental data. For the heat transfer coefficient closure, a proper average for both fluid and solid is investigated. Different types of heating are also investigated in order to determine how it influences the heat transfer coefficient. A higher heat fluxes in small area condensers led us to the micro channels in contrast to the classical heat fin design. A micro channel can have various shapes to enhance heat transfer, but the shape that will lead to a higher heat flux removal with a moderate pumping power needs to be determined. The standard micro-channel terminology is usually used for channels with a simple cross section, e.g. square, round, triangle, etc., but here the micro channel cross section is going to be expanded to describe more complicated and interconnected micro scale channel cross sections. The micro channel geometries explored are pin fins (in-line and staggered) and sintered porous micro channels. The problem solved here is a conjugate problem involving two heat transfer mechanisms; (1) porous media conductivity and (2) internal heat transfer coefficient. Volume averaging theory (VAT) is used to rigorously cast the point wise conservation of energy, momentum and mass equations into a form that represents the thermal and hydraulic properties of the micro channel (porous media) morphology. Using the resulting VAT based field equations, optimization of a micro channel heated from one side is used to determine the optimum micro channel morphology. A small square of 1 cm2 is chosen as an example and the thermal resistance, 0C/W, and pressure drop are shown as a function of Reynolds number. The high heat flux removal on small surfaces at moderately small temperatures is achieved by bi-porous evaporator The device was analyzed with the possibility of heat flux magnitudes exceeding 1kW/cm2 by using advantages of a dual pore structure of a bi-porous wick. The heat transfer model of a thin bi-porous wick is developed and it incorporates thermo-physical properties of a bi-porous media. It is shown that physics of heat removal is characterized in three stages; conduction, big pore drying out and small pore drying out. The operating conditions of the wick have to be in a safe margin away from the total dry out. A complete dry out of the wick inevitably leads to the burn out, therefore more concern has been added to modeling of big pore dry out, since this will be a desired operational. The construction of the boiling/evaporation curves was successfully constructed by the model showing that the physic of heat removal on two different length scales is governed by thermo-physical properties for the appropriate scale. The model shows good prediction for various combinations of big and small pores size in the bi-porous wicks tested.

The Electrophysiological MEMS Device with Micro Channel Array for Cellular Network Analysis

NASA Astrophysics Data System (ADS)

Tonomura, Wataru; Kurashima, Toshiaki; Takayama, Yuzo; Moriguchi, Hiroyuki; Jimbo, Yasuhiko; Konishi, Satoshi

This paper describes a new type of MCA (Micro Channel Array) for simultaneous multipoint measurement of cellular network. Presented MCA employing the measurement principles of the patch-clamp technique is designed for advanced neural network analysis which has been studied by co-authors using 64ch MEA (Micro Electrode Arrays) system. First of all, sucking and clamping of cells through channels of developed MCA is expected to improve electrophysiological signal detections. Electrophysiological sensing electrodes integrated around individual channels of MCA by using MEMS (Micro Electro Mechanical System) technologies are electrically isolated for simultaneous multipoint measurement. In this study, we tested the developed MCA using the non-cultured rat's cerebral cortical slice and the hippocampal neurons. We could measure the spontaneous action potential of the slice simultaneously at multiple points and culture the neurons on developed MCA. Herein, we describe the experimental results together with the design and fabrication of the electrophysiological MEMS device with MCA for cellular network analysis.

Discussion on the solar concentrating thermoelectric generation using micro-channel heat pipe array

NASA Astrophysics Data System (ADS)

Li, Guiqiang; Feng, Wei; Jin, Yi; Chen, Xiao; Ji, Jie

2017-11-01

Heat pipe is a high efficient tool in solar energy applications. In this paper, a novel solar concentrating thermoelectric generation using micro-channel heat pipe array (STEG-MCHP) was presented. The flat-plate micro-channel heat pipe array not only has a higher heat transfer performance than the common heat pipe, but also can be placed on the surface of TEG closely, which can further reduce the thermal resistance between the heat pipe and the TEG. A preliminary comparison experiment was also conducted to indicate the advantages of the STEG-MCHP. The optimization based on the model verified by the experiment was demonstrated, and the concentration ratio and selective absorbing coating area were also discussed. In addition, the cost analysis was also performed to compare between the STEG-MCHP and the common solar concentrating TEGs in series. The outcome showed that the solar concentrating thermoelectric generation using micro-channel heat pipe array has the higher electrical efficiency and lower cost, which may provide a suitable way for solar TEG applications.

Fabrication of microfluidic architectures for optimal flow rate and concentration measurement for lab on chip application

NASA Astrophysics Data System (ADS)

Adam, Tijjani; Hashim, U.

2017-03-01

Optimum flow in micro channel for sensing purpose is challenging. In this study, The optimizations of the fluid sample flows are made through the design and characterization of the novel microfluidics' architectures to achieve the optimal flow rate in the micro channels. The biocompatibility of the Polydimetylsiloxane (Sylgard 184 silicon elastomer) polymer used to fabricate the device offers avenue for the device to be implemented as the universal fluidic delivery system for bio-molecules sensing in various bio-medical applications. The study uses the following methodological approaches, designing a novel microfluidics' architectures by integrating the devices on a single 4 inches silicon substrate, fabricating the designed microfluidic devices using low-cost solution soft lithography technique, characterizing and validating the flow throughput of urine samples in the micro channels by generating pressure gradients through the devices' inlets. The characterization on the urine samples flow in the micro channels have witnessed the constant flow throughout the devices.

[Studies on a sequential injection renewable surface reflectance spectrophotometric system using a microchip flow cell].

PubMed

Wang, Jian-ya; Fang, Zhao-lun

2002-02-01

A microchip flow cell was developed for flow injection renewable surface assay by reflectance spectrophotometry. The flow cell was coupled to a sequential injection system and optical fiber photometric detection system. The flow cell featured a three-layer structure. The flow channel was cut into a silicone rubber membrance which formed the middle layer, and a porous filter was inlayed across a widened section of the channel to trap microbeads introduced into the flow cell. The area of the detection window of the flow cell was approximately 3.6 mm2, the volume of the bead trapped in the flow cell was 2.2 microL, the depth of the bead layer was 600 microns. A multistrand bifurcated optical fiber was coupled with incident light, detector and flow cell. The chromogenic reaction of Cr(VI) with 1,5-diphenylcarbohydrazide (DPC) which was adsorbed on trapped Polysorb C-18 beads was used as a model reaction to optimize the flow cell design and the experimental system. The reflectance of the renewable reaction surface was monitored at 540 nm. With 100 microL sample loaded and 1.0 mL.min-1 carrier flow rate, the linear response range was 0-0.6 microgram.mL-1 Cr(VI). A detection limit (3 sigma) of 6 ng.mL-1, precision of 1.5% RSD(n = 11), and a throughput of 64 samples per hour were achieved. Considerations in system and flow cell design, the influence of depth of the bead layer, weight of beads used, and the flow rates of carrier stream on the performance were discussed.

Microwave Imaging in Large Helical Device

NASA Astrophysics Data System (ADS)

Yoshinaga, T.; Nagayama, Y.; Tsuchiya, H.; Kuwahara, D.; Tsuji-Iio, S.; Akaki, K.; Mase, A.; Kogi, Y.; Yamaguchi, S.; Shi, Z. B.; Hojo, H.

2011-02-01

Microwave imaging reflectometry (MIR) system and electron cyclotron emission imaging (ECEI) system are under development for the simultaneous reconstruction of the electron density and temperature fluctuation structures in the Large Helical Device (LHD). The MIR observes three-dimensional structure of disturbed cutoff surfaces by using the two-dimensionally distributed horn-antenna mixer array (HMA) of 5 × 7 channels in combination with the simultaneous projection of microwaves with four different frequency components (60.410, 61.808, 63.008 and 64.610 GHz). The ECEI is designed to observe two-dimensional structure of electron temperature by detecting second-harmonic ECE at 97-107 GHz with the one-dimensional HMA (7 channels) in the common optics with MIR system. Both the MIR and the ECEI are realized by the HMA and the band-pass filter (BPF) arrays, which are fabricated by micro-strip-line technique at low-cost.

All-optical regenerator of multi-channel signals.

PubMed

Li, Lu; Patki, Pallavi G; Kwon, Young B; Stelmakh, Veronika; Campbell, Brandon D; Annamalai, Muthiah; Lakoba, Taras I; Vasilyev, Michael

2017-10-12

One of the main reasons why nonlinear-optical signal processing (regeneration, logic, etc.) has not yet become a practical alternative to electronic processing is that the all-optical elements with nonlinear input-output relationship have remained inherently single-channel devices (just like their electronic counterparts) and, hence, cannot fully utilise the parallel processing potential of optical fibres and amplifiers. The nonlinear input-output transfer function requires strong optical nonlinearity, e.g. self-phase modulation, which, for fundamental reasons, is always accompanied by cross-phase modulation and four-wave mixing. In processing multiple wavelength-division-multiplexing channels, large cross-phase modulation and four-wave mixing crosstalks among the channels destroy signal quality. Here we describe a solution to this problem: an optical signal processor employing a group-delay-managed nonlinear medium where strong self-phase modulation is achieved without such nonlinear crosstalk. We demonstrate, for the first time to our knowledge, simultaneous all-optical regeneration of up to 16 wavelength-division-multiplexing channels by one device. This multi-channel concept can be extended to other nonlinear-optical processing schemes.Nonlinear optical processing devices are not yet fully practical as they are single channel. Here the authors demonstrate all-optical regeneration of up to 16 channels by one device, employing a group-delay-managed nonlinear medium where strong self-phase modulation is achieved without nonlinear inter-channel crosstalk.

Nateglinide, a D-phenylalanine derivative lacking either a sulfonylurea or benzamido moiety, specifically inhibits pancreatic beta-cell-type K(ATP) channels.

PubMed

Chachin, Motohiko; Yamada, Mitsuhiko; Fujita, Akikazu; Matsuoka, Tetsuro; Matsushita, Kenji; Kurachi, Yoshihisa

2003-03-01

A novel antidiabetic agent, nateglinide, is a D-phenylalanine derivative lacking either a sulfonylurea or benzamido moiety. We examined with the patch-clamp method the effect of nateglinide on recombinant ATP-sensitive K(+) (K(ATP)) channels expressed in human embryonic kidney 293T cells transfected with a Kir6.2 subunit and either of a sulfonylurea receptor (SUR) 1, SUR2A, and SUR2B. In inside-out patches, nateglinide reversibly inhibited the spontaneous openings of all three types of SUR/Kir6.2 channels. Nateglinide inhibited SUR1/Kir6.2 channels with high and low affinities (K(i) = 75 nM and 114 microM) but SUR2A/Kir6.2 and SUR2B/Kir6.2 channels only with low affinity (K(i) = 105 and 111 microM, respectively). Nateglinide inhibited the K(ATP) current mediated by Kir6.2 lacking C-terminal 26 amino acids only with low affinity (K(i) = 290 microM) in the absence of SUR. Replacement of serine at position 1237 of SUR1 to tyrosine [SUR1(S1237Y)] specifically abolished the high-affinity inhibition of SUR1/Kir6.2 channels by nateglinide. MgADP or MgUDP (100 microM) augmented the inhibitory effect of nateglinide on SUR1/Kir6.2 but not SUR1(S1237Y)/Kir6.2 or SUR2A/Kir6.2 channels. This augmenting effect of MgADP was also observed with the SUR1/Kir6.2(K185Q) channel, which was not inhibited by MgADP, but not with the SUR1(K1384A)/Kir6.2 channel, which was not activated by MgADP. These results indicate that therapeutic concentrations of nateglinide (approximately 10 microM) may selectively inhibit pancreatic type SUR1/Kir6.2 channels through SUR1, especially when the channel is activated by intracellular MgADP, even though the agent does not contain either a sulfonylurea or benzamido moiety.

Microfluidic in-channel multi-electrode platform for neurotransmitter sensing

NASA Astrophysics Data System (ADS)

Kara, A.; Mathault, J.; Reitz, A.; Boisvert, M.; Tessier, F.; Greener, J.; Miled, A.

2016-03-01

In this project we present a microfluidic platform with in-channel micro-electrodes for in situ screening of bio/chemical samples through a lab-on-chip system. We used a novel method to incorporate electrochemical sensors array (16x20) connected to a PCB, which opens the way for imaging applications. A 200 μm height microfluidic channel was bonded to electrochemical sensors. The micro-channel contains 3 inlets used to introduce phosphate buffer saline (PBS), ferrocynide and neurotransmitters. The flow rate was controlled through automated micro-pumps. A multiplexer was used to scan electrodes and perform individual cyclic voltammograms by a custom potentiostat. The behavior of the system was linear in terms of variation of current versus concentration. It was used to detect the neurotransmitters serotonin, dopamine and glutamate.

Local x-ray structure analysis of optically manipulated biological micro-objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cojoc, Dan; Ferrari, Enrico; Santucci, Silvia C.

2010-12-13

X-ray diffraction using micro- and nanofocused beams is well suited for nanostructure analysis at different sites of a biological micro-object. To conduct in vitro studies without mechanical contact, we developed object manipulation by optical tweezers in a microfluidic cell. Here we report x-ray microdiffraction analysis of a micro-object optically trapped in three dimensions. We revealed the nanostructure of a single starch granule at different points and investigated local radiation damage induced by repeated x-ray exposures at the same position, demonstrating high stability and full control of the granule orientation by multiple optical traps.

Aerosol Correction for Remotely Sensed Sea Surface Temperatures From the NOAA AVHRR: Phase II

NASA Astrophysics Data System (ADS)

Nalli, N. R.; Ignatov, A.

2002-05-01

For over two decades, the National Oceanic and Atmospheric Administration (NOAA) has produced global retrievals of sea surface temperature (SST) using infrared (IR) data from the Advanced Very High Resolution Radiometer (AVHRR). The standard multichannel retrieval algorithms are derived from regression analyses of AVHRR window channel brightness temperatures against in situ buoy measurements under non-cloudy conditions thus providing a correction for IR attenuation due to molecular water vapor absorption. However, for atmospheric conditions with elevated aerosol levels (e.g., arising from dust, biomass burning and volcanic eruptions), such algorithms lead to significant negative biases in SST because of IR attenuation arising from aerosol absorption and scattering. This research presents the development of a 2nd-phase aerosol correction algorithm for daytime AVHRR SST. To accomplish this, a long-term (1990-1998), global AVHRR-buoy matchup database was created by merging the Pathfinder Atmospheres (PATMOS) and Oceans (PFMDB) data sets. The merged data are unique in that they include multi-year, global daytime estimates of aerosol optical depth (AOD) derived from AVHRR channels 1 and 2 (0.63 and 0.83 μ m, respectively), along with an effective Angstrom exponent derived from the AOD retrievals (Ignatov and Nalli, 2002). Recent enhancements in the aerosol data constitute an improvement over the Phase I algorithm (Nalli and Stowe, 2002) which relied only on channel 1 AOD and the ratio of normalized reflectance from channels 1 and 2. The Angstrom exponent and channel 2 AOD provide important statistical information about the particle size distribution of the aerosol. The SST bias can be parametrically expressed as a function of observed AVHRR channels 1 and 2 slant-path AOD, normalized reflectance ratio and the Angstrom exponent. Based upon these empirical relationships, aerosol correction equations are then derived for the daytime multichannel and nonlinear SST (MCSST and NLSST) algorithms. Separate sets of coefficients are utilized for two aerosol modes, these being stratospheric/tropospheric (e.g., volcanic aerosol) and tropospheric (e.g., dust, smoke). The algorithms are subsequently applied to retrospective PATMOS data to demonstrate the potential for climate applications. The minimization of cold biases in the AVHRR SST, as demonstrated in this work, should improve its overall utility for the general user community.

Amiodarone inhibits sarcolemmal but not mitochondrial KATP channels in Guinea pig ventricular cells.

PubMed

Sato, Toshiaki; Takizawa, Taichi; Saito, Tomoaki; Kobayashi, Satoru; Hara, Yukio; Nakaya, Haruaki

2003-12-01

ATP-sensitive K(+) (KATP) channels are present on the sarcolemma (sarcKATP channels) and mitochondria (mitoKATP channels) of cardiac myocytes. Amiodarone, a class III antiarrhythmic drug, reduces sudden cardiac death in patients with organic heart disease. The objective of the present study was to investigate the effects of amiodarone on sarcKATP and mitoKATP channels. Single sarcKATP channel current and flavoprotein fluorescence were measured in guinea pig ventricular myocytes to assay sarcKATP and mitoKATP channel activity, respectively. Amiodarone inhibited the sarcKATP channel currents in a concentration-dependent manner without affecting its unitary amplitude. The IC50 values were 0.35 microM in the inside-out patch exposed to an ATP-free solution and 2.8 microM in the cell-attached patch under metabolic inhibition, respectively. Amiodarone (10 microM) alone did not oxidize the flavoprotein. In addition, the oxidative effect of the mitoKATP channel opener diazoxide (100 microM) was unaffected by amiodarone. Exposure to ouabain (1 mM) for 30 min produced mitochondrial Ca(2+) overload, and the intensity of rhod-2 fluorescence increased to 246 +/- 16% of baseline (n = 9). Amiodarone did not alter the ouabain-induced mitochondrial Ca(2+) overload (236 +/- 10% of baseline, n = 7). Treatment with diazoxide significantly reduced the ouabain-induced mitochondrial Ca(2+) overload (158 +/- 15% of baseline, n = 8, p < 0.05 versus ouabain); this effect was not abolished by amiodarone (154 +/- 10% of baseline, n = 8, p < 0.05 versus ouabain). These results suggest that amiodarone inhibits sarcKATP but not mitoKATP channels in cardiac myocytes. Such an action of amiodarone may effectively prevent ischemic arrhythmias without causing ischemic damage.

Preface

NASA Astrophysics Data System (ADS)

Zhuge, Qunbi; Chen, Xi

2018-02-01

Global IP traffic is predicted to increase nearly threefold over the next 5 years, driven by emerging high-bandwidth-demanding applications, such as cloud computing, 5G wireless, high-definition video streaming, and virtual reality. This results in a continuously increasing demand on the capacity of backbone optical networks. During the past decade, advanced digital signal processing (DSP), modulation formats, and forward error correction (FEC) were commercially realized to exploit the capacity potential of long-haul fiber channels, and have increased per channel data rate from 10 Gb/s to 400 Gb/s. DSP has played a crucial role in coherent transceivers to accommodate channel impairments including chromatic dispersion (CD), polarization mode dispersion (PMD), laser phase noise, fiber nonlinearities, clock jitter, and so forth. The advance of DSP has also enabled innovations in modulation formats to increase spectral efficiency, improve linear/nonlinear noise tolerance, and realize flexible bandwidth. Moving forward to next generation 1 Tb/s systems on conventional single mode fiber (SMF) platform, more innovations in DSP techniques are needed to further reduce cost per bit, increase network efficiency, and close the gap to the Shannon limit. To further increase capacity per fiber, spatial-division multiplexing (SDM) systems can be used. DSP techniques such as advanced channel equalization methods and distortion compensation can help SDM systems to achieve higher system capacity. In the area of short-reach transmission, the rapid increase of data center network traffic has driven the development of optical technologies for both intra- and inter-data center interconnects (DCI). In particular, DSP has been exploited in intensity-modulation direct detection (IM/DD) systems to realize 400 Gb/s pluggable optical transceivers. In addition, multi-dimensional direct detection modulation schemes are being investigated to increase the data rate per wavelength targeting 1 Tb/s interface.

