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Sample records for ftir-fiber optic method

  1. FTIR fiber optic methods for the analysis of Hanford Site waste

    SciTech Connect

    Rebagay, T.V.; Cash, R.J.; Dodd, D.A.

    1995-06-01

    Sampling and chemical characterization of mixed high-level waste stored in underground tanks at the Hanford Site is currently in progress. Waste tank safety concerns have provided impetus to analyze this waste. A major safety issue is the possibility of significant concentrations of fuel (ferrocyanide and/or organic compounds) in contact with oxidizers (nitrates and nitrites). It is postulated that under dry conditions and elevated temperatures, ferrocyanide- and/or organic-bearing wastes could undergo rapid exothermic reactions. To maintain the tanks in a safe condition, data are needed on the moisture and fuel concentrations in the waste. Because of the highly radioactive nature of the waste, non-radioactive waste simulants mimicking actual waste are used to provide an initial basis for identifying realistic waste tank safety concerns. Emphasis has been placed on the use of new or existing Fourier transform infrared (FTIR)-based systems with potential for field or tank deployment to perform in situ remote waste characterization. Near-infrared diffuse reflectance and mid-infrared attenuated total reflectance fiber optic probes coupled to a Bio-Rad FTS 60A spectrometry system have been evaluated. The near-infrared diffuse reflectance fiber probe system has also been used for preliminary screening of the moisture content and chemical composition of actual Hanford Site waste tank waste core samples. The attributes of this method for analyzing actual radioactive waste are discussed.

  2. Rapid characterization of mixed waste by FTIR-fiber optic method

    SciTech Connect

    Rebagay, T.V., Westinghouse Hanford

    1996-07-26

    Tank waste characterization requires various analytical systems to identify and quantify the chemical composition and water content of Hanford Site high-level waste. Safe long-term storage of the waste depends on its chemical and physical data. An analytical database is also the key to the design and implementation of pre-treatment and disposal processes. To provide a faster, cheaper, and safer technique to monitor the moisture content of tank waste, two types of near-infrared (NIR) diffuse reflectance fiber optic probes interfaced to a Fouiier transform infrared (FTIR) spectrometry system were studied. Lower absorptivities in the NIR region enable longer pathlengths to be used leading to easier nondestructive sampling. Both overtone and combination bands Of Water can be used for moisture measurements. While a previous report` provides evidence for the feasibility of using fiber optic probes, the results were strictly qualitative. In this study, the fiber optic probe is installed in a hot cell making it possible to characterize highly radioactive mixed waste rapidly and quantitatively. In seeking a strategy to identify individual species in the waste with minimal sample preparation, a modular transfer optic system equipped with a mid-infrared diffuse reflectance sampler was assessed. Light pipes were used to present the sample to the FTIR spectrometer. Its performance for obtaining rapid, high quality mid-infrared (MIR) spectra of mixed waste is compared with FTIR- photoacoustic spectroscopy.

  3. Fourier transform infrared (FTIR) fiber optic monitoring of composites during cure in an autoclave

    NASA Technical Reports Server (NTRS)

    Druy, Mark A.; Elandjian, Lucy; Stevenson, William A.; Driver, Richard D.; Leskowitz, Garett M.

    1990-01-01

    Real-time in situ monitoring of the chemical states of epoxy resins was investigated during cure in an autoclave using infrared evanescent spectroscopy. Fiber evanescent sensors were developed which may be sandwiched between the plies of the prepreg sample. A short length of sapphire fiber was used as the sensor cell portion of the fiber probe. Heavy metal fluoride glass optical fiber cables were designed for connecting the FTIR spectrometer to the sensor fiber within the autoclave. The sapphire fibers have outstanding mechanical thermal properties which should permit their use as an embedded link in all thermoset composites. The system is capable of operation at a temperature of 250 C for periods up to 8 hours without major changes to the fiber transmission. A discussion of the selection of suitable sensor fibers, the construction of a fiber-optic interface, and the interpretation of in situ infrared spectra of the curing process is presented.

  4. Fourier transform infrared (FTIR) fiber optic monitoring of composites during cure in an autoclave

    NASA Technical Reports Server (NTRS)

    Druy, Mark A.; Elandjian, Lucy; Stevenson, William A.; Driver, Richard D.; Leskowitz, Garett M.

    1990-01-01

    Real-time in situ monitoring of the chemical states of epoxy resins was investigated during cure in an autoclave using infrared evanescent spectroscopy. Fiber evanescent sensors were developed which may be sandwiched between the plies of the prepreg sample. A short length of sapphire fiber was used as the sensor cell portion of the fiber probe. Heavy metal fluoride glass optical fiber cables were designed for connecting the FTIR spectrometer to the sensor fiber within the autoclave. The sapphire fibers have outstanding mechanical thermal properties which should permit their use as an embedded link in all thermoset composites. The system is capable of operation at a temperature of 250 C for periods up to 8 hours without major changes to the fiber transmission. A discussion of the selection of suitable sensor fibers, the construction of a fiber-optic interface, and the interpretation of in situ infrared spectra of the curing process is presented.

  5. Optical switches and switching methods

    DOEpatents

    Doty, Michael

    2008-03-04

    A device and method for collecting subject responses, particularly during magnetic imaging experiments and testing using a method such as functional MRI. The device comprises a non-metallic input device which is coupled via fiber optic cables to a computer or other data collection device. One or more optical switches transmit the subject's responses. The input device keeps the subject's fingers comfortably aligned with the switches by partially immobilizing the forearm, wrist, and/or hand of the subject. Also a robust nonmetallic switch, particularly for use with the input device and methods for optical switching.

  6. Atmospheric studies by optical methods

    NASA Astrophysics Data System (ADS)

    Steen, Åke

    The 19th Annual European Meeting on Atmospheric Studies by Optical Methods was held in Kiruna, Sweden, from August 10 to 14. About 120 scientists from thirteen countries contributed talks and posters to eight topical sessions.The annual optical meeting, which was first held in Stockholm in 1972, provides a platform for the exchange of ideas, scientific results, and instrumental information on atmospheric studies collected by optical methods. Although the primary objective is to stimulate high-level scientific discussions, social activities are included in the conference program to expose participants to the host city's local culture, industry, and sights. Participants from all parts of the world are welcome to attend.

  7. Optical measurement methods in thermogasdynamics

    NASA Technical Reports Server (NTRS)

    Stursberg, K.; Erhardt, K.; Krahr, W.; Becker, M.

    1978-01-01

    A review is presented of a number of optical methods of flow measurements. Consideration is given to such spectroscopic methods as emission and absorption techniques, electron beam-stimulated fluorescence, and light scattering - Rayleigh, Raman and Mie - methods. The following visualization methods are also discussed: shadow photography, schlieren photography, interferometry, holographic interferometry, laser anemometry, particle holography, and electron-excitation imaging. A large bibliography is presented and the work is copiously illustrated with figures and photographs.

  8. Methods for globally treating silica optics to reduce optical damage

    DOEpatents

    Miller, Philip Edward; Suratwala, Tayyab Ishaq; Bude, Jeffrey Devin; Shen, Nan; Steele, William Augustus; Laurence, Ted Alfred; Feit, Michael Dennis; Wong, Lana Louie

    2012-11-20

    A method for preventing damage caused by high intensity light sources to optical components includes annealing the optical component for a predetermined period. Another method includes etching the optical component in an etchant including fluoride and bi-fluoride ions. The method also includes ultrasonically agitating the etching solution during the process followed by rinsing of the optical component in a rinse bath.

  9. Coherent optical methods for metallography

    SciTech Connect

    Pechersky, M.J.

    1991-01-01

    Numerous methods based on coherent optical techniques have been developed over the past two decades for nondestructive evaluation, vibration analysis and experimental mechanics. These methods have a great deal of potential for the enhancement of metallographic evaluations and for materials characterization in general. One such technique described in this paper is the determination of the material damping factors in metals. Damping loss factors as low as 10-5 were measured on bronze and aluminum specimens using a technique based on laser vibrometry. Differences between cast and wrought bronze were easily distinguishable as well as the difference between the bronze and aluminum. Other coherent optical techniques may be used to evaluate residual stresses and to locate and identify microcracking, subsurface voids and other imperfections. These techniques and others can serve as a bridge between microstructural investigations and the macroscopic behavior of materials.

  10. Coherent optical methods for metallography

    SciTech Connect

    Pechersky, M.J.

    1991-12-31

    Numerous methods based on coherent optical techniques have been developed over the past two decades for nondestructive evaluation, vibration analysis and experimental mechanics. These methods have a great deal of potential for the enhancement of metallographic evaluations and for materials characterization in general. One such technique described in this paper is the determination of the material damping factors in metals. Damping loss factors as low as 10-5 were measured on bronze and aluminum specimens using a technique based on laser vibrometry. Differences between cast and wrought bronze were easily distinguishable as well as the difference between the bronze and aluminum. Other coherent optical techniques may be used to evaluate residual stresses and to locate and identify microcracking, subsurface voids and other imperfections. These techniques and others can serve as a bridge between microstructural investigations and the macroscopic behavior of materials.

  11. Method of lightening radiation darkened optical elements

    DOEpatents

    Reich, Frederich R.; Schwankoff, Albert R.

    1980-01-01

    A method of lightening a radiation-darkened optical element in wich visible optical energy or electromagnetic radiation having a wavelength in the range of from about 2000 to about 20,000 angstroms is directed into the radiation-darkened optical element; the method may be used to lighten radiation-darkened optical element in-situ during the use of the optical element to transmit data by electronically separating the optical energy from the optical output by frequency filtering, data cooling, or interlacing the optic energy between data intervals.

  12. Fiber optic sensor and method for making

    DOEpatents

    Vartuli, James Scott; Bousman, Kenneth Sherwood; Deng, Kung-Li; McEvoy, Kevin Paul; Xia, Hua

    2010-05-18

    A fiber optic sensor including a fiber having a modified surface integral with the fiber wherein the modified surface includes an open pore network with optical agents dispersed within the open pores of the open pore network. Methods for preparing the fiber optic sensor are also provided. The fiber optic sensors can withstand high temperatures and harsh environments.

  13. Optical design and active optics methods in astronomy

    NASA Astrophysics Data System (ADS)

    Lemaitre, Gerard R.

    2013-03-01

    Optical designs for astronomy involve implementation of active optics and adaptive optics from X-ray to the infrared. Developments and results of active optics methods for telescopes, spectrographs and coronagraph planet finders are presented. The high accuracy and remarkable smoothness of surfaces generated by active optics methods also allow elaborating new optical design types with high aspheric and/or non-axisymmetric surfaces. Depending on the goal and performance requested for a deformable optical surface analytical investigations are carried out with one of the various facets of elasticity theory: small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, weakly conical shell theory. The resulting thickness distribution and associated bending force boundaries can be refined further with finite element analysis.

  14. Reflective optical imaging method and circuit

    DOEpatents

    Shafer, David R.

    2001-01-01

    An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements are characterized in order from object to image as convex, concave, convex and concave mirrors. The optical system is particularly suited for step and scan lithography methods. The invention increases the slit dimensions associated with ringfield scanning optics, improves wafer throughput and allows higher semiconductor device density.

  15. Method for optical and mechanically coupling optical fibers

    DOEpatents

    Toeppen, J.S.

    1996-10-01

    A method and apparatus are disclosed for splicing optical fibers. A fluorescing solder glass frit having a melting point lower than the melting point of first and second optical fibers is prepared. The solder glass frit is then attached to the end of the first optical fiber and/or the end of the second optical fiber. The ends of the optical fibers are aligned and placed in close proximity to each other. The solder glass frit is then heated to a temperature which is lower than the melting temperature of the first and second optical fibers, but which is high enough to melt the solder glass frit. A force is applied to the first and second optical fibers pushing the ends of the fibers towards each other. As the solder glass flit becomes molten, the layer of molten solder glass is compressed into a thin layer between the first and second optical fibers. The thin compressed layer of molten solder glass is allowed to cool such that the first and second optical fibers are bonded to each other by the hardened layer of solder glass. 6 figs.

  16. Optical distance measurement device and method thereof

    DOEpatents

    Bowers, Mark W.

    2003-05-27

    A system and method of efficiently obtaining distance measurements of a target. A modulated optical beam may be used to determine the distance to the target. A first beam splitter may be used to split the optical beam and a second beam splitter may be used to recombine a reference beam with a return ranging beam. An optical mixing detector may be used in a receiver to efficiently detect distance measurement information.

  17. Whole beam method for photorefractive nonlinear optics

    NASA Astrophysics Data System (ADS)

    Cronin-Golomb, Mark

    1992-05-01

    A whole beam split step method is developed for photorefractive nonlinear optics. The nonlinear optical beam coupling process is separated into short steps of diffractive propagation and application of calculated nonlinearity. The method includes the effects of diffractive propagation without using multi-wave coupled wave theory. Two-beam coupling of continous wave, femtosecond and reduced spatial coherence gaussian beams is used to illustrate the method.

  18. Optical Element, Device, Method, and Applications

    DTIC Science & Technology

    2011-04-14

    optical element is a phase-only element; and h) repeating steps ( c -f). 28. The method of claim 26, further comprising: c1) in step (c), setting...jl(l;, 11) to 0, wherein the optical element is an amplitude-only element; and h) repeating steps ( c -f). * * * * *

  19. Optical Distance Measurement Device And Method Thereof

    DOEpatents

    Bowers, Mark W.

    2004-06-15

    A system and method of efficiently obtaining distance measurements of a target by scanning the target. An optical beam is provided by a light source and modulated by a frequency source. The modulated optical beam is transmitted to an acousto-optical deflector capable of changing the angle of the optical beam in a predetermined manner to produce an output for scanning the target. In operation, reflected or diffused light from the target may be received by a detector and transmitted to a controller configured to calculate the distance to the target as well as the measurement uncertainty in calculating the distance to the target.

  20. Package for integrated optic circuit and method

    DOEpatents

    Kravitz, S.H.; Hadley, G.R.; Warren, M.E.; Carson, R.F.; Armendariz, M.G.

    1998-08-04

    A structure and method are disclosed for packaging an integrated optic circuit. The package comprises a first wall having a plurality of microlenses formed therein to establish channels of optical communication with an integrated optic circuit within the package. A first registration pattern is provided on an inside surface of one of the walls of the package for alignment and attachment of the integrated optic circuit. The package in one embodiment may further comprise a fiber holder for aligning and attaching a plurality of optical fibers to the package and extending the channels of optical communication to the fibers outside the package. In another embodiment, a fiber holder may be used to hold the fibers and align the fibers to the package. The fiber holder may be detachably connected to the package. 6 figs.

  1. Package for integrated optic circuit and method

    DOEpatents

    Kravitz, Stanley H.; Hadley, G. Ronald; Warren, Mial E.; Carson, Richard F.; Armendariz, Marcelino G.

    1998-01-01

    A structure and method for packaging an integrated optic circuit. The package comprises a first wall having a plurality of microlenses formed therein to establish channels of optical communication with an integrated optic circuit within the package. A first registration pattern is provided on an inside surface of one of the walls of the package for alignment and attachment of the integrated optic circuit. The package in one embodiment may further comprise a fiber holder for aligning and attaching a plurality of optical fibers to the package and extending the channels of optical communication to the fibers outside the package. In another embodiment, a fiber holder may be used to hold the fibers and align the fibers to the package. The fiber holder may be detachably connected to the package.

  2. Optical switching system and method

    DOEpatents

    Ranganathan, Radha; Gal, Michael; Taylor, P. Craig

    1992-01-01

    An optically bistable device is disclosed. The device includes a uniformly thick layer of amorphous silicon to constitute a Fabry-Perot chamber positioned to provide a target area for a probe beam. The probe beam has a maximum energy less than the energy band gap of the amorphous semiconductor. In a preferred embodiment, a multilayer dielectric mirror is positioned on the Fabry-Perot chamber to increase the finesse of switching of the device. The index of refraction of the amorphous material is thermally altered to alter the transmission of the probe beam.

  3. Method and apparatus for staking optical elements

    DOEpatents

    Woods, Robert O.

    1988-01-01

    A method and apparatus for staking two optical elements together in order to retain their alignment is disclosed. The apparatus includes a removable adaptor made up of first and second adaptor bodies each having a lateral slot in their front and side faces. The adaptor also includes a system for releasably attaching each adaptor body to a respective optical element such that when the two optical elements are positioned relative to one another the adaptor bodies are adjacent and the lateral slots therein are aligned to form key slots. The adaptor includes keys which are adapted to fit into the key slots. A curable filler material is employed to retain the keys in the key slots and thereby join the first and second adaptor bodies to form the adaptor. Also disclosed is a method for staking together two optical elements employing the adaptor of the present invention.

  4. Method and apparatus for staking optical elements

    DOEpatents

    Woods, Robert O.

    1988-10-04

    A method and apparatus for staking two optical elements together in order to retain their alignment is disclosed. The apparatus includes a removable adaptor made up of first and second adaptor bodies each having a lateral slot in their front and side faces. The adaptor also includes a system for releasably attaching each adaptor body to a respective optical element such that when the two optical elements are positioned relative to one another the adaptor bodies are adjacent and the lateral slots therein are aligned to form key slots. The adaptor includes keys which are adapted to fit into the key slots. A curable filler material is employed to retain the keys in the key slots and thereby join the first and second adaptor bodies to form the adaptor. Also disclosed is a method for staking together two optical elements employing the adaptor of the present invention.

  5. Front lighted optical tooling method and apparatus

    DOEpatents

    Stone, William J.

    1985-06-18

    An optical tooling method and apparatus uses a front lighted shadowgraphic technique to enhance visual contrast of reflected light. The apparatus includes an optical assembly including a fiducial mark, such as cross hairs, reflecting polarized light with a first polarization, a polarizing element backing the fiducial mark and a reflective surface backing the polarizing element for reflecting polarized light bypassing the fiducial mark and traveling through the polarizing element. The light reflected by the reflecting surface is directed through a second pass of the polarizing element toward the frontal direction with a polarization differing from the polarization of the light reflected by the fiducial mark. When used as a tooling target, the optical assembly may be mounted directly to a reference surface or may be secured in a mounting, such as a magnetic mounting. The optical assembly may also be mounted in a plane defining structure and used as a spherometer in conjunction with an optical depth measuring instrument. A method of measuring a radius of curvature of an unknown surface includes positioning the spherometer on a surface between the surface and a depth measuring optical instrument. As the spherometer is frontally illuminated, the distance from the depth measuring instrument to the fiducial mark and the underlying surface are alternately measured and the difference in these measurements is used as the sagittal height to calculate a radius of curvature.

  6. Latest optical methods for industrial dimensional metrology

    NASA Astrophysics Data System (ADS)

    Harding, Kevin

    2005-11-01

    Applying optical methods to a simple inspection problem, such as the presence or absence of an assembly component, is likely the least restrictive of any machine vision application. The setup, alignment, and components can be made very simply by using any feature which appears different if the component of interest is present. Gaging to verify proper construction, however, can be a much more complicated task. To take advantage of the capability of machine vision and other optical technologies, some flexibility in part position, orientation, and speed of presentation may be desired. This paper will review the types of methods available from optical methods for industrial dimensional metrology. The emphasis of the discussion will be 2D and 3D gaging applications.

  7. New Optical Methods for Signal Processing

    NASA Astrophysics Data System (ADS)

    Zhang, Yan

    This doctoral thesis studies the optical implementations of various new algorithms and methods for large bandwidth signal and image processing. Among the schemes to be studied are the long data stream convolution/correlation, the Gabor and the wavelet transforms, and their applications to system failure prediction, dense target signal processing and image coding. Based on the Chinese remainder theorem, optically implementable algorithms are described, which convert the convolution/correlation of long data streams to relatively small scale linear operations such as a group of short -term vector-matrix multiplications or short-term convolutions/correlations. The proposed algorithms can be realized by using the existing optical analog data processors. Simulations were performed to prove their validity. Technical problems and fundamental limitations of the above schemes are studied. Following the consideration of the above time domain operations, signal's representations in joint time -frequency (scale) domain are then considered. An opto -electronic Gabor coefficient processor is designed to perform the Gabor transform on short one-dimensional (1-D) signals in real-time. Some experimental results are presented to confirm the operational principle of the system. As an application of this processor, Gabor transform based transient signal detection is studied. Other schemes for implementing Gabor transform of long 1-D signals based on the long data stream convolver, and 2-D signals are also investigated. Following the study of the Gabor transform, the newly suggested wavelet transform is considered for its optical implementation. Using commercially available opto-electronic components, an optical wavelet processor is designed and built to perform the wavelet transforms on short 1-D signals in real-time. As an extension, architectures for 2-D optical wavelet transform are also described and computer simulated with the consideration of their technical problems of optical

  8. Plasma channel optical pumping device and method

    DOEpatents

    Judd, O.P.

    1983-06-28

    A device and method are disclosed for optically pumping a gaseous laser using blackbody radiation produced by a plasma channel which is formed from an electrical discharge between two electrodes spaced at opposite longitudinal ends of the laser. A preionization device which can comprise a laser or electron beam accelerator produces a preionization beam which is sufficient to cause an electrical discharge between the electrodes to initiate the plasma channel along the preionization path. The optical pumping energy is supplied by a high voltage power supply rather than by the preionization beam. High output optical intensities are produced by the laser due to the high temperature blackbody radiation produced by the plasma channel, in the same manner as an exploding wire type laser. However, unlike the exploding wire type laser, the disclosed invention can be operated in a repetitive manner by utilizing a repetitive pulsed preionization device. 5 figs.

  9. Chip-to-chip optical link by using optical wiring method

    NASA Astrophysics Data System (ADS)

    Cho, In-Kui; Ahn, Seoung Ho; Jeong, Myung-Yung; Rho, Byung Sup; Park, Hyo Hoon

    2008-01-01

    A practical optical link system was prepared with a transmitter (Tx) and receiver (Rx). The optical TRx module consisted of a metal optical bench, a module printed circuit board (PCB), a driver/receiver IC, a VCSEL/PD array, and an optical link block composed of plastic optical fiber (POF). For the optical interconnection between the light-sources and detectors, an optical wiring method has been proposed to enable easy assembly. This paper provides a method for optical interconnection between an optical Tx and an optical Rx, comprising the following steps: (a) forming a light source device, an optical detection device, and an optical transmission unit on a substrate (metal optical bench (MOB)); (b) preparing a flexible optical transmission-connection medium (optical wiring link) to optically connect the light source device formed on the substrate with the optical detection device; and (c) directly connecting one end of the surface-finished optical transmission connection medium with the light source device and the other end with the optical detection device. A chip-to-chip optical link system constructed with TRx modules was fabricated and the optical characteristics were measured. The results clearly demonstrate that the use of an optical wiring method can provide robust and cost-effective assembly for vertical-cavity surface-emitting lasers (VCSELs) and photodiodes (PDs). We successfully achieved a 5 Gb/s data transmission rate with this optical link.

  10. Optical apparatus and method for sensing uranyl

    DOEpatents

    Baylor, L.C.; Buchanan, B.R.

    1994-01-01

    An optical sensing device for uranyl and other substances, a method for making an optical sensing device and a method for chemically binding uranyl and other indicators to glass, quartz, cellulose and similar substrates. The indicator, such as arsenazo III, is immobilized on the substrate using a chemical binding process. The immobilized arsenazo III causes uranyl from a fluid sample to bind irreversibly to the substrate at its active sites, thus causing absorption of a portion of light transmitted through the substrate. Determination of the amount of light absorbed, using conventional means, yields the concentration of uranyl present in the sample fluid. The binding of uranyl on the substrate can be reversed by subsequent exposure of the substrate to a solution of 2,6-pyridinedicarboxylic acid. The chemical binding process is suitable for similarly binding other indicators, such as bromocresol green.

  11. Computational methods for optical molecular imaging

    PubMed Central

    Chen, Duan; Wei, Guo-Wei; Cong, Wen-Xiang; Wang, Ge

    2010-01-01

    Summary A new computational technique, the matched interface and boundary (MIB) method, is presented to model the photon propagation in biological tissue for the optical molecular imaging. Optical properties have significant differences in different organs of small animals, resulting in discontinuous coefficients in the diffusion equation model. Complex organ shape of small animal induces singularities of the geometric model as well. The MIB method is designed as a dimension splitting approach to decompose a multidimensional interface problem into one-dimensional ones. The methodology simplifies the topological relation near an interface and is able to handle discontinuous coefficients and complex interfaces with geometric singularities. In the present MIB method, both the interface jump condition and the photon flux jump conditions are rigorously enforced at the interface location by using only the lowest-order jump conditions. This solution near the interface is smoothly extended across the interface so that central finite difference schemes can be employed without the loss of accuracy. A wide range of numerical experiments are carried out to validate the proposed MIB method. The second-order convergence is maintained in all benchmark problems. The fourth-order convergence is also demonstrated for some three-dimensional problems. The robustness of the proposed method over the variable strength of the linear term of the diffusion equation is also examined. The performance of the present approach is compared with that of the standard finite element method. The numerical study indicates that the proposed method is a potentially efficient and robust approach for the optical molecular imaging. PMID:20485461

  12. Two optical methods for vehicle tagging

    NASA Astrophysics Data System (ADS)

    Coulter, John K.; Klein, Christopher F.; Jafolla, James C.

    2002-08-01

    Optical tagging methods have the advantage that they cannot be detected by a suspicious criminal or terrorist using a radio frequency (RF) sensitive device to scan his vehicle for the presence of an RF emitting tag. We will describe two optical tagging methods in which the presence of the tagging marks can be visually discovered only by very close observation. On the other hand, the tags can be readily recognized by a surveillance team through the use of infrared imagers, either in the longwave infrared (LWIR) or in the near infrared (NIR). The first approach uses a clear coating that has a higher thermal emissivity than the glass window to which it is applied. This coating can be viewed with a thermal imager that operates in the LWIR, with the tags appearing as bright marks on a dark background. The second method uses an NIR laser illuminator and also quarter-wave thick layers applied to the license plate of a vehicle. When viewed with a polarization-sensitive imager that operates in the NIR, these quarter-wave tags appear as bright marks on a dark background. We will show sample images of both of these optical tags, as viewed in the LWIR and NIR regions, respectively.

  13. Optical domain analog to digital conversion methods and apparatus

    SciTech Connect

    Vawter, Gregory A

    2014-05-13

    Methods and apparatus for optical analog to digital conversion are disclosed. An optical signal is converted by mapping the optical analog signal onto a wavelength modulated optical beam, passing the mapped beam through interferometers to generate analog bit representation signals, and converting the analog bit representation signals into an optical digital signal. A photodiode receives an optical analog signal, a wavelength modulated laser coupled to the photodiode maps the optical analog signal to a wavelength modulated optical beam, interferometers produce an analog bit representation signal from the mapped wavelength modulated optical beam, and sample and threshold circuits corresponding to the interferometers produce a digital bit signal from the analog bit representation signal.

  14. Optical method of atomic ordering estimation

    SciTech Connect

    Prutskij, T.; Attolini, G.

    2013-12-04

    It is well known that within metal-organic vapor-phase epitaxy (MOVPE) grown semiconductor III-V ternary alloys atomically ordered regions are spontaneously formed during the epitaxial growth. This ordering leads to bandgap reduction and to valence bands splitting, and therefore to anisotropy of the photoluminescence (PL) emission polarization. The same phenomenon occurs within quaternary semiconductor alloys. While the ordering in ternary alloys is widely studied, for quaternaries there have been only a few detailed experimental studies of it, probably because of the absence of appropriate methods of its detection. Here we propose an optical method to reveal atomic ordering within quaternary alloys by measuring the PL emission polarization.

  15. Method of parallel switching of optical channels

    SciTech Connect

    Kompanets, I N; Neevina, T A; Kompanets, S I

    2012-12-31

    The possibility of creating parallel-type switches for N Multiplication-Sign N optical waveguide channel communication is studied. A method based on bit-by-bit channel addressing is proposed and one of its possible implementations using the photorefractive effect in the waveguide material is considered. The method is modelled by the example of switching of 8 Multiplication-Sign 8 channels, controlled by reconfigurable matrix of light signals. (special issue devoted to the 90th anniversary of n.g. basov)

  16. Electro-Optic Modulator and Method

    DTIC Science & Technology

    An optical intensity modulator which uses a Sagnac interferometer having an electro - optic phase modulator therein. An electric modulation signal is...modulating the optical signals by the electrical signal, the electro - optic effect in the modulator phase shifts the optical signals with respect to one another

  17. Optical fiber coupling method and apparatus

    NASA Technical Reports Server (NTRS)

    Goss, W. C.; Nelson, M. D.; Mclauchlan, J. M. (Inventor)

    1985-01-01

    Systems are described for coupling a pair of optical fibers to pass light between them, which enables a coupler to be easily made, and with simple equipment, while closely controlling the characteristics of the coupler. One method includes mounting a pair of optical fibers on a block having a large hole therein, so the fibers extend across the hole while lying adjacent and parallel to one another. The fibers are immersed in an etchant to reduce the thickness of cladding around the fiber core. The fibers are joined together by applying a liquid polymer so the polymer-air interface moves along the length of the fibers to bring the fibers together in a zipper-like manner, and to progressively lay a thin coating of the polymer on the fibers.

  18. Parametric reconstruction method in optical tomography.

    PubMed

    Gu, Xuejun; Ren, Kui; Masciotti, James; Hielscher, Andreas H

    2006-01-01

    Optical tomography consists of reconstructing the spatial of a medium's optical properties from measurements of transmitted light on the boundary of the medium. Mathematically this problem amounts to parameter identification for the radiative transport equation (ERT) or diffusion approximation (DA). However, this type of boundary-value problem is highly ill-posed and the image reconstruction process is often unstable and non-unique. To overcome this problem, we present a parametric inverse method that considerably reduces the number of variables being reconstructed. In this way the amount of measured data is equal or larger than the number of unknowns. Using synthetic data, we show examples that demonstrate how this approach leads to improvements in imaging quality.

  19. Optical methods for measuring DNA folding

    NASA Astrophysics Data System (ADS)

    Smith, Adam D.; Ukogu, Obinna A.; Devenica, Luka M.; White, Elizabeth D.; Carter, Ashley R.

    2017-03-01

    One of the most important biological processes is the dynamic folding and unfolding of deoxyribonucleic acid (DNA). The folding process is crucial for DNA to fit within the boundaries of the cell, while the unfolding process is essential for DNA replication and transcription. To accommodate both processes, the cell employs a highly active folding mechanism that has been the subject of intense study over the last few decades. Still, many open questions remain. What are the pathways for folding or unfolding? How does the folding equilibrium shift? And, what is the energy landscape for a particular process? Here, we review these emerging questions and the in vitro, optical methods that have provided answers, introducing the topic for those physicists seeking to step into biology. Specifically, we discuss two iconic experiments for DNA folding, the tethered particle motion (TPM) experiment and the optical tweezers experiment.

  20. Optical nulling apparatus and method for testing an optical surface

    NASA Technical Reports Server (NTRS)

    Olczak, Eugene (Inventor); Hannon, John J. (Inventor); Dey, Thomas W. (Inventor); Jensen, Arthur E. (Inventor)

    2008-01-01

    An optical nulling apparatus for testing an optical surface includes an aspheric mirror having a reflecting surface for imaging light near or onto the optical surface under test, where the aspheric mirror is configured to reduce spherical aberration of the optical surface under test. The apparatus includes a light source for emitting light toward the aspheric mirror, the light source longitudinally aligned with the aspheric mirror and the optical surface under test. The aspheric mirror is disposed between the light source and the optical surface under test, and the emitted light is reflected off the reflecting surface of the aspheric mirror and imaged near or onto the optical surface under test. An optical measuring device is disposed between the light source and the aspheric mirror, where light reflected from the optical surface under test enters the optical measuring device. An imaging mirror is disposed longitudinally between the light source and the aspheric mirror, and the imaging mirror is configured to again reflect light, which is first reflected from the reflecting surface of the aspheric mirror, onto the optical surface under test.

  1. Method and system for processing optical elements using magnetorheological finishing

    DOEpatents

    Menapace, Joseph Arthur; Schaffers, Kathleen Irene; Bayramian, Andrew James; Molander, William A

    2012-09-18

    A method of finishing an optical element includes mounting the optical element in an optical mount having a plurality of fiducials overlapping with the optical element and obtaining a first metrology map for the optical element and the plurality of fiducials. The method also includes obtaining a second metrology map for the optical element without the plurality of fiducials, forming a difference map between the first metrology map and the second metrology map, and aligning the first metrology map and the second metrology map. The method further includes placing mathematical fiducials onto the second metrology map using the difference map to form a third metrology map and associating the third metrology map to the optical element. Moreover, the method includes mounting the optical element in the fixture in an MRF tool, positioning the optical element in the fixture; removing the plurality of fiducials, and finishing the optical element.

  2. Method and apparatus for optical temperature measurement

    DOEpatents

    O'Rourke, Patrick E.; Livingston, Ronald R.; Prather, William S.

    1994-01-01

    A temperature probe and a method for using said probe for temperature measurements based on changes in light absorption by the probe. The probe comprises a first and a second optical fiber that carry light to and from the probe, and a temperature sensor material, the absorbance of which changes with temperature, through which the light is directed. Light is directed through the first optical fiber, passes through the temperature sensor material, and is transmitted by a second optical fiber from the material to a detector. Temperature-dependent and temperature-independent factors are derived from measurements of the transmitted light intensity. For each sensor material, the temperature T is a function of the ratio, R, of these factors. The temperature function f(R) is found by applying standard data analysis techniques to plots of T versus R at a series of known temperatures. For a sensor having a known temperature function f(R) and known characteristic and temperature-dependent factors, the temperature can be computed from a measurement of R. Suitable sensor materials include neodymium-doped boresilicate glass, accurate to .+-.0.5.degree. C. over an operating temperature range of about -196.degree. C. to 400.degree. C.; and a mixture of D.sub.2 O and H.sub.2 O, accurate to .+-.0.1.degree. C. over an operating range of about 5.degree. C. to 90.degree. C.

  3. Method and apparatus for optical temperature measurement

    DOEpatents

    O'Rourke, P.E.; Livingston, R.R.; Prather, W.S.

    1994-09-20

    A temperature probe and a method for using said probe for temperature measurements based on changes in light absorption by the probe are disclosed. The probe comprises a first and a second optical fiber that carry light to and from the probe, and a temperature sensor material, the absorbance of which changes with temperature, through which the light is directed. Light is directed through the first optical fiber, passes through the temperature sensor material, and is transmitted by a second optical fiber from the material to a detector. Temperature-dependent and temperature-independent factors are derived from measurements of the transmitted light intensity. For each sensor material, the temperature T is a function of the ratio, R, of these factors. The temperature function f(R) is found by applying standard data analysis techniques to plots of T versus R at a series of known temperatures. For a sensor having a known temperature function f(R) and known characteristic and temperature-dependent factors, the temperature can be computed from a measurement of R. Suitable sensor materials include neodymium-doped borosilicate glass, accurate to [+-]0.5 C over an operating temperature range of about [minus]196 C to 400 C; and a mixture of D[sub 2]O and H[sub 2]O, accurate to [+-]0.1 C over an operating range of about 5 C to 90 C. 13 figs.

  4. Optical feedback structures and methods of making

    DOEpatents

    Snee, Preston T; Chan, Yin Thai; Nocera, Daniel G; Bawendi, Moungi G

    2014-11-18

    An optical resonator can include an optical feedback structure disposed on a substrate, and a composite including a matrix including a chromophore. The composite disposed on the substrate and in optical communication with the optical feedback structure. The chromophore can be a semiconductor nanocrystal. The resonator can provide laser emission when excited.

  5. A method which can enhance the optical-centering accuracy

    NASA Astrophysics Data System (ADS)

    Zhang, Xue-min; Zhang, Xue-jun; Dai, Yi-dan; Yu, Tao; Duan, Jia-you; Li, Hua

    2014-09-01

    Optical alignment machining is an effective method to ensure the co-axiality of optical system. The co-axiality accuracy is determined by optical-centering accuracy of single optical unit, which is determined by the rotating accuracy of lathe and the optical-centering judgment accuracy. When the rotating accuracy of 0.2um can be achieved, the leading error can be ignored. An axis-determination tool which is based on the principle of auto-collimation can be used to determine the only position of centerscope is designed. The only position is the position where the optical axis of centerscope is coincided with the rotating axis of the lathe. Also a new optical-centering judgment method is presented. A system which includes the axis-determination tool and the new optical-centering judgment method can enhance the optical-centering accuracy to 0.003mm.

  6. Method for Implementing Optical Phase Adjustment

    NASA Technical Reports Server (NTRS)

    Hovde, David C.; Corsini, Eric

    2011-01-01

    A method has been developed to mechanically implement the optical phase shift by adjusting the polarization of the pump and probe beams in an NMOR (nonlinear magneto-optical rotation) magnetometer as the proper phase shift is necessary to induce self-oscillation. This innovation consists of mounting the pump beam on a ring that surrounds the atomic vapor sample. The propagation of the probe beam is perpendicular to that of the pump beam. The probe beam can be considered as defining the axis of a cylinder, while the pump beam is directed radially. The magnetic field to be measured defines a third vector, but it is also taken to lie along the cylinder axis. Both the pump and probe beams are polarized such that their electric field vectors are substantially perpendicular to the magnet field. By rotation of the ring supporting the pump beam, its direction can be varied relative to the plane defined by the probe electric field and the magnetic field to be measured.

  7. System and method for attitude determination based on optical imaging

    NASA Technical Reports Server (NTRS)

    Junkins, John L. (Inventor); Pollock, Thomas C. (Inventor); Mortari, Daniele (Inventor)

    2003-01-01

    A method and apparatus is provide for receiving a first set of optical data from a first field of view and receiving a second set of optical data from a second field of view. A portion of the first set of optical data is communicated and a portion of the second set of optical data is reflected, both toward an optical combiner. The optical combiner then focuses the portions onto the image plane such that information at the image plane that is associated with the first and second fields of view is received by an optical detector and used to determine an attitude characteristic.

  8. Systems and methods for free space optical communication

    DOEpatents

    Harper, Warren W [Benton City, WA; Aker, Pamela M [Richland, WA; Pratt, Richard M [Richland, WA

    2011-05-10

    Free space optical communication methods and systems, according to various aspects are described. The methods and systems are characterized by transmission of data through free space with a digitized optical signal acquired using wavelength modulation, and by discrimination between bit states in the digitized optical signal using a spectroscopic absorption feature of a chemical substance.

  9. Smart Optical Material Characterization System and Method

    NASA Technical Reports Server (NTRS)

    Choi, Sang Hyouk (Inventor); Park, Yeonjoon (Inventor)

    2015-01-01

    Disclosed is a system and method for characterizing optical materials, using steps and equipment for generating a coherent laser light, filtering the light to remove high order spatial components, collecting the filtered light and forming a parallel light beam, splitting the parallel beam into a first direction and a second direction wherein the parallel beam travelling in the second direction travels toward the material sample so that the parallel beam passes through the sample, applying various physical quantities to the sample, reflecting the beam travelling in the first direction to produce a first reflected beam, reflecting the beam that passes through the sample to produce a second reflected beam that travels back through the sample, combining the second reflected beam after it travels back though the sample with the first reflected beam, sensing the light beam produced by combining the first and second reflected beams, and processing the sensed beam to determine sample characteristics and properties.