Study on micro-bend light transmission performance of novel liquid-core optical fiber

NASA Astrophysics Data System (ADS)

Ma, Junyan; Zhao, Zhimin; Wang, Kaisheng; Guo, Linfeng

2007-01-01

With the increasing development of material technology and electronic integration technology, optical fiber and its using in smart structure have become hot in the field of material research. And liquid-core optical fiber is a special kind of optical fiber, which is made using liquid material as core and polymer material as optical layer and protective covering, and it has the characteristics of large core diameter, high numerical aperture, large-scope and efficient spectrum transmission and long life for using. So the liquid-core optical fiber is very suitable for spectrum cure, ultraviolet solidification, fluorescence detection, criminal investigation and evidence obtainment, etc, and especially as light transfer element in some new structures for the measurement of some signals, such as concentration, voltage, temperature, light intensity and so on. In this paper, the novel liquid-core optical fiber is self-made, and then through the test of its light transmission performance in free state, the relation between axial micro-bend and light-intensity loss are presented. When the liquid-core optical fiber is micro-bent axially, along with the axial displacement's increase, output power of light is reducing increasingly, and approximately has linear relation to micro-displacement in a range. According to the results liquid-core fiber-optic micro-bend sensor can be designed to measure micro-displacement of the tested objects. Experimental data and analysis provide experimental basis for further application of liquid-core optical fiber.

Micro-elastometry on whole blood clots using actuated surface-attached posts (ASAPs).

PubMed

Judith, Robert M; Fisher, Jay K; Spero, Richard Chasen; Fiser, Briana L; Turner, Adam; Oberhardt, Bruce; Taylor, R M; Falvo, Michael R; Superfine, Richard

2015-03-07

We present a novel technology for microfluidic elastometry and demonstrate its ability to measure stiffness of blood clots as they form. A disposable micro-capillary strip draws small volumes (20 μL) of whole blood into a chamber containing a surface-mounted micropost array. The posts are magnetically actuated, thereby applying a shear stress to the blood clot. The posts' response to magnetic field changes as the blood clot forms; this response is measured by optical transmission. We show that a quasi-static model correctly predicts the torque applied to the microposts. We experimentally validate the ability of the system to measure clot stiffness by correlating our system with a commercial thromboelastograph. We conclude that actuated surface-attached post (ASAP) technology addresses a clinical need for point-of-care and small-volume elastic haemostatic assays.

Systems, methods, and apparatus of a low conductance silicon micro-leak for mass spectrometer inlet

NASA Technical Reports Server (NTRS)

Harpold, Dan N. (Inventor); Niemann, Hasso B. (Inventor); Jamieson, Brian G. (Inventor); Lynch, Bernard A. (Inventor)

2011-01-01

Systems, methods and apparatus are provided through which in some embodiments a mass spectrometer micro-leak includes a number of channels fabricated by semiconductor processing tools and that includes a number of inlet holes that provide access to the channels.

Systems, Methods, and Apparatus of a Low Conductance Silicon Micro-Leak for Mass Spectrometer Inlet

NASA Technical Reports Server (NTRS)

Harpold, Dan N. (Inventor); Niemann, Hasso B. (Inventor); Jamieson, Brian G. (Inventor); Lynch, Bernard A. (Inventor)

2013-01-01

Systems, methods and apparatus are provided through which in some embodiments a mass spectrometer micro-leak includes a number of channels fabricated by semiconductor processing tools and that includes a number of inlet holes that provide access to the channels.

A micro-machined piezoelectric flexural-mode hydrophone with air backing: a hydrostatic pressure-balancing mechanism for integrity preservation.

PubMed

Choi, Sungjoon; Lee, Haksue; Moon, Wonkyu

2010-09-01

Although an air-backed thin plate is an effective sound receiver structure, it is easily damaged via pressure unbalance caused by external hydrostatic pressure. To overcome this difficulty, a simple pressure-balancing module is proposed. Despite its small size and relative simplicity, with proper design and operation, micro-channel structure provides a solution to the pressure-balancing problem. If the channel size is sufficiently small, the gas-liquid interface may move back and forth without breach by the hydrostatic pressure since the surface tension can retain the interface surface continuously. One input port of the device is opened to an intermediate liquid, while the other port is connected to the air-backing chamber. As the hydrostatic pressure increases, the liquid in the micro-channel compresses the air, and the pressure in the backing chamber is then equalized to match the external hydrostatic pressure. To validate the performance of the proposed mechanism, a micro-channel prototype is designed and integrated with the piezoelectric micro-machined flexural sensor developed in our previous work. The working principle of the mechanism is experimentally verified. In addition, the effect of hydrostatic pressure on receiving sensitivity is evaluated and compared with predicted behavior.

Recent progress in liquid crystal projection displays

NASA Astrophysics Data System (ADS)

Hamada, Hiroshi

1997-05-01

An LC-projector usually contains 3 monochrome TFT-LCDs with a 3-channel dichroic system or a single TFT-LCD with a micro color filter. The liquid crystal operation mode adopted in a TFT-LCD is TN. The optical throughput of an LC-projector is reduced by a pair of polarizers, an aperture ratio of a TFT- LCD and a color filter in a single-LCD projector. In order to eliminate absorption loss by a color filter, a single LCD projection system which consists of a monochrome LCD with a microlens array and a color splitting system using tilted dichroic mirrors or another optical element such as a holographic optical element or a blazed grating has been developed. And LC rear projection TVs have started to challenge CRT-based rear projection TVs. In addition to this system, new technologies to improve optical throughput have been developed to the practical stage such as an active- matrix-addressed PDLC and a reflective type LCD on a Si-LSI chip. Merits and technical issues of newly developed systems and conventional systems including a-Si TFT-LCDs and p-Si TFT-LCDs are discussed mainly in terms of optical throughput.

LOCSET Phase Locking: Operation, Diagnostics, and Applications

NASA Astrophysics Data System (ADS)

Pulford, Benjamin N.

The aim of this dissertation is to discuss the theoretical and experimental work recently done with the Locking of Optical Coherence via Single-detector Electronic-frequency Tagging (LOCSET) phase locking technique developed and employed here are AFRL. The primary objectives of this effort are to detail the fundamental operation of the LOCSET phase locking technique, recognize the conditions in which the LOCSET control electronics optimally operate, demonstrate LOCSET phase locking with higher channel counts than ever before, and extend the LOCSET technique to correct for low order, atmospherically induced, phase aberrations introduced to the output of a tiled array of coherently combinable beams. The experimental work performed for this effort resulted in the coherent combination of 32 low power optical beams operating with unprecedented LOCSET phase error performance of lambda/71 RMS in a local loop beam combination configuration. The LOCSET phase locking technique was also successfully extended, for the first time, into an Object In the Loop (OIL) configuration by utilizing light scattered off of a remote object as the optical return signal for the LOCSET phase control electronics. Said LOCSET-OIL technique is capable of correcting for low order phase aberrations caused by atmospheric turbulence disturbances applied across a tiled array output.

Analysis of creating an innovative micro-lens made of polydimethylsiloxane polymer on the end of the optical fibers

NASA Astrophysics Data System (ADS)

Zboril, O.; Cubik, J.; Nedoma, J.; Fajkus, M.; Novak, M.; Jargus, J.; Stratil, T.; Vasinek, V.

2017-10-01

The article describes a method for fabrication of polymer optical micro-lenses using polydimethylsiloxane (PDMS) at the end of optical fibers. PDMS is an optically clear substance having a refractive index very similar to the optical fibers. Therefore it is an interesting material for optical purposes. PDMS is characterized by resistance to electromagnetic interference (EMI), enabling the use in electromagnetically noisy environments. These lenses could be used for example for the security applications. For the manufacture of the micro-lenses is used Sylgard silicone elastomer 184. When applied to the end of conventional optical fiber is cured by treatment at 100 °C +/- 5 °C. Authors performed a series of experimental measurements. The optical characteristics of the treated fibers compared with conventional fibers without micro-lenses. The fibers provided with optical lenses made of PDMS may be used for security applications, in the visible light communication (VLC) or as a microprobe.

A Rapid Capillary-Pressure Driven Micro-Channel to Demonstrate Newtonian Fluid Behavior of Zebrafish Blood at High Shear Rates.

PubMed

Lee, Juhyun; Chou, Tzu-Chieh; Kang, Dongyang; Kang, Hanul; Chen, Junjie; Baek, Kyung In; Wang, Wei; Ding, Yichen; Carlo, Dino Di; Tai, Yu-Chong; Hsiai, Tzung K

2017-05-16

Blood viscosity provides the rheological basis to elucidate shear stress underlying developmental cardiac mechanics and physiology. Zebrafish is a high throughput model for developmental biology, forward-genetics, and drug discovery. The micro-scale posed an experimental challenge to measure blood viscosity. To address this challenge, a microfluidic viscometer driven by surface tension was developed to reduce the sample volume required (3μL) for rapid (<2 min) and continuous viscosity measurement. By fitting the power-law fluid model to the travel distance of blood through the micro-channel as a function of time and channel configuration, the experimentally acquired blood viscosity was compared with a vacuum-driven capillary viscometer at high shear rates (>500 s -1 ), at which the power law exponent (n) of zebrafish blood was nearly 1 behaving as a Newtonian fluid. The measured values of whole blood from the micro-channel (4.17cP) and the vacuum method (4.22cP) at 500 s -1 were closely correlated at 27 °C. A calibration curve was established for viscosity as a function of hematocrits to predict a rise and fall in viscosity during embryonic development. Thus, our rapid capillary pressure-driven micro-channel revealed the Newtonian fluid behavior of zebrafish blood at high shear rates and the dynamic viscosity during development.

High Efficiency Coupling of Optical Fibres with SU8 Micro-droplet Using Laser Welding Process

NASA Astrophysics Data System (ADS)

Yardi, Seema; Gupta, Ankur; Sundriyal, Poonam; Bhatt, Geeta; Kant, Rishi; Boolchandani, D.; Bhattacharya, Shantanu

2016-09-01

Apart from micro- structure fabrication, ablation, lithography etc., lasers find a lot of utility in various areas like precision joining, device fabrication, local heat delivery for surface texturing and local change of microstructure fabrication of standalone optical micro-devices (like microspheres, micro-prisms, micro-scale ring resonators, optical switches etc). There is a wide utility of such systems in chemical/ biochemical diagnostics and also communications where the standalone optical devices exist at a commercial scale but chip based devices with printed optics are necessary due to coupling issues between printed structures and external optics. This paper demonstrates a novel fabrication strategy used to join standalone optical fibres to microchip based printed optics using a simple SU8 drop. The fabrication process is deployed for fiber to fiber optical coupling and coupling between fiber and printed SU-8 waveguides. A CO2 laser is used to locally heat the coupling made up of SU8 material. Optimization of various dimensional parameters using design of experiments (DOE) on the bonded assembly has been performed as a function of laser power, speed, cycle control, spot size so on so forth. Exclusive optical [RF] modelling has been performed to estimate the transmissibility of the optical fibers bonded to each other on a surface with SU8. Our studies indicate the formation of a Whispering gallery mode (WGM) across the micro-droplet leading to high transmissibility of the signal. Through this work we have thus been able to develop a method of fabrication for optical coupling of standalone fibers or coupling of on-chip optics with off-chip illumination/detection.

Energy calibration of the fly's eye detector

NASA Technical Reports Server (NTRS)

Baltrusaitis, R. M.; Cassiday, G. L.; Cooper, R.; Elbert, J. W.; Gerhardy, P. R.; Ko, S.; Loh, E. C.; Mizumoto, Y.; Sokolsky, P.; Steck, D.

1985-01-01

The methods used to calibrate the Fly's eye detector to evaluate the energy of EAS are discussed. The energy of extensive air showers (EAS) as seen by the Fly's Eye detector are obtained from track length integrals of observed shower development curves. The energy of the parent cosmic ray primary is estimated by applying corrections to account for undetected energy in the muon, neutrino and hadronic channels. Absolute values for E depend upon the measurement of shower sizes N sub e(x). The following items are necessary to convert apparent optical brightness into intrinsical optical brightness: (1) an assessment of those factors responsible for light production by the relativistic electrons in an EAS and the transmission of light thru the atmosphere, (2) calibration of the optical detection system, and (3) a knowledge of the trajectory of the shower.

A novel micro/nano 1 × 4 mechanical optical switch

NASA Astrophysics Data System (ADS)

Lin, Wu-Lang; Fan, Kuang-Chao; Chiang, Li-Hung; Yang, Yao-Joe; Kuo, Wen-Cheng; Chung, Tien-Tung

2006-07-01

This paper presents the design, fabrication and testing of a novel 1 × 4 mechanical optical switch, whose components are fabricated by precision machining and MEMS technologies. The switch uses two relays as the two actuators whose switching direction is perpendicular to each other by an orthogonal arrangement. We adopt a direct fiber-to-fiber principle that aligns the input fiber directly to four output fibers. This configuration eliminates the use of traditional parts such as collimators, turning mirrors or prisms. In addition, due to the use of a fiber holder, the fiber position errors could be reduced to less than 0.27 µm using the two-stage geometry error reduction principle. We have successfully developed a simple and low-cost switch, which performs like most of the 1 × 4 mechanical optical switches that dominate the optics communications market. The advantages of our switch are a small size (20 × 20 × 25 mm3), low cost, high reliability, and the latching function does not need external force for maintaining the state. The experimental results showed that the insertion losses of the four channels are ch1: 0.68 dB, ch2: 1.49 dB, ch3: 0.71 dB and ch4: 0.97 dB. The switching time is 5 ms, the crosstalk <=80 dB. The reliability tests of the insertion loss after 10 000 cycles in four channels yield ch1: 1.67 dB, ch2: 1.63 dB, ch3: 0.75 dB and ch4: 0.98 dB. The size and the cost of our 1 × 4 mechanical optical switch are only about 1/5-1/10 and 1/10 of the series-connect-type and prism-type switches, respectively.

Behavior of micro-particles in monolith ceramic membrane filtration with pre-coagulation.

PubMed

Yonekawa, H; Tomita, Y; Watanabe, Y

2004-01-01

This paper is intended to clarify the characteristics unique to monolith ceramic membranes with pre-coagulation by referring to the behavior of micro-particles. Flow analysis and experiments have proved that monolith ceramic membranes show a unique flow pattern in the channels within the element, causing extremely rapid flocculation in the channel during dead-end filtration. It was assumed that charge-neutralized micro-particles concentrated near the membrane surface grow in size due to flocculation, and as a result, coarse micro-particles were taken up by the shearing force to flow out. As the dead end points of flow in all the channels are located near the end of the channels with higher filterability, most of the flocculated coarse particles are formed to a columnar cake intensively at the dead end point. Therefore cake layer forming on the membrane other than around the dead end point is alleviated. This behavior of particle flocculation and cake formation at the dead end point within the channels are unique characteristics of monolith ceramic membranes. This is why all monolith ceramic membrane water purification systems operating in Japan do not have pretreatment equipment for flocculation and sedimentation.

Linear Collider Test Facility: Twiss Parameter Analysis at the IP/Post-IP Location of the ATF2 Beam Line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolzon, Benoit; /Annecy, LAPP; Jeremie, Andrea

2012-07-02

At the first stage of the ATF2 beam tuning, vertical beam size is usually bigger than 3 {micro}m at the IP. Beam waist measurements using wire scanners and a laser wire are usually performed to check the initial matching of the beam through to the IP. These measurements are described in this paper for the optics currently used ({beta}{sub x} = 4cm and {beta}{sub y} = 1mm). Software implemented in the control room to automate these measurements with integrated analysis is also described. Measurements showed that {beta} functions and emittances were within errors of measurements when no rematching and couplingmore » corrections were done. However, it was observed that the waist in the horizontal (X) and vertical (Y) plane was abnormally shifted and simulations were performed to try to understand these shifts. They also showed that multiknobs are needed in the current optics to correct simultaneously {alpha}{sub x}, {alpha}{sub y} and the horizontal dispersion (D{sub x}). Such multiknobs were found and their linearity and orthogonality were successfully checked using MAD optics code. The software for these multiknobs was implemented in the control room and waist scan measurements using the {alpha}{sub y} knob were successfully performed.« less

Use of micro-resistivity imaging tools in developing lower Pennsylvanian Morrow channel sandstone reservoirs, Cheyenne, Kiowa and Lincoln Counties, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Germinario, M.P.

1996-12-31

In southeastern Colorado, Lower Pennsylvanian Morrow channel sandstones are part of complex valley-fill sequences incised into Morrow marine deposits. Morrow valleys are approximately {1/2} to 1 mile wide. Valley-fill consists of floodplain and channel filling shales, very fine-grained estuarine sandstones and fine- to coarse-grained channel sandstones that are up to 50` thick. Channel sandstones represent a sequence of stacked fluvial bars deposited in braided, anastomosing and meandering fluvial environments. Cross-stratification in channel sandstones can be imaged by micro-resistivity wireline logging tools and interpreted interactively on various workstation software packages. Recognition, interpretation and measurement of current, stoss face, and lateral accretionmore » beds in these sandstones can result in an estimated direction of paleocurrent flow of the channel. Determination of the channel`s local paleoflow direction can provide significant sand risk reduction in developmental drilling, especially in 80 acre or less spacing patterns. As the distance between offset drilling locations increases, the reliability of paleoflow prediction decreases, and the corresponding sand risk rises. Lateral accretion bedding in Morrow channel sandstones has proven to be a poor indicator of sand thickening direction, due to the complex stacking of multiple channel sandstones within any given valley-fill sequence. Micro-resistivity imaging reduces risk in Morrow channel sandstone development drilling programs. Furthermore, these interpretation techniques could be applicable in other fluvial channel sandstone plays.« less

Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

PubMed

Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

2016-04-15

A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

Micro guidance and control synthesis: New components, architectures, and capabilities

NASA Technical Reports Server (NTRS)

Mettler, Edward; Hadaegh, Fred Y.

1993-01-01

New GN&C (guidance, navigation and control) system capabilities are shown to arise from component innovations that involve the synergistic use of microminiature sensors and actuators, microelectronics, and fiber optics. Micro-GN&C system and component concepts are defined that include micro-actuated adaptive optics, micromachined inertial sensors, fiber-optic data nets and light-power transmission, and VLSI microcomputers. The thesis is advanced that these micro-miniaturization products are capable of having a revolutionary impact on space missions and systems, and that GN&C is the pathfinder micro-technology application that can bring that about.

Note: A timing micro-channel plate detector with backside fast preamplifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei; University of Chinese Academy of Sciences, Beijing 100049; School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000

2014-03-15

A timing micro-channel plate detector with a backside double-channel fast preamplifier was developed to avoid distortion during signal propagation from the anode to the preamplifier. The mechanical and electronic structure is described. The detector including its backside preamplifier is tested by a {sup 241}Am α-source and a rise time of ∼2 ns with an output background noise of 4 mV{sub rms} was achieved.

Polarization division multiplexing for optical data communications

NASA Astrophysics Data System (ADS)

Ivanovich, Darko; Powell, Samuel B.; Gruev, Viktor; Chamberlain, Roger D.

2018-02-01

Multiple parallel channels are ubiquitous in optical communications, with spatial division multiplexing (separate physical paths) and wavelength division multiplexing (separate optical wavelengths) being the most common forms. Here, we investigate the viability of polarization division multiplexing, the separation of distinct parallel optical communication channels through the polarization properties of light. Two or more linearly polarized optical signals (at different polarization angles) are transmitted through a common medium, filtered using aluminum nanowire optical filters fabricated on-chip, and received using individual silicon photodetectors (one per channel). The entire receiver (including optics) is compatible with standard CMOS fabrication processes. The filter model is based upon an input optical signal formed as the sum of the Stokes vectors for each individual channel, transformed by the Mueller matrix that models the filter proper, resulting in an output optical signal that impinges on each photodiode. The results show that two- and three-channel systems can operate with a fixed-threshold comparator in the receiver circuit, but four-channel systems (and larger) will require channel coding of some form. For example, in the four-channel system, 10 of 16 distinct bit patterns are separable by the receiver. The model supports investigation of the range of variability tolerable in the fabrication of the on-chip polarization filters.

Fabrication of an Optical Fiber Micro-Sphere with a Diameter of Several Tens of Micrometers.