  10. Methods for optical adjustment in lidar systems.

    PubMed

    Liu, Bo; Yi, Fan; Yu, Chang Ming

    2005-03-10

    In a lidar system, both a well-adjusted receiving telescope and an accurate transmitter-receiver alignment are essential for obtaining reliable data, but usually these are time consuming and difficult to accomplish, especially when the optical axis of the telescope is fixed. To solve these problems, we present a novel method, to our knowledge, for the receiving telescope adjustment, which is carried out mainly with a commercial laser plummet. A simple, fast alignment procedure is also described. These are tested by adjustment of the Fe-resonance fluorescence lidar system of Wuhan University and proved to be effective and convenient. The lidar system is applied to monitor the Fe layer in the mesosphere, leading to continuous retrieval of the iron density profiles with fine spatiotemporal resolution.

  11. Method for producing damage resistant optics

    DOEpatents

    Hackel, Lloyd A.; Burnham, Alan K.; Penetrante, Bernardino M.; Brusasco, Raymond M.; Wegner, Paul J.; Hrubesh, Lawrence W.; Kozlowski, Mark R.; Feit, Michael D.

    2003-01-01

    The present invention provides a system that mitigates the growth of surface damage in an optic. Damage to the optic is minimally initiated. In an embodiment of the invention, damage sites in the optic are initiated, located, and then treated to stop the growth of the damage sites. The step of initiating damage sites in the optic includes a scan of the optic using a laser to initiate defects. The exact positions of the initiated sites are identified. A mitigation process is performed that locally or globally removes the cause of subsequent growth of the damaged sites.

  12. Optical scattering methods applicable to drops and bubbles

    NASA Technical Reports Server (NTRS)

    Marston, Philip L.

    1990-01-01

    An overview of optical scattering properties of drops and bubbles is presented. The properties lead to unconventional methods for optically monitoring the size or shape of a scatterer and are applicable to acoustically levitated objects. Several of the methods are applicable to the detection and measurement of small amplitude oscillations. Relevant optical phenomena include: (1) rainbows; (2) diffraction catastrophes from spheroids; (3) critical angle scattering; (4) effects of coatings; (5) glory scattering; and (6) optical levitation.

  13. Method of shifting and fixing optical frequency of an optical resonator, and optical resonator made by same

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy A. (Inventor); Strekalov, Dmitry V. (Inventor); Maleki, Lute (Inventor); Matsko, Andrey B. (Inventor); Iltchenko, Vladimir S. (Inventor); Martin, Jan M. (Inventor)

    2010-01-01

    A method of shifting and fixing an optical frequency of an optical resonator to a desired optical frequency, and an optical resonator made by such a method are provided. The method includes providing an optical resonator having a surface and a refractive index, and obtaining a coating composition having a predetermined concentration of a substance and having a refractive index that is substantially similar to the refractive index of the optical resonator. The coating composition inherently possesses a thickness when it is applied as a coating. The method further includes determining a coating ratio for the surface of the optical resonator and applying the coating composition onto a portion of the surface of the optical resonator based upon the determined coating ratio.

  14. Acousto-Optics as an Efficient Method for Physical Measurements

    NASA Astrophysics Data System (ADS)

    Kulakov, Sergei V.; Balysheva, Olga L.; Zhdanov, Arcenii Yu.; Kludzin, Victor V.; Shakin, Oleg V.

    In addition to acousto-optic information processing and manufacturing of such devices, the interaction between optical and acoustic waves are an efficient method for physical measurements. The paper analyses the potential of the acousto-optic method for measurement and investigation of crystal properties. It also presents some examples of this method applied to such measurements and investigations. The acousto-optic implementation of the pulse-phase method is used for acoustic velocity measurements. Velocities in an arbitrary directions can be measured using the Shaefer-Bergman method (the visualization of the angular distribution of the inverse phase velocities) together with the pulse-phase method. The matrices of crystal elastic coefficients can be evaluated using the Shaefer-Bergman patterns, using the minimum number of tested samples. The Schlieren (shadow) image method can give information both on the characteristics of acoustic and optical fields. The acousto-optic interaction is Efficient Method for determination of elastic material nonlinearity parameters.

  15. Apparatus and method for optical pulse measurement

    SciTech Connect

    Trebino, Rick P.; Tsang, Thomas; Fittinghoff, David N.; Sweetser, John N.; Krumbuegel, Marco A.

    1999-12-28

    Practical third-order frequency-resolved optical grating (FROG) techniques for characterization of ultrashort optical pulses are disclosed. The techniques are particularly suited to the measurement of single and/or weak optical pulses having pulse durations in the picosecond and subpicosecond regime. The relative quantum inefficiency of third-order nonlinear optical effects is compensated for through i) use of phase-matched transient grating beam geometry to maximize interaction length, and ii) use of interface-enhanced third-harmonic generation.

  16. Optical conversion method. [for spacecraft television

    NASA Technical Reports Server (NTRS)

    Perry, W. E. (Inventor)

    1978-01-01

    An optical pickup comprising an electrooptical device located between two crossed polarizing devices all positioned along a common optical axis is described for switching a TV system between a color mode and a black and white mode. Embodiments in which the electrooptical system is used as a neutral density filter, a selective color filter, or a light shutter as applied to a television camera are described. Where the optical system is used as a selective color filter to produce light beams of alternating color in a field sequential color television system, deactivation of the optical system renders the television a black and white system.

  17. Optical caliper with compensation for specimen deflection and method

    DOEpatents

    Bernacki, Bruce E.

    1997-01-01

    An optical non-contact profilometry system and method provided by an optical caliper with matched optical sensors that are arranged conjugate to each other so that the surface profile and thickness of an article can be measured without using a fixed reference surface and while permitting the article to deflect in space within the acquisition range of the optical sensors. The output signals from the two optical sensors are algebraically added to compensate for any such deflection of the article and provide a so compensated signal, the balance and sign of which provides a measurement of the actual thickness of the article at the optical sensors.

  18. Optical caliper with compensation for specimen deflection and method

    DOEpatents

    Bernacki, B.E.

    1997-12-09

    An optical non-contact profilometry system and method provided by an optical caliper with matched optical sensors that are arranged conjugate to each other so that the surface profile and thickness of an article can be measured without using a fixed reference surface and while permitting the article to deflect in space within the acquisition range of the optical sensors. The output signals from the two optical sensors are algebraically added to compensate for any such deflection of the article and provide a so compensated signal, the balance and sign of which provides a measurement of the actual thickness of the article at the optical sensors. 2 figs.

  19. Optical seismic sensor systems and methods

    DOEpatents

    Beal, A. Craig; Cummings, Malcolm E.; Zavriyev, Anton; Christensen, Caleb A.; Lee, Keun

    2015-12-08

    Disclosed is an optical seismic sensor system for measuring seismic events in a geological formation, including a surface unit for generating and processing an optical signal, and a sensor device optically connected to the surface unit for receiving the optical signal over an optical conduit. The sensor device includes at least one sensor head for sensing a seismic disturbance from at least one direction during a deployment of the sensor device within a borehole of the geological formation. The sensor head includes a frame and a reference mass attached to the frame via at least one flexure, such that movement of the reference mass relative to the frame is constrained to a single predetermined path.

  20. Method of optical image coding by time integration

    NASA Astrophysics Data System (ADS)

    Evtikhiev, Nikolay N.; Starikov, Sergey N.; Cheryomkhin, Pavel A.; Krasnov, Vitaly V.; Rodin, Vladislav G.

    2012-06-01

    Method of optical image coding by time integration is proposed. Coding in proposed method is accomplished by shifting object image over photosensor area of digital camera during registration. It results in optically calculated convolution of original image with shifts trajectory. As opposed to optical coding methods based on the use of diffractive optical elements the described coding method is feasible for implementation in totally incoherent light. The method was preliminary tested by using LC monitor for image displaying and shifting. Shifting of object image is realized by displaying video consisting of frames with image to be encoded at different locations on screen of LC monitor while registering it by camera. Optical encoding and numerical decoding of test images were performed successfully. Also more practical experimental implementation of the method with use of LCOS SLM Holoeye PLUTO VIS was realized. Objects images to be encoded were formed in monochromatic spatially incoherent light. Shifting of object image over camera photosensor area was accomplished by displaying video consisting of frames with blazed gratings on LCOS SLM. Each blazed grating deflects reflecting from SLM light at different angle. Results of image optical coding and encoded images numerical restoration are presented. Obtained experimental results are compared with results of numerical modeling. Optical image coding with time integration could be used for accessible quality estimation of optical image coding using diffractive optical elements or as independent optical coding method which can be implemented in incoherent light.

  1. Method and apparatus for bistable optical information storage for erasable optical disks

    DOEpatents

    Land, Cecil E.; McKinney, Ira D.

    1990-01-01

    A method and an optical device for bistable storage of optical information, together with reading and erasure of the optical information, using a photoactivated shift in a field dependent phase transition between a metastable or a bias-stabilized ferroelectric (FE) phase and a stable antiferroelectric (AFE) phase in an lead lanthanum zirconate titanate (PLZT). An optical disk contains the PLZT. Writing and erasing of optical information can be accomplished by a light beam normal to the disk. Reading of optical information can be accomplished by a light beam at an incidence angle of 15 to 60 degrees to the normal of the disk.

  2. Method and apparatus for bistable optical information storage for erasable optical disks

    DOEpatents

    Land, C.E.; McKinney, I.D.

    1988-05-31

    A method and an optical device for bistable storage of optical information, together with reading and erasure of the optical information, using a photoactivated shift in a field dependent phase transition between a metastable or a bias-stabilized ferroelectric (FE) phase and a stable antiferroelectric (AFE) phase in a lead lanthanum zirconate titanate (PLZT). An optical disk contains the PLZT. Writing and erasing of optical information can be accomplished by a light beam normal to the disk. Reading of optical information can be accomplished by a light beam at an incidence angle of 15 to 60 degrees to the normal of the disk. 10 figs.

  3. All-optical relative intensity noise suppression method for the high precision fiber optic gyroscope

    NASA Astrophysics Data System (ADS)

    Zheng, Yue; Zhang, Chunxi; Li, Lijing; Song, Lailiang; Zhang, Yuhui

    2016-10-01

    The relative intensity noise (RIN) is a main factor that limits the detection accuracy of the high precision fiber optic gyroscope (FOG). The RIN spectrum is determined by the normalized autocorrelation of the optical spectrum of the broadband source and is intrinsically different from other fundamental noises. In this paper, we propose an all-optical technique to suppress the RIN. With the power addition of the optical waves from the signal optical path and the reference optical path, the RIN is effectively eliminated at the eigen frequency of the FOG, which is also the demodulation window for the rotation rate signal. Compared with the traditional optical configuration of the FOG, there is only one additional optical component. Experimental results show that, with this method, we can achieve a nearly 3-fold improvement in the angular random walk coefficient. The improved optical configuration for RIN suppression is simple to realize and suitable for engineering application.

  4. Improved hybrid SMS-DSF method of nonimaging optical design

    NASA Astrophysics Data System (ADS)

    Bortz, John; Shatz, Narkis

    2011-10-01

    The hybrid SMS-DSF method of nonimaging optical design combines the discrete simultaneous multiple surface (SMS) method with the dual-surface functional (DSF) method to obtain improved optical performance relative to the discrete SMS method alone. In this contribution we present a new extension of the hybrid SMS-DSF method that uses differential ray tracing to produce designs having significantly improved performance relative to the original hybrid SMS-DSF method.

  5. Laser Safety Method For Duplex Open Loop Parallel Optical Link

    DOEpatents

    Baumgartner, Steven John; Hedin, Daniel Scott; Paschal, Matthew James

    2003-12-02

    A method and apparatus are provided to ensure that laser optical power does not exceed a "safe" level in an open loop parallel optical link in the event that a fiber optic ribbon cable is broken or otherwise severed. A duplex parallel optical link includes a transmitter and receiver pair and a fiber optic ribbon that includes a designated number of channels that cannot be split. The duplex transceiver includes a corresponding transmitter and receiver that are physically attached to each other and cannot be detached therefrom, so as to ensure safe, laser optical power in the event that the fiber optic ribbon cable is broken or severed. Safe optical power is ensured by redundant current and voltage safety checks.

  6. Method of making a small inlet optical panel

    DOEpatents

    Veligdan, James T.; Slobodin, David E.

    2004-02-03

    An optical panel having a small inlet, and a method of making a small inlet optical panel, are disclosed, which optical panel includes a individually coating, stacking, and cutting a first plurality of stacked optical waveguides to form an outlet face body with an outlet face, individually coating, stacking, and cutting a second plurality of stacked optical waveguides to form an inlet face body with an inlet face, and connecting an optical coupling element to the first plurality and second plurality of stacked optical waveguides, wherein the optical coupling element redirects light along a parallel axis of the inlet face to a parallel axis of the outlet face. In the preferred embodiment of the present invention, the inlet face is disposed obliquely with and askew from the outlet face.

  7. Method of holding optical elements without deformation during their fabrication

    DOEpatents

    Hed, P. Paul

    1997-01-01

    An improved method for securing and removing an optical element to and from a blocking tool without causing deformation of the optical element. A lens tissue is placed on the top surface of the blocking tool. Dots of UV cement are applied to the lens tissue without any of the dots contacting each other. An optical element is placed on top of the blocking tool with the lens tissue sandwiched therebetween. The UV cement is then cured. After subsequent fabrication steps, the bonded blocking tool, lens tissue, and optical element are placed in a debonding solution to soften the UV cement. The optical element is then removed from the blocking tool.

  8. Methods of formation and nonlinear conversion of Bessel optical vortices

    NASA Astrophysics Data System (ADS)

    Belyi, V. N.; King, Terence A.; Kazak, Nikolai S.; Khilo, Nikolay A.; Katranji, Evgeni G.; Ryzhevich, Anatol A.

    2001-05-01

    Linear and nonlinear processes of generation and transformation of optical vortices in crystals were investigated. New universal methods for production of Bessel light beams with optical vortices of the first, second and higher order by means of uniaxial and biaxial crystals were proposed. Light beams with optical vortices of topological charge +/- 1 and +/- 2 are experimentally obtained using KTP and HIO3 (iodic acid) biaxial crystals. We studied type II second harmonic generation by Bessel beams with optical vortices in nonlinear crystals. Results of investigation of the processes of Bessel light vortex order doubling, transfer of vortex to the second harmonic radiation, and annihilation of optical vortices with the opposite signa are presented.

  9. A Method of Assembling Compact Coherent Fiber-Optic Bundles

    NASA Technical Reports Server (NTRS)

    Martin, Stefan; Liu, Duncan; Levine, Bruce Martin; Shao, Michael; Wallace, James

    2007-01-01

    A method of assembling coherent fiber-optic bundles in which all the fibers are packed together as closely as possible is undergoing development. The method is based, straightforwardly, on the established concept of hexagonal close packing; hence, the development efforts are focused on fixtures and techniques for practical implementation of hexagonal close packing of parallel optical fibers.

  10. Methods and apparatus for optical switching using electrically movable optical fibers

    DOEpatents

    Peterson, Kenneth A.

    2007-03-13

    Methods and apparatuses for electrically controlled optical switches are presented. An electrically controlled optical switch includes a fixture formed using a laminated dielectric material, a first optical fiber having a fixed segment supported by the fixture and a movable segment extending into a cavity, a second optical fiber having a fixed segment supported by the fixture and an extended segment where an optical interconnect may be established between the first optical fiber and the second optical fiber, and a first electrical actuator functionally coupled to the fixture and the first fiber which alters a position of the moveable segment, based upon a control signal, for changing a state of the optical interconnect between one of two states.

  11. Inorganic optical taggant and method of making

    DOEpatents

    Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.

    2005-05-31

    Sintered, translucent ceramic microbeads, preferably alumina, titania, zirconia, yttria, zirconium phosphate, or yttrium aluminum garnet (YAG) are doped with one or more optically active species. The beads may be added to substances such as explosives in order to create a distinctive optical signature that identifies a manufacturer, lot number, etc. in the event of the need for forensic analysis. Because the beads have a generally spherical surface, the radius of curvature provides an additional distinguishing characteristic by which a particular sample may be identified. The beads could also be formulated into paints if needed to create distinctive optical signatures for camouflage, decoys, or other countermeasures and could also be applied as a dust to track the movement of personnel, vehicles, etc.

  12. Fiber-optic backreflectance method for determining the effective focal lengths of optical elements.

    PubMed

    Ilev, I; Uttamchandani, D; Culshaw, B

    1996-02-01

    An alternative and simple fiber-optic backreflectance method for indirectly determining the effective focal lengths of optical elements by the spatial location of three specific points (the focal point and two object points) is presented. The basic optical element of the method is the single-mode optical fiber. It serves simultaneously as a point light source, an object for projecting, and a point receiver that is highly sensitive to spatial displacements for focused backreflectance laser emission. The method provides high accuracy for both locating the spatial points (1 µm) and determining the effective focal length (less than 0.5%).

  13. New optical frequency domain differential mode delay measurement method for a multimode optical fiber.

    PubMed

    Ahn, T; Moon, S; Youk, Y; Jung, Y; Oh, K; Kim, D

    2005-05-30

    A novel mode analysis method and differential mode delay (DMD) measurement technique for a multimode optical fiber based on optical frequency domain reflectometry has been proposed for the first time. We have used a conventional OFDR with a tunable external cavity laser and a Michelson interferometer. A few-mode optical multimode fiber was prepared to test our proposed measurement technique. We have also compared the OFDR measurement results with those obtained using a traditional time-domain measurement method.

  14. Simulative method for the optical processor reconfiguration on a dynamically reconfigurable optical platform.

    PubMed

    Wang, Hongjian; Song, Kai

    2012-01-10

    With the reconfiguration technique, users can configure the optical processor of a new optical computing platform, the ternary optical computer (TOC), into 42 specific basic operation units, and reconfigure it when the computation is completed. A simulative method of software for this technique is proposed in this paper. Also, an elaborate experiment based on this software is discussed. This simulation of reconfiguration demonstrates that the theory of reconfiguring optical processor in TOC is valid and also lays the foundation for the hardware implementation of the reconfiguration technique. © 2012 Optical Society of America

  15. REVIEW OF METHODS OF OPTICAL GAS Detection by Direct Optical Spectroscopy, with Emphasis on Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dakin, John P.; Chambers, Paul

    This chapter reviews the development of optical gas sensors, starting with an initial emphasis on optical-fibre remoted techniques and finishing with a particular focus on our own group's work on highly selective methods using correlation spectroscopy. This latter section includes extensive theoretical modelling of a correlation spectroscopy method, and compares theory with practice for a CO2 sensor.

  16. ANALYSIS OF CARBONACEOUS AEROSOLS USING THE THERMAL OPTICAL TRANSMITTANCE AND THERMAL OPTICAL REFLECTANCE METHODS

    EPA Science Inventory

    Carbonaceous particulate typically represents a large fraction of PM2.5 (20 - 40%). Two primary techniques presently used for the analysis of particulate carbon are Thermal Optical Transmission (TOT - NIOSH Method 5040) and Thermal Optical Reflectance (TOR). These two methods b...

  17. ANALYSIS OF CARBONACEOUS AEROSOLS USING THE THERMAL OPTICAL TRANSMITTANCE AND THERMAL OPTICAL REFLECTANCE METHODS

    EPA Science Inventory

    Carbonaceous particulate typically represents a large fraction of PM2.5 (20 - 40%). Two primary techniques presently used for the analysis of particulate carbon are Thermal Optical Transmission (TOT - NIOSH Method 5040) and Thermal Optical Reflectance (TOR). These two methods b...

  18. A method of developing frequency encoded multi-bit optical data comparator using semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Garai, Sisir Kumar

    2011-02-01

    Optical data comparator is the part and parcel of arithmetic and logical unit of any optical data processor and it is working as a building block in a larger optical circuit, as an optical switch in all optical header processing and optical packet switching based all optical telecommunications system. In this article the author proposes a method of developing an all optical single bit comparator unit and subsequently extending the proposal to develop a n-bit comparator exploiting the nonlinear rotation of the state of polarization of the probe beam in semiconductor optical amplifier (SOA). Here the dataset to be compared are taken in frequency encoded/decoded form throughout the communication. The major advantages of frequency encoding over all other conventional techniques are that as the frequency of any signal is fundamental one so it can preserve its identity throughout the communication of optical signal and minimizes the probability of bit error problem. For frequency routing purpose optical add/drop multiplexer (ADM) is used which not only route the pump beams properly but also to amplify the pump beams efficiently. Switching speed of 'MZI-SOA switch' as well as SOA based switches are very fast with good on-off contrast ratio and as a result it is possible to obtain very fast action of optical data comparator.

  19. Optical method for the determination of stress in thin films

    DOEpatents

    Maris, Humphrey J.

    1999-01-01

    A method and optical system is disclosed for measuring an amount of stress in a film layer disposed over a substrate. The method includes steps of: (A) applying a sequence of optical pump pulses to the film layer, individual ones of said optical pump pulses inducing a propagating strain pulse in the film layer, and for each of the optical pump pulses, applying at least one optical probe pulse, the optical probe pulses being applied with different time delays after the application of the corresponding optical probe pulses; (B) detecting variations in an intensity of a reflection of portions of the optical probe pulses, the variations being due at least in part to the propagation of the strain pulse in the film layer; (C) determining, from the detected intensity variations, a sound velocity in the film layer; and (D) calculating, using the determined sound velocity, the amount of stress in the film layer. In one embodiment of this invention the step of detecting measures a period of an oscillation in the intensity of the reflection of portions of the optical probe pulses, while in another embodiment the step of detecting measures a change in intensity of the reflection of portions of the optical probe pulses and determines a time at which the propagating strain pulse reflects from a boundary of the film layer.

  20. Optical method for the determination of stress in thin films

    DOEpatents

    Maris, H.J.

    1999-01-26

    A method and optical system is disclosed for measuring an amount of stress in a film layer disposed over a substrate. The method includes steps of: (A) applying a sequence of optical pump pulses to the film layer, individual ones of said optical pump pulses inducing a propagating strain pulse in the film layer, and for each of the optical pump pulses, applying at least one optical probe pulse, the optical probe pulses being applied with different time delays after the application of the corresponding optical probe pulses; (B) detecting variations in an intensity of a reflection of portions of the optical probe pulses, the variations being due at least in part to the propagation of the strain pulse in the film layer; (C) determining, from the detected intensity variations, a sound velocity in the film layer; and (D) calculating, using the determined sound velocity, the amount of stress in the film layer. In one embodiment of this invention the step of detecting measures a period of an oscillation in the intensity of the reflection of portions of the optical probe pulses, while in another embodiment the step of detecting measures a change in intensity of the reflection of portions of the optical probe pulses and determines a time at which the propagating strain pulse reflects from a boundary of the film layer. 16 figs.

  1. HOMES Holographic Optical Method for Exoplanet Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; McGrew, Stephen P.

    2013-09-01

    A novel telescope architecture is proposed specifically for the purpose of taking spectra of exoplanets orbiting stars within 10 pc ("the neighborhood"). The primary objective and the secondary spectrograph are holographic optical elements (HOEs) formed on flat membrane substrates of low areal mass that can be transported on cylinder rolls that are compatible with the payload geometry of delivery vehicles. Ribbon-shaped HOEs of up to 100 x 10 meters are contemplated. Computer models are presented with these dimensions. The models predict resolving power better than 10 mas. Because the primary separates wavelengths, we consider coronagraphs that use the divide and conquer strategy of one wavelength at a time. After delivery at the second Lagrange point, the stowed membranes are unfurled into flat holographic optics positioned in a four part formation spanning 1 km of open space.

  2. Optical steam quality measurement system and method

    DOEpatents

    Davidson, James R.; Partin, Judy K.

    2006-04-25

    An optical measurement system is presented that offers precision on-line monitoring of the quality of steam. Multiple wavelengths of radiant energy are passed through the steam from an emitter to a detector. By comparing the amount of radiant energy absorbed by the flow of steam for each wavelength, a highly accurate measurement of the steam quality can be determined on a continuous basis in real-time. In an embodiment of the present invention, the emitter, comprises three separate radiant energy sources for transmitting specific wavelengths of radiant energy through the steam. In a further embodiment, the wavelengths of radiant energy are combined into a single beam of radiant energy for transmission through the steam using time or wavelength division multiplexing. In yet a further embodiment, the single beam of radiant energy is transmitted using specialized optical elements.

  3. Small inlet optical panel and a method of making a small inlet optical panel

    DOEpatents

    Veligdan, James T.; Slobodin, David

    2001-01-01

    An optical panel having a small inlet, and a method of making a small inlet optical panel, are disclosed, which optical panel includes a individually coating, stacking, and cutting a first plurality of stacked optical waveguides to form an outlet face body with an outlet face, individually coating, stacking, and cutting a second plurality of stacked optical waveguides to form an inlet face body with an inlet face, and connecting an optical coupling element to the first plurality and to the second plurality, wherein the optical coupling element redirects light along a parallel axis of the inlet face to a parallel axis of the outlet face. In the preferred embodiment of the present invention, the inlet face is disposed obliquely with and askew from the outlet face.

  4. Optical methods in diagnostics of liver fibrosis via blood observation

    NASA Astrophysics Data System (ADS)

    Kruchinina, Margarita V.; Generalov, Vladimir M.; Atuchin, Victor V.; Kruchinin, Vladimir N.; Volodin, Vladimir A.; Gromov, Andrey A.; Rykhlitsky, Sergey V.

    2016-11-01

    A possible application of optical methods (dielectrophoresis, spectral and imaging ellipsometry, Fourier- transform infrared spectroscopy, Raman spectroscopy) for the early diagnostics in studies of red blood cells and serum in patients with the diffuse liver disease, with varying degrees of fibrosis, has been evaluated. As experimentally confirmed, the combined optical methods significantly improve the sensitivity, specificity and accuracy index in the diagnosis of both severe fibrosis and slight ulterior liver fibrosis. The identified optical methods diagnostic potential can be efficiently utilized in noninvasive screening evaluation of the stages of diffuse liver disease of various genesis.

  5. Ultrasound-mediated optical tomography: a review of current methods

    PubMed Central

    Elson, Daniel S.; Li, Rui; Dunsby, Christopher; Eckersley, Robert; Tang, Meng-Xing

    2011-01-01

    Ultrasound-mediated optical tomography (UOT) is a hybrid technique that is able to combine the high penetration depth and high spatial resolution of ultrasound imaging to overcome the limits imposed by optical scattering for deep tissue optical sensing and imaging. It has been proposed as a method to detect blood concentrations, oxygenation and metabolism at depth in tissue for the detection of vascularized tumours or the presence of absorbing or scattering contrast agents. In this paper, the basic principles of the method are outlined and methods for simulating the UOT signal are described. The main detection methods are then summarized with a discussion of the advantages and disadvantages of each. The recent focus on increasing the weak UOT signal through the use of the acoustic radiation force is explained, together with a summary of our results showing sensitivity to the mechanical shear stiffness and optical absorption properties of tissue-mimicking phantoms. PMID:22866234

  6. Simple fiber-optic autocollimation method for determining the focal lengths of optical elements.

    PubMed

    Ilev, I K

    1995-03-15

    A novel simple fiber-optic autocollimation method for determining the focal lengths of lenses and objectives is presented. This method is based on the intensity sensing of reflected light, photoelectric measurement, and the use of single-mode optical fiber. This fiber serves simultaneously as a point light source for the formation of a collimated input laser beam and as a receiver that is highly sensitive to spatial displacements for the autocollimation backreflectance. The method permits us to locate the focal point spatially and to determine the back focal length of a focusing optical element with accuracies exceeding 1 and 2 microm, respectively, which are confirmed by both experimental and analytical investigations.

  7. Evaluation of FTIR-based analytical methods for the analysis of simulated wastes

    SciTech Connect

    Rebagay, T.V.; Cash, R.J.; Dodd, D.A.; Lockrem, L.L.; Meacham, J.E.; Winkelman, W.D.

    1994-09-30

    Three FTIR-based analytical methods that have potential to characterize simulated waste tank materials have been evaluated. These include: (1) fiber optics, (2) modular transfer optic using light guides equipped with non-contact sampling peripherals, and (3) photoacoustic spectroscopy. Pertinent instrumentation and experimental procedures for each method are described. The results show that the near-infrared (NIR) region of the infrared spectrum is the region of choice for the measurement of moisture in waste simulants. Differentiation of the NIR spectrum, as a preprocessing steps, will improve the analytical result. Preliminary data indicate that prominent combination bands of water and the first overtone band of the ferrocyanide stretching vibration may be utilized to measure water and ferrocyanide species simultaneously. Both near-infrared and mid-infrared spectra must be collected, however, to measure ferrocyanide species unambiguously and accurately. For ease of sample handling and the potential for field or waste tank deployment, the FTIR-Fiber Optic method is preferred over the other two methods. Modular transfer optic using light guides and photoacoustic spectroscopy may be used as backup systems and for the validation of the fiber optic data.

  8. Theoretical research and comparison of forces in optical tweezers based on ray optics method and T matrix method

    NASA Astrophysics Data System (ADS)

    Li, Zhenggang; Hu, Huizhu; Fu, ZhenHai; Zhu, Qi; Shen, Yu

    2016-10-01

    Based on ray tracing method of ray optics (RO) theory and T-matrix method of electromagnetic scattering theory, we establish optical trap force model and calculate the optical trap force of trapped microspheres whose size is in the beam wavelength scale. Calculation results of axial and transverse trapping efficiency based on the two models agree qualitatively, but differ quantitatively. Then we introduce a trapping efficiency calculation deviation parameter to characterize the difference between these two methods, and analyze how the deviation parameter is influenced by trapped microsphere radius and trapping beam waist radius. Simulation result shows that best agreement between RO model and T matrix calculation method is met when a strongly focused laser beam traps a large microsphere in near the beam waist plane area. In such cases both ray optics approximation conditions and T matrix method approximate conditions are satisfied. Numerical results coincide well with theoretical expectations.

  9. Method for ultrafast optical deflection enabling optical recording via serrated or graded light illumination

    DOEpatents

    Heebner, John E [Livermore, CA

    2009-09-08

    In one general embodiment, a method for deflecting an optical signal input into a waveguide is provided. In operation, an optical input signal is propagated through a waveguide. Additionally, an optical control signal is applied to a mask positioned relative to the waveguide such that the application of the optical control signal to the mask is used to influence the optical input signal propagating in the waveguide. Furthermore, the deflected optical input signal output from the waveguide is detected in parallel on an array of detectors. In another general embodiment, a beam deflecting structure is provided for deflecting an optical signal input into a waveguide, the structure comprising at least one wave guiding layer for guiding an optical input signal and at least one masking layer including a pattern configured to influence characteristics of a material of the guiding layer when an optical control signal is passed through the masking layer in a direction of the guiding layer. In another general embodiment, a system is provided including a waveguide, an attenuating mask positioned on the waveguide, and an optical control source positioned to propagate pulsed laser light towards the attenuating mask and the waveguide such that a pattern of the attenuating mask is applied to the waveguide and material properties of at least a portion of the waveguide are influenced.

  10. Preform For Producing An Optical Fiber And Method Therefor

    DOEpatents

    Kliner, Dahv A. V.; Koplow, Jeffery P.

    2004-08-10

    The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

  11. Preform For Producing An Optical Fiber And Method Therefor

    DOEpatents

    Kliner, Dahv A. V.; Koplow, Jeffery P.

    2005-04-19

    The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

  12. Optical limiting device and method of preparation thereof

    DOEpatents

    Wang, Hsing-Lin; Xu, Su; McBranch, Duncan W.

    2003-01-01

    Optical limiting device and method of preparation thereof. The optical limiting device includes a transparent substrate and at least one homogeneous layer of an RSA material in polyvinylbutyral attached to the substrate. The device may be produced by preparing a solution of an RSA material, preferably a metallophthalocyanine complex, and a solution of polyvinylbutyral, and then mixing the two solutions together to remove air bubbles. The resulting solution is layered onto the substrate and the solvent is evaporated. The method can be used to produce a dual tandem optical limiting device.

  13. Living Brain Optical Imaging: Technology, Methods and Applications

    PubMed Central

    Tsytsarev, Vassiliy; Bernardelli, Chad; Maslov, Konstantin I.

    2017-01-01

    Within the last few decades, optical imaging methods have yielded revolutionary results when applied to all parts of the central nervous system. The purpose of this review is to analyze research possibilities and limitations of several novel imaging techniques and show some of the most interesting achievements obtained by these methods. Here we covered intrinsic optical imaging, voltage-sensitive dye, photoacoustic, optical coherence tomography, near-infrared spectroscopy and some other techniques. All of them are mainly applicable for experimental neuroscience but some of them also suitable for the clinical studies. PMID:28251038

  14. Protection method for an optical information carrier

    NASA Astrophysics Data System (ADS)

    Pitsyuga, Vitaly V.; Kolesnikov, Michael Y.; Kosyak, Igor V.

    1997-02-01

    Now information protection on personal carriers (for example, cards) from an unauthorized access (UA) is a very important problem in connection with wide introduction of proper automatic systems for information processing in different spheres of human activity. These are financial, medical and information services, an access to restricted units and so on. There is proposed to use physical parameters of the special coating part (so-called restricted zone) to information protection on optical carriers (laser cards). There is formed restricted zone on the surface of the recording coating of a laser card. The unique information about every laser card to creating a protective passport from UA is obtained by readout of defects parameters.

  15. Simple method for measuring reflectance of optical coatings

    SciTech Connect

    Wen Gui Wang; Yi Sheng Chen

    1995-12-31

    The quality of optical coatings has an important effect on the performance of optical instrument. The last few years, the requirements for super low loss dielectric mirror coatings used in low gain laser systems such as free electron laser and the ring laser etc., have given an impetus to the development of the technology of precise reflectance measurement of optical coatings. A reliable and workable technique is to measure the light intensity decay time of optical resonant cavity. This paper describes a measuring method which is dependent on direct measurement of the light intensity decay time of a resonant cavity comprised of low loss optical components. According to the evolution of a luminous flux stored inside the cavity, this method guarantees not only a quick and precise reflectance measurements of low loss highly reflecting mirror coatings but also transmittance measurements of low loss antireflection coatings and is especially effective with super los loss highly reflecting mirror. From the round-trip path length of the cavity and the speed of light, the light intensity exponential decay time of an optical cavity is easy to obtain and the cavity losses can be deduced. An optical reflectance of low loss highly mirror coatings and antireflection coatings is precisely measured as well. This is highly significant for the discrimination of the coating surface characteristics, the improvement of the performance of optical instrument and the development of high technology.

  16. Detection of Extraterrestrial Life. Method II- Optical Rotatory Dispersion

    NASA Technical Reports Server (NTRS)

    1963-01-01

    The object of this study is to develop polarimetric methods to detect the presence of DNA (deoxyribonucleic acid) or its congeners in soil suspensions, and through these methods determine the existence of life (as known terrestrially) on other planets. The cotton region associated with optically active organic compounds is being used to detect and characterize the compounds above. An apparatus has been designed and assembled which can measure optical rotations in systems which strongly attenuate incident-polarized, monochromatic light. This instrument was used to measure the optical rotatory dispersion spectra of nucleosides, a polynucleotide, and proteins whose optical density at 260 microns approached 1.0. This work is discussed in the final report on Contract NASR-85, Detection of Extraterrestrial Life, Method II: Optical Rotatory Dispersion. Recent work in Melpar laboratories has reaffirmed these rotatory dispersion spectra. Based upon the analysis of the optical components associated with this apparatus, however, these measurements must be considered as qualitative rather than quantitative. The reason for this is discussed in greater detail subsequently in this report. In addition, an evaluation of the theoretical and instrumental aspects of making rotatory-dispersion measurements in the cotton region has resulted in a procedure for measuring optical rotation.

  17. Method of holding optical elements without deformation during their fabrication

    DOEpatents

    Hed, P.P.

    1997-04-29

    An improved method for securing and removing an optical element to and from a blocking tool without causing deformation of the optical element is disclosed. A lens tissue is placed on the top surface of the blocking tool. Dots of UV cement are applied to the lens tissue without any of the dots contacting each other. An optical element is placed on top of the blocking tool with the lens tissue sandwiched therebetween. The UV cement is then cured. After subsequent fabrication steps, the bonded blocking tool, lens tissue, and optical element are placed in a debonding solution to soften the UV cement. The optical element is then removed from the blocking tool. 16 figs.

  18. Optical trapping apparatus, methods and applications using photonic crystal resonators

    SciTech Connect

    Erickson, David; Chen, Yih-Fan

    2015-06-16

    A plurality of photonic crystal resonator optical trapping apparatuses and a plurality optical trapping methods using the plurality of photonic crystal resonator optical trapping apparatuses include located and formed over a substrate a photonic waveguide that is coupled (i.e., either separately coupled or integrally coupled) with a photonic crystal resonator. In a particular embodiment, the photonic waveguide and the photonic crystal resonator comprise a monocrystalline silicon (or other) photonic material absent any chemical functionalization. In another particular embodiment, the photonic waveguide and the photonic crystal resonator comprise a silicon nitride material which when actuating the photonic crystal resonator optical trapping apparatus with a 1064 nanometer resonant photonic radiation wavelength (or other resonant photonic radiation wavelength in a range from about 700 to about 1200 nanometers) provides no appreciable heating of an aqueous sample fluid that is analyzed by the photonic crystal resonator optical trapping apparatus.

  19. Polarization sensitive optical coherence tomography detection method

    SciTech Connect

    Everett, M J; Sathyam, U S; Colston, B W; DaSilva, L B; Fried, D; Ragadio, J N; Featherstone, J D B

    1999-05-12

    This study demonstrates the potential of polarization sensitive optical coherence tomography (PS-OCT) for non-invasive in vivo detection and characterization of early, incipient caries lesions. PS-OCT generates cross-sectional images of biological tissue while measuring the effect of the tissue on the polarization state of incident light. Clear discrimination between regions of normal and demineralized enamel is first shown in PS-OCT images of bovine enamel blocks containing well-characterized artificial lesions. High-resolution, cross-sectional images of extracted human teeth are then generated that clearly discriminate between the normal and carious regions on both the smooth and occlusal surfaces. Regions of the teeth that appeared to be demineralized in the PS-OCT images were verified using histological thin sections examined under polarized light microscopy. The PS-OCT system discriminates between normal and carious regions by measuring the polarization state of the back-scattered 1310 nm light, which is affected by the state of demineralization of the enamel. Demineralization of enamel increases the scattereing coefficient, thus depolarizing the incident light. This study shows that PS-OCT has great potential for the detection, characterization, and monitoring of incipient caries lesions.

  20. Electro-optical method for polarimetric measurement

    NASA Astrophysics Data System (ADS)

    Díaz, Lázaro J. M.

    2011-05-01

    When passing a pulsing beam of polarize light of a light emitter d iode (LED) or a semiconductor laser thru an optical system and two photodiodes spatially arranged at 900 to each other and both with their detection surfaces parallel to the transmission shaft of light, and polarization axis oriented at 450 of the vertices of the edges where the photodiodes join, in the outputs of two operational amplifiers, e have two signals with the same shape in time, i.e. a pulse train with the same phase, but when you turn the polarization plane, change the radiance of the light projected onto the photodiodes, being out of phase signals to the outputs of the amplifiers, where the d ifference between the fronts of the pulses is proportional to the angle of rotation of the plane of polarization of polarization light. In a digital circuit phase discriminator, a puls e is obtained equal to the time d ifference between two sides of the rise time in the output of two amplifiers. The width of this is directly proportional to the value of rotation the plane of polarization of light, that is, the greater the rotation, the greater the width of this.