PubMed

Yu, Huijuan; Huang, Qiangxian; Zhao, Jian

2014-06-25

A new method to fabricate an integrated optical fiber micro-sphere with a diameter within 100 µm, based on the optical fiber tapering technique and the Taguchi method is proposed. Using a 125 µm diameter single-mode (SM) optical fiber, an optical fiber taper with a cone angle is formed with the tapering technique, and the fabrication optimization of a micro-sphere with a diameter of less than 100 µm is achieved using the Taguchi method. The optimum combination of process factors levels is obtained, and the signal-to-noise ratio (SNR) of three quality evaluation parameters and the significance of each process factors influencing them are selected as the two standards. Using the minimum zone method (MZM) to evaluate the quality of the fabricated optical fiber micro-sphere, a three-dimensional (3D) numerical fitting image of its surface profile and the true sphericity are subsequently realized. From the results, an optical fiber micro-sphere with a two-dimensional (2D) diameter less than 80 µm, 2D roundness error less than 0.70 µm, 2D offset distance between the micro-sphere center and the fiber stylus central line less than 0.65 µm, and true sphericity of about 0.5 µm, is fabricated.

3D filling simulation of micro- and nanostructures in comparison to iso- and variothermal injection moulding trials

NASA Astrophysics Data System (ADS)

Rytka, C.; Lungershausen, J.; Kristiansen, P. M.; Neyer, A.

2016-06-01

Flow simulations can cut down both costs and time for the development of injection moulded polymer parts with functional surfaces used in life science and optical applications. We simulated the polymer melt flow into 3D micro- and nanostructures with Moldflow and Comsol and compared the results to real iso- and variothermal injection moulding trials below, at and above the transition temperature of the polymer. By adjusting the heat transfer coefficient and the transition temperature in the simulation it was possible to achieve good correlation with experimental findings at different processing conditions (mould temperature, injection velocity) for two polymers, namely polymethylmethacrylate and amorphous polyamide. The macroscopic model can be scaled down in volume and number of elements to save computational time for microstructure simulation and to enable first and foremost the nanostructure simulation, as long as local boundary conditions such as flow front speed are transferred correctly. The heat transfer boundary condition used in Moldflow was further evaluated in Comsol. Results showed that the heat transfer coefficient needs to be increased compared to macroscopic moulding in order to represent interfacial polymer/mould effects correctly. The transition temperature is most important in the packing phase for variothermal injection moulding.

Extremely stable piezo mechanisms for the new gravitational wave observatory

NASA Astrophysics Data System (ADS)

Pijnenburg, Joep; Rijnveld, Niek; Hogenhuis, Harm

2017-11-01

Detection and observation of gravitational waves requires extreme stability in the frequency range 3e-5 Hz to 1 Hz. NGO/LISA will attain this by creating a giant interferometer in space, based on free floating proof masses in three spacecrafts. To operate NGO/LISA, the following piezo mechanisms are developed: 1. A piezo stack mechanism (Point Angle Ahead Mechanism) Due to time delay in the interferometer arms, the beam angle needs to be corrected. A mechanism rotating a mirror with a piezo stack performs this task. The critical requirements are the contribution to the optical path difference (less than 1.4 pm/√Hz) and the angular jitter (less than 8 nrad/√Hz). 2. A piezo sliding mechanism (Fiber Switching Unit Actuator) To switch from primary to the redundant laser source, a Fiber Switching Unit Actuator (FSUA) is developed. The critical requirements are the coalignment of outgoing beams of <+/-1 micro radian and <+/-1 micro meter. A redundant piezo sliding mechanism rotates a wave plate over 45 degrees. 3. A piezo stepping mechanism (In Field Pointing Mechanism) Due to seasonal orbit evolution effects, beams have to be corrected over a stroke of +/-2.5 degrees. The critical requirements are the contribution to the optical path difference (less than 3.0 pm/√Hz) and the angular jitter (less than 1 nrad/√Hz). Due to the large stroke, a piezo stepping concept was selected. Dedicated control algorithms have been implemented to achieve these challenging requirements. This paper gives description of the designs and the ongoing process of qualifying the mechanisms for space applications.

Wafer-level fabrication of arrays of glass lens doublets

NASA Astrophysics Data System (ADS)

Passilly, Nicolas; Perrin, Stéphane; Albero, Jorge; Krauter, Johann; Gaiffe, Olivier; Gauthier-Manuel, Ludovic; Froehly, Luc; Lullin, Justine; Bargiel, Sylwester; Osten, Wolfgang; Gorecki, Christophe

2016-04-01

Systems for imaging require to employ high quality optical components in order to dispose of optical aberrations and thus reach sufficient resolution. However, well-known methods to get rid of optical aberrations, such as aspherical profiles or diffractive corrections are not easy to apply to micro-optics. In particular, some of these methods rely on polymers which cannot be associated when such lenses are to be used in integrated devices requiring high temperature process for their further assembly and separation. Among the different approaches, the most common is the lens splitting that consists in dividing the focusing power between two or more optical components. In here, we propose to take advantage of a wafer-level technique, devoted to the generation of glass lenses, which involves thermal reflow in silicon cavities to generate lens doublets. After the convex lens sides are generated, grinding and polishing of both stack sides allow, on the first hand, to form the planar lens backside and, on the other hand, to open the silicon cavity. Nevertheless, silicon frames are then kept and thinned down to form well-controlled and auto-aligned spacers between the lenses. Subsequent accurate vertical assembly of the glass lens arrays is performed by anodic bonding. The latter ensures a high level of alignment both laterally and axially since no additional material is required. Thanks to polishing, the generated lens doublets are then as thin as several hundreds of microns and compatible with micro-opto-electro-systems (MOEMS) technologies since they are only made of glass and silicon. The generated optical module is then robust and provide improved optical performances. Indeed, theoretically, two stacked lenses with similar features and spherical profiles can be almost diffraction limited whereas a single lens characterized by the same numerical aperture than the doublet presents five times higher wavefront error. To demonstrate such assumption, we fabricated glass lens doublets and compared them to single lenses of equivalent focusing power. For similar illumination, the optical aberrations are significantly reduced.

Optical assembly of bio-hybrid micro-robots.

PubMed

Barroso, Álvaro; Landwerth, Shirin; Woerdemann, Mike; Alpmann, Christina; Buscher, Tim; Becker, Maike; Studer, Armido; Denz, Cornelia

2015-04-01

The combination of micro synthetic structures with bacterial flagella motors represents an actual trend for the construction of self-propelled micro-robots. The development of methods for fabrication of these bacteria-based robots is a first crucial step towards the realization of functional miniature and autonomous moving robots. We present a novel scheme based on optical trapping to fabricate living micro-robots. By using holographic optical tweezers that allow three-dimensional manipulation in real time, we are able to arrange the building blocks that constitute the micro-robot in a defined way. We demonstrate exemplarily that our method enables the controlled assembly of living micro-robots consisting of a rod-shaped prokaryotic bacterium and a single elongated zeolite L crystal, which are used as model of the biological and abiotic components, respectively. We present different proof-of-principle approaches for the site-selective attachment of the bacteria on the particle surface. The propulsion of the optically assembled micro-robot demonstrates the potential of the proposed method as a powerful strategy for the fabrication of bio-hybrid micro-robots.

The application of micro-lesson in optics teaching

NASA Astrophysics Data System (ADS)

Yuan, Suzhen; Mao, Xuefeng; Lu, Yongle; Wang, Yan; Luo, Yuan

2017-08-01

In order to improve students' ability on self-study, this paper discusses the application of micro-lesson as a supplementary way in the course of optics teaching. Both geometric optics and wave optics require a lot of demos, fortunately, micro-lesson just meets this requirement. Nowadays, college education focuses on quality education, so the new nurture scheme of most universities shortened the class hours. However, the development of students and the social needs also require students to have a solid foundation. The effective way to solve this contradiction is to improve the efficiency of classroom teaching and provide the repeatable learning form, micro-lesson.

Testing of Piezo-Actuated Glass Micro-Membranes by Optical Low-Coherence Reflectometry.

PubMed

Merlo, Sabina; Poma, Paolo; Crisà, Eleonora; Faralli, Dino; Soldo, Marco

2017-02-25

In this work, we have applied optical low-coherence reflectometry (OLCR), implemented with infra-red light propagating in fiberoptic paths, to perform static and dynamic analyses on piezo-actuated glass micro-membranes. The actuator was fabricated by means of thin-film piezoelectric MEMS technology and was employed for modifying the micro-membrane curvature, in view of its application in micro-optic devices, such as variable focus micro-lenses. We are here showing that OLCR incorporating a near-infrared superluminescent light emitting diode as the read-out source is suitable for measuring various parameters such as the micro-membrane optical path-length, the membrane displacement as a function of the applied voltage (yielding the piezo-actuator hysteresis) as well as the resonance curve of the fundamental vibration mode. The use of an optical source with short coherence-time allows performing interferometric measurements without spurious resonance effects due to multiple parallel interfaces of highly planar slabs, furthermore selecting the plane/layer to be monitored. We demonstrate that the same compact and flexible setup can be successfully employed to perform spot optical measurements for static and dynamic characterization of piezo-MEMS in real time.

Testing of Piezo-Actuated Glass Micro-Membranes by Optical Low-Coherence Reflectometry

PubMed Central

Merlo, Sabina; Poma, Paolo; Crisà, Eleonora; Faralli, Dino; Soldo, Marco

2017-01-01

In this work, we have applied optical low-coherence reflectometry (OLCR), implemented with infra-red light propagating in fiberoptic paths, to perform static and dynamic analyses on piezo-actuated glass micro-membranes. The actuator was fabricated by means of thin-film piezoelectric MEMS technology and was employed for modifying the micro-membrane curvature, in view of its application in micro-optic devices, such as variable focus micro-lenses. We are here showing that OLCR incorporating a near-infrared superluminescent light emitting diode as the read-out source is suitable for measuring various parameters such as the micro-membrane optical path-length, the membrane displacement as a function of the applied voltage (yielding the piezo-actuator hysteresis) as well as the resonance curve of the fundamental vibration mode. The use of an optical source with short coherence-time allows performing interferometric measurements without spurious resonance effects due to multiple parallel interfaces of highly planar slabs, furthermore selecting the plane/layer to be monitored. We demonstrate that the same compact and flexible setup can be successfully employed to perform spot optical measurements for static and dynamic characterization of piezo-MEMS in real time. PMID:28245603

Development of a shear stress sensor to analyse the influence of polymers on the turbulent wall shear stress.

PubMed

Nottebrock, Bernardo; Grosse, Sebastian; Schröder, Wolfgang

2011-05-11

The drag reducing effect of polymers in a channel flow is well known and it is assumed that the polymer filaments interfere with the turbulent structures in the very near-wall flow. To analyse their precise effect, a micro-pillar shear stress sensor (MPS³) measurement system is developed which allows the detection of wall shear stress at high spatial and temporal resolutions. Different manufacturing techniques for the required micro-pillars are discussed and their influence on the flow is investigated evidencing the non-intrusive character of the pillars. Subsequently, a complete calibration is presented to relate the recorded deflection to wall shear stress values and to assure the correct detection over the whole expected frequency spectrum. A feasibility study about the ability to visualize the two-dimensional wall shear stress distribution completes the discussion about the validity of MPS³. In the last step, the drag reduction of a polymer filament grafted on a micro-pillar compared to a plain pillar and the application of MPS³ in an ocean-type polymer solution are investigated. The results confirm the expected behaviour found in the literature.

Note: Neutron bang time diagnostic system on Shenguang-III prototype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Qi; Chen, Jiabin; Liu, Zhongjie

A neutron bang time (NBT) diagnostic system has been implemented on Shenguang-III prototype. The bang time diagnostic system is based on a sensitive fusion neutron detector, which consists of a plastic scintillator and a micro-channel plate photomultiplier tube (PMT). An optical fiber bundle is used to couple the scintillator and the PMT. The bang time system is able to measure bang time above a neutron yield of 10{sup 7}. Bang times and start time of laser were related by probing x-ray pulses produced by 200 ps laser irradiating golden targets. Timing accuracy of the NBT is better than 60 ps.

Discriminant analysis of functional optical topography for schizophrenia diagnosis

NASA Astrophysics Data System (ADS)

Chuang, Ching-Cheng; Nakagome, Kazuyuki; Pu, Shenghong; Lan, Tsuo-Hung; Lee, Chia-Yen; Sun, Chia-Wei

2014-01-01

Abnormal prefrontal function plays a central role in the cognition deficits of schizophrenic patients; however, the character of the relationship between discriminant analysis and prefrontal activation remains undetermined. Recently, evidence of low prefrontal cortex (PFC) activation in individuals with schizophrenia has also been found during verbal fluency tests (VFT) and other cognitive tests with several neuroimaging methods. The purpose of this study is to assess the hemodynamic changes of the PFC and discriminant analysis between schizophrenia patients and healthy controls during VFT task by utilizing functional optical topography. A total of 99 subjects including 53 schizophrenic patients and 46 age- and gender-matched healthy controls were studied. The results showed that the healthy group had larger activation in the right and left PFC than in the middle PFC. Besides, the schizophrenic group showed weaker task performance and lower activation in the whole PFC than the healthy group. The result of the discriminant analysis showed a significant difference with P value <0.001 in six channels (CH 23, 29, 31, 40, 42, 52) between the schizophrenic and healthy groups. Finally, 68.69% and 71.72% of subjects are correctly classified as being schizophrenic or healthy with all 52 channels and six significantly different channels, respectively. Our findings suggest that the left PFC can be a feature region for discriminant analysis of schizophrenic diagnosis.

Optical biosensor system with integrated microfluidic sample preparation and TIRF based detection

NASA Astrophysics Data System (ADS)

Gilli, Eduard; Scheicher, Sylvia R.; Suppan, Michael; Pichler, Heinz; Rumpler, Markus; Satzinger, Valentin; Palfinger, Christian; Reil, Frank; Hajnsek, Martin; Köstler, Stefan

2013-05-01

There is a steadily growing demand for miniaturized bioanalytical devices allowing for on-site or point-of-care detection of biomolecules or pathogens in applications like diagnostics, food testing, or environmental monitoring. These, so called labs-on-a-chip or micro-total analysis systems (μ-TAS) should ideally enable convenient sample-in - result-out type operation. Therefore, the entire process from sample preparation, metering, reagent incubation, etc. to detection should be performed on a single disposable device (on-chip). In the early days such devices were mainly fabricated using glass or silicon substrates and adapting established fabrication technologies from the electronics and semiconductor industry. More recently, the development focuses on the use of thermoplastic polymers as they allow for low-cost high volume fabrication of disposables. One of the most promising materials for the development of plastic based lab-on-achip systems are cyclic olefin polymers and copolymers (COP/COC) due to their excellent optical properties (high transparency and low autofluorescence) and ease of processing. We present a bioanalytical system for whole blood samples comprising a disposable plastic chip based on TIRF (total internal reflection fluorescence) optical detection. The chips were fabricated by compression moulding of COP and microfluidic channels were structured by hot embossing. These microfluidic structures integrate several sample pretreatment steps. These are the separation of erythrocytes, metering of sample volume using passive valves, and reagent incubation for competitive bioassays. The surface of the following optical detection zone is functionalized with specific capture probes in an array format. The plastic chips comprise dedicated structures for simple and effective coupling of excitation light from low-cost laser diodes. This enables TIRF excitation of fluorescently labeled probes selectively bound to detection spots at the microchannel surface. The fluorescence of these detection arrays is imaged using a simple set-up based on a digital consumer camera. Image processing for spot detection and intensity calculation is accomplished using customized software. Using this combined TIRF excitation and imaging based detection approach allowes for effective suppression of background fluorescence from the sample, multiplexed detection in an array format, as well as internal calibration and background correction.

Reconfigurable and responsive droplet-based compound micro-lenses.

PubMed

Nagelberg, Sara; Zarzar, Lauren D; Nicolas, Natalie; Subramanian, Kaushikaram; Kalow, Julia A; Sresht, Vishnu; Blankschtein, Daniel; Barbastathis, George; Kreysing, Moritz; Swager, Timothy M; Kolle, Mathias

2017-03-07

Micro-scale optical components play a crucial role in imaging and display technology, biosensing, beam shaping, optical switching, wavefront-analysis, and device miniaturization. Herein, we demonstrate liquid compound micro-lenses with dynamically tunable focal lengths. We employ bi-phase emulsion droplets fabricated from immiscible hydrocarbon and fluorocarbon liquids to form responsive micro-lenses that can be reconfigured to focus or scatter light, form real or virtual images, and display variable focal lengths. Experimental demonstrations of dynamic refractive control are complemented by theoretical analysis and wave-optical modelling. Additionally, we provide evidence of the micro-lenses' functionality for two potential applications-integral micro-scale imaging devices and light field display technology-thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses.

Reconfigurable and responsive droplet-based compound micro-lenses

PubMed Central

Nagelberg, Sara; Zarzar, Lauren D.; Nicolas, Natalie; Subramanian, Kaushikaram; Kalow, Julia A.; Sresht, Vishnu; Blankschtein, Daniel; Barbastathis, George; Kreysing, Moritz; Swager, Timothy M.; Kolle, Mathias

2017-01-01

Micro-scale optical components play a crucial role in imaging and display technology, biosensing, beam shaping, optical switching, wavefront-analysis, and device miniaturization. Herein, we demonstrate liquid compound micro-lenses with dynamically tunable focal lengths. We employ bi-phase emulsion droplets fabricated from immiscible hydrocarbon and fluorocarbon liquids to form responsive micro-lenses that can be reconfigured to focus or scatter light, form real or virtual images, and display variable focal lengths. Experimental demonstrations of dynamic refractive control are complemented by theoretical analysis and wave-optical modelling. Additionally, we provide evidence of the micro-lenses' functionality for two potential applications—integral micro-scale imaging devices and light field display technology—thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses. PMID:28266505

Micro-laser

DOEpatents

Hutchinson, Donald P.; Richards, Roger K.

2003-07-22

A micro-laser is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide and at least one amplifying medium in the waveguide. PBG features are positioned between the first and second subwavelength resonant gratings and allow introduction of amplifying mediums into the highly resonant guided micro-laser microcavity. The micro-laser may be positioned on a die of a bulk substrate material with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a micro-laser is disclosed. A method for tuning the micro-laser is also disclosed. The micro-laser may be used as an optical regenerator, or a light source for data transfer or for optical computing.

Use of micro-resistivity imaging tools in developing lower Pennsylvanian Morrow channel sandstone reservoirs, Cheyenne, Kiowa and Lincoln Counties, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Germinario, M.P.

1996-01-01

In southeastern Colorado, Lower Pennsylvanian Morrow channel sandstones are part of complex valley-fill sequences incised into Morrow marine deposits. Morrow valleys are approximately [1/2] to 1 mile wide. Valley-fill consists of floodplain and channel filling shales, very fine-grained estuarine sandstones and fine- to coarse-grained channel sandstones that are up to 50' thick. Channel sandstones represent a sequence of stacked fluvial bars deposited in braided, anastomosing and meandering fluvial environments. Cross-stratification in channel sandstones can be imaged by micro-resistivity wireline logging tools and interpreted interactively on various workstation software packages. Recognition, interpretation and measurement of current, stoss face, and lateral accretionmore » beds in these sandstones can result in an estimated direction of paleocurrent flow of the channel. Determination of the channel's local paleoflow direction can provide significant sand risk reduction in developmental drilling, especially in 80 acre or less spacing patterns. As the distance between offset drilling locations increases, the reliability of paleoflow prediction decreases, and the corresponding sand risk rises. Lateral accretion bedding in Morrow channel sandstones has proven to be a poor indicator of sand thickening direction, due to the complex stacking of multiple channel sandstones within any given valley-fill sequence. Micro-resistivity imaging reduces risk in Morrow channel sandstone development drilling programs. Furthermore, these interpretation techniques could be applicable in other fluvial channel sandstone plays.« less

MEMS compatible illumination and imaging micro-optical systems

NASA Astrophysics Data System (ADS)

Bräuer, A.; Dannberg, P.; Duparré, J.; Höfer, B.; Schreiber, P.; Scholles, M.