  1. Boundary element method for optical force calibration in microfluidic dual-beam optical trap

    NASA Astrophysics Data System (ADS)

    Solmaz, Mehmet E.; Çetin, Barbaros; Baranoǧlu, Besim; Serhathoǧlu, Murat; Biyikli, Necmi

    2015-08-01

    The potential use of optical forces in microfluidic environment enables highly selective bio-particle manipulation. Manipulation could be accomplished via trapping or pushing a particle due to optical field. Empirical determination of optical force is often needed to ensure efficient operation of manipulation. The external force applied to a trapped particle in a microfluidic channel is a combination of optical and drag forces. The optical force can be found by measuring the particle velocity for a certain laser power level and a multiplicative correction factor is applied for the proximity of the particle to the channel surface. This method is not accurate especially for small microfluidic geometries where the particle size is in Mie regime and is comparable to channel cross section. In this work, we propose to use Boundary Element Method (BEM) to simulate fluid flow within the micro-channel with the presence of the particle to predict drag force. Pushing experiments were performed in a dual-beam optical trap and particle's position information was extracted. The drag force acting on the particle was then obtained using BEM and other analytical expressions, and was compared to the calculated optical force. BEM was able to predict the behavior of the optical force due to the inclusion of all the channel walls.

  2. Method to improve optical parametric oscillator beam quality

    DOEpatents

    Smith, Arlee V.; Alford, William J.; Bowers, Mark S.

    2003-11-11

    A method to improving optical parametric oscillator (OPO) beam quality having an optical pump, which generates a pump beam at a pump frequency greater than a desired signal frequency, a nonlinear optical medium oriented so that a signal wave at the desired signal frequency and a corresponding idler wave are produced when the pump beam (wave) propagates through the nonlinear optical medium, resulting in beam walk off of the signal and idler waves, and an optical cavity which directs the signal wave to repeatedly pass through the nonlinear optical medium, said optical cavity comprising an equivalently even number of non-planar mirrors that produce image rotation on each pass through the nonlinear optical medium. Utilizing beam walk off where the signal wave and said idler wave have nonparallel Poynting vectors in the nonlinear medium and image rotation, a correlation zone of distance equal to approximately .rho.L.sub.crystal is created which, through multiple passes through the nonlinear medium, improves the beam quality of the OPO output.

  3. Calibration method of absolute orientation of camera optical axis

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Guo, Pengyu; Zhang, Xiaohu; Ding, Shaowen; Su, Ang; Li, Lichun

    2013-08-01

    Camera calibration is one of the most basic and important processes in optical measuring field. Generally, the objective of camera calibration is to estimate the internal and external parameters of object cameras, while the orientation error of optical axis is not included yet. Orientation error of optical axis is a important factor, which seriously affects measuring precision in high-precision measurement field, especially for those distant aerospace measurement in which object distance is much longer than focal length, that lead to magnifying the orientation errors to thousands times. In order to eliminate the influence of orientation error of camera optical axis, the imaging model of camera is analysed and established in this paper, and the calibration method is also introduced: Firstly, we analyse the reasons that cause optical axis error and its influence. Then, we find the model of optical axis orientation error and imaging model of camera basing on it's practical physical meaning. Furthermore, we derive the bundle adjustment algorithm which could compute the internal and external camera parameters and absolute orientation of camera optical axis simultaneously at high precision. In numeric simulation, we solve the camera parameters by using bundle adjustment optimization algorithm, then we correct the image points by calibration results according to the model of optical axis error, and the simulation result shows that our calibration model is reliable, effective and precise.

  4. Actively Heated Fiber Optic Method for Distributed Soil Moisture Monitoring

    NASA Astrophysics Data System (ADS)

    Sayde, C.; Selker, J. S.; Rodriguez-Sinobas, L.; Gil-Rodriguez, M.; Cuenca, R. H.; Tyler, S. W.; English, M.

    2010-12-01

    The temporal and spatial distribution of soil water at scales from 1 to 10,000m is both poorly understood and critical to terrestrial processes. Areas of great uncertainty include the spatio-temporal patterns of: soil water; evapo-transpiration; recharge during and following rainfalls. Observation of dynamics at these scales requires an innovative measurement approach. A novel in-situ distributed measurement of soil water content using temperature measured with Raman scattering in fiber optic cables is presented. This technology, called “Actively Heated Fiber Optic Method,” demonstrated in the lab setting by Sayde et al. 2010 in Water Resources Research involves use of a heat pulse method with fiber optic temperature sensing to obtain precise, distributed measurements of soil water content, with high temporal resolution and sub-meter scale spatial resolution, along a fiber optic cable that can exceed several km in length. The method is based on the influence of water content on soil thermal properties as observed with a buried fiber optical cable monitored by a laser Raman backscatter DTS system. The buried fiber optic is actively heated via electrical resistance, using the steel elements that surround the fiber, and the optical fiber is used as a sub-meter scale thermal sensor to monitor the changes in soil thermal responses every meter along the fiber optic cable. A response metric that has not been previously employed “the time integral of temperature deviation” is used as a simple interpretation of heat data that takes advantage of the characteristics of fiber optic measurements. Validation of the method based on large-column laboratory tests, and field testing results using and 750 m of fiber optic cable buried at 30, 60, and 90 cm depth in the field are presented. The results indicate the feasibility of using the actively heated fiber optic method to monitor soil water content at temporal resolution well under one hour and spatial resolution of 1 m

  5. Optical methods for the analysis of dermatopharmacokinetics

    NASA Astrophysics Data System (ADS)

    Lademann, Juergen; Weigmann, Hans-Juergen; von Pelchrzim, R.; Sterry, Wolfram

    2002-07-01

    The method of tape stripping in combination with spectroscopic measurements is a simple and noninvasive method for the analysis of dermatopharmacokinetics of cosmetic products and topically applied drugs. The absorbance at 430 nm was used for the characterization of the amount of corneocytes on the tape strips. It was compared to the increase of weight of the tapes after removing them from the skin surface. The penetration profiles of two UV filter substances used in sunscreens were determined. The combined method of tape stripping and spectroscopic measurements can be also used for the investigation of the dermatopharmacokinetics of topically applied drugs passing through the skin. Differences in the penetration profiles of the steroid compound clobetasol, applied in the same concentration in different formulations on the skin are presented.

  6. Optical tissue phantoms based on spin coating method

    NASA Astrophysics Data System (ADS)

    Park, Jihoon; Ha, Myungjin; Yu, Sung Kon; Radfar, Edalat; Jun, Eunkwon; Lee, Nara; Jung, Byungjo

    2015-03-01

    Fabrication of optical tissue phantom (OTP) simulating whole skin structure has been regarded as laborious and time consuming work. This study fabricated multilayer OTP optically and structurally simulating epidermis-dermis structure including blood vessel. Spin coating method was used to produce thin layer mimicking epidermal layer, then optimized for reference epoxy and silicone matrix. Adequacy of both materials in phantom fabrication was considered by comparison the fabrication results. In addition similarities between OTP and biological tissue in optical property and thickness was measured to evaluate this fabrication process.

  7. Method and apparatus for optical temperature measurements

    DOEpatents

    Angel, S.M.; Hirschfeld, T.B.

    1986-04-22

    A method and apparatus are provided for remotely monitoring temperature. Both method and apparatus employ a temperature probe material having an excitation-dependent emission line whose fluorescence intensity varies directly with temperature whenever excited by light having a first wavelength and whose fluorescence intensity varies inversely with temperature whenever excited by light having a second wavelength. Temperature is measured by alternatively illiminating the temperature probe material with light having the first wavelength and light having the second wavelength, monitoring the intensity of the successive emissions of the excitation-dependent emission line, and relating the intensity ratio of successive emissions to temperature. 3 figs.

  8. Method and apparatus for optical temperature measurements

    DOEpatents

    Angel, S. Michael; Hirschfeld, Tomas B.

    1988-01-01

    A method and apparatus are provided for remotely monitoring temperature. Both method and apparatus employ a temperature probe material having an excitation-dependent emission line whose fluorescence intensity varies directly with temperature whenever excited by light having a first wavelength and whose fluorescence intensity varies inversely with temperature whenever excited by light having a second wavelength. Temperature is measured by alternatively illuminating the temperature probe material with light having the first wavelength and light having the second wavelength, monitoring the intensity of the successive emissions of the excitation-dependent emission line, and relating the intensity ratio of successive emissions to temperature.

  9. Whispering Gallery Optical Resonator Spectroscopic Probe and Method

    NASA Technical Reports Server (NTRS)

    Anderson, Mark S. (Inventor)

    2014-01-01

    Disclosed herein is a spectroscopic probe comprising at least one whispering gallery mode optical resonator disposed on a support, the whispering gallery mode optical resonator comprising a continuous outer surface having a cross section comprising a first diameter and a second diameter, wherein the first diameter is greater than the second diameter. A method of measuring a Raman spectrum and an Infra-red spectrum of an analyte using the spectroscopic probe is also disclosed.

  10. Data Optical Networking Architecture Using Wavelength-Division Multiplexing Method for Optical Sensors

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.

    2008-01-01

    Recently there has been a growth in the number of fiber optical sensors used for health monitoring in the hostile environment of commercial aircraft. Health monitoring to detect the onset of failure in structural systems from such causes as corrosion, stress corrosion cracking, and fatigue is a critical factor in safety as well in aircraft maintenance costs. This report presents an assessment of an analysis model of optical data networking architectures used for monitoring data signals among these optical sensors. Our model is focused on the design concept of the wavelength-division multiplexing (WDM) method since most of the optical sensors deployed in the aircraft for health monitoring typically operate in a wide spectrum of optical wavelengths from 710 to 1550 nm.

  11. Using moire method of measuring optical disks

    NASA Astrophysics Data System (ADS)

    Cheng, Ter-Chin; Jiang, Sheng-Nan; Chang, Rang-Seng

    1992-12-01

    A primary function of compact disk measuring systems is the measurement of various types of defects which represent either functional or cosmetic flaws and the measurement of the profile of the compact disk. Functional flaws can make a very bad interference with the reproduction of the recorded music. Cosmetic flaws are visual imperfections whose presence can cause the rejecting of the disc by the production line. A projection moire method is invented in which a light beam passes through a grating, and is projected onto the object by overlapping with the virtual grating in the computer software. The object's 3-dimensional profile will be reconstructed and the object's profile quality can be improved by our new method for moire image processing.

  12. Method to render second order beam optics programs symplectic

    SciTech Connect

    Douglas, D.; Servranckx, R.V.

    1984-10-01

    We present evidence that second order matrix-based beam optics programs violate the symplectic condition. A simple method to avoid this difficulty, based on a generating function approach to evaluating transfer maps, is described. A simple example illustrating the non-symplectricity of second order matrix methods, and the effectiveness of our solution to the problem, is provided. We conclude that it is in fact possible to bring second order matrix optics methods to a canonical form. The procedure for doing so has been implemented in the program DIMAT, and could be implemented in programs such as TRANSPORT and TURTLE, making them useful in multiturn applications. 15 refs.

  13. Optical methods in nano-biotechnology

    NASA Astrophysics Data System (ADS)

    Bruno, Luigi; Gentile, Francesco

    2016-01-01

    A scientific theory is not a mathematical paradigm. It is a framework that explains natural facts and may predict future observations. A scientific theory may be modified, improved, or rejected. Science is less a collection of theories and more the process that brings either to deny some hypothesis, maintain or accept somehow universal beliefs (or disbeliefs), and create new models that may improve or replace precedent theories. This process cannot be entrusted to common sense, personal experiences or anecdotes (many precepts in physics are indeed counterintuitive), but on a rigorous design, observation and rational to statistical analysis of new experiments. Scientific results are always provisional: scientists rarely proclaim an absolute truth or absolute certainty. Uncertainty is inevitable at the frontiers of knowledge. Notably, this is the definition of the scientific method and what we have written in the above echoes the opinion Marcia McNutt who is the Editor of Science 'Science is a method for deciding whether what we choose to believe has a basis in the laws of nature or not'. A new discovery, a new theory that explains that discovery and the scientific method itself need observations, verifications and are susceptible of falsification.

  14. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Weimer, Carl S. (Inventor); Nelson, Loren D. (Inventor)

    2005-01-01

    Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

  15. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-yu (Inventor); O'Brien, Martin (Inventor)

    2010-01-01

    Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

  16. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-yu (Inventor); Acott, Phillip E. (Inventor); Spaeth, Lisa G. (Inventor); O'Brien, Martin (Inventor)

    2011-01-01

    Systems and methods for sensing air includes at least one, and in some embodiments three, transceivers for projecting the laser energy as laser radiation to the air. The transceivers are scanned or aligned along several different axes. Each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines air temperatures, wind speeds, and wind directions based on the scattered laser radiation. Applications of the system to wind power site evaluation, wind turbine control, traffic safety, general meteorological monitoring and airport safety are presented.

  17. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-Yu (Inventor); O'Brien, Martin J. (Inventor)

    2011-01-01

    A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

  18. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-Yu (Inventor); O'Brien, Martin J. (Inventor)

    2009-01-01

    A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

  19. Optical methods for measurements of skin penetration.

    PubMed

    Gotter, B; Faubel, W; Neubert, R H H

    2008-01-01

    Fourier transform infrared photoacoustic (PAS), photothermal deflection (PDS) and Raman spectroscopy belong to the modern innovative noninvasive analytical tools that are beginning to be recognized as highly potential techniques for the noninvasive study of biological tissues and human skin under in vivo conditions. They can be applied to obtain information regarding the molecular composition of the skin down to several hundred micrometers below the skin surface. All three methods allow depth-resolved investigations. While PAS and PDS use a frequency modulation of the excitation beam to reach deeper regions in the sample, the principle of confocal Raman microspectroscopy (CRM) is a movement of the specimen in the focal plane. In consideration of depth measurements PAS and PDS complete the applicable spectrum of CRM, since Raman microscopy requires particular transparent materials.

  20. Method for producing angled optical fiber tips in the laboratory

    NASA Astrophysics Data System (ADS)

    Davenport, John J.; Hickey, Michelle; Phillips, Justin P.; Kyriacou, Panicos A.

    2016-02-01

    A simple laboratory method is presented for producing optical fibers with tips polished at various angles. Angled optical fiber tips are used in applications such as optical sensing and remote laser surgery, where they can be used to control the angle of light leaving the fiber or direct it to the side. This allows for greater control and allows areas to be reached that otherwise could not. Optical fibers were produced with tip angles of 45 deg using a Perspex mounting block with an aluminum base plate. The dispersion of light leaving the tip was tested using a blue (470 nm) LED. The angle imposed an angular shift on the light diffracting out of the tip of approximately 30 deg. Additionally, some light reflected from the tip surface to diffract at 90 deg through the side of the fiber. These observations are consistent with theory and those seen by other studies, validating the method. The method was simple to perform and does not require advanced manufacturing tools. The method is suitable for producing small quantities of angle-tipped optical fibers for research applications.

  1. Optical pickup adjustment system using a passive alignment method

    NASA Astrophysics Data System (ADS)

    Abiko, Yukihiro; Yabuki, Akihiko; Koezuka, Tetsuo

    2002-03-01

    The optical pickup of a magneto-optical drive is constructed of millimeter-size optical components, including a laser diode (LD), a collimating lens (CL), a polarizing beam splitter, some kinds of prisms, and photo detectors (PD). Each component must be assembled with micrometer-order accuracy. In particular, the astigmatism, which is adjusted by changing the position of the CL, must be within 0.65 micrometers in the optical axis direction. To enable the CL position to be adjusted quantitatively, we developed an adjustment method that uses passive alignment. We estimated the astigmatism by analyzing an image of the LD, which is acquired through the CL by illuminating the LD with the polarized light. We developed an optical-pickup adjustment system using the proposed method and tested its effectiveness experimentally. The results showed that this system can be used to adjust the accuracy to within 0.65 micrometers. Because the image of the LD and the PD are acquired clearly by this system, it should be useful for not only adjusting the optical pickup but also for visually inspecting the LD and PD.

  2. System and Method for Multi-Wavelength Optical Signal Detection

    NASA Technical Reports Server (NTRS)

    McGlone, Thomas D. (Inventor)

    2017-01-01

    The system and method for multi-wavelength optical signal detection enables the detection of optical signal levels significantly below those processed at the discrete circuit level by the use of mixed-signal processing methods implemented with integrated circuit technologies. The present invention is configured to detect and process small signals, which enables the reduction of the optical power required to stimulate detection networks, and lowers the required laser power to make specific measurements. The present invention provides an adaptation of active pixel networks combined with mixed-signal processing methods to provide an integer representation of the received signal as an output. The present invention also provides multi-wavelength laser detection circuits for use in various systems, such as a differential absorption light detection and ranging system.

  3. Relaxation method of compensation in an optical correlator

    NASA Technical Reports Server (NTRS)

    Juday, Richard D.; Daiuto, Brian J.

    1987-01-01

    An iterative method is proposed for the sharpening of programmable filters in a 4-f optical correlator. Continuously variable spatial light modulators (SLMs) permit the fine adjustment of optical processing filters so as to compensate for the departures from ideal behavior of a real optical system. Although motivated by the development of continuously variable phase-only SLMs, the proposed sharpening method is also applicable to amplitude modulators and, with appropriate adjustments, to binary modulators as well. A computer simulation is presented that illustrates the potential effectiveness of the method: an image is placed on the input to the correlator, and its corresponding phase-only filter is adjusted (allowed to relax) so as to produce a progressively brighter and more centralized peak in the correlation plane. The technique is highly robust against the form of the system's departure from ideal behavior.

  4. Initial alignment method for free space optics laser beam

    NASA Astrophysics Data System (ADS)

    Shimada, Yuta; Tashiro, Yuki; Izumi, Kiyotaka; Yoshida, Koichi; Tsujimura, Takeshi

    2016-08-01

    The authors have newly proposed and constructed an active free space optics transmission system. It is equipped with a motor driven laser emitting mechanism and positioning photodiodes, and it transmits a collimated thin laser beam and accurately steers the laser beam direction. It is necessary to introduce the laser beam within sensible range of the receiver in advance of laser beam tracking control. This paper studies an estimation method of laser reaching point for initial laser beam alignment. Distributed photodiodes detect laser luminescence at respective position, and the optical axis of laser beam is analytically presumed based on the Gaussian beam optics. Computer simulation evaluates the accuracy of the proposed estimation methods, and results disclose that the methods help us to guide the laser beam to a distant receiver.

  5. Application of optical diffraction method in designing phase plates

    NASA Astrophysics Data System (ADS)

    Lei, Ze-Min; Sun, Xiao-Yan; Lv, Feng-Nian; Zhang, Zhen; Lu, Xing-Qiang

    2016-11-01

    Continuous phase plate (CPP), which has a function of beam shaping in laser systems, is one kind of important diffractive optics. Based on the Fourier transform of the Gerchberg-Saxton (G-S) algorithm for designing CPP, we proposed an optical diffraction method according to the real system conditions. A thin lens can complete the Fourier transform of the input signal and the inverse propagation of light can be implemented in a program. Using both of the two functions can realize the iteration process to calculate the near-field distribution of light and the far-field repeatedly, which is similar to the G-S algorithm. The results show that using the optical diffraction method can design a CPP for a complicated laser system, and make the CPP have abilities of beam shaping and phase compensation for the phase aberration of the system. The method can improve the adaptation of the phase plate in systems with phase aberrations.

  6. Relaxation method of compensation in an optical correlator

    NASA Technical Reports Server (NTRS)

    Juday, Richard D.; Daiuto, Brian J.

    1987-01-01

    An iterative method is proposed for the sharpening of programmable filters in a 4-f optical correlator. Continuously variable spatial light modulators (SLMs) permit the fine adjustment of optical processing filters so as to compensate for the departures from ideal behavior of a real optical system. Although motivated by the development of continuously variable phase-only SLMs, the proposed sharpening method is also applicable to amplitude modulators and, with appropriate adjustments, to binary modulators as well. A computer simulation is presented that illustrates the potential effectiveness of the method: an image is placed on the input to the correlator, and its corresponding phase-only filter is adjusted (allowed to relax) so as to produce a progressively brighter and more centralized peak in the correlation plane. The technique is highly robust against the form of the system's departure from ideal behavior.

  7. Phased-array optical whispering gallery mode modulation and method

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry V. (Inventor)

    2009-01-01

    A whispering gallery mode (WGM) resonator device and method capable of filtering sidebands of optical modulators are provided. The method includes providing an optical resonator adapted to support whispering gallery modes and forming a first field and a second field from a first location and a second location, respectively, at the circumference of the optical resonator and being separated by an arc angle, .alpha.. The method includes adjusting relative phase between the first field and the second field in accordance to a differential phase, .beta., and combining the first and the second fields into an output. Particular selection of the arc angle, .alpha., and the differential phase, .beta., can determine the function of the output.

  8. Optic disk localization by a robust fusion method

    NASA Astrophysics Data System (ADS)

    Zhang, Jielin; Yin, Fengshou; Wong, Damon W. K.; Liu, Jiang; Baskaran, Mani; Cheng, Ching-Yu; Wong, Tien Yin

    2013-02-01

    The optic disk localization plays an important role in developing computer-aided diagnosis (CAD) systems for ocular diseases such as glaucoma, diabetic retinopathy and age-related macula degeneration. In this paper, we propose an intelligent fusion of methods for the localization of the optic disk in retinal fundus images. Three different approaches are developed to detect the location of the optic disk separately. The first method is the maximum vessel crossing method, which finds the region with the most number of blood vessel crossing points. The second one is the multichannel thresholding method, targeting the area with the highest intensity. The final method searches the vertical and horizontal region-of-interest separately on the basis of blood vessel structure and neighborhood entropy profile. Finally, these three methods are combined using an intelligent fusion method to improve the overall accuracy. The proposed algorithm was tested on the STARE database and the ORIGAlight database, each consisting of images with various pathologies. The preliminary result on the STARE database can achieve 81.5%, while a higher result of 99% can be obtained for the ORIGAlight database. The proposed method outperforms each individual approach and state-of-the-art method which utilizes an intensity-based approach. The result demonstrates a high potential for this method to be used in retinal CAD systems.

  9. Frequency domain optical tomography using a Monte Carlo perturbation method

    NASA Astrophysics Data System (ADS)

    Yamamoto, Toshihiro; Sakamoto, Hiroki

    2016-04-01

    A frequency domain Monte Carlo method is applied to near-infrared optical tomography, where an intensity-modulated light source with a given modulation frequency is used to reconstruct optical properties. The frequency domain reconstruction technique allows for better separation between the scattering and absorption properties of inclusions, even for ill-posed inverse problems, due to cross-talk between the scattering and absorption reconstructions. The frequency domain Monte Carlo calculation for light transport in an absorbing and scattering medium has thus far been analyzed mostly for the reconstruction of optical properties in simple layered tissues. This study applies a Monte Carlo calculation algorithm, which can handle complex-valued particle weights for solving a frequency domain transport equation, to optical tomography in two-dimensional heterogeneous tissues. The Jacobian matrix that is needed to reconstruct the optical properties is obtained by a first-order "differential operator" technique, which involves less variance than the conventional "correlated sampling" technique. The numerical examples in this paper indicate that the newly proposed Monte Carlo method provides reconstructed results for the scattering and absorption coefficients that compare favorably with the results obtained from conventional deterministic or Monte Carlo methods.

  10. Comparison of interpolation and approximation methods for optical freeform synthesis

    NASA Astrophysics Data System (ADS)

    Voznesenskaya, Anna; Krizskiy, Pavel

    2017-06-01

    Interpolation and approximation methods for freeform surface synthesis are analyzed using the developed software tool. Special computer tool is developed and results of freeform surface modeling with piecewise linear interpolation, piecewise quadratic interpolation, cubic spline interpolation, Lagrange polynomial interpolation are considered. The most accurate interpolation method is recommended. Surface profiles are approximated with the square least method. The freeform systems are generated in optical design software.

  11. Simple method for manufacturing and optical characterization of tapered optical fibres

    NASA Astrophysics Data System (ADS)

    Zakrzewski, A.; Pięta, A.; Patela, S.

    2016-12-01

    Photonic devices often use light delivered by a single-mode telecommunication fibre. However, as the diameter of the core of the optical fibre is of 10 microns, and the transverse dimensions of the photonic waveguides are usually micrometer or less, there is an issue of incompatibility. The problem may be solved by application of tapered optical fibres. For efficient light coupling, the taper should be prepared so as to create a beam of long focal length and small spot diameter in the focus. The article describes the design, fabrication and characterization of tapered optical fibres prepared with a fibre-optic fusion splicer. We modelled the tapers with FDTD method, for estimation of the influence of the tapered length and angle on the spot diameter and the focal length of an outgoing beam. We fabricated tapers from a standard single mode fibre by the Ericsson 995 PMfi- bre-optic fusion splicer. We planned the splicing technology so as to get the needed features of the beam. We planned a multistep fusion process, with optimized fusion current and fusion time. The experimental measurements of best tapered optical fibres were carried out by the knife-edge method.

  12. CFO compensation method using optical feedback path for coherent optical OFDM system

    NASA Astrophysics Data System (ADS)

    Moon, Sang-Rok; Hwang, In-Ki; Kang, Hun-Sik; Chang, Sun Hyok; Lee, Seung-Woo; Lee, Joon Ki

    2017-07-01

    We investigate feasibility of carrier frequency offset (CFO) compensation method using optical feedback path for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. Recently proposed CFO compensation algorithms provide wide CFO estimation range in electrical domain. However, their practical compensation range is limited by sampling rate of an analog-to-digital converter (ADC). This limitation has not drawn attention, since the ADC sampling rate was high enough comparing to the data bandwidth and CFO in the wireless OFDM system. For CO-OFDM, the limitation is becoming visible because of increased data bandwidth, laser instability (i.e. large CFO) and insufficient ADC sampling rate owing to high cost. To solve the problem and extend practical CFO compensation range, we propose a CFO compensation method having optical feedback path. By adding simple wavelength control for local oscillator, the practical CFO compensation range can be extended to the sampling frequency range. The feasibility of the proposed method is experimentally investigated.

  13. Wavelet methods in multi-conjugate adaptive optics

    NASA Astrophysics Data System (ADS)

    Helin, T.; Yudytskiy, M.

    2013-08-01

    The next generation ground-based telescopes rely heavily on adaptive optics for overcoming the limitation of atmospheric turbulence. In the future adaptive optics modalities, like multi-conjugate adaptive optics (MCAO), atmospheric tomography is the major mathematical and computational challenge. In this severely ill-posed problem, a fast and stable reconstruction algorithm is needed that can take into account many real-life phenomena of telescope imaging. We introduce a novel reconstruction method for the atmospheric tomography problem and demonstrate its performance and flexibility in the context of MCAO. Our method is based on using locality properties of compactly supported wavelets, both in the spatial and frequency domains. The reconstruction in the atmospheric tomography problem is obtained by solving the Bayesian MAP estimator with a conjugate-gradient-based algorithm. An accelerated algorithm with preconditioning is also introduced. Numerical performance is demonstrated on the official end-to-end simulation tool OCTOPUS of European Southern Observatory.

  14. Optically Stimulated Electron Emission Contamination Monitor and Method

    NASA Technical Reports Server (NTRS)

    Welch, Christopher S. (Inventor); Perey, Daniel F. (Inventor)

    2005-01-01

    An apparatus and method for performing quality inspections on a test surface based on optically stimulated emission of electrons. In one embodiment, the apparatus comprises a device for producing optical radiation having a plurality of different spectrum lines, selecting at least one of the spectrum lines, and directing the selected spectrum line to the test surface, and circuitry for detecting a current of photoelectrons emitted from the test surface, generating a signal indicative of photoelectron current, and for indicating a condition of quality based on the generated signal indicative of the photoelectron current. In one embodiment, the method comprises producing optical radiation having a plurality of different spectrum lines, selecting at least one of the spectrum lines and directing the selected spectrum line to the test surface, detecting a current of photoelectrons emitted from the test surface and generating a signal indicative of photoelectron current, and indicating a condition of quality based on the generated signal indicative of the photoelectron current.

  15. Method for quantifying optical properties of the human lens

    SciTech Connect

    Loree, T.R.; Bigio, I.J.; Zuclich, J.A.; Shimada, Tsutomu; Strobl, K.

    1999-04-13

    A method is disclosed for quantifying optical properties of the human lens. The present invention includes the application of fiberoptic, OMA-based instrumentation as an in vivo diagnostic tool for the human ocular lens. Rapid, noninvasive and comprehensive assessment of the optical characteristics of a lens using very modest levels of exciting light are described. Typically, the backscatter and fluorescence spectra (from about 300- to 900-nm) elicited by each of several exciting wavelengths (from about 300- to 600-nm) are collected within a few seconds. The resulting optical signature of individual lenses is then used to assess the overall optical quality of the lens by comparing the results with a database of similar measurements obtained from a reference set of normal human lenses having various ages. Several metrics have been identified which gauge the optical quality of a given lens relative to the norm for the subject`s chronological age. These metrics may also serve to document accelerated optical aging and/or as early indicators of cataract or other disease processes. 8 figs.

  16. Method for quantifying optical properties of the human lens

    DOEpatents

    Loree, deceased, Thomas R.; Bigio, Irving J.; Zuclich, Joseph A.; Shimada, Tsutomu; Strobl, Karlheinz

    1999-01-01

    Method for quantifying optical properties of the human lens. The present invention includes the application of fiberoptic, OMA-based instrumentation as an in vivo diagnostic tool for the human ocular lens. Rapid, noninvasive and comprehensive assessment of the optical characteristics of a lens using very modest levels of exciting light are described. Typically, the backscatter and fluorescence spectra (from about 300- to 900-nm) elicited by each of several exciting wavelengths (from about 300- to 600-nm) are collected within a few seconds. The resulting optical signature of individual lenses is then used to assess the overall optical quality of the lens by comparing the results with a database of similar measurements obtained from a reference set of normal human lenses having various ages. Several metrics have been identified which gauge the optical quality of a given lens relative to the norm for the subject's chronological age. These metrics may also serve to document accelerated optical aging and/or as early indicators of cataract or other disease processes.

  17. Method for quantifying optical properties of the human lens

    DOEpatents

    Loree, T.R.; Bigio, I.J.; Zuclich, J.A.; Shimada, Tsutomu; Strobl, K.

    1999-04-13

    A method is disclosed for quantifying optical properties of the human lens. The present invention includes the application of fiberoptic, OMA-based instrumentation as an in vivo diagnostic tool for the human ocular lens. Rapid, noninvasive and comprehensive assessment of the optical characteristics of a lens using very modest levels of exciting light are described. Typically, the backscatter and fluorescence spectra (from about 300- to 900-nm) elicited by each of several exciting wavelengths (from about 300- to 600-nm) are collected within a few seconds. The resulting optical signature of individual lenses is then used to assess the overall optical quality of the lens by comparing the results with a database of similar measurements obtained from a reference set of normal human lenses having various ages. Several metrics have been identified which gauge the optical quality of a given lens relative to the norm for the subject`s chronological age. These metrics may also serve to document accelerated optical aging and/or as early indicators of cataract or other disease processes. 8 figs.

  18. Imaging Methods in the Diagnosis of Optic Disc Drusen

    PubMed Central

    Tuğcu, Betül; Özdemir, Hakan

    2016-01-01

    Optic disc drusen (ODD) are benign congenital anomalies of the optic nerve characterized by calcified hyaline bodies. While superficial drusen can be diagnosed easily during fundus examination, detecting buried drusen requires the use of additional imaging methods such as B-scan ultrasonography (USG), fundus fluorescein angiography (FFA), computed tomography (CT) and fundus autofluorescence (FAF). ODD can be detected by USG with the presentation of highly reflective round structures. ODD appear as hyperautofluorescent areas on FAF and bright spots on CT scans. FFA can be helpful in differentiating ODD from true optic disc edema. Optic disc edema shows early hyperfluorescence due to diffuse leakage whereas ODD presents as well-defined hyperfluorescence in the late phase. In recent years, it has been reported that optical coherence tomography (OCT) examination has allowed more detailed evaluation of ODD and yielded useful findings for the differentiation of optic disc edema from ODD. In this review, the role of OCT in the diagnosis of ODD is discussed. PMID:28058166

  19. Comparative study of optical fiber cure-monitoring methods

    NASA Astrophysics Data System (ADS)

    Crosby, Peter A.; Powell, Graham R.; Fernando, Gerard F.; Waters, David N.; France, Chris M.; Spooncer, Ronald C.

    1997-06-01

    This paper reports on a comparative study undertaken for different types of optical fiber sensor developed to monitor the cure of an epoxy resin system. The optical fiber sensors used to monitor the cure process were based on transmission spectroscopy, evanescent wave spectroscopy and refractive index monitoring. The transmission sensor was prepared by aligning two optical fibers within a specially prepared sleeve with a gap between the optical fiber end-faces. During cure, resin from the specimen flowed into the gap between the optical fibers allowing transmission spectra of the resin to be obtained. The evanescent wave sensor was prepared by stripping the cladding from a high refractive index core optical fiber. The prepared sensor was embedded in the sample and attenuated total reflectance spectra recorded from the resin/core boundary. Refractive index monitoring was undertaken using a high refractive index core optical fiber which had a small portion of its cladding removed. The prepared sensor was embedded in the resin specimen and light from a single wavelength source was launched into the fiber. Changes in the guiding characteristics of the sensor due to refractive index changes at the resin/core boundary were used to monitor the progress of the cure reaction. The transmission and evanescent wave spectroscopy sensors were used to follow changes in characteristic near-infrared absorption bands of the resin over the range 1450 - 1700 nm during the cure reaction. Consequently these techniques required tunable wavelength sources covering specific wavelength ranges. However, the refractive index based sensor used a single wavelength source. Therefore the equipment costs for this type of sensor were considerably less. Additionally, the refractive index sensor did not require a single wavelength source at any particular wavelength and could be applied to any spectral region in which the optical fiber would transmit light. The advantages and disadvantages of these

  20. Deformation analysis of optical flat surface with finite element method

    NASA Astrophysics Data System (ADS)

    Fu, Pengqiang; Ren, Boyuan; Wang, Yiwen; Zhang, Dewei; Zhang, Longjiang; Su, Xing

    2016-10-01

    Proposing a new method for testing the ultra-precision aerostatic spindle motion accuracy based on analyzing the online real-time dynamic interference image. Optical flat crystal as the testing standard will be installed at the end of the ultra precision aerostatic spindle and will motion along with the spindle. On the other end of the spindle, the tool will be installed for online processing. The image data of optical flat crystal collected by the high-precision dynamic interferometer will be processed for analyzing the spindle error. For collecting higher accuracy image data, the installation way of optical flat crystal is one of the key technologies. Base on this, the effects of the clamping means on the surface accuracy of optical flat crystal is studied. At first, the finite element model of the optical flat crystal`s clamping structure were established. Secondly, the influence of the material of the supporting annulus, preload lateral clamping and spindle speed on the surface accuracy of optical flat crystal had been analyzed. At last, the improved and optimized structure of the optical flat crystal has been presented. As the analysis results shown, the RMS value of reference surface is 9.47nm and the deformation values of the central region is 0.17nm which satisfies the requirement of surface accuracy and installation of optical flat crystal. It has a very important theoretical and practical significance to establish spindle online testing system and research rotary error generating mechanism of ultra-precision spindle to improve surface accuracy of ultra-precision machining.

  1. Role of Optical Spectroscopic Methods in Neuro-Oncological Sciences

    PubMed Central

    Bahreini, Maryam

    2015-01-01

    In the surgical treatment of malignant tumors, it is crucial to characterize the tumor as precisely as possible. The determination of the exact tumor location as well as the analysis of its properties is very important in order to obtain an accurate diagnosis as early as possible. In neurosurgical applications, the optical, non-invasive and in situ techniques allow for the label-free analysis of tissue, which is helpful in neuropathology. In the past decades, optical spectroscopic methods have been investigated drastically in the management of cancer. In the optical spectroscopic techniques, tissue interrogate with sources of light which are ranged from the ultraviolet to the infrared wavelength in the spectrum. The information accumulation of light can be in a reflection which is named reflectance spectroscopy; or interactions with tissue at different wavelengths which are called fluorescence and Raman spectroscopy. This review paper introduces the optical spectroscopic methods which are used to characterize brain tumors (neuro-oncology). Based on biochemical information obtained from these spectroscopic methods, it is possible to identify tumor from normal brain tissues, to indicate tumor margins, the borders towards normal brain tissue and infiltrating gliomas, to distinguish radiation damage of tissues, to detect particular central nervous system (CNS) structures to identify cell types using particular neurotransmitters, to detect cells or drugs which are optically labeled within therapeutic intermediations and to estimate the viability of tissue and the prediction of apoptosis beginning in vitro and in vivo. The label-free, optical biochemical spectroscopic methods can provide clinically relevant information and need to be further exploited to develop a safe and easy-to-use technology for in situ diagnosis of malignant tumors. PMID:25987969

  2. Novel method for high accuracy figure measurement of optical flat

    NASA Astrophysics Data System (ADS)

    E, Kewei; Li, Dahai; Yang, Lijie; Guo, Guangrao; Li, Mengyang; Wang, Xuemin; Zhang, Tao; Xiong, Zhao

    2017-01-01

    Phase Measuring Deflectometry (PMD) is a non-contact, high dynamic-range and full-field metrology which becomes a serious competitor to interferometry. However, the accuracy of deflectometry metrology is strongly influenced by the level of the calibrations, including test geometry, imaging pin-hole camera and digital display. In this paper, we propose a novel method that can measure optical flat surface figure to a high accuracy. We first calibrate the camera using a checker pattern shown on a LCD display at six different orientations, and the last orientation is aligned at the same position as the test optical flat. By using this method, lens distortions and the mapping relationship between the CCD pixels and the subaperture coordinates on the test optical flat can be determined at the same time. To further reduce the influence of the calibration errors on measurements, a reference optical flat with a high quality surface is measured, and then the system errors in our PMD setup can be eliminated by subtracting the figure of the reference flat from the figure of the test flat. Although any expensive coordinates measuring machine, such as laser tracker and coordinates measuring machine are not applied in our measurement, our experimental results of optical flat figure from low to high order aberrations still show a good agreement with that from the Fizeau interferometer.

  3. Optical method for the determination of grain orientation in films

    DOEpatents

    Maris, Humphrey J.

    2003-05-13

    A method for the determination of grain orientation in a film sample is provided comprising the steps of measuring a first transient optical response of the film and determining the contribution to the transient optical response arising from a change in the energy distribution of the electrons in the sample, determining the contribution to the transient optical response arising from a propagating strain pulse within the sample, and determining the contribution to the transient optical response arising from a change in sample temperature of the sample. The grain orientation of the sample may be determined using the contributions to the transient optical response arising from the change in the energy distribution of the electrons, the propagating strain pulse, and the change in sample temperature. Additionally, a method for determination of the thickness of a film sample is provided. The grain orientation of the sample is first determined. The grain orientation, together with the velocity of sound and a propagation time of a strain pulse through the sample are then used to determine the thickness of the film sample.

  4. Optical method for the determination of grain orientation in films

    DOEpatents

    Maris, Humphrey J.

    2001-01-01

    A method for the determination of grain orientation in a film sample is provided comprising the steps of measuring a first transient optical response of the film and determining the contribution to the transient optical response arising from a change in the energy distribution of the electrons in the sample, determining the contribution to the transient optical response arising from a propagating strain pulse within the sample, and determining the contribution to the transient optical response arising from a change in sample temperature of the sample. The grain orientation of the sample may be determined using the contributions to the transient optical response arising from the change in the energy distribution of the electrons, the propagating strain pulse, and the change in sample temperature. Additionally, a method for determination of the thickness of a film sample is provided. The grain orientation of the sample is first determined. The grain orientation, together with the velocity of sound and a propagation time of a strain pulse through the sample are then used to determine the thickness of the film sample.