2007-01-01

The development of new MOEMS demands for cooperation between researchers in micromechanics, optoelectronics and microoptics at a very early state. Additionally, microoptical technologies being compatible with structured silicon have to be developed. The microoptical technologies used for two silicon based microsystems are described in the paper. First, a very small scanning laser projector with a volume of less than 2 cm 3, which operates with a directly modulated lasers collimated with a microlens, is shown. The laser radiation illuminates a 2D-MEMS scanning mirror. The optical design is optimized for high resolution (VGA). Thermomechanical stability is realized by design and using a structured ceramics motherboard. Secondly, an ultrathin CMOS-camera having an insect inspired imaging system has been realized. It is the first experimental realization of an artificial compound eye. Micro-optical design principles and technology is used. The overall thickness of the imaging system is only 320 μm, the diagonal field of view is 21°, and the f-number is 2.6. The monolithic device consists of an UV-replicated microlens array upon a thin silica substrate with a pinhole array in a metal layer on the back side. The pitch of the pinholes differs from that of the lens array to provide individual viewing angle for each channel. The imaging chip is directly glued to a CMOS sensor with adapted pitch. The whole camera is less than 1mm thick. New packaging methods for these systems are under development.

Discovery deep space optical communications (DSOC) transceiver

NASA Astrophysics Data System (ADS)

Roberts, W. Thomas

2017-02-01

NASA's 22 cm diameter Deep Space Optical Communications (DSOC) Transceiver is designed to provide a bidirectional optical link between a spacecraft in the inner solar system and an Earth-based optical ground station. This design, optimized for operation across a wide range of illumination conditions, is focused on minimizing blinding from stray light, and providing reliable, accurate attitude information to point its narrow communication beam accurately to the future location of the ground terminal. Though our transceiver will transmit in the 1550 nm waveband and receive in the 1064 nm waveband, the system design relies heavily on reflective optical elements, extending flexibility to be modified for use at different wavebands. The design makes use of common path propagation among transmit, receive and pointing verification optical channels to maintain precise alignment among its components, and to naturally correct for element misalignment resulting from launch or thermal element perturbations. This paper presents the results of trade studies showing the evolution of the design, unique operational characteristics of the design, elements that help to maintain minimal stray light contamination, and preliminary results from development and initial testing of a functional aluminum test model.

Performance of an optical relay satellite using Reed-Solomon coding over a cascaded optical PPM and BPSK channel

NASA Technical Reports Server (NTRS)

Divsalar, D.; Naderi, F.

1982-01-01

The nature of the optical/microwave interface aboard the relay satellite is considered. To allow for the maximum system flexibility, without overburdening either the optical or RF channel, demodulating the optical on board the relay satellite but leaving the optical channel decoding to be performed at the ground station is examined. The occurrence of erasures in the optical channel is treated. A hard decision on the erasure (i.e., the relay selecting a symbol at random in case of erasure occurrence) seriously degrades the performance of the overall system. Coding the erasure occurrences at the relay and transmitting this information via an extra bit to the ground station where it can be used by the decoder is suggested. Many examples with varying bit/photon energy efficiency and for the noisy and noiseless optical channel are considered. It is shown that coding the erasure occurrences dramatically improves the performance of the cascaded channel relative to the case of hard decision on the erasure by the relay.

Laser-Driven Ion Acceleration from Plasma Micro-Channel Targets

PubMed Central

Zou, D. B.; Pukhov, A.; Yi, L. Q.; Zhou, H. B.; Yu, T. P.; Yin, Y.; Shao, F. Q.

2017-01-01

Efficient energy boost of the laser-accelerated ions is critical for their applications in biomedical and hadron research. Achiev-able energies continue to rise, with currently highest energies, allowing access to medical therapy energy windows. Here, a new regime of simultaneous acceleration of ~100 MeV protons and multi-100 MeV carbon-ions from plasma micro-channel targets is proposed by using a ~1020 W/cm2 modest intensity laser pulse. It is found that two trains of overdense electron bunches are dragged out from the micro-channel and effectively accelerated by the longitudinal electric-field excited in the plasma channel. With the optimized channel size, these “superponderomotive” energetic electrons can be focused on the front surface of the attached plastic substrate. The much intense sheath electric-field is formed on the rear side, leading to up to ~10-fold ionic energy increase compared to the simple planar geometry. The analytical prediction of the optimal channel size and ion maximum energies is derived, which shows good agreement with the particle-in-cell simulations. PMID:28218247

Laser-Driven Ion Acceleration from Plasma Micro-Channel Targets

NASA Astrophysics Data System (ADS)

Zou, D. B.; Pukhov, A.; Yi, L. Q.; Zhou, H. B.; Yu, T. P.; Yin, Y.; Shao, F. Q.

2017-02-01

Efficient energy boost of the laser-accelerated ions is critical for their applications in biomedical and hadron research. Achiev-able energies continue to rise, with currently highest energies, allowing access to medical therapy energy windows. Here, a new regime of simultaneous acceleration of ~100 MeV protons and multi-100 MeV carbon-ions from plasma micro-channel targets is proposed by using a ~1020 W/cm2 modest intensity laser pulse. It is found that two trains of overdense electron bunches are dragged out from the micro-channel and effectively accelerated by the longitudinal electric-field excited in the plasma channel. With the optimized channel size, these “superponderomotive” energetic electrons can be focused on the front surface of the attached plastic substrate. The much intense sheath electric-field is formed on the rear side, leading to up to ~10-fold ionic energy increase compared to the simple planar geometry. The analytical prediction of the optimal channel size and ion maximum energies is derived, which shows good agreement with the particle-in-cell simulations.

Fiber optic engine for micro projection display.

PubMed

Arabi, Hesam Edin; An, Sohee; Oh, Kyunghwan

2010-03-01

A novel compact optical engine for a micro projector display is experimentally demonstrated, which is composed of RGB light sources, a tapered 3 x 1 Fiber Optic Color Synthesizer (FOCS) along with a fiberized ball-lens, and a two dimensional micro electromechanical scanning mirror. In the proposed optical engine, we successfully employed an all-fiber beam shaping technique combining optical fiber taper and fiberized ball lens that can render a narrow beam and enhance the resolution of the screened image in the far field. Optical performances of the proposed device assembly are investigated in terms of power loss, collimating strength of the collimator assembly, and color gamut of the output.

Massively parallel processor networks with optical express channels

DOEpatents

Deri, R.J.; Brooks, E.D. III; Haigh, R.E.; DeGroot, A.J.

1999-08-24

An optical method for separating and routing local and express channel data comprises interconnecting the nodes in a network with fiber optic cables. A single fiber optic cable carries both express channel traffic and local channel traffic, e.g., in a massively parallel processor (MPP) network. Express channel traffic is placed on, or filtered from, the fiber optic cable at a light frequency or a color different from that of the local channel traffic. The express channel traffic is thus placed on a light carrier that skips over the local intermediate nodes one-by-one by reflecting off of selective mirrors placed at each local node. The local-channel-traffic light carriers pass through the selective mirrors and are not reflected. A single fiber optic cable can thus be threaded throughout a three-dimensional matrix of nodes with the x,y,z directions of propagation encoded by the color of the respective light carriers for both local and express channel traffic. Thus frequency division multiple access is used to hierarchically separate the local and express channels to eliminate the bucket brigade latencies that would otherwise result if the express traffic had to hop between every local node to reach its ultimate destination. 3 figs.

Massively parallel processor networks with optical express channels

DOEpatents

Deri, Robert J.; Brooks, III, Eugene D.; Haigh, Ronald E.; DeGroot, Anthony J.

1999-01-01

An optical method for separating and routing local and express channel data comprises interconnecting the nodes in a network with fiber optic cables. A single fiber optic cable carries both express channel traffic and local channel traffic, e.g., in a massively parallel processor (MPP) network. Express channel traffic is placed on, or filtered from, the fiber optic cable at a light frequency or a color different from that of the local channel traffic. The express channel traffic is thus placed on a light carrier that skips over the local intermediate nodes one-by-one by reflecting off of selective mirrors placed at each local node. The local-channel-traffic light carriers pass through the selective mirrors and are not reflected. A single fiber optic cable can thus be threaded throughout a three-dimensional matrix of nodes with the x,y,z directions of propagation encoded by the color of the respective light carriers for both local and express channel traffic. Thus frequency division multiple access is used to hierarchically separate the local and express channels to eliminate the bucket brigade latencies that would otherwise result if the express traffic had to hop between every local node to reach its ultimate destination.

Design of Cherenkov bars for the optical part of the time-of-flight detector in Geant4.

PubMed

Nozka, L; Brandt, A; Rijssenbeek, M; Sykora, T; Hoffman, T; Griffiths, J; Steffens, J; Hamal, P; Chytka, L; Hrabovsky, M

2014-11-17

We present the results of studies devoted to the development and optimization of the optical part of a high precision time-of-flight (TOF) detector for the Large Hadron Collider (LHC). This work was motivated by a proposal to use such a detector in conjunction with a silicon detector to tag and measure protons from interactions of the type p + p → p + X + p, where the two outgoing protons are scattered in the very forward directions. The fast timing detector uses fused silica (quartz) bars that emit Cherenkov radiation as a relativistic particle passes through and the emitted Cherenkov photons are detected by, for instance, a micro-channel plate multi-anode Photomultiplier Tube (MCP-PMT). Several possible designs are implemented in Geant4 and studied for timing optimization as a function of the arrival time, and the number of Cherenkov photons reaching the photo-sensor.

Perspectives of mid-infrared optical coherence tomography for inspection and micrometrology of industrial ceramics

PubMed Central

Su, Rong; Kirillin, Mikhail; Chang, Ernest W.; Sergeeva, Ekaterina; Yun, Seok H.; Mattsson, Lars

2014-01-01

Optical coherence tomography (OCT) is a promising tool for detecting micro channels, metal prints, defects and delaminations embedded in alumina and zirconia ceramic layers at hundreds of micrometers beneath surfaces. The effect of surface roughness and scattering of probing radiation within sample on OCT inspection is analyzed from the experimental and simulated OCT images of the ceramic samples with varying surface roughnesses and operating wavelengths. By Monte Carlo simulations of the OCT images in the mid-IR the optimal operating wavelength is found to be 4 µm for the alumina samples and 2 µm for the zirconia samples for achieving sufficient probing depth of about 1 mm. The effects of rough surfaces and dispersion on the detection of the embedded boundaries are discussed. Two types of image artefacts are found in OCT images due to multiple reflections between neighboring boundaries and inhomogeneity of refractive index. PMID:24977838

Design and analysis of optical waveguide elements in planar geometry

NASA Astrophysics Data System (ADS)

Mirkov, Mirko Georgiev

1998-10-01

This dissertation presents the theoretical analysis and practical design considerations for planar optical waveguide devices. The analysis takes into account both transverse dimensions of the waveguides and is based on the supermode theory combined with the resonance method for determination of the propagation constants and field profiles of the supermodes. An improved accuracy has been achieved by including the corrections due to the fields in the corner regions of the waveguides using perturbation theory. The following two classes of devices have been analyzed in detail. Curved rectangular waveguides are a common element in an integrated optics circuit. The theoretical analysis in this work shows that some commonly used approximations for determination of the propagation constants of the quasi-modes of the bent waveguides are not necessary. Specifically the imaginary part of the mode propagation constant, which determines the power loss, is calculated exactly using the resonance method, combined with a two- dimensional optimization routine for determination of the real and the imaginary parts of the propagation constants. Subsequently, the results are corrected for the effects of the fields in the corner regions. The latter corrections have not been previously computed and are shown to be significant. Power splitters are another common element of an integrated optical circuit. A new 'bend-free' splitter is suggested and analyzed. The new splitter design consists of only straight parallel channels, which considerably simplify both the analysis and the fabrication of the device. It is shown that a single design parameter determines the power splitting ratio, which can take any given value. The intrinsic power loss in the proposed splitter is minimal, which makes it an attractive alternative to the conventional Y-splitters. The accurate methods of analysis of planar optical waveguides developed in the present work can easily be applied to other integrated optic devices consisting of rectangular waveguides.

Correction of terrestrial LiDAR intensity channel using Oren-Nayar reflectance model: An application to lithological differentiation

NASA Astrophysics Data System (ADS)

Carrea, Dario; Abellan, Antonio; Humair, Florian; Matasci, Battista; Derron, Marc-Henri; Jaboyedoff, Michel

2016-03-01

Ground-based LiDAR has been traditionally used for surveying purposes via 3D point clouds. In addition to XYZ coordinates, an intensity value is also recorded by LiDAR devices. The intensity of the backscattered signal can be a significant source of information for various applications in geosciences. Previous attempts to account for the scattering of the laser signal are usually modelled using a perfect diffuse reflection. Nevertheless, experience on natural outcrops shows that rock surfaces do not behave as perfect diffuse reflectors. The geometry (or relief) of the scanned surfaces plays a major role in the recorded intensity values. Our study proposes a new terrestrial LiDAR intensity correction, which takes into consideration the range, the incidence angle and the geometry of the scanned surfaces. The proposed correction equation combines the classical radar equation for LiDAR with the bidirectional reflectance distribution function of the Oren-Nayar model. It is based on the idea that the surface geometry can be modelled by a relief of multiple micro-facets. This model is constrained by only one tuning parameter: the standard deviation of the slope angle distribution (σslope) of micro-facets. Firstly, a series of tests have been carried out in laboratory conditions on a 2 m2 board covered by black/white matte paper (perfect diffuse reflector) and scanned at different ranges and incidence angles. Secondly, other tests were carried out on rock blocks of different lithologies and surface conditions. Those tests demonstrated that the non-perfect diffuse reflectance of rock surfaces can be practically handled by the proposed correction method. Finally, the intensity correction method was applied to a real case study, with two scans of the carbonate rock outcrop of the Dents-du-Midi (Swiss Alps), to improve the lithological identification for geological mapping purposes. After correction, the intensity values are proportional to the intrinsic material reflectance and are independent from range, incidence angle and scanned surface geometry. The corrected intensity values significantly improve the material differentiation.

Transient electroosmotic flow induced by AC electric field in micro-channel with patchwise surface heterogeneities.

PubMed

Luo, Win-Jet

2006-03-15

This paper investigates two-dimensional, time-dependent electroosmotic flow driven by an AC electric field via patchwise surface heterogeneities distributed along the micro-channel walls. The time-dependent flow fields through the micro-channel are simulated for various patchwise heterogeneous surface patterns using the backwards-Euler time stepping numerical method. Different heterogeneous surface patterns are found to create significantly different electrokinetic transport phenomena. The transient behavior characteristics of the generated electroosmotic flow are then discussed in terms of the influence of the patchwise surface heterogeneities, the direction of the applied AC electric field, and the velocity of the bulk flow. It is shown that the presence of oppositely charged surface heterogeneities on the micro-channel walls results in the formation of localized flow circulations within the bulk flow. These circulation regions grow and decay periodically in phase with the applied periodic AC electric field intensity. The location and rotational direction of the induced circulations are determined by the directions of the bulk flow velocity and the applied electric field.

Sensitivity of atmospheric correction to loading and model of the aerosol

NASA Astrophysics Data System (ADS)

Bassani, Cristiana; Braga, Federica; Bresciani, Mariano; Giardino, Claudia; Adamo, Maria; Ananasso, Cristina; Alberotanza, Luigi

2013-04-01

The physically-based atmospheric correction requires knowledge of the atmospheric conditions during the remotely data acquisitions [Guanter et al., 2007; Gao et al., 2009; Kotchenova et al. 2009; Bassani et al., 2010]. The propagation of solar radiation in the atmospheric window of visible and near-infrared spectral domain, depends on the aerosol scattering. The effects of solar beam extinction are related to the aerosol loading, by the aerosol optical thickness @550nm (AOT) parameter [Kaufman et al., 1997; Vermote et al., 1997; Kotchenova et al., 2008; Kokhanovsky et al. 2010], and also to the aerosol model. Recently, the atmospheric correction of hyperspectral data is considered sensitive to the micro-physical and optical characteristics of aerosol, as reported in [Bassani et al., 2012]. Within the framework of CLAM-PHYM (Coasts and Lake Assessment and Monitoring by PRISMA HYperspectral Mission) project, funded by Italian Space Agency (ASI), the role of the aerosol model on the accuracy of the atmospheric correction of hyperspectral image acquired over water target is investigated. In this work, the results of the atmospheric correction of HICO (Hyperspectral Imager for the Coastal Ocean) images acquired on Northern Adriatic Sea in the Mediterranean are presented. The atmospheric correction has been performed by an algorithm specifically developed for HICO sensor. The algorithm is based on the equation presented in [Vermote et al., 1997; Bassani et al., 2010] by using the last generation of the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) radiative transfer code [Kotchenova et al., 2008; Vermote et al., 2009]. The sensitive analysis of the atmospheric correction of HICO data is performed with respect to the aerosol optical and micro-physical properties used to define the aerosol model. In particular, a variable mixture of the four basic components: dust- like, oceanic, water-soluble, and soot, has been considered. The water reflectance, obtained from the atmospheric correction with variable model and fixed loading of the aerosol, has been compared. The results highlight the requirements to define the aerosol characteristics, loading and model, to simulate the radiative field in the atmosphere system for an accurate atmospheric correction of hyperspectral data, improving the accuracy of the results for surface reflectance process over water, a dark-target. As conclusion, the aerosol model plays a crucial role for an accurate physically-based atmospheric correction of hyperspectral data over water. Currently, the PRISMA mission provides valuable opportunities to study aerosol and their radiative effects on the hyperspectral data. Bibliography Guanter, L.; Estellès, V.; Moreno, J. Spectral calibration and atmospheric correction of ultra-fine spectral and spatial resolution remote sensing data. Application to CASI-1500 data. Remote Sens. Environ. 2007, 109, 54-65. Gao, B.-C.; Montes, M.J.; Davis, C.O.; Goetz, A.F.H. Atmospheric correction algorithms for hyperspectral remote sensing data of land and ocean. Remote Sens. Environ. 2009, 113, S17-S24. Kotchenova, S. Atmospheric correction for the monitoring of land surfaces. J. Geophys. Res. 2009, 113, D23. Bassani C.; Cavalli, R.M.; Pignatti S. Aerosol optical retrieval and surface reflectance from airborne remote sensing data over land. Sens. 2010, 10, 6421-6438. Kaufman, Y. J., Tanrè, D., Gordon H. R., Nakajima T., Lenoble J., Frouin R., Grassl H., Herman B.M., King M., and Teillet P.M.: Operational remote sensing of tropospheric aerosol over land from EOS moderate resolution imaging spectroradiometer, J. Geophys. Res., 102(D14), 17051-17067, 1997. Vermote, E.F.; Tanrè , D.; Deuzè´ , J.L.; Herman M.; Morcrette J.J. Second simulation of the satellite signal in the solar spectrum, 6S: An overview. IEEE Trans. Geosci. Remote Sens. 1997, 35, 675-686. Kotchenova, S.Y.; Vermote, E.F.; Levy, R.; Lyapustin, A. Radiative transfer codes for atmospheric correction and aerosol retrieval: Intercomparison study. Appl. Optics 2008, 47, 2215-2226. Kokhanovsky A.A., Deuzè J.L., Diner D.J., Dubovik O., Ducos F., Emde C., Garay M.J., Grainger R.G., Heckel A., Herman M., Katsev I.L., Keller J., Levy R., North P.R.J., Prikhach A.S., Rozanov V.V., Sayer A.M., Ota Y., Tanrè D., Thomas G.E., Zege E.P. The inter-comparison of major satellite aerosol retrieval algorithms using simulated intensity and polarization characteristics of reflected light. Atmos. Meas. Tech., 3, 909-932, 2010. Bassani C.; Cavalli, R.M.; Antonelli, P. Influence of aerosol and surface reflectance variability on hyperspectral observed radiance. Atmos. Meas. Tech. 2012, 5, 1193-1203. Vermote , E.F.; Kotchenova, S. Atmospheric correction for the monitoring of land surfaces. J. Geophys. Res. 2009, 113, D23.

Simulation of electrokinetic flow in microfluidic channels

NASA Astrophysics Data System (ADS)

Sabur, Romena; Matin, M.