  5. Computed Optical Interferometric Imaging: Methods, Achievements, and Challenges

    PubMed Central

    South, Fredrick A.; Liu, Yuan-Zhi; Carney, P. Scott; Boppart, Stephen A.

    2016-01-01

    Three-dimensional high-resolution optical imaging systems are generally restricted by the trade-off between resolution and depth-of-field as well as imperfections in the imaging system or sample. Computed optical interferometric imaging is able to overcome these longstanding limitations using methods such as interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO) which manipulate the complex interferometric data. These techniques correct for limited depth-of-field and optical aberrations without the need for additional hardware. This paper aims to outline these computational methods, making them readily available to the research community. Achievements of the techniques will be highlighted, along with past and present challenges in implementing the techniques. Challenges such as phase instability and determination of the appropriate aberration correction have been largely overcome so that imaging of living tissues using ISAM and CAO is now possible. Computed imaging in optics is becoming a mature technology poised to make a significant impact in medicine and biology. PMID:27795663

  6. Protocol independent transmission method in software defined optical network

    NASA Astrophysics Data System (ADS)

    Liu, Yuze; Li, Hui; Hou, Yanfang; Qiu, Yajun; Ji, Yuefeng

    2016-10-01

    With the development of big data and cloud computing technology, the traditional software-defined network is facing new challenges (e.i., ubiquitous accessibility, higher bandwidth, more flexible management and greater security). Using a proprietary protocol or encoding format is a way to improve information security. However, the flow, which carried by proprietary protocol or code, cannot go through the traditional IP network. In addition, ultra- high-definition video transmission service once again become a hot spot. Traditionally, in the IP network, the Serial Digital Interface (SDI) signal must be compressed. This approach offers additional advantages but also bring some disadvantages such as signal degradation and high latency. To some extent, HD-SDI can also be regard as a proprietary protocol, which need transparent transmission such as optical channel. However, traditional optical networks cannot support flexible traffics . In response to aforementioned challenges for future network, one immediate solution would be to use NFV technology to abstract the network infrastructure and provide an all-optical switching topology graph for the SDN control plane. This paper proposes a new service-based software defined optical network architecture, including an infrastructure layer, a virtualization layer, a service abstract layer and an application layer. We then dwell on the corresponding service providing method in order to implement the protocol-independent transport. Finally, we experimentally evaluate that proposed service providing method can be applied to transmit the HD-SDI signal in the software-defined optical network.

  7. Method for forming hermetic coatings for optical fibers

    DOEpatents

    Michalske, Terry A.; Rye, Robert R.; Smith, William L.

    1993-01-01

    A method for forming hermetic coatings on optical fibers by hot filament assisted chemical vapor deposition advantageously produces a desirable coating while maintaining the pristine strength of the pristine fiber. The hermetic coatings may be formed from a variety of substances, such as, for example, boron nitride and carbon.

  8. Optical methods for diagnostic of cell-tissue grafts

    NASA Astrophysics Data System (ADS)

    Timchenko, P. E.; Timchenko, E. V.; Volova, L. T.; Boltovskaya, V. V.; Zherdeva, L. A.; Belousov, N. V.; Pershutkina, S. V.

    2015-08-01

    In this work the results of cell-tissue grafts research with a complex of optical methods - confocal fluorescent microscopy and Raman spectroscopy are presented. It was established that coefficient M scatter is related to irregularity of demineralization process. It was microscopically shown that the quantity of integrated cells into these types of transplants amounts to 20% of its surface.

  9. Apparatus and method for determining the optical power passing through an optical fiber

    DOEpatents

    Toeppen, John S.

    1995-04-04

    An apparatus and method for determining the optical power transmitted through an optical fiber. The invention is based on measuring the intensity of the fluorescence produced by a doped segment of an optical fiber. The dopant is selected so that it emits light at a different wavelength than that responsible for producing the fluorescence. The doped segment is of sufficient length and dopant concentration to provide a detectable signal, but short enough to prevent the doped segment from serving as a gain medium, resulting in amplified spontaneous emission and excess fluorescence traveling along the optical fiber. The dopant material is excited by the optical signal carried by the fiber, causing a fluorescence. In the preferred embodiment the intensity of the fluorescence is proportional to the intensity of the propagating light. The signal power is then determined from the intensity of the fluorescence. The intensity of the fluorescent signal is measured by a photodetector placed so as to detect the light emitted through the side of the doped segment. The detector may wrap around the circumference of the fiber, or be placed to one side and used in conjunction with a reflector placed on the opposing side of the fiber. Filters may be used to shield the detector from other light sources and assist with accurately determining the optical power of the signal propagating within the fiber.

  10. Apparatus and method for determining the optical power passing through an optical fiber

    DOEpatents

    Toeppen, John S.

    1995-01-01

    An apparatus and method for determining the optical power transmitted through an optical fiber. The invention is based on measuring the intensity of the fluorescence produced by a doped segment of an optical fiber. The dopant is selected so that it emits light at a different wavelength than that responsible for producing the fluorescence. The doped segment is of sufficient length and dopant concentration to provide a detectable signal, but short enough to prevent the doped segment from serving as a gain medium, resulting in amplified spontaneous emission and excess fluorescence traveling along the optical fiber. The dopant material is excited by the optical signal carried by the fiber, causing a fluorescence. In the preferred embodiment the intensity of the fluorescence is proportional to the intensity of the propagating light. The signal power is then determined from the intensity of the fluorescence. The intensity of the fluorescent signal is measured by a photodetector placed so as to detect the light emitted through the side of the doped segment. The detector may wrap around the circumference of the fiber, or be placed to one side and used in conjunction with a reflector placed on the opposing side of the fiber. Filters may be used to shield the detector from other light sources and assist with accurately determining the optical power of the signal propagating within the fiber.

  11. Dynamic Optical Grating Device and Associated Method for Modulating Light

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Chu, Sang-Hyon (Inventor)

    2012-01-01

    A dynamic optical grating device and associated method for modulating light is provided that is capable of controlling the spectral properties and propagation of light without moving mechanical components by the use of a dynamic electric and/or magnetic field. By changing the electric field and/or magnetic field, the index of refraction, the extinction coefficient, the transmittivity, and the reflectivity fo the optical grating device may be controlled in order to control the spectral properties of the light reflected or transmitted by the device.

  12. Rays inserting method (RIM) to design dielectric optical devices

    NASA Astrophysics Data System (ADS)

    Taskhiri, Mohammad Mahdi; Khalaj Amirhosseini, Mohammad

    2017-01-01

    In this article, a novel approach, called Rays Inserted Method (RIM), is introduced to design dielectric optical devices. In this approach, some rays are inserted between two ends of desired device and then the refractive index of the points along the route of rays are obtained. The validity of the introduced approach is verified by designing three types of optical devices, i.e. power splitter, bend, and flat lens. The results are confirmed with numerical simulations by the means of FDTD scheme at the frequency of 100 GHz.

  13. Method for enhancing signals transmitted over optical fibers

    DOEpatents

    Ogle, James W.; Lyons, Peter B.

    1983-01-01

    A method for spectral equalization of high frequency spectrally broadband signals transmitted through an optical fiber. The broadband signal input is first dispersed by a grating. Narrow spectral components are collected into an array of equalizing fibers. The fibers serve as optical delay lines compensating for material dispersion of each spectral component during transmission. The relative lengths of the individual equalizing fibers are selected to compensate for such prior dispersion. The output of the equalizing fibers couple the spectrally equalized light onto a suitable detector for subsequent electronic processing of the enhanced broadband signal.

  14. Method for enhancing signals transmitted over optical fibers

    DOEpatents

    Ogle, J.W.; Lyons, P.B.

    1981-02-11

    A method for spectral equalization of high frequency spectrally broadband signals transmitted through an optical fiber is disclosed. The broadband signal input is first dispersed by a grating. Narrow spectral components are collected into an array of equalizing fibers. The fibers serve as optical delay lines compensating for material dispersion of each spectral component during transmission. The relative lengths of the individual equalizing fibers are selected to compensate for such prior dispersion. The output of the equalizing fibers couple the spectrally equalized light onto a suitable detector for subsequent electronic processing of the enhanced broadband signal.

  15. Water jet: a promising method for cutting optical glass.

    PubMed

    Salinas-Luna, Javier; Machorro, Roberto; Camacho, Javier; Luna, Esteban; Nunez, Juan

    2006-05-20

    We present an alternative method for cutting optical glass. It works with a high-pressure fluid, carring abrasive powder. This technique offers some advantages over conventional methods that use diamond abrasive covered wires or disks. We make a critical comparison between those two techniques, characterizing cuts with interferometric, polarimetric, and Ronchi testing. The main feature of the water-jet technique is that it allows surface of any shape, already polished, to be cut safely.

  16. Water jet: a promising method for cutting optical glass

    NASA Astrophysics Data System (ADS)

    Salinas-Luna, Javier; Machorro, Roberto; Camacho, Javier; Luna, Esteban; Nunez, Juan

    2006-05-01

    We present an alternative method for cutting optical glass. It works with a high-pressure fluid, carring abrasive powder. This technique offers some advantages over conventional methods that use diamond abrasive covered wires or disks. We make a critical comparison between those two techniques, characterizing cuts with interferometric, polarimetric, and Ronchi testing. The main feature of the water-jet technique is that it allows surface of any shape, already polished, to be cut safely.

  17. Method of Bonding Optical Elements with Near-Zero Displacement

    NASA Technical Reports Server (NTRS)

    Robinson, David; McClelland, Ryan; Byron, Glenn; Evans, Tyler

    2012-01-01

    The International X-ray Project seeks to build an x-ray telescope using thousands of pieces of thin and flexible glass mirror segments. Each mirror segment must be bonded into a housing in nearly perfect optical alignment without distortion. Forces greater than 0.001 Newton, or displacements greater than 0.5 m of the glass, cause unacceptable optical distortion. All known epoxies shrink as they cure. Even the epoxies with the least amount of shrinkage (<0.01%) cause unacceptable optical distortion and misalignment by pulling the mirror segments towards the housing as it cures. A related problem is that the shrinkage is not consistent or predictable so that it cannot be accounted for in the setup (i.e., if all of the bonds shrunk an equal amount, there would be no problem). A method has been developed that allows two components to be joined with epoxy in such a way that reduces the displacement caused by epoxy shrinking as it cures to less than 200 nm. The method involves using ultraviolet-cured epoxy with a displacement sensor and a nanoactuator in a control loop. The epoxy is cured by short-duration exposures to UV light. In between each exposure, the nano-actuator zeroes out the displacement caused by epoxy shrinkage and thermal expansion. After a few exposures, the epoxy has cured sufficiently to prevent further displacement of the two components. Bonding of optical elements has been done for many years, but most optics are thick and rigid elements that resist micro-Newton-level forces without causing distortion. When bonding thin glass optics such as the 0.40-mm thick IXO X-ray mirrors, forces in the micro- and milli-Newton levels cause unacceptable optical figure error. This innovation can now repeatedly and reliably bond a thin glass mirror to a metal housing with less than 0.2 m of displacement (<200 nm). This is an enabling technology that allows the installation of virtually stress-free, undistorted thin optics onto structures. This innovation is

  18. Application of optical controlling methods for plants under external influence

    NASA Astrophysics Data System (ADS)

    Timchenko, E. V.; Taskina, L. A.

    2012-10-01

    The experimental study results of spectral characteristic change of different types of plants influenced by external factors (synthetic superficially active substances, salts of heavy metals and nitrate fertilizers) are presented. Differential optical factor was used as the monitored optical parameter that characterizes the chlorophyll concentration change. The differential backscatter method which has high test-sensitivity and provides with the most complete information on the plant condition was the main optical monitoring method. For understanding the mechanisms of external factor accumulation and influence on plants the confocal fluorescent microscopy method providing contrast micrographs of high resolution was used for microscopic analysis in the study. It was revealed that synthetic superficially active substances and heavy metal presence lead to quasilinear decrease of differential backscatter factor with time. It was shown that the presence of salts of heavy metals in a water solution leads to chlorophyll "binding" which is microscopically shown as their «adhesion» near the cell membranes. On the contrary, the presence of synthetic superficially active substances maintains the uniformity of chlorophyll distribution in a cell, but its concentration falls with increasing the concentration in a major emission. The latter depends on the fact that synthetic superficially active substances solubilize the cell membrane proteins, increasing its penetrability. It causes pigment release ("washing away") from a plant, thereby leading to differential optical factor change. It was shown that nitrate fertilizer presence leads to increase of differential backscatter factor with time which is microscopically connected to increase in chlorophyll concentration.

  19. The optical density of erythrolabe determined by a new method

    PubMed Central

    King-Smith, P. E.

    1973-01-01

    1. A new method is described for the determination of optical density by retinal densitometry based on an analysis of stray light. 2. The basic assumption used is that the stray light present in retinal densitometry is independent of wave-length. The justification for this assumption is considered. 3. The stray light and hence the optical density was determined by a method of successive approximations using a Linc 8 computer. 4. The optical density of erythrolabe for the direction of maximum Stiles—Crawford efficiency was determined for five subjects, two deuteranopes, two deuteranomalous and one red-rich normal subject. The mean values for three of the subjects were close to the grand mean value of 0·42, but the other two subjects had considerably higher and lower values respectively. 5. The results are in satisfactory agreement with optical density values determined by the self-screening method using retinal densitometry, and also with determinations using microspectrophotometry and psychophysics. 6. The relevance of dielectric wave-guide modes in the outer segments is considered. PMID:4541512

  20. Optical methods for monitoring harmful gas in animal facilities

    NASA Astrophysics Data System (ADS)

    Zhang, Shirui; Dong, Daming; Zheng, Wengang; Wang, Jihua

    2014-06-01

    Animal facilities produce large amounts of harmful gases such as ammonia, hydrogen sulfide, and methane, many of which have a pungent odor. The harmful gases produced by animal housing not only affect the health of people and livestock but also pollute the air. The detection of the harmful gases can effectively improve efficiency of livestock production and reduce environmental pollution. More and more optical detection methods are applied to the detection of the harmful gases produced by animal housing. This summarizes optical detection methods for monitoring the harmful gases in animal housing recently, including nondispersive infrared gas analyzer, ultraviolet differential optical absorption spectroscopy, Fourier transform infrared spectroscopy, and tunable diode laser absorption spectroscopy. The basic principle and the characteristics of these methods are illustrated and the applications on the detection of harmful gases in animal housing are described. Meanwhile, the research of harmful gases monitoring for livestock production based on these methods were listed. The current situation and future development of the detection methods for harmful gases generated by animal housing were summarized by comparing the advantages and disadvantages of each method.

  1. In vivo imaging methods to assess glaucomatous optic neuropathy

    PubMed Central

    Fortune, Brad

    2015-01-01

    The goal of this review is to summarize the most common imaging methods currently applied for in vivo assessment of ocular structure in animal models of experimental glaucoma with an emphasis on translational relevance to clinical studies of the human disease. The most common techniques in current use include optical coherence tomography and scanning laser ophthalmoscopy. In reviewing the application of these and other imaging modalities to study glaucomatous optic neuropathy, this article is organized into three major sections: 1) imaging the optic nerve head, 2) imaging the retinal nerve fiber layer and 3) imaging retinal ganglion cell soma and dendrites. The article concludes with a brief section on possible future directions. PMID:26048475

  2. Plasma channel optical-pumping device and method

    SciTech Connect

    Judd, O.P.

    1981-07-17

    A device and method are described for optically pumping a gaseous laser using blackbody radiation produced by a plasma channel which is formed from an electrical discharge between two electrodes spaced at opposite longitudinal ends of the laser. A preionization device which can comprise a laser or electron beam accelerator produces a preionization beam which is sufficient to cause an elctrical discharge between the electrodes to initiate the plasma channel along the preionization path. The optical pumping energy is supplied by a high voltage power supply rather than by the preionization beam. High output optical intensities are produced by the laser due to the high temperature black-body radiation produced by the plasma channel, in the same manner as an exploding wire type laser. However, unlike the exploding wire type laser, the disclosed invention can be operated in a repetitive manner by utilizing a repetitive pulsed preionization device.

  3. Nodal line-scanning method for maskless optical lithography.

    PubMed

    Johnson, Kenneth C

    2014-12-01

    Maskless optical lithography can improve the economics and performance of multi-patterning by eliminating photomasks and by simplifying the lithography exposure technology. It could also potentially eliminate the need for multi-patterning by enabling dual-wavelength, nonlinear optical recording methods. High-resolution, maskless patterning can be achieved with a scanned-spot-array system in which modulated, diffraction-limited focus spots write the exposure pattern. Each spot has a central zero-intensity interference null along a line parallel to the scan direction for printing sub-resolution line patterns. High throughput can be achieved at the comparatively low repetition rate of excimer lasers (e.g., 6 kHz). The low repetition rate simplifies the optical modulation technology, enabling the use of supplemental modulation controls including dynamic gray-level and beam-centration controls for resolution enhancement.

  4. Ultrafast optical imaging technology: principles and applications of emerging methods

    NASA Astrophysics Data System (ADS)

    Mikami, Hideharu; Gao, Liang; Goda, Keisuke

    2016-09-01

    High-speed optical imaging is an indispensable technology for blur-free observation of fast transient dynamics in virtually all areas including science, industry, defense, energy, and medicine. High temporal resolution is particularly important for microscopy as even a slow event appears to occur "fast" in a small field of view. Unfortunately, the shutter speed and frame rate of conventional cameras based on electronic image sensors are significantly constrained by their electrical operation and limited storage. Over the recent years, several unique and unconventional approaches to high-speed optical imaging have been reported to circumvent these technical challenges and achieve a frame rate and shutter speed far beyond what can be reached with the conventional image sensors. In this article, we review the concepts and principles of such ultrafast optical imaging methods, compare their advantages and disadvantages, and discuss an entirely new class of applications that are possible using them.

  5. Method of fabricating optical waveguides by ion implantation doping

    DOEpatents

    Appleton, Bill R.; Ashley, Paul R.; Buchal, Christopher J.

    1989-01-01

    A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO.sub.3 crystals are implanted with high concentrations of Ti dopant at ion energies of about 350 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000.degree. C. produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality single crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguides properties.

  6. Method of fabricating optical waveguides by ion implantation doping

    DOEpatents

    Appleton, B.R.; Ashley, P.R.; Buchal, C.J.

    1987-03-24

    A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO/sub 3/ crystals are implanted with high concentrations of Ti dopant at ion energies of about 360 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000/degree/C produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguiding properties.

  7. A source number estimation method for single optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Hu, Junpeng; Huang, Zhiping; Su, Shaojing; Zhang, Yimeng; Liu, Chunwu

    2015-10-01

    The single-channel blind source separation (SCBSS) technique makes great significance in many fields, such as optical fiber communication, sensor detection, image processing and so on. It is a wide range application to realize blind source separation (BSS) from a single optical fiber sensor received data. The performance of many BSS algorithms and signal process methods will be worsened with inaccurate source number estimation. Many excellent algorithms have been proposed to deal with the source number estimation in array signal process which consists of multiple sensors, but they can not be applied directly to the single sensor condition. This paper presents a source number estimation method dealing with the single optical fiber sensor received data. By delay process, this paper converts the single sensor received data to multi-dimension form. And the data covariance matrix is constructed. Then the estimation algorithms used in array signal processing can be utilized. The information theoretic criteria (ITC) based methods, presented by AIC and MDL, Gerschgorin's disk estimation (GDE) are introduced to estimate the source number of the single optical fiber sensor's received signal. To improve the performance of these estimation methods at low signal noise ratio (SNR), this paper make a smooth process to the data covariance matrix. By the smooth process, the fluctuation and uncertainty of the eigenvalues of the covariance matrix are reduced. Simulation results prove that ITC base methods can not estimate the source number effectively under colored noise. The GDE method, although gets a poor performance at low SNR, but it is able to accurately estimate the number of sources with colored noise. The experiments also show that the proposed method can be applied to estimate the source number of single sensor received data.