2005-08-01

Electrokinetic phenomena become an increasingly efficient fluid transport mechanism in micro- and nano-fluidic fields. These phenomena have also been applied successfully in microfluidic devices to achieve particle separation, pre-concentration and mixing. Electrokinetic is the flow produced by the action of an electric field on a fluid with a net charge, where the charged ions of fluid are able to drag the whole solution through the channels in the microfluidic device from one analyzing point to the other. We will present the simulation results of electrokinetic transports of fluid in various typical micro-channel geometries such as T-channel, Y-channel, cross channel and straight channel. In practice, high-speed micro-PIV technique is used to measure transient fluidic phenomena in a microfluidic channel. Particle Image Velocimetry (PIV) systems provide two- or three-dimensional velocity maps in flows using whole field techniques based on imaging the light scattered by small particles in the flow illuminated by a laser light sheet. The system generally consists of an epifluorescent microscope, CW laser and a high-speed CMOS of CCD camera. The flow of a liquid, (water for example), containing fluorescent particle is then analyzed in a counter microchannel by the highly accurate PIV method. One can then compare the simulated and experimental microfluidic flow due to electroosmotic effect.

MEMS: A new approach to micro-optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sniegowski, J.J.

1997-12-31

MicroElectroMechanical Systems (MEMS) and their fabrication technologies provide great opportunities for application to micro-optical systems (MOEMS). Implementing MOEMS technology ranges from simple, passive components to complicated, active systems. Here, an overview of polysilicon surface micromachining MEMS combined with optics is presented. Recent advancements to the technology, which may enhance its appeal for micro-optics applications are emphasized. Of all the MEMS fabrication technologies, polysilicon surface micromachining technology has the greatest basis in and leverages the most the infrastructure for silicon integrated circuit fabrication. In that respect, it provides the potential for very large volume, inexpensive production of MOEMS. This paper highlightsmore » polysilicon surface micromachining technology in regards to its capability to provide both passive and active mechanical elements with quality optical elements.« less

Thermo-optical dynamics in an optically pumped Photonic Crystal nano-cavity.

PubMed

Brunstein, M; Braive, R; Hostein, R; Beveratos, A; Rober-Philip, I; Sagnes, I; Karle, T J; Yacomotti, A M; Levenson, J A; Moreau, V; Tessier, G; De Wilde, Y

2009-09-14

Linear and non-linear thermo-optical dynamical regimes were investigated in a photonic crystal cavity. First, we have measured the thermal relaxation time in an InP-based nano-cavity with quantum dots in the presence of optical pumping. The experimental method presented here allows one to obtain the dynamics of temperature in a nanocavity based on reflectivity measurements of a cw probe beam coupled through an adiabatically tapered fiber. Characteristic times of 1.0+/-0.2 micros and 0.9+/-0.2 micros for the heating and the cooling processes were obtained. Finally, thermal dynamics were also investigated in a thermo-optical bistable regime. Switch-on/off times of 2 micros and 4 micros respectively were measured, which could be explained in terms of a simple non-linear dynamical representation.

Low-cost integrated-optic fiber couplers

NASA Astrophysics Data System (ADS)

Sheem, Sang K.; Zhang, Feng; Choi, Jong-Ho; Lee, Yong-Woo; Low, Sarah; Lu, Shih-Yau

1997-04-01

In an effort to lower the cost of fiber optic couplers, integrated optic channel waveguide circuits are made of a UV-curable polymer using a molding technique, and then a novel fiber-to-channel connecting approach is employed in which UV light radiating from an optical fiber core cures the polymer in the channel, thus accomplishing a 'touchdown' of the core-extension waveguide onto the walls of the channel waveguide.

Fabrication and characterization of microelectromechanical systems-based gas chromatography column with embedded micro-posts for separation of environmental carcinogens.

PubMed

Sun, Jianhai; Cui, Dafu; Chen, Xing; Zhang, Lulu; Cai, Haoyuan; Li, Hui

2013-05-24

In this paper, a micro gas chromatography (μGC) column with embedded micro-posts was developed for increasing overall surface area of the columns which is able to support more of the stationary phase and reducing the effective width of the column, leading to higher separation efficiency. The proposed columns have a higher sample capacity as the overall surface area is about 3 times larger than that of open columns with the same dimensions. In order to achieve an even flow velocity in the channels, the location of the micro-posts in the linear channels and the configuration of curved channels were optimized by numerical simulation. The results have indicated that the proposed column separated 5 environmental carcinogens in less than 50s, achieved a separation efficiency of about 9500plates/m and eluted highly symmetrical Gaussian peaks. Copyright © 2013 Elsevier B.V. All rights reserved.

Varying the agglomeration position of particles in a micro-channel using Acoustic Radiation Force beyond the resonance condition.

PubMed

Dron, Olivier; Aider, Jean-Luc

2013-09-01

It is well-known that particles can be focused at mid-height of a micro-channel using Acoustic Radiation Force (ARF) tuned at the resonance frequency (h=λ/2). The resonance condition is a strong limitation to the use of acoustophoresis (particles manipulation using acoustic force) in many applications. In this study we show that it is possible to focus the particles anywhere along the height of a micro-channel just by varying the acoustic frequency, in contradiction with the resonance condition. This result has been thoroughly checked experimentally. The different physical properties as well as wall materials have been changed. The wall materials is finally the only critical parameters. One of the specificity of the micro-channel is the thickness of the carrier and reflector layer. A preliminary analysis of the experimental results suggests that the acoustic focusing beyond the classic resonance condition can be explained in the framework of the multilayered resonator proposed by Hill [1]. Nevertheless, further numerical studies are needed in order to confirm and fully understand how the acoustic pressure node can be moved over the entire height of the micro channel by varying the acoustic frequency. Despite some uncertainties about the origin of the phenomenon, it is robust and can be used for improved acoustic sorting or manipulation of particles or biological cells in confined set-ups. Copyright © 2013 Elsevier B.V. All rights reserved.

Image simulation for electron energy loss spectroscopy

DOE PAGES

Oxley, Mark P.; Pennycook, Stephen J.

2007-10-22

In this paper, aberration correction of the probe forming optics of the scanning transmission electron microscope has allowed the probe-forming aperture to be increased in size, resulting in probes of the order of 1 Å in diameter. The next generation of correctors promise even smaller probes. Improved spectrometer optics also offers the possibility of larger electron energy loss spectrometry detectors. The localization of images based on core-loss electron energy loss spectroscopy is examined as function of both probe-forming aperture and detector size. The effective ionization is nonlocal in nature, and two common local approximations are compared to full nonlocal calculations.more » Finally, the affect of the channelling of the electron probe within the sample is also discussed.« less

Aerosol correction for remotely sensed sea surface temperatures from the National Oceanic and Atmospheric Administration advanced very high resolution radiometer

NASA Astrophysics Data System (ADS)

Nalli, Nicholas R.; Stowe, Larry L.

2002-10-01

This research presents the first-phase derivation and implementation of daytime aerosol correction algorithms for remotely sensed sea surface temperature (SST) from the advanced very high resolution radiometer (AVHRR) instrument flown onboard NOAA polar orbiting satellites. To accomplish this, a long-term (1990-1998), global AVHRR-buoy match-up database was created by merging the NOAA/NASA Pathfinder Atmospheres and Pathfinder Oceans data sets. The merged data set is unique in that it includes daytime estimates of aerosol optical depth (AOD) derived from AVHRR channel 1 (0.63 μm) under global conditions of significant aerosol loading. Histograms of retrieved AOD reveal monomodal, lognormal distributions for both tropospheric and stratospheric aerosol modes. It is then shown empirically that the SST depression caused under each aerosol mode can be expressed as a linear function in two predictors, these being the slant path AOD retrieved from AVHRR channel 1 along with the ratio of channels 1 and 2 normalized reflectances. On the basis of these relationships, parametric equations are derived to provide an aerosol correction for retrievals from the daytime NOAA operational multichannel and nonlinear SST algorithms. Separate sets of coefficients are utilized for two aerosol modes: tropospheric (i.e., dust, smoke, haze) and stratospheric/tropospheric (i.e., following a major volcanic eruption). The equations are shown to significantly reduce retrieved SST bias using an independent set of match-ups. Eliminating aerosol-induced bias in both real-time and retrospective processing will enhance the utility of the AVHRR SST for the general user community and in climate research.

Method and device for measuring single-shot transient signals

DOEpatents

Yin, Yan

2004-05-18

Methods, apparatus, and systems, including computer program products, implementing and using techniques for measuring multi-channel single-shot transient signals. A signal acquisition unit receives one or more single-shot pulses from a multi-channel source. An optical-fiber recirculating loop reproduces the one or more received single-shot optical pulses to form a first multi-channel pulse train for circulation in the recirculating loop, and a second multi-channel pulse train for display on a display device. The optical-fiber recirculating loop also optically amplifies the first circulating pulse train to compensate for signal losses and performs optical multi-channel noise filtration.

Direct modulation of tracheal Cl--channel activity by 5,6- and 11,12-EET.

PubMed

Salvail, D; Dumoulin, M; Rousseau, E

1998-09-01

Using microelectrode potential measurements, we tested the involvement of Cl- conductances in the hyperpolarization induced by 5,6- and 11,12-epoxyeicosatrienoic acid (EET) in airway smooth muscle (ASM) cells. 5,6-EET and 11,12-EET (0.75 microM) caused -5.4 +/- 1.1- and -3.34 +/- 0.95-mV hyperpolarizations, respectively, of rabbit tracheal cells (from a resting membrane potential of -53.25 +/- 0.44 mV), with significant residual repolarizations remaining after the Ca2+-activated K+ channels had been blocked by 10 nM iberiotoxin. In bilayer reconstitution experiments, we demonstrated that the EETs directly inhibit a Ca2+-insensitive Cl- channel from bovine ASM; 1 microM 5,6-EET and 1.5 microM 11,12-EET lowered the unitary current amplitude by 40 (n = 6 experiments) and 44.7% (n = 4 experiments), respectively. Concentration-dependent decreases in channel open probability were observed, with estimated IC50 values of 0.26 microM for 5,6- and 1.15 microM for 11,12-EET. Furthermore, pharmacomechanical tension measurements showed that both regioisomers induced significant bronchorelaxations in epithelium-denuded ASM strips. These results suggest that 5,6- and 11,12-EET can act in ASM as epithelium-derived hyperpolarizing factors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrett, J C; Karmanos Cancer Institute McLaren-Macomb, Clinton Township, MI; Knill, C

Purpose: To determine small field correction factors for PTW’s microDiamond detector in Elekta’s Gamma Knife Model-C unit. These factors allow the microDiamond to be used in QA measurements of output factors in the Gamma Knife Model-C; additionally, the results also contribute to the discussion on the water equivalence of the relatively-new microDiamond detector and its overall effectiveness in small field applications. Methods: The small field correction factors were calculated as k correction factors according to the Alfonso formalism. An MC model of the Gamma Knife and microDiamond was built with the EGSnrc code system, using BEAMnrc and DOSRZnrc user codes.more » Validation of the model was accomplished by simulating field output factors and measurement ratios for an available ABS plastic phantom and then comparing simulated results to film measurements, detector measurements, and treatment planning system (TPS) data. Once validated, the final k factors were determined by applying the model to a more waterlike solid water phantom. Results: During validation, all MC methods agreed with experiment within the stated uncertainties: MC determined field output factors agreed within 0.6% of the TPS and 1.4% of film; and MC simulated measurement ratios matched physically measured ratios within 1%. The final k correction factors for the PTW microDiamond in the solid water phantom approached unity to within 0.4%±1.7% for all the helmet sizes except the 4 mm; the 4 mm helmet size over-responded by 3.2%±1.7%, resulting in a k factor of 0.969. Conclusion: Similar to what has been found in the Gamma Knife Perfexion, the PTW microDiamond requires little to no corrections except for the smallest 4 mm field. The over-response can be corrected via the Alfonso formalism using the correction factors determined in this work. Using the MC calculated correction factors, the PTW microDiamond detector is an effective dosimeter in all available helmet sizes. The authors would like to thank PTW (Friedberg, Germany) for providing the PTW microDiamond detector for this research.« less

Monolithic integration of elliptic-symmetry diffractive optical element on silicon-based 45 degrees micro-reflector.

PubMed

Lan, Hsiao-Chin; Hsiao, Hsu-Liang; Chang, Chia-Chi; Hsu, Chih-Hung; Wang, Chih-Ming; Wu, Mount-Learn

2009-11-09

A monolithically integrated micro-optical element consisting of a diffractive optical element (DOE) and a silicon-based 45 degrees micro-reflector is experimentally demonstrated to facilitate the optical alignment of non-coplanar fiber-to-fiber coupling. The slanted 45 degrees reflector with a depth of 216 microm is fabricated on a (100) silicon wafer by anisotropic wet etching. The DOE with a diameter of 174.2 microm and a focal length of 150 microm is formed by means of dry etching. Such a compact device is suitable for the optical micro-system to deflect the incident light by 90 degrees and to focus it on the image plane simultaneously. The measured light pattern with a spot size of 15 microm has a good agreement with the simulated result of the elliptic-symmetry DOE with an off-axis design for eliminating the strongly astigmatic aberration. The coupling efficiency is enhanced over 10-folds of the case without a DOE on the 45 degrees micro-reflector. This device would facilitate the optical alignment of non-coplanar light coupling and further miniaturize the volume of microsystem.

Effect of temporal location of correction of monochromatic aberrations on the dynamic accommodation response

PubMed Central

Hampson, Karen M.; Chin, Sem Sem; Mallen, Edward A. H.

2010-01-01

Dynamic correction of monochromatic aberrations of the eye is known to affect the accommodation response to a step change in stimulus vergence. We used an adaptive optics system to determine how the temporal location of the correction affects the response. The system consists of a Shack-Hartmann sensor sampling at 20 Hz and a 37-actuator piezoelectric deformable mirror. An extra sensing channel allows for an independent measure of the accommodation level of the eye. The accommodation response of four subjects was measured during a +/− 0.5 D step change in stimulus vergence whilst aberrations were corrected at various time locations. We found that continued correction of aberrations after the step change decreased the gain for disaccommodation, but increased the gain for accommodation. These results could be explained based on the initial lag of accommodation to the stimulus and changes in the level of aberrations before and after the stimulus step change. Future considerations for investigations of the effect of monochromatic aberrations on the dynamic accommodation response are discussed. PMID:21258515

A differential optical absorption spectroscopy method for retrieval from ground-based Fourier transform spectrometers measurements of the direct solar beam

NASA Astrophysics Data System (ADS)

Huo, Yanfeng; Duan, Minzheng; Tian, Wenshou; Min, Qilong

2015-08-01

A differential optical absorption spectroscopy (DOAS)-like algorithm is developed to retrieve the column-averaged dryair mole fraction of carbon dioxide from ground-based hyper-spectral measurements of the direct solar beam. Different to the spectral fitting method, which minimizes the difference between the observed and simulated spectra, the ratios of multiple channel-pairs—one weak and one strong absorption channel—are used to retrieve from measurements of the shortwave infrared (SWIR) band. Based on sensitivity tests, a super channel-pair is carefully selected to reduce the effects of solar lines, water vapor, air temperature, pressure, instrument noise, and frequency shift on retrieval errors. The new algorithm reduces computational cost and the retrievals are less sensitive to temperature and H2O uncertainty than the spectral fitting method. Multi-day Total Carbon Column Observing Network (TCCON) measurements under clear-sky conditions at two sites (Tsukuba and Bremen) are used to derive xxxx for the algorithm evaluation and validation. The DOAS-like results agree very well with those of the TCCON algorithm after correction of an airmass-dependent bias.

From optics testing to micro optics testing

NASA Astrophysics Data System (ADS)

Brock, Christian; Dorn, Ralf; Pfund, Johannes

2017-10-01

Testing micro optics, i.e. lenses with dimensions down to 0.1mm and less, with high precision requires a dedicated design of the testing device, taking into account propagation and wave-optical effects. In this paper, we discuss testing methods based on Shack-Hartmann wavefront technology for functional testing in transmission and for the measurement of surface shape in reflection. As a first example of more conventional optics testing, i.e. optics in the millimeter range, we present the measurement of binoculars in transmission, and discuss the measured wave aberrations and imaging quality. By repeating the measurement at different wavelengths, information on chromatic effects is retrieved. A task that is often tackled using Shack-Hartman wavefront sensors is the alignment of collimation optics in front of a light source. In case of a micro-optical collimation unit with a 1/e² beam diameter of ca. 1mm, we need adapted relay optics for suitable beam expansion and well-defined imaging conditions. In this example, we will discuss the alignment process and effects of the relay optics magnification, as well as typical performance data. Oftentimes, micro optics are fabricated not as single pieces, but as mass optics, e.g. by lithographic processes. Thus, in order to reduce tooling and alignment time, an automated test procedure is necessary. We present an approach for the automated testing of wafer- or tray-based micro optics, and discuss transmission and reflection measurement capabilities. Exemplary performance data is shown for a sample type with 30 microns in diameter, where typical repeatabilities of a few nanometers (rms) are reached.

Slant-path coherent free space optical communications over the maritime and terrestrial atmospheres with the use of adaptive optics for beam wavefront correction.

PubMed

Li, Ming; Gao, Wenbo; Cvijetic, Milorad

2017-01-10

As a continuation of our previous work [Appl. Opt.54, 1453 (2015)APOPAI0003-693510.1364/AO.54.001453] in which we have studied the performance of coherent free space optical (FSO) communication systems operating over a horizontal path, in this paper we study the coherent FSO system operating over a general slant path. We evaluated system bit-error-rate (BER) in the case when the quadrature phase-shift keying (QPSK) modulation format is applied and when an adaptive optics (AO) system is employed to mitigate the air turbulence effects for both maritime and terrestrial air transmission scenarios. We adopted a multiple-layer scheme to efficiently model the FSO slant-path links. The atmospheric channel fading was characterized by the wavefront phase distortions and the log-amplitude fluctuations. We derived analytical expressions to characterize log-amplitude fluctuations of air turbulence by asserting the aperture averaging within the frame of the multiple-layer model. The obtained results showed that use of AO enabled improvement of system performance for both uplinks and downlinks, and also revealed that it is more beneficial for the FSO downlinks. Also, AO employment brought larger enhancements in BER performance for the maritime slant-path FSO links than for the terrestrial ones, with an additional striking increase in performance when the AO correction is combined with the aperture averaging.

A modified experimental setup for sedimentation equilibrium experiments with gels. Part 2: Technical developments.

PubMed

Cölfen, H; Borchard, W

1994-06-01

This part of the paper trilogy describes technical developments for an efficient experimental setup to investigate gels with equilibrium analytical ultracentrifugation. New 10-channel centerpieces for the Schlieren optics, a new programmable multiplexer, a modified Schlieren optical system, and a photo pickup with impulse transformer are introduced as major developments. Also, some new centerpieces suitable for equilibrium experiments with solutions using the Rayleigh interference and the uv-absorption optics are presented. These centerpieces allow the investigation of 10, 12, or even 26 samples per centerpiece. The problem to find suitable materials for cell centerpieces and windows in the case of adhering samples is discussed for the system gelatin/water. A phase volume calculation for circular sample channels as a correction for the case of broadened menisci is presented. The method described allows an accurate measurement of up to 70 samples simultaneously in an equilibrium experiment if the 8-hole rotor presented in part 1 of the trilogy is used. The number of samples is sufficient to characterize a gel/solvent system in the experimentally accessible range under identical conditions, which is not possible by means of any of the methods known before. All parts described are also applicable for the investigation of solutions.

Optics of Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII): Delay Lines and Alignment

NASA Technical Reports Server (NTRS)

Dhabal, Arnab; Rinehart, Stephen A.; Rizzo, Maxime J.; Mundy, Lee; Fixsen, Dale; Sampler, Henry; Mentzell, Eric; Veach, Todd; Silverberg, Robert F.; Furst, Stephen;

cDPD: A new dissipative particle dynamics method for modeling electrokinetic phenomena at the mesoscale

NASA Astrophysics Data System (ADS)

Deng, Mingge; Li, Zhen; Borodin, Oleg; Karniadakis, George Em

2016-10-01

We develop a "charged" dissipative particle dynamics (cDPD) model for simulating mesoscopic electrokinetic phenomena governed by the stochastic Poisson-Nernst-Planck and the Navier-Stokes equations. Specifically, the transport equations of ionic species are incorporated into the DPD framework by introducing extra degrees of freedom and corresponding evolution equations associated with each DPD particle. Diffusion of ionic species driven by the ionic concentration gradient, electrostatic potential gradient, and thermal fluctuations is captured accurately via pairwise fluxes between DPD particles. The electrostatic potential is obtained by solving the Poisson equation on the moving DPD particles iteratively at each time step. For charged surfaces in bounded systems, an effective boundary treatment methodology is developed for imposing both the correct hydrodynamic and electrokinetics boundary conditions in cDPD simulations. To validate the proposed cDPD model and the corresponding boundary conditions, we first study the electrostatic structure in the vicinity of a charged solid surface, i.e., we perform cDPD simulations of the electrostatic double layer and show that our results are in good agreement with the well-known mean-field theoretical solutions. We also simulate the electrostatic structure and capacity densities between charged parallel plates in salt solutions with different salt concentrations. Moreover, we employ the proposed methodology to study the electro-osmotic and electro-osmotic/pressure-driven flows in a micro-channel. In the latter case, we simulate the dilute poly-electrolyte solution drifting by electro-osmotic flow in a micro-channel, hence demonstrating the flexibility and capability of this method in studying complex fluids with electrostatic interactions at the micro- and nano-scales.

Macro- and micro-designed chitosan-alginate scaffold architecture by three-dimensional printing and directional freezing.

PubMed

Reed, Stephanie; Lau, Grace; Delattre, Benjamin; Lopez, David Don; Tomsia, Antoni P; Wu, Benjamin M

2016-01-07

While many tissue-engineered constructs aim to treat cartilage defects, most involve chondrocyte or stem cell seeding on scaffolds. The clinical application of cell-based techniques is limited due to the cost of maintaining cellular constructs on the shelf, potential immune response to allogeneic cell lines, and autologous chondrocyte sources requiring biopsy from already diseased or injured, scarce tissue. An acellular scaffold that can induce endogenous influx and homogeneous distribution of native stem cells from bone marrow holds great promise for cartilage regeneration. This study aims to develop such an acellular scaffold using designed, channeled architecture that simultaneously models the native zones of articular cartilage and subchondral bone. Highly porous, hydrophilic chitosan-alginate (Ch-Al) scaffolds were fabricated in three-dimensionally printed (3DP) molds designed to create millimeter scale macro-channels. Different polymer preform casting techniques were employed to produce scaffolds from both negative and positive 3DP molds. Macro-channeled scaffolds improved cell suspension distribution and uptake overly randomly porous scaffolds, with a wicking volumetric flow rate of 445.6 ± 30.3 mm(3) s(-1) for aqueous solutions and 177 ± 16 mm(3) s(-1) for blood. Additionally, directional freezing was applied to Ch-Al scaffolds, resulting in lamellar pores measuring 300 μm and 50 μm on the long and short axes, thus creating micrometer scale micro-channels. After directionally freezing Ch-Al solution cast in 3DP molds, the combined macro- and micro-channeled scaffold architecture enhanced cell suspension uptake beyond either macro- or micro-channels alone, reaching a volumetric flow rate of 1782.1 ± 48 mm(3) s(-1) for aqueous solutions and 440.9 ± 0.5 mm(3) s(-1) for blood. By combining 3DP and directional freezing, we can control the micro- and macro-architecture of Ch-Al to drastically improve cell influx into and distribution within the scaffold, while achieving porous zones that mimic articular cartilage zonal architecture. In future applications, precisely controlled micro- and macro-channels have the potential to assist immediate endogenous bone marrow uptake, stimulate chondrogenesis, and encourage vascularization of bone in an osteochondral scaffold.

Challenges and solutions for the analysis of in situ , in crystallo micro-spectrophotometric data

DOE PAGES

Dworkowski, Florian S. N.; Hough, Michael A.; Pompidor, Guillaume; ...

2015-01-01

Combining macromolecular crystallography with in crystallo micro-spectrophotometry yields valuable complementary information on the sample, including the redox states of metal cofactors, the identification of bound ligands and the onset and strength of undesired photochemistry, also known as radiation damage. However, the analysis and processing of the resulting data differs significantly from the approaches used for solution spectrophotometric data. The varying size and shape of the sample, together with the suboptimal sample environment, the lack of proper reference signals and the general influence of the X-ray beam on the sample have to be considered and carefully corrected for. In the presentmore » article, we discuss how to characterize and treat these sample-dependent artefacts in a reproducible manner and we demonstrate the SLS-APE in situ, in crystallo optical spectroscopy data-analysis toolbox.« less

Mid infrared observations of Van Maanen 2: no substellar companion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farihi, J; Becklin, E; Macintosh, B

2004-11-03

The results of a comprehensive infrared imaging search for the putative 0.06 M{sub {circle_dot}} astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 {micro}m reveal a diffraction limited core of 0.09 inch and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50 M{sub J} brown dwarf would be only 1 magnitude fainter than van Maanen 2 at this wavelength and the astrometric analysis suggested a separation of 0.2 inch. In the case of a chance alignment along the line of sight, a 0.4 mag excessmore » should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published ISO observations of van Maanen 2 at 6.8 {micro}m and 15.0 {micro}m which are consistent with photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with T{sub eff} {approx}> 500 K.« less

Benefit of adaptive FEC in shared backup path protected elastic optical network.

PubMed

Guo, Hong; Dai, Hua; Wang, Chao; Li, Yongcheng; Bose, Sanjay K; Shen, Gangxiang

2015-07-27

We apply an adaptive forward error correction (FEC) allocation strategy to an Elastic Optical Network (EON) operated with shared backup path protection (SBPP). To maximize the protected network capacity that can be carried, an Integer Linear Programing (ILP) model and a spectrum window plane (SWP)-based heuristic algorithm are developed. Simulation results show that the FEC coding overhead required by the adaptive FEC scheme is significantly lower than that needed by a fixed FEC allocation strategy resulting in higher network capacity for the adaptive strategy. The adaptive FEC allocation strategy can also significantly outperform the fixed FEC allocation strategy both in terms of the spare capacity redundancy and the average FEC coding overhead needed per optical channel. The proposed heuristic algorithm is efficient and not only performs closer to the ILP model but also does much better than the shortest-path algorithm.

Multispectral breast imaging using a ten-wavelength, 64 x 64 source/detector channels silicon photodiode-based diffuse optical tomography system.

PubMed

Li, Changqing; Zhao, Hongzhi; Anderson, Bonnie; Jiang, Huabei

2006-03-01

We describe a compact diffuse optical tomography system specifically designed for breast imaging. The system consists of 64 silicon photodiode detectors, 64 excitation points, and 10 diode lasers in the near-infrared region, allowing multispectral, three-dimensional optical imaging of breast tissue. We also detail the system performance and optimization through a calibration procedure. The system is evaluated using tissue-like phantom experiments and an in vivo clinic experiment. Quantitative two-dimensional (2D) and three-dimensional (3D) images of absorption and reduced scattering coefficients are obtained from these experiments. The ten-wavelength spectra of the extracted reduced scattering coefficient enable quantitative morphological images to be reconstructed with this system. From the in vivo clinic experiment, functional images including deoxyhemoglobin, oxyhemoglobin, and water concentration are recovered and tumors are detected with correct size and position compared with the mammography.

Activation of brain nitric oxide synthase in depolarized human temporal cortex slices: differential role of voltage-sensitive calcium channels.

PubMed

Fontana, G; Fedele, E; Cossu, M; Munari, C; Raiteri, M

1997-11-01

1. Nitric oxide (NO) synthase activity was studied in slices of human temporal cortex samples obtained in neurosurgery by measuring the conversion of L-[3H]-arginine to L-[3H]-citrulline. 2. Elevation of extracellular K+ to 20, 35 or 60 mM concentration-dependently augmented L-[3H]-citrulline production. The response to 35 mM KCl was abolished by N(G)-nitro-L-arginine (100 microM) demonstrating NO synthase specific conversion of L-arginine to L-citrulline. Increasing extracellular MgCl2 concentration up to 10 mM also prevented the K+ (35 mM)-induced NO synthase activation, suggesting the absolute requirement of external calcium ions for enzyme activity. 3. However, the effect of high K+ (35 mM) on citrulline synthesis was insensitive to the antagonists of ionotropic and metabotropic glutamate receptors dizocilpine (MK-801), 6-nitro-7-sulphamoylbenzo(f)-quinoxaline-2-3-dione (NBQX) or L-2-amino-3-phosphonopropionic acid (L-AP3) as well as to the nicotinic receptor antagonist, mecamylamine. 4. The 35 mM K+ response was insensitive to omega-conotoxin GVIA (1 microM) and nifedipine (100 microM), but could be prevented in part by omega-agatoxin IVA (0.1 and 1 microM). The inhibition caused by 0.1 microM omega-agatoxin IVA (approximately 30%) was enhanced by adding omega-conotoxin GVIA (1 microM) or nifedipine (100 microM). Further inhibition (up to above 70%) could be observed when the three Ca2+ channel blockers were added together. Similarly, synthetic FTX 3.3 arginine polyamine (sFTX) prevented (50% at 100 microM) the K+-evoked NO synthase activation. This effect of sFTX was further enhanced (up to 70%) by adding 1 microM omega-conotoxin GVIA plus 100 microM nifedipine. No further inhibition could be observed upon addition of MK-801 or/and NBQX. 5. It was concluded that elevation of extracellular [K+] causes NO synthase activation by external Ca2+ entering cells mainly through channels of the P/Q-type. Other Ca2+ channels (L- and N-type) appear to contribute when P/Q-channels are blocked.

Multiple component codes based generalized LDPC codes for high-speed optical transport.

PubMed

Djordjevic, Ivan B; Wang, Ting

2014-07-14

A class of generalized low-density parity-check (GLDPC) codes suitable for optical communications is proposed, which consists of multiple local codes. It is shown that Hamming, BCH, and Reed-Muller codes can be used as local codes, and that the maximum a posteriori probability (MAP) decoding of these local codes by Ashikhmin-Lytsin algorithm is feasible in terms of complexity and performance. We demonstrate that record coding gains can be obtained from properly designed GLDPC codes, derived from multiple component codes. We then show that several recently proposed classes of LDPC codes such as convolutional and spatially-coupled codes can be described using the concept of GLDPC coding, which indicates that the GLDPC coding can be used as a unified platform for advanced FEC enabling ultra-high speed optical transport. The proposed class of GLDPC codes is also suitable for code-rate adaption, to adjust the error correction strength depending on the optical channel conditions.

Miniature high-resolution guided-wave spectrometer for atmospheric remote sensing

NASA Astrophysics Data System (ADS)

Sloan, James; Kruzelecky, Roman; Wong, Brian; Zou, Jing; Jamroz, Wes; Haddad, Emile; Poirier, Michel

This paper describes the design and application of an innovative spectrometer in which a guided-wave integrated optical spectrometer (IOSPEC) has been coupled with a Fabry-Perot (FP) interferometer. This miniature spectrometer has a net mass under 3 kg, but is capable of broadband operation at spectral resolutions below 0.03 nm full width half maximum (FWHM). The tuneable FP filter provides very high spectral resolution combined with a large input aper-ture. The solid state guided-wave spectrometer is currently configured for a 512-channel array detector, which provides sub-nm coarse resolution. The ultimate resolution is determined by the FP filter, which is tuned across the desired spectral bands, thereby providing a signal-to-noise ratio (SNR) advantage over scanned spectrometer systems of the square root of the number of detector channels. The guided-wave optics provides robust, long-term optical alignment, while minimising the mechanical complexity. The miniaturisation of the FP-IOSPEC spectrometer allows multiple spectrometers to be accommodated on a single MicroSat. Each of these can be optimised for selected measurement tasks and views, thereby enabling more flexible data acquisition strategies with enhanced information content, while minimizing the mission cost. The application of this innovative technology in the proposed Miniature Earth Observation Satellite (MEOS) mission will also be discussed. The MEOS mission, which is designed for the investigation of the carbon and water cycles, relies on multiple IO-SPEC instruments for the simultaneous measurement of a range of atmospheric and surface properties important to climate change.

Novel Programmable Shape Memory Polystyrene Film: A Thermally Induced Beam-power Splitter.

PubMed

Li, Peng; Han, Yu; Wang, Wenxin; Liu, Yanju; Jin, Peng; Leng, Jinsong

2017-03-09

Micro/nanophotonic structures that are capable of optical wave-front shaping are implemented in optical waveguides and passive optical devices to alter the phase of the light propagating through them. The beam division directions and beam power distribution depend on the design of the micro/nanostructures. The ultimate potential of advanced micro/nanophotonic structures is limited by their structurally rigid, functional singleness and not tunable against external impact. Here, we propose a thermally induced optical beam-power splitter concept based on a shape memory polystyrene film with programmable micropatterns. The smooth film exhibits excellent transparency with a transmittance of 95% in the visible spectrum and optical stability during a continuous heating process up to 90 °C. By patterning double sided shape memory polystyrene film into erasable and switchable micro-groove gratings, the transmission light switches from one designed light divided directions and beam-power distribution to another because of the optical diffraction effect of the shape changing micro gratings during the whole thermal activated recovery process. The experimental and theoretical results demonstrate a proof-of-principle of the beam-power splitter. Our results can be adapted to further extend the applications of micro/nanophotonic devices and implement new features in the nanophotonics.

Novel Programmable Shape Memory Polystyrene Film: A Thermally Induced Beam-power Splitter

PubMed Central

Li, Peng; Han, Yu; Wang, Wenxin; Liu, Yanju; Jin, Peng; Leng, Jinsong

2017-01-01

Micro/nanophotonic structures that are capable of optical wave-front shaping are implemented in optical waveguides and passive optical devices to alter the phase of the light propagating through them. The beam division directions and beam power distribution depend on the design of the micro/nanostructures. The ultimate potential of advanced micro/nanophotonic structures is limited by their structurally rigid, functional singleness and not tunable against external impact. Here, we propose a thermally induced optical beam-power splitter concept based on a shape memory polystyrene film with programmable micropatterns. The smooth film exhibits excellent transparency with a transmittance of 95% in the visible spectrum and optical stability during a continuous heating process up to 90 °C. By patterning double sided shape memory polystyrene film into erasable and switchable micro-groove gratings, the transmission light switches from one designed light divided directions and beam-power distribution to another because of the optical diffraction effect of the shape changing micro gratings during the whole thermal activated recovery process. The experimental and theoretical results demonstrate a proof-of-principle of the beam-power splitter. Our results can be adapted to further extend the applications of micro/nanophotonic devices and implement new features in the nanophotonics. PMID:28276500

Novel Programmable Shape Memory Polystyrene Film: A Thermally Induced Beam-power Splitter

NASA Astrophysics Data System (ADS)

Li, Peng; Han, Yu; Wang, Wenxin; Liu, Yanju; Jin, Peng; Leng, Jinsong

2017-03-01

Micro/nanophotonic structures that are capable of optical wave-front shaping are implemented in optical waveguides and passive optical devices to alter the phase of the light propagating through them. The beam division directions and beam power distribution depend on the design of the micro/nanostructures. The ultimate potential of advanced micro/nanophotonic structures is limited by their structurally rigid, functional singleness and not tunable against external impact. Here, we propose a thermally induced optical beam-power splitter concept based on a shape memory polystyrene film with programmable micropatterns. The smooth film exhibits excellent transparency with a transmittance of 95% in the visible spectrum and optical stability during a continuous heating process up to 90 °C. By patterning double sided shape memory polystyrene film into erasable and switchable micro-groove gratings, the transmission light switches from one designed light divided directions and beam-power distribution to another because of the optical diffraction effect of the shape changing micro gratings during the whole thermal activated recovery process. The experimental and theoretical results demonstrate a proof-of-principle of the beam-power splitter. Our results can be adapted to further extend the applications of micro/nanophotonic devices and implement new features in the nanophotonics.

Micro electro mechanical system optical switching

DOEpatents

Thorson, Kevin J; Stevens, Rick C; Kryzak, Charles J; Leininger, Brian S; Kornrumpf, William P; Forman, Glenn A; Iannotti, Joseph A; Spahn, Olga B; Cowan, William D; Dagel, Daryl J

2013-12-17

The present disclosure includes apparatus, system, and method embodiments that provide micro electo mechanical system optical switching and methods of manufacturing switches. For example, one optical switch embodiment includes at least one micro electro mechanical system type pivot mirror structure disposed along a path of an optical signal, the structure having a mirror and an actuator, and the mirror having a pivot axis along a first edge and having a second edge rotatable with respect to the pivot axis, the mirror being capable of and arranged to be actuated to pivot betweeen a position parallel to a plane of an optical signal and a position substantially normal to the plane of the optical signal.

Effects of BRL 38227 on neurally-mediated responses in the guinea-pig isolated bronchus.

PubMed

Good, D M; Clapham, J C; Hamilton, T C

1992-04-01

1. In guinea-pig isolated bronchus treated with indomethacin (2.8 microM), electrical field stimulation (EFS; 10 Hz, 0.5 ms, 60-70 V, for 10 s) evoked a tetrodotoxin (3 microM)-sensitive, biphasic contraction comprising a rapid, atropine (1 microM)-sensitive cholinergic response succeeded by a slowly developing, capsaicin (10 microM)-sensitive, non-adrenergic, non-cholinergic excitatory (NANCe) response. 2. BRL 38227 (0.3-3 microM), salmeterol (0.003-3 microM) and ketotifen (1.0-300 microM) each produced concentration-dependent inhibition of both NANCe and cholinergic responses to EFS in guinea-pig isolated bronchus. 3. Substance P (SP; 1 microM) and neurokinin A (NKA; 0.07 microM) produced contractions equivalent in magnitude to the NANCe response to EFS, which were inhibited by salmeterol (1 microM), but not by BRL 38227 (3 microM) or ketotifen (100 microM). 4. Acetylcholine (ACh; 6 microM) was equi-effective with the electrical activation of cholinergic neurones. BRL 38227 (3 microM) slightly inhibited responses to ACh (6 microM). Salmeterol (1 microM) and ketotifen (100 microM) markedly inhibited responses to ACh (6 microM). 5. In bronchial rings pre-contracted with ACh (100 microM), BRL 38227 (0.1-30 microM), salmeterol (0.001-3 microM) and ketotifen (0.1-100 microM) each produced concentration-dependent relaxation. Unlike ketotifen, BRL 38227 and salmeterol only partially (18.8 +/- 2.1% and 51.8 +/- 3.9% respectively) reversed the ACh-induced contraction. 6. The (+)-analogue of BRL 38227, BRL 38226 (0.3-100 microM), was without effect on responses to EFS and had no effect on the inhibition caused by BRL 38227. The K+-channel activators pinacidil (3.0-30 microM) and RP 52891 (3.0-30 microM) exerted similar inhibitory actions on responses to EFS as BRL 38227, but were less potent. Glibenclamide (0.1-1.O microM) and phentolamine (3 microM) antagonized the inhibitory effects of BRL 38227 on responses to EFS.7. It is concluded that BRL 38227 and ketotifen can inhibit NANCe neuroeffector transmission at concentrations exerting little or no inhibitory effects on responses to exogenously applied tachykinins.By contrast, in addition to suppressing NANCe responses to EFS, salmeterol also markedly inhibits responses to SP and NKA. At concentrations markedly suppressing cholinergic neuroeffector transmission, BRL 38227 has only minor effects on responses to exogenously-applied ACh. Salmeterol and ketotifen both depress responses to ACh within the concentration-range over which they inhibit cholinergic responses to EFS. The inhibitory effects of BRL 38227 on responses to EFS exhibit stereo-specificity and may involve the opening of a neuronal K+-channel. This K+-channel is glibenclamide-and phentolamine-sensitive and appears similar to the smooth muscle K+-channel which is modulated by BRL 38227.

Imaging the Human Aqueous Humor Outflow Pathway in Human Eyes by Three Dimensional Micro-Computed Tomography (3D micro-CT)

PubMed Central

Hann, Cheryl R.; Bentley, Michael D.; Vercnocke, Andrew; Ritman, Erik L.; Fautsch, Michael P.

2011-01-01

The site of outflow resistance leading to elevated intraocular pressure in primary open angle glaucoma is believed to be located in the region of Schlemm’s canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Traditional imaging modalities limit the ability to view both proximal and distal portions of the trabecular outflow pathway as a single unit. In this study, we examined the effectiveness of three-dimensional micro-computed tomography (3D micro-CT) as a potential method to view the trabecular outflow pathway. Two normal human eyes were used: one immersion fixed in 4% paraformaldehyde, and one with anterior chamber perfusion at 10 mmHg followed by perfusion fixation in 4% paraformaldehyde/2% glutaraldehyde. Both eyes were postfixed in 1% osmium tetroxide, and scanned with 3D micro-CT at 2 µm or 5 µm voxel resolution. In the immersion fixed eye, 24 collector channels were identified with an average orifice size of 27.5 ± 5 µm. In comparison, the perfusion fixed eye had 29 collector channels with a mean orifice size of 40.5 ± 13 µm. Collector channels were not evenly dispersed around the circumference of the eye. There was no significant difference in the length of Schlemm’s canal in the immersed versus the perfused eye (33.2 versus 35.1 mm). Structures, locations and size measurements identified by 3D micro-CT were confirmed by correlative light microscopy. These findings confirm 3D micro-CT can be used effectively for the non-invasive examination of the trabecular meshwork, Schlemm’s canal, collector channels and intrascleral vasculature that comprise the distal outflow pathway. This imaging modality will be useful for noninvasive study of the role of the trabecular outflow pathway as a whole unit. PMID:21187085

Imaging the Aqueous Humor Outflow Pathway in Human Eyes by Three-dimensional Micro-computed Tomography (3D micro-CT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

C Hann; M Bentley; A Vercnocke

2011-12-31

The site of outflow resistance leading to elevated intraocular pressure in primary open-angle glaucoma is believed to be located in the region of Schlemm's canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Traditional imaging modalities limit the ability to view both proximal and distal portions of the trabecular outflow pathway as a single unit. In this study, we examined the effectiveness of three-dimensional micro-computed tomography (3D micro-CT) as a potential method to view the trabecularmore » outflow pathway. Two normal human eyes were used: one immersion fixed in 4% paraformaldehyde and one with anterior chamber perfusion at 10 mmHg followed by perfusion fixation in 4% paraformaldehyde/2% glutaraldehyde. Both eyes were postfixed in 1% osmium tetroxide and scanned with 3D micro-CT at 2 {mu}m or 5 {mu}m voxel resolution. In the immersion fixed eye, 24 collector channels were identified with an average orifice size of 27.5 {+-} 5 {mu}m. In comparison, the perfusion fixed eye had 29 collector channels with a mean orifice size of 40.5 {+-} 13 {mu}m. Collector channels were not evenly dispersed around the circumference of the eye. There was no significant difference in the length of Schlemm's canal in the immersed versus the perfused eye (33.2 versus 35.1 mm). Structures, locations and size measurements identified by 3D micro-CT were confirmed by correlative light microscopy. These findings confirm 3D micro-CT can be used effectively for the non-invasive examination of the trabecular meshwork, Schlemm's canal, collector channels and intrascleral vasculature that comprise the distal outflow pathway. This imaging modality will be useful for non-invasive study of the role of the trabecular outflow pathway as a whole unit.« less

Pharmacological characterization of the voltage-dependent Ca2+ channels present in synaptosomes from rat and chicken central nervous system.

PubMed

Alvarez Maubecin, V; Sanchez, V N; Rosato Siri, M D; Cherksey, B D; Sugimori, M; Llinás, R; Uchitel, O D

1995-06-01

The voltage-dependent calcium channels present in mammalian and chicken brain synaptosomes were characterized pharmacologically using specific blockers of L-type channels (1,4-dihydropyridines), N-type channels (omega-conotoxin GVIA), and P-type channels [funnel web toxin (FTX) and omega-agatoxin IVA]. K(+)-induced Ca2+ uptake by chicken synaptosomes was blocked by omega-conotoxin GVIA (IC50 = 250 nM). This toxin at 5 microM did not block Ca2+ entry into rat frontal cortex synaptosomes. FTX and omega-agatoxin IVA blocked Ca2+ uptake by rat synaptosomes (IC50 = 0.17 microliter/ml and 40 nM, respectively). Likewise, in chicken synaptosomes, FTX and omega-agatoxin IVA affected Ca2+ uptake, FTX (3 microliters/ml) exerted a maximal inhibition of 40% with an IC50 similar to the one obtained in rat preparations, whereas with omega-agatoxin IVA saturation was not reached even at 5 microM. In chicken preparations, the combined effect of saturating concentrations of FTX (1 microliter/ml) and different concentrations of omega-conotoxin GVIA showed no additive effects. However, the effect of saturating concentrations of FTX and omega-conotoxin GVIA was never greater than the one observed with omega-conotoxin GVIA. We also found that 60% of the Ca2+ uptake by rat and chicken synaptosomes was inhibited by omega-conotoxin MVIID (1 microM), a toxin that has a high index of discrimination against N-type channels. Conversely, nitrendipine (10 microM) had no significant effect on Ca2+ uptake in either the rat or the chicken. In conclusion, Ca2+ uptake by rat synaptosomes is potently inhibited by different P-type Ca2+ channel blockers, thus indicating that P-type channels are predominant in this preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Automatic irradiation control by an optical feedback technique for selective retina treatment (SRT) in a rabbit model

NASA Astrophysics Data System (ADS)

Seifert, Eric; Roh, Young-Jung; Fritz, Andreas; Park, Young Gun; Kang, Seungbum; Theisen-Kunde, Dirk; Brinkmann, Ralf

2013-06-01

Selective Retina Therapy (SRT) targets the Retinal Pigment Epithelium (RPE) without effecting neighboring layers as the photoreceptors or the choroid. SRT related RPE defects are ophthalmoscopically invisible. Owing to this invisibility and the variation of the threshold radiant exposure for RPE damage the treating physician does not know whether the treatment was successful or not. Thus measurement techniques enabling a correct dosing are a demanded element in SRT devices. The acquired signal can be used for monitoring or automatic irradiation control. Existing monitoring techniques are based on the detection of micro-bubbles. These bubbles are the origin of RPE cell damage for pulse durations in the ns and μs time regime 5μs. The detection can be performed by optical or acoustical approaches. Monitoring based on an acoustical approach has already been used to study the beneficial effects of SRT on diabetic macula edema and central serous retinopathy. We have developed a first real time feedback technique able to detect micro-bubble induced characteristics in the backscattered laser light fast enough to cease the laser irradiation within a burst. Therefore the laser energy within a burst of at most 30 pulses is increased linearly with every pulse. The laser irradiation is ceased as soon as micro-bubbles are detected. With this automatic approach it was possible to observe invisible lesions, an intact photoreceptor layer and a reconstruction of the RPE within one week.

Coding for Communication Channels with Dead-Time Constraints

NASA Technical Reports Server (NTRS)

Moision, Bruce; Hamkins, Jon

2004-01-01

Coding schemes have been designed and investigated specifically for optical and electronic data-communication channels in which information is conveyed via pulse-position modulation (PPM) subject to dead-time constraints. These schemes involve the use of error-correcting codes concatenated with codes denoted constrained codes. These codes are decoded using an interactive method. In pulse-position modulation, time is partitioned into frames of Mslots of equal duration. Each frame contains one pulsed slot (all others are non-pulsed). For a given channel, the dead-time constraints are defined as a maximum and a minimum on the allowable time between pulses. For example, if a Q-switched laser is used to transmit the pulses, then the minimum allowable dead time is the time needed to recharge the laser for the next pulse. In the case of bits recorded on a magnetic medium, the minimum allowable time between pulses depends on the recording/playback speed and the minimum distance between pulses needed to prevent interference between adjacent bits during readout. The maximum allowable dead time for a given channel is the maximum time for which it is possible to satisfy the requirement to synchronize slots. In mathematical shorthand, the dead-time constraints for a given channel are represented by the pair of integers (d,k), where d is the minimum allowable number of zeroes between ones and k is the maximum allowable number of zeroes between ones. A system of the type to which the present schemes apply is represented by a binary- input, real-valued-output channel model illustrated in the figure. At the transmitting end, information bits are first encoded by use of an error-correcting code, then further encoded by use of a constrained code. Several constrained codes for channels subject to constraints of (d,infinity) have been investigated theoretically and computationally. The baseline codes chosen for purposes of comparison were simple PPM codes characterized by M-slot PPM frames separated by d-slot dead times.

Diazoxide triggers cardioprotection against apoptosis induced by oxidative stress.

PubMed

Ichinose, Masashi; Yonemochi, Hidetoshi; Sato, Toshiaki; Saikawa, Tetsunori

2003-06-01

Although mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels have been reported to reduce the extent of apoptosis, the critical timing of mitoK(ATP) channel opening required to protect myocytes against apoptosis remains unclear. In the present study, we examined whether the mitoK(ATP) channel serves as a trigger of cardioprotection against apoptosis induced by oxidative stress. Apoptosis of cultured neonatal rat cardiomyocytes was determined by flow cytometry (light scatter and propidium iodide/annexin V-FITC fluorescence) and by nuclear staining with Hoechst 33342. Mitochondrial membrane potential (DeltaPsi) was measured by flow cytometry of cells stained with rhodamine-123 (Rh-123). Exposure to H(2)O(2) (500 microM) induced apoptosis, and the percentage of apoptotic cells increased progressively and peaked at 2 h. This H(2)O(2)-induced apoptosis was associated with the loss of DeltaPsi, and the time course of decrease in Rh-123 fluorescence paralleled that of apoptosis. Pretreatment of cardiomyocytes with diazoxide (100 microM), a putative mitoK(ATP) channel opener, for 30 min before exposure to H(2)O(2) elicited transient and mild depolarization of DeltaPsi and consequently suppressed both apoptosis and DeltaPsi loss after 2-h exposure to H(2)O(2). These protective effects of diazoxide were abrogated by the mitoK(ATP) channel blocker 5-hydroxydecanoate (500 microM) but not by the sarcolemmal K(ATP) channel blocker HMR-1098 (30 microM). Our results suggest for the first time that diazoxide-induced opening of mitoK(ATP) channels triggers cardioprotection against apoptosis induced by oxidative stress in rat cardiomyocytes.

Slopes To Prevent Trapping of Bubbles in Microfluidic Channels

NASA Technical Reports Server (NTRS)

Greer, Harold E.; Lee, Michael C.; Smith, J. Anthony; Willis, Peter A.

2010-01-01

The idea of designing a microfluidic channel to slope upward along the direction of flow of the liquid in the channel has been conceived to help prevent trapping of gas bubbles in the channel. In the original application that gave rise to this idea, the microfluidic channels are parts of micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. It is necessary to prevent trapping of gas bubbles in these devices because uninterrupted liquid pathways are essential for sustaining the electrical conduction and flows that are essential for CE. The idea is also applicable to microfluidic devices that may be developed for similar terrestrial microCE biotechnological applications or other terrestrial applications in which trapping of bubbles in microfluidic channels cannot be tolerated. A typical microCE device in the original application includes, among other things, multiple layers of borosilicate float glass wafers. Microfluidic channels are formed in the wafers, typically by use of wet chemical etching. The figure presents a simplified cross section of part of such a device in which the CE channel is formed in the lowermost wafer (denoted the channel wafer) and, according to the present innovation, slopes upward into a via hole in another wafer (denoted the manifold wafer) lying immediately above the channel wafer. Another feature of the present innovation is that the via hole in the manifold wafer is made to taper to a wider opening at the top to further reduce the tendency to trap bubbles. At the time of reporting the information for this article, an effort to identify an optimum technique for forming the slope and the taper was in progress. Of the techniques considered thus far, the one considered to be most promising is precision milling by use of femtosecond laser pulses. Other similar techniques that may work equally well are precision milling using a focused ion beam, or a small diamond-tipped drill bit.

Imatinib-mesylate blocks recombinant T-type calcium channels expressed in human embryonic kidney-293 cells by a protein tyrosine kinase-independent mechanism.

PubMed

Cataldi, Mauro; Gaudino, Annarita; Lariccia, Vincenzo; Russo, Michela; Amoroso, Salvatore; di Renzo, Gianfranco; Annunziato, Lucio

2004-04-01

The 2-phenylaminopyrimidine derivative imatinib-mesylate, a powerful protein tyrosine kinase (PTK) inhibitor that targets abl, c-kit, and the platelet-derived growth factor receptors, is rapidly gaining a relevant role in the treatment of several types of neoplasms. Because first generation PTK inhibitors affect the activity of a large number of voltage-dependent ion channels, the present study explored the possibility that imatinib-mesylate could interfere with the activity of T-type channels, a class of voltage-dependent Ca2+ channels that take part in the chain of events elicited by PTK activation. The effect of the drug on T-type channel activity was examined using the whole-cell patch-clamp technique with Ba2+ (10 mM) as the permeant ion in human embryonic kidney-293 cells, stably expressing the rat Ca(V)3.3 channels. Imatinib-mesylate concentrations, ranging from 30 to 300 microM, reversibly decreased Ca(V)3.3 current amplitude with an IC(50) value of 56.9 microM. By contrast, when imatinib-mesylate (500 microM) was intracellularly dialyzed with the pipette solution, no reduction in Ba2+ current density was observed. The 2-phenylaminopyrimidine derivative modified neither the voltage dependence of activation nor the steady-state inactivation of Ca(V)3.3 channels. The decrease in extracellular Ba2+ concentration from 10 to 2 mM and the substitution of Ca2+ for Ba2+ increased the extent of 30 microM imatinib-mesylate-induced percentage of channel blockade from 25.9 +/- 2.4 to 36.3 +/- 0.9% in 2 mM Ba2+ and 44.2 +/- 2.3% in 2 mM Ca2+. In conclusion, imatinib-mesylate blocked the cloned Ca(V)3.3 channels by a PTK-independent mechanism. Specifically, the drug did not affect the activation or the inactivation of the channel but interfered with the ion permeation process.

Digital optical feeder links system for broadband geostationary satellite

NASA Astrophysics Data System (ADS)

Poulenard, Sylvain; Mège, Alexandre; Fuchs, Christian; Perlot, Nicolas; Riedi, Jerome; Perdigues, Josep

2017-02-01

An optical link based on a multiplex of wavelengths at 1.55μm is foreseen to be a valuable solution for the feeder link of the next generation of high-throughput geostationary satellite. The main satellite operator specifications for such link are an availability of 99.9% over the year, a capacity around 500Gbit/s and to be bent-pipe. Optical ground station networks connected to Terabit/s terrestrial fibers are proposed. The availability of the optical feeder link is simulated over 5 years based on a state-of-the-art cloud mask data bank and an atmospheric turbulence strength model. Yearly and seasonal optical feeder link availabilities are derived and discussed. On-ground and on-board terminals are designed to be compliant with 10Gbit/s per optical channel data rate taking into account adaptive optic systems to mitigate the impact of atmospheric turbulences on single-mode optical fiber receivers. The forward and return transmission chains, concept and implementation, are described. These are based on a digital transparent on-off keying optical link with digitalization of the DVB-S2 and DVB-RCS signals prior to the transmission, and a forward error correcting code. In addition, the satellite architecture is described taking into account optical and radiofrequency payloads as well as their interfaces.

Waveguide-loaded silica fibers for coupling to high-index micro-resonators

NASA Astrophysics Data System (ADS)

Latawiec, P.; Burek, M. J.; Venkataraman, V.; Lončar, M.

2016-01-01

Tapered silica fibers are often used to rapidly probe the optical properties of micro-resonators. However, their low refractive index precludes phase-matching when coupling to high-index micro-resonators, reducing efficiency. Here, we demonstrate efficient optical coupling from tapered fibers to high-index micro-resonators by loading the fibers with an ancillary adiabatic waveguide-coupler fabricated via angled-etching. We demonstrate greatly enhanced coupling to a silicon multimode micro-resonator when compared to coupling via the bare fiber only. Signatures of resonator optical bistability are observed at high powers. This scheme can be applied to resonators of any size and material, increasing the functional scope of fiber coupling.

Omega-conotoxin- and nifedipine-insensitive voltage-operated calcium channels mediate K(+)-induced release of pro-thyrotropin-releasing hormone-connecting peptides Ps4 and Ps5 from perifused rat hypothalamic slices.

PubMed

Valentijn, K; Tranchand Bunel, D; Vaudry, H

1992-07-01

The rat thyrotropin-releasing hormone (TRH) precursor (prepro-TRH) contains five copies of the TRH progenitor sequence linked together by intervening sequences. Recently, we have shown that the connecting peptides prepro-TRH-(160-169) (Ps4) and prepro-TRH-(178-199) (Ps5) are released from rat hypothalamic neurones in response to elevated potassium concentrations, in a calcium-dependent manner. In the present study, the role of voltage-operated calcium channels in potassium-induced release of Ps4 and Ps5 was investigated, using a perifusion system for rat hypothalamic slices. The release of Ps4 and Ps5 stimulated by potassium (70 mM) was blocked by the inorganic ions Co2+ (2.6 mM) and Ni2+ (5 mM). In contrast, the stimulatory effect of KCl was insensitive to Cd2+ (100 microM). The dihydropyridine antagonist nifedipine (10 microM) had no effect on K(+)-evoked release of Ps4 and Ps5. Furthermore, the response to KCl was not affected by nifedipine (10 microM) in combination with diltiazem (1 microM), a benzothiazepine which increases the affinity of dihydropyridine antagonists for their receptor. The dihydropyridine agonist BAY K 8644, at concentrations as high as 1 mM, did not stimulate the basal secretion of Ps4 and Ps5. In addition, BAY K 8644 had no potentiating effect on K(+)-induced release of Ps4 and Ps5. The marine cone snail toxin omega-conotoxin, a blocker of both L- and N-type calcium channels had no effect on the release of Ps4 and Ps5 stimulated by potassium. Similarly, the omega-conopeptide SNX-111, a selective blocker of N-type calcium channels, did not inhibit the stimulatory effect of potassium. The release of Ps4 and Ps5 evoked by high K+ was insensitive to the non-selective calcium channel blocker verapamil (20 microM). Amiloride (1 microM), a putative blocker of T-type calcium channels, did not affect KCl-induced secretion of the two connecting peptides. Taken together, these results indicate that two connecting peptides derived from the pro-TRH, Ps4 and Ps5, are released by K(+)-induced depolarization through activation of voltage-sensitive calcium channels. The calcium channels appear to have a pharmacological profile different from that of L- and N-type channels. Although, their insensitivity to low Cd2+ concentrations and sensitivity to Ni2+ ions would support the involvement of T-type calcium channels, the lack of effect of amiloride suggests that they belong to a yet undefined class of calcium channels.

Imprinting continuously varying topographical structure onto large-aperture optical surfaces using magnetorheological finishing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menapace, J A; Davis, P J; Dixit, S

2007-03-07

Over the past four years we have advanced Magnetorheological Finishing (MRF) techniques and tools to imprint complex continuously varying topographical structures onto large-aperture (430 x 430 mm) optical surfaces. These optics, known as continuous phase plates (CPPs), are important for high-power laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm and surface peak-to-valleys as high as 22 {micro}m. During this discussion, we will present the evolution of the MRF imprinting technology and themore » MRF tools designed to manufacture large-aperture 430 x 430 mm CPPs. Our results will show how the MRF removal function impacts and limits imprint fidelity and what must be done to arrive at a high-quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use in high-power laser applications.« less

Infrared Hollow Optical Fiber Probe for Localized Carbon Dioxide Measurement in Respiratory Tracts

PubMed Central

Katagiri, Takashi; Shibayama, Kyosuke; Iida, Takeru

2018-01-01

A real-time gas monitoring system based on optical absorption spectroscopy is proposed for localized carbon dioxide (CO2) measurement in respiratory tracts. In this system, a small gas cell is attached to the end of a hollow optical fiber that delivers mid-infrared light with small transmission loss. The diameters of the fiber and the gas cell are smaller than 1.2 mm so that the probe can be inserted into a working channel of common bronchoscopes. The dimensions of the gas cell are designed based on absorption spectra of CO2 standard gases in the 4.2 μm wavelength region, which are measured using a Fourier-transform infrared spectrometer. A miniature gas cell that is comprised of a stainless-steel tube with slots for gas inlet and a micro-mirror is fabricated. A compact probing system with a quantum cascade laser (QCL) light source is built using a gas cell with a hollow optical fiber for monitoring CO2 concentration. Experimental results using human breaths show the feasibility of the system for in-situ measurement of localized CO2 concentration in human airways. PMID:29584666

Characterizing relationship between optical microangiography signals and capillary flow using microfluidic channels

PubMed Central

Choi, Woo June; Qin, Wan; Chen, Chieh-Li; Wang, Jingang; Zhang, Qinqin; Yang, Xiaoqi; Gao, Bruce Z.; Wang, Ruikang K.

2016-01-01

Optical microangiography (OMAG) is a powerful optical angio-graphic tool to visualize micro-vascular flow in vivo. Despite numerous demonstrations for the past several years of the qualitative relationship between OMAG and flow, no convincing quantitative relationship has been proven. In this paper, we attempt to quantitatively correlate the OMAG signal with flow. Specifically, we develop a simplified analytical model of the complex OMAG, suggesting that the OMAG signal is a product of the number of particles in an imaging voxel and the decorrelation of OCT (optical coherence tomography) signal, determined by flow velocity, inter-frame time interval, and wavelength of the light source. Numerical simulation with the proposed model reveals that if the OCT amplitudes are correlated, the OMAG signal is related to a total number of particles across the imaging voxel cross-section per unit time (flux); otherwise it would be saturated but its strength is proportional to the number of particles in the imaging voxel (concentration). The relationship is validated using microfluidic flow phantoms with various preset flow metrics. This work suggests OMAG is a promising quantitative tool for the assessment of vascular flow. PMID:27446700

Design, fabrication and testing of hierarchical micro-optical structures and systems

NASA Astrophysics Data System (ADS)

Cannistra, Aaron Thomas

Micro-optical systems are becoming essential components in imaging, sensing, communications, computing, and other applications. Optically based designs are replacing electronic, chemical and mechanical systems for a variety of reasons, including low power consumption, reduced maintenance, and faster operation. However, as the number and variety of applications increases, micro-optical system designs are becoming smaller, more integrated, and more complicated. Micro and nano-optical systems found in nature, such as the imaging systems found in many insects and crustaceans, can have highly integrated optical structures that vary in size by orders of magnitude. These systems incorporate components such as compound lenses, anti-reflective lens surface structuring, spectral filters, and polarization selective elements. For animals, these hybrid optical systems capable of many optical functions in a compact package have been repeatedly selected during the evolutionary process. Understanding the advantages of these designs gives motivation for synthetic optical systems with comparable functionality. However, alternative fabrication methods that deviate from conventional processes are needed to create such systems. Further complicating the issue, the resulting device geometry may not be readily compatible with existing measurement techniques. This dissertation explores several nontraditional fabrication techniques for optical components with hierarchical geometries and measurement techniques to evaluate performance of such components. A micro-transfer molding process is found to produce high-fidelity micro-optical structures and is used to fabricate a spectral filter on a curved surface. By using a custom measurement setup we demonstrate that the spectral filter retains functionality despite the nontraditional geometry. A compound lens is fabricated using similar fabrication techniques and the imaging performance is analyzed. A spray coating technique for photoresist application to curved surfaces combined with interference lithography is also investigated. Using this technique, we generate polarizers on curved surfaces and measure their performance. This work furthers an understanding of how combining multiple optical components affects the performance of each component, the final integrated devices, and leads towards realization of biomimetically inspired imaging systems.

Chiral recognition of pinacidil and its 3-pyridyl isomer by canine cardiac and smooth muscle: Antagonism by sulfonylureas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinberg, M.I.; Wiest, S.A.; Zimmerman, K.M.

1991-01-01

Pinacidil, a potassium channel opener (PCO), relaxes vascular smooth muscle by increasing potassium ion membrane conductance, thereby causing membrane hyperpolarization. PCOs also act on cardiac muscle to decrease action potential duration (APD) selectively. To examine the enantiomeric selectivity of pinacidil, the stereoisomers of pinacidil (a 4-pyridylcyanoguanidine) and its 3-pyridyl isomer (LY222675) were synthesized and studied in canine Purkinje fibers and cephalic veins. The (-)-enantiomers of both pinacidil and LY222675 were more potent in relaxing phenylephrine-contracted cephalic veins and decreasing APD than were their corresponding (+)-enantiomers. The EC50 values for (-)-pinacidil and (-)-LY222675 in relaxing cephalic veins were 0.44 and 0.09more » microM, respectively. In decreasing APD, the EC50 values were 3.2 microM for (-)-pinacidil and 0.43 microM for (-)-LY222675. The eudismic ratio was greater for the 3-pyridyl isomer than for pinacidil in both cardiac (71 vs. 22) and vascular (53 vs. 17) tissues. (-)-LY222675 and (-)-pinacidil (0.1-30 microM) also increased 86Rb efflux from cephalic veins to a greater extent than did their respective optical antipodes. The antidiabetic sulfonylurea, glyburide (1-30 microM), shifted the vascular concentration-response curve of (-)-pinacidil to the right by a similar extent at each inhibitor concentration. Glipizide also antagonized the response to (-)-pinacidil, but was about 1/10 as potent with a maximal shift occurring at 10 and 30 microM. Glyburide antagonized the vascular relaxant effects of 0.3 microM (-)-LY222675 (EC50, 2.3 microM) and reversed the decrease in APD caused by 3 microM (-)-LY222675 (EC50, 1.9 microM). Nitroprusside did not alter 86Rb efflux, and vascular relaxation induced by sodium nitroprusside was unaffected by sulfonylureas.« less

Synchrotron X-ray studies of the keel of the short-spined sea urchin Lytechinus variegatus: absorption microtomography (microCT) and small beam diffraction mapping.

PubMed

Stock, S R; Barss, J; Dahl, T; Veis, A; Almer, J D; Carlo, F

2003-05-01

In sea urchin teeth, the keel plays an important structural role, and this paper reports results of microstructural characterization of the keel of Lytechinus variegatus using two noninvasive synchrotron x-ray techniques: x-ray absorption microtomography (microCT) and x-ray diffraction mapping. MicroCT with 14 keV x-rays mapped the spatial distribution of mineral at the 1.3 microm level in a millimeter-sized fragment of a mature portion of the keel. Two rows of low absorption channels (i.e., primary channels) slightly less than 10 microm in diameter were found running linearly from the flange to the base of the keel and parallel to its sides. The primary channels paralleled the oral edge of the keel, and the microCT slices revealed a planar secondary channel leading from each primary channel to the side of the keel. The primary and secondary channels were more or less coplanar and may correspond to the soft tissue between plates of the carinar process. Transmission x-ray diffraction with 80.8 keV x-rays and a 0.1 mm beam mapped the distribution of calcite crystal orientations and the composition Ca(1-x)Mg(x)CO(3) of the calcite. Unlike the variable Mg concentration and highly curved prisms found in the keel of Paracentrotus lividus, a constant Mg content (x = 0.13) and relatively little prism curvature was found in the keel of Lytechinus variegatus.

Note: A resonating reflector-based optical system for motion measurement in micro-cantilever arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sathishkumar, P.; Punyabrahma, P.; Sri Muthu Mrinalini, R.

A robust, compact optical measurement unit for motion measurement in micro-cantilever arrays enables development of portable micro-cantilever sensors. This paper reports on an optical beam deflection-based system to measure the deflection of micro-cantilevers in an array that employs a single laser source, a single detector, and a resonating reflector to scan the measurement laser across the array. A strategy is also proposed to extract the deflection of individual cantilevers from the acquired data. The proposed system and measurement strategy are experimentally evaluated and demonstrated to measure motion of multiple cantilevers in an array.

Trapping of a micro-bubble by non-paraxial Gaussian beam: computation using the FDTD method.

PubMed

Sung, Seung-Yong; Lee, Yong-Gu

2008-03-03

Optical forces on a micro-bubble were computed using the Finite Difference Time Domain method. Non-paraxial Gaussian beam equation was used to represent the incident laser with high numerical aperture, common in optical tweezers. The electromagnetic field distribution around a micro-bubble was computed using FDTD method and the electromagnetic stress tensor on the surface of a micro-bubble was used to compute the optical forces. By the analysis of the computational results, interesting relations between the radius of the circular trapping ring and the corresponding stability of the trap were found.

Microfabricated capillary array electrophoresis device and method

DOEpatents

Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

2000-01-01

A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

Microfabricated capillary array electrophoresis device and method

DOEpatents

Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

2004-06-15

A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

A theoretical study on the impact of particle scattering on the channel characteristics of underwater optical communication system

NASA Astrophysics Data System (ADS)

Sahu, Sanjay Kumar; Shanmugam, Palanisamy

2018-02-01

Scattering by water molecules and particulate matters determines the path and distance of photon propagation in underwater medium. Consequently, photon angle of scattering (given by scattering phase function) requires to be considered in addition to the extinction coefficient of the aquatic medium governed by the absorption and scattering coefficients in channel characterization for an underwater wireless optical communication (UWOC) system. This study focuses on analyzing the received signal power and impulse response of UWOC channel based on Monte-Carlo simulations for different water types, link distances, link geometries and transceiver parameters. A newly developed scattering phase function (referred to as SS phase function), which represents the real water types more accurately like the Petzold phase function, is considered for quantification of the channel characteristics along with the effects of absorption and scattering coefficients. A comparison between the results simulated using various phase function models and the experimental measurements of Petzold revealed that the SS phase function model predicts values closely matching with the actual values of the Petzold's phase function, which further establishes the importance of using a correct scattering phase function model while estimating the channel capacity of UWOC system in terms of the received power and channel impulse response. Results further demonstrate a great advantage of considering the nonzero probability of receiving scattered photons in estimating channel capacity rather than considering the reception of only ballistic photons as in Beer's Law, which severely underestimates the received power and affects the range of communication especially in the scattering water column. The received power computed based on the Monte-Carlo method by considering the receiver aperture sizes and field of views in different water types are further analyzed and discussed. These results are essential for evaluating the underwater link budget and constructing different system and design parameters for an UWOC system.

MicroSight Optics

ScienceCinema

None

2018-05-16

MicroSight is an innovative gunsight technology that allows a marksman's eye to focus on both the front gunsight and the intended target. The MicroSight improves both firearm safety and performance by imaging two objects at different focal distances. The MicroSight was developed at Idaho National Laboratory, and has been licensed by Apollo Optical Systems. You can learn more about INL's research programs at http://www.facebook.com/idahonationallaboratory.

MicroSight Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-01-01

MicroSight is an innovative gunsight technology that allows a marksman's eye to focus on both the front gunsight and the intended target. The MicroSight improves both firearm safety and performance by imaging two objects at different focal distances. The MicroSight was developed at Idaho National Laboratory, and has been licensed by Apollo Optical Systems. You can learn more about INL's research programs at http://www.facebook.com/idahonationallaboratory.

Continuous Diffusion Flames and Flame Streets in Micro-Channels

NASA Astrophysics Data System (ADS)

Mohan, Shikhar; Matalon, Moshe

2015-11-01

Experiments of non-premixed combustion in micro-channels have shown different modes of burning. Normally, a flame is established along, or near the axis of a channel that spreads the entire mixing layer and separates a region of fuel but no oxidizer from a region with only oxidizer. Often, however, a periodic sequence of extinction and reignition events, termed collectively as ``flame streets'', are observed. They constitute a series of diffusion flames, each with a tribrachial leading edge stabilized along the channel. This work focuses on understanding the underlying mechanism responsible for these distinct observations. Numerical simulations were conducted in the thermo-diffusive limit in order to study the effects of confinement and heat loss on non-premixed flames in three-dimensional micro-channels with low aspect ratios. The three dimensionality of the channel was captured qualitatively through a systematic asymptotic analysis that led to a two dimensional problem with an effective parameter representing heat losses in the vertical direction. There exist three key flame regimes: (1) a stable continuous diffusion flame, (2) an unsteady flame, and (3) a stable ``flame street'' the transition between regimes demarcated primarily by Reynolds and Nusselt numbers.

Optical Design of the WFIRST Phase-A Integral Field Channel

NASA Technical Reports Server (NTRS)

Gao, Guangjun; Pasquale, Bert A.; Marx, Catherine T.; Chambers, Victor

2017-01-01

WFIRST is one of NASA's Decadal Survey Missions and is currently in Phase-A development. The optical design of the WFIRST Integral Field Channel (IFC), one of three main optical channels of WFIRST, is presented, and the evolution of the IFC channel since Mission Concept Review (MCR, end of Pre-Phase A) is discussed. The IFC has two sub-channels: Supernova (IFC-S) and Galaxy (IFC-G) channels, with Fields of View of 3"x4.5" and 4.2"x9" respectively, and approximately R 75 spectral analysis over waveband 0.42 approximately 2.0 micrometers. The Phase-A IFC optical design meets image quality requirements over the FOV areas while balancing cost and volume constraints.

Deformation-induced release of ATP from erythrocytes in a poly(dimethylsiloxane)-based microchip with channels that mimic resistance vessels.

PubMed

Price, Alexander K; Fischer, David J; Martin, R Scott; Spence, Dana M

2004-08-15

The ability of nitric oxide to relax smooth muscle cells surrounding resistance vessels in vivo is well documented. Here, we describe a series of studies designed to quantify amounts of adenosine triphosphate (ATP), a known stimulus of NO production in endothelial cells, released from erythrocytes that are mechanically deformed as these cells traverse microbore channels in lithographically patterned microchips. Results indicate that micromolar amounts of ATP are released from erythrocytes flowing through channels having cross sectional dimensions of 60 x 38 micron (2.22 +/- 0.50 microM ATP). Microscopic images indicate that erythrocytes, when being pumped through the microchip channels, migrate toward the center of the channels, leaving a cell-free or skimming layer at the walls of the channel, a profile known to exist in circulatory vessels in vivo. A comparison of the amounts of ATP released from RBCs mechanically deformed in microbore tubing (2.54 +/- 0.15 microM) vs a microchip (2.59 +/- 0.32 microM) suggests that channels in microchips may serve as functional biomimics of the microvasculature. Control studies involving diamide, a membrane-stiffening agent, suggest that the RBC-derived ATP is not due to cell lysis but rather physical deformation.

Localization algorithms for micro-channel x-ray telescope on board SVOM space mission

NASA Astrophysics Data System (ADS)

Gosset, L.; Götz, D.; Osborne, J.; Willingale, R.

2016-07-01

SVOM is a French-Chinese space mission to be launched in 2021, whose goal is the study of Gamma-Ray Bursts, the most powerful stellar explosions in the Universe. The Micro-channel X-ray Telescope (MXT) is an X-ray focusing telescope, on board SVOM, with a field of view of 1 degree (working in the 0.2-10 keV energy band), dedicated to the rapid follow-up of the Gamma-Ray Bursts counterparts and to their precise localization (smaller than 2 arc minutes). In order to reduce the optics mass and to have an angular resolution of few arc minutes, a "lobster-Eye" configuration has been chosen. Using a numerical model of the MXT Point Spread Function (PSF) we simulated MXT observations of point sources in order to develop and test different localization algorithms to be implemented on board MXT. We included preliminary estimations of the instrumental and sky background. The algorithms on board have to be a combination of speed and precision (the brightest sources are expected to be localized at a precision better than 10 arc seconds in the MXT reference frame). We present the comparison between different methods such as barycentre, PSF fitting in one or two dimensions. The temporal performance of the algorithms is being tested using the X-ray afterglow data base of the XRT telescope on board the NASA Swift satellite.

Magnetic field detection using magnetorheological optical resonators

NASA Astrophysics Data System (ADS)

Rubino, Edoardo; Ioppolo, Tindaro

2018-02-01

In this paper, we investigate the feasibility of a magnetic field sensor that is based on a magnetorheological micro-optical resonator. The optical resonator has a spherical shape and a diameter of a few hundred micrometers. The resonator is fabricated by using a polymeric matrix made of polyvinyl chloride (PVC) plastisol with embedded magnetically polarizable micro-particles. When the optical resonator is subjected to an external magnetic field, the morphology (radius and refractive index) of the resonator is perturbed by the magnetic forces acting on it, leading to a shift of the optical resonances also known as whispering gallery modes (WGM). In this study, the effect of a static and harmonic magnetic field, as well as the concentration of the magnetic micro-particles on the optical mode shift is investigated. The optical resonances obtained with the PVC plastisol resonator showed a quality factor of 106 . The dynamical behavior of the optical resonator is investigated in the range between 0 and 200 Hz. The sensitivity of the optical resonator reaches a maximum value for a ratio between micro-particles and the polymeric matrix of 2:1 in weight. Experimental results indicate a sensitivity of 0.297 pm/mT leading to a resolution of 336 μT.

Adaptive channel estimation for soft decision decoding over non-Gaussian optical channel

NASA Astrophysics Data System (ADS)

Xiang, Jing-song; Miao, Tao-tao; Huang, Sheng; Liu, Huan-lin

2016-10-01

An adaptive priori likelihood ratio (LLR) estimation method is proposed over non-Gaussian channel in the intensity modulation/direct detection (IM/DD) optical communication systems. Using the nonparametric histogram and the weighted least square linear fitting in the tail regions, the LLR is estimated and used for the soft decision decoding of the low-density parity-check (LDPC) codes. This method can adapt well to the three main kinds of intensity modulation/direct detection (IM/DD) optical channel, i.e., the chi-square channel, the Webb-Gaussian channel and the additive white Gaussian noise (AWGN) channel. The performance penalty of channel estimation is neglected.

A Conceptual Design For A Spaceborne 3D Imaging Lidar

NASA Technical Reports Server (NTRS)

Degnan, John J.; Smith, David E. (Technical Monitor)

2002-01-01

First generation spaceborne altimetric approaches are not well-suited to generating the few meter level horizontal resolution and decimeter accuracy vertical (range) resolution on the global scale desired by many in the Earth and planetary science communities. The present paper discusses the major technological impediments to achieving few meter transverse resolutions globally using conventional approaches and offers a feasible conceptual design which utilizes modest power kHz rate lasers, array detectors, photon-counting multi-channel timing receivers, and dual wedge optical scanners with transmitter point-ahead correction.

Molecular analysis of the Na+ channel blocking actions of the novel class I anti-arrhythmic agent RSD 921.

PubMed

Pugsley, M K; Goldin, A L

1999-05-01

RSD 921 is a novel, structurally unique, class I Na+ channel blocking drug under development as a local anaesthetic agent and possibly for the treatment of cardiac arrhythmias. The effects of RSD 921 on wild-type heart, skeletal muscle, neuronal and non-inactivating IFMQ3 mutant neuronal Na+ channels expressed in Xenopus laevis oocytes were examined using a two-electrode voltage clamp. RSD 921 produced similarly potent tonic block of all three wild-type channel isoforms, with EC50 values between 35 and 47 microM, whereas the EC50 for block of the IFMQ3 mutant channel was 110+5.5 microM. Block of Na+ channels by RSD 921 was concentration and use-dependent, with marked frequency-dependent block of heart channels and mild frequency-dependent block of skeletal muscle, wild-type neuronal and IFMQ3 mutant channels. RSD 921 produced a minimal hyperpolarizing shift in the steady-state voltage-dependence of inactivation of all three wild-type channel isoforms. Open channel block of the IFMQ3 mutant channel was best fit with a first order blocking scheme with k(on) equal to 0.11+/-0.012x10(6) M(-1) s(-1) and k(off) equal to 12.5+/-2.5 s(-1), resulting in KD of 117+/-31 microM. Recovery from open channel block occurred with a time constant of 14+/-2.7 s(-1). These results suggest that RSD 921 preferentially interacts with the open state of the Na+ channel, and that the drug may produce potent local anaesthetic or anti-arrhythmic action under conditions of shortened action potentials, such as during anoxia or ischaemia.