  8. Design method for automotive high-beam LED optics

    NASA Astrophysics Data System (ADS)

    Byzov, Egor V.; Moiseev, Mikhail A.; Doskolovich, Leonid L.; Kazanskiy, Nikolay L.

    2015-09-01

    New analytical method for the calculation of the LED secondary optics for automotive high-beam lamps is presented. Automotive headlamps should illuminate the road and the curb at the distance of 100-150 meters and create a bright, flat, relatively powerful light beam. To generate intensity distribution of this kind we propose to use TIR optical element (collimator working on the total internal reflection principle) with array of microlenses (optical corrector) on the upper surface. TIR part of the optical element enables reflection of the side rays to the front direction and provides a collimated beam which incidents on the microrelief. Microrelief, in its turn, dissipates the light flux in horizontal direction to meet the requirements of the Regulations 112, 113 and to provide well-illuminated area across the road in the far field. As an example, we computed and simulated the optical element with the diameter of 33 millimeters and the height of 22 millimeters. Simulation data shows that three illuminating modules including Cree XP-G2 LED and lens allow generating an appropriate intensity distribution for the class D of UNECE Regulations.

  9. Method for absolute flatness measurement of optical surfaces.

    PubMed

    Xu, Chen; Chen, Lei; Yin, Jiayi

    2009-05-01

    To determine the absolute flatness deviations of optical surfaces, a novel method using two optical plates to achieve the absolute flatness test is presented. Absolute deviations of three surfaces, the rear surface of plate I and the front and rear surfaces of plate II, are obtained by four measurements. Wavefront error due to the inhomogeneity of plate II is measured beforehand and is then subtracted from the test results. Vertical profiles of the three surfaces are compared with the measurement results obtained by Zygo's three-flat application. Good agreement validates our method. The advantage of our method is that only one transmission flat is needed during the absolute test, which is especially useful for large-aperture interferometer calibration.

  10. Red blood cell tracking using optical flow methods.

    PubMed

    Guo, Dongmin; van de Ven, Anne L; Zhou, Xiaobo

    2014-05-01

    The investigation of microcirculation is an important task in biomedical and physiological research because the microcirculation information, such as flow velocity and vessel density, is critical to monitor human conditions and develop effective therapies of some diseases. As one of the tasks of the microcirculation study, red blood cell (RBC) tracking presents an effective approach to estimate some parameters in microcirculation. The common method for RBC tracking is based on spatiotemporal image analysis, which requires the image to have high qualification and cells should have fixed velocity. Besides, for in vivo cell tracking, cells may disappear in some frames, image series may have spatial and temporal distortions, and vessel distribution can be complex, which increase the difficulties of RBC tracking. In this paper, we propose an optical flow method to track RBCs. It attempts to describe the local motion for each visible point in the frames using a local displacement vector field. We utilize it to calculate the displacement of a cell in two adjacent frames. Additionally, another optical flow-based method, scale invariant feature transform (SIFT) flow, is also presented. The experimental results show that optical flow is quite robust to the case where the velocity of cell is unstable, while SIFT flow works well when there is a large displacement of the cell between two adjacent frames. Our proposed methods outperform other methods when doing in vivo cell tracking, which can be used to estimate the blood flow directly and help to evaluate other parameters in microcirculation.

  11. Optical methods for measurements of surface shape in optical components for high power laser beam forming

    NASA Astrophysics Data System (ADS)

    Józwik, Michał; Trusiak, Maciej; LiŻewski, Kamil; Martínez-Carranza, Juan; Voznesenskiy, Nikolay; Kujawińska, Małgorzata

    2016-12-01

    The paper presents modifications of full-field optical methods commonly used to test the surface quality of optical components used for forming a high power laser beam and tests of a final wavefront. The modifications in reference to surface measurements rely on implementation of the novel fringe pattern processing methods including the quality improvement of initial interferogram and analysis of a reconstructed phase based on Hilbert-Huang transform aided by the principal component analysis. Also the Point Diffraction Interferometer as the efficient tool for high quality measurements of elements with high NA is introduced. In reference to a wavefront quality measurements two solutions are discussed: the use of a lateral shear interferometer and the system employing Transport of Intensity Equation method. The pros and cons for both methods are discussed.

  12. Study of methods for direct optical address of integrated optical circuits

    NASA Technical Reports Server (NTRS)

    Wood, V. E.; Verber, C. M.

    1979-01-01

    Methods for introducing optical information directly, without intervening recording and storage steps, into integrated optical data-processing devices are surveyed. The information is taken to be in the form of a one-dimensional variation of intensity across the beam. Physical phenomena that may be utilized are evaluated, and the most suitable presently known classes of materials for exploitation of each type of interaction are discussed. A variety of possible device configurations are suggested and general principles are outlined whereby many more device types can be generated. A simple experimental device was demonstrated and its operation was analyzed.

  13. Optical efficiency of solar concentrators by a reverse optical path method.

    PubMed

    Parretta, A; Antonini, A; Milan, E; Stefancich, M; Martinelli, G; Armani, M

    2008-09-15

    A method for the optical characterization of a solar concentrator, based on the reverse illumination by a Lambertian source and measurement of intensity of light projected on a far screen, has been developed. It is shown that the projected light intensity is simply correlated to the angle-resolved efficiency of a concentrator, conventionally obtained by a direct illumination procedure. The method has been applied by simulating simple reflective nonimaging and Fresnel lens concentrators.

  14. The optical nonlinearity of gold nanoparticles prepared by bioreduction method

    NASA Astrophysics Data System (ADS)

    Balbuena Ortega, A.; Arroyo Carrasco, M. L.; Gayou, V. L.; Orduña Díaz, A.; Delgado Macuil, R.; Rojas López, Marlon

    2013-11-01

    Nonlinear optical and electronic properties of nanosized metal particles have drawn considerable attention because of their strong and size-dependent plasmon resonance absorption. In a metal nanoparticle system such as gold dispersed in a transparent matrix, an absorption peak due to surface plasmon resonance is usually observed in the visible spectral region. Metal nanoparticles are of special interest as nonlinear materials for optical switching and computing because of their relatively large third-order nonlinearity (χ3) and ultrafast response time. The purpose of this study was to analyze the nonlinear optical properties of biosynthesized gold nanoparticles. The samples were prepared by biosynthesis method using yeast extract as reducing agent and the nonlinear optical properties of the nanoparticles were investigated using a single beam Z-scan technique with a beam power of 20 mW and operated at wavelength of 514 nm. The reaction between metal ions and yeast extracts were monitored by UV-visible spectra of Au nanoparticles in aqueous solution with different pH (3-6). The surface plasmon peak position was shifted from 528 nm to 573 nm, according to of pH variation 4 to 6. The average particle size was calculated by the absorption peak position using the Fernig method, from 42 to 103 nm. The z-scan curves showed a negative nonlocal nonlinear refractive index with a magnitude dependent on the nanoparticle size.

  15. Worthwhile optical method for free-form mirrors qualification

    NASA Astrophysics Data System (ADS)

    Sironi, G.; Canestrari, R.; Toso, G.; Pareschi, G.

    2013-09-01

    We present an optical method for free-form mirrors qualification developed by the Italian National Institute for Astrophysics (INAF) in the context of the ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) Project which includes, among its items, the design, development and installation of a dual-mirror telescope prototype for the Cherenkov Telescope Array (CTA) observatory. The primary mirror panels of the telescope prototype are free-form concave mirrors with few microns accuracy required on the shape error. The developed technique is based on the synergy between a Ronchi-like optical test performed on the reflecting surface and the image, obtained by means of the TraceIT ray-tracing proprietary code, a perfect optics should generate in the same configuration. This deflectometry test allows the reconstruction of the slope error map that the TraceIT code can process to evaluate the measured mirror optical performance at the telescope focus. The advantages of the proposed method is that it substitutes the use of 3D coordinates measuring machine reducing production time and costs and offering the possibility to evaluate on-site the mirror image quality at the focus. In this paper we report the measuring concept and compare the obtained results to the similar ones obtained processing the shape error acquired by means of a 3D coordinates measuring machine.

  16. Ultrathin optical panel and a method of making an ultrathin optical panel

    DOEpatents

    Biscardi, Cyrus; Brewster, Calvin; DeSanto, Leonard; Veligdan, James T.

    2001-10-09

    An ultrathin optical panel, and a method of producing an ultrathin optical panel, are disclosed, including stacking a plurality of glass sheets, which sheets may be coated with a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler. The light generator is preferably placed parallel to and proximate with the inlet face, thereby allowing for a reduction in the depth of the housing.

  17. Ultrathin Optical Panel And A Method Of Making An Ultrathin Optical Panel.

    DOEpatents

    Biscardi, Cyrus; Brewster, Calvin; DeSanto, Leonard; Veligdan, James T.

    2005-02-15

    An ultrathin optical panel, and a method of producing an ultrathin optical panel, are disclosed, including stacking a plurality of glass sheets, which sheets may be coated with a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler. The light generator is preferably placed parallel to and proximate with the inlet face, thereby allowing for a reduction in the depth of the housing.

  18. Ultrathin optical panel and a method of making an ultrathin optical panel

    DOEpatents

    Biscardi, Cyrus; Brewster, Calvin; DeSanto, Leonard; Veligdan, James T.

    2003-02-11

    An ultrathin optical panel, and a method of producing an ultrathin optical panel, are disclosed, including stacking a plurality of glass sheets, which sheets may be coated with a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler. The light generator is preferably placed parallel to and proximate with the inlet face, thereby allowing for a reduction in the depth of the housing.

  19. Ultrathin optical panel and a method of making an ultrathin optical panel

    DOEpatents

    Biscardi, Cyrus; Brewster, Calvin; DeSanto, Leonard; Veligdan, James T.

    2002-01-01

    An ultrathin optical panel, and a method of producing an ultrathin optical panel, are disclosed, including stacking a plurality of glass sheets, which sheets may be coated With a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler. The light generator is preferably placed parallel to and proximate with the inlet face, thereby allowing for a reduction in the depth of the housing.

  20. Ultrathin Optical Panel And A Method Of Making An Ultrathin Optical Panel.

    DOEpatents

    Biscardi, Cyrus; Brewster, Calvin; DeSanto, Leonard; Veligdan, James T.

    2005-05-17

    An ultrathin optical panel, and a method of producing an ultrathin optical panel, are disclosed, including stacking a plurality of glass sheets, which sheets may be coated with a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler. The light generator is preferably placed parallel to and proximate with the inlet face, thereby allowing for a reduction in the depth of the housing.

  1. Emerging optical methods for surveillance of Barrett’s oesophagus

    PubMed Central

    Sturm, Matthew B; Wang, Thomas D

    2016-01-01

    The rapid rise in incidence of oesophageal adenocarcinoma has motivated the need for improved methods for surveillance of Barrett’s oesophagus. Early neoplasia is flat in morphology and patchy in distribution and is difficult to detect with conventional white light endoscopy (WLE). Light offers numerous advantages for rapidly visualising the oesophagus, and advanced optical methods are being developed for wide-field and cross-sectional imaging to guide tissue biopsy and stage early neoplasia, respectively. We review key features of these promising methods and address their potential to improve detection of Barrett’s neoplasia. The clinical performance of key advanced imaging technologies is reviewed, including (1) wide-field methods, such as high-definition WLE, chromoendoscopy, narrow-band imaging, autofluorescence and trimodal imaging and (2) cross-sectional techniques, such as optical coherence tomography, optical frequency domain imaging and confocal laser endomicroscopy. Some of these instruments are being adapted for molecular imaging to detect specific biological targets that are overexpressed in Barrett’s neoplasia. Gene expression profiles are being used to identify early targets that appear before morphological changes can be visualised with white light. These targets are detected in vivo using exogenous probes, such as lectins, peptides, antibodies, affibodies and activatable enzymes that are labelled with fluorescence dyes to produce high contrast images. This emerging approach has potential to provide a ‘red flag’ to identify regions of premalignant mucosa, outline disease margins and guide therapy based on the underlying molecular mechanisms of cancer progression. PMID:25975605

  2. Underwater Optical Wireless Channel Modeling Using Monte-Carlo Method

    NASA Astrophysics Data System (ADS)

    Saini, P. Sri; Prince, Shanthi

    2011-10-01

    At present, there is a lot of interest in the functioning of the marine environment. Unmanned or Autonomous Underwater Vehicles (UUVs or AUVs) are used in the exploration of the underwater resources, pollution monitoring, disaster prevention etc. Underwater, where radio waves do not propagate, acoustic communication is being used. But, underwater communication is moving towards Optical Communication which has higher bandwidth when compared to Acoustic Communication but has shorter range comparatively. Underwater Optical Wireless Communication (OWC) is mainly affected by the absorption and scattering of the optical signal. In coastal waters, both inherent and apparent optical properties (IOPs and AOPs) are influenced by a wide array of physical, biological and chemical processes leading to optical variability. The scattering effect has two effects: the attenuation of the signal and the Inter-Symbol Interference (ISI) of the signal. However, the Inter-Symbol Interference is ignored in the present paper. Therefore, in order to have an efficient underwater OWC link it is necessary to model the channel efficiently. In this paper, the underwater optical channel is modeled using Monte-Carlo method. The Monte Carlo approach provides the most general and most flexible technique for numerically solving the equations of Radiative transfer. The attenuation co-efficient of the light signal is studied as a function of the absorption (a) and scattering (b) coefficients. It has been observed that for pure sea water and for less chlorophyll conditions blue wavelength is less absorbed whereas for chlorophyll rich environment red wavelength signal is absorbed less comparative to blue and green wavelength.

  3. Three optical methods for remotely measuring aerosol size distributions.

    NASA Technical Reports Server (NTRS)

    Reagan, J. A.; Herman, B. M.

    1971-01-01

    Three optical probing methods for remotely measuring atmospheric aerosol size distributions are discussed and contrasted. The particular detection methods which are considered make use of monostatic lidar (laser radar), bistatic lidar, and solar radiometer sensing techniques. The theory of each of these measurement techniques is discussed briefly, and the necessary constraints which must be applied to obtain aerosol size distribution information from such measurements are pointed out. Theoretical and/or experimental results are also presented which demonstrate the utility of the three proposed probing methods.

  4. Expected Energy Method for Electro-Optical SNR Calculations.

    DTIC Science & Technology

    1984-02-02

    r’AD-Ri39 984 EXPECTED ENERGY METHOD FOR ELECTPO-OPTICRL SNR i/i CALCULRTIONS(U) MASSRCHUSETTS INST OF TECH LEXINGTON LINCOLN LAB G J MAYER 82 FEB 84...ENERGY METHOD FOR ELECTRO-OPTICAL SNR CALCULATIONS * Ci. MA YER Group 9 TECHNICAL REPORT 634 2 FEBRUARY 1984 Approved for public release; distribution...analysis of image and sensor element configuration. This method allows the optimal pixel size to be selected to maximize the expected SNR for any point

  5. Methods to assess sensitivity of optical coherence tomography systems

    PubMed Central

    Agrawal, Anant; Pfefer, T. Joshua; Woolliams, Peter D.; Tomlins, Peter H.; Nehmetallah, George

    2017-01-01

    Measuring the sensitivity of an optical coherence tomography (OCT) system determines the minimum sample reflectivity it can detect and provides a figure of merit for system optimization and comparison. The published literature lacks a detailed description of OCT sensitivity measurement procedures. Here we describe a commonly-used measurement method and introduce two new phantom-based methods, which also offer a means to directly visualize low reflectivity conditions relevant to biological tissue. We provide quantitative results for the three methods from different OCT system configurations and discuss the methods’ advantages and disadvantages. PMID:28270992

  6. Beam propagation method analysis of optical waveguide lenses.

    PubMed

    Ishikawa, A; Izutsu, M; Sueta, T

    1990-12-01

    Focusing characteristics of optical waveguide lenses are analyzed by the beam propagation method (BPM) instead of the ray tracing method. By use of the BPM, we can observe field distributions of a converging or diverging light beam after it passes through a waveguide lens. Variations of the spot width and magnitude of diffraction can immediately be evaluated with this calculation. The BPM calculations are used for a mode-index, Luneburg, and geodesic lenses. For the application of the method to the geodesic lens, the surface deformation is converted into an equivalent index.

  7. New Optical Methods for Liveness Detection on Fingers

    PubMed Central

    Dolezel, Michal; Vana, Jan; Brezinova, Eva; Yim, Jaegeol; Shim, Kyubark

    2013-01-01

    This paper is devoted to new optical methods, which are supposed to be used for liveness detection on fingers. First we describe the basics about fake finger use in fingerprint recognition process and the possibilities of liveness detection. Then we continue with introducing three new liveness detection methods, which we developed and tested in the scope of our research activities—the first one is based on measurement of the pulse, the second one on variations of optical characteristics caused by pressure change, and the last one is based on reaction of skin to illumination with different wavelengths. The last part deals with the influence of skin diseases on fingerprint recognition, especially on liveness detection. PMID:24151584

  8. Method for polishing the end of an optical fiber

    NASA Technical Reports Server (NTRS)

    Dholakia, Anil R. (Inventor)

    1988-01-01

    A method of polishing a roof-shaped, or bevelled, tip having a predetermined angle on the end of an optical fiber is disclosed. The method comprises placing an optical fiber in contact with an abrasive tape at an angle corresponding to the desired predetermined angle. The fiber is moved towards the tape beyond the point of contact so as to cause a bend in the fiber. Upon moving the abrasive tape, the compliance of the fiber, by virtue of the bend, provides a pressure of the fiber against the tape to enable polishing to occur. As polishing continues the pressure decreases until enough material is removed so as to eliminate the bend and impart the predetermined angle to the fiber tip. The fiber may be rotated to polish the other side in a similar manner, if so desired.

  9. Fast calculation method of complex space targets' optical cross section.

    PubMed

    Han, Yi; Sun, Huayan; Li, Yingchun; Guo, Huichao

    2013-06-10

    This paper utilizes the optical cross section (OCS) to characterize the optical scattering characteristics of a space target under the conditions of Sun lighting. We derive the mathematical expression of OCS according to the radiometric theory, and put forward a fast visualization calculation method of complex space targets' OCS based on an OpenGL and 3D model. Through the OCS simulation of Lambert bodies (cylinder and sphere), the computational accuracy and speed of the algorithm were verified. By using this method, the relative error for OCS will not exceed 0.1%, and it only takes 0.05 s to complete a complex calculation. Additionally, we calculated the OCS of three actual satellites with bidirectional reflectance distribution function model parameters in visible bands, and results indicate that it is easy to distinguish the three targets by comparing their OCS curves. This work is helpful for the identification and classification of unresolved space target based on photometric characteristics.

  10. New compensation method for bulk optical sensors with multiple birefringences.

    PubMed

    Lee, K S

    1989-06-01

    The dielectric tensor of an anisotropic crystal with multiple perturbations is presented to include the effects of multiple perturbations. To study electromagnetic wave propagation in anisotropic crystals subject to various influences the perturbed dielectric tensor is substituted into Maxwell's equation. Then, a 2 x 2 transmission matrix formalism, based on a normal-mode approach, is extended to anisotropic crystals possessing multiple birefringences to develop compensation schemes for ac optical sensors employing the crystal. It is shown that a new compensation method utilizing two analyzers can eliminate the effects of both unwanted linear birefringences and unwanted circular birefringences on the stability of the ac bulk polarimetric optical sensor. The conditions (here referred to as the quenching condition) in which the compensation method becomes important are also derived for both the voltage (or electric field) and current (or magnetic field) sensors.

  11. Anisotropy minimization via least squares method for transformation optics.

    PubMed

    Junqueira, Mateus A F C; Gabrielli, Lucas H; Spadoti, Danilo H

    2014-07-28

    In this work the least squares method is used to reduce anisotropy in transformation optics technique. To apply the least squares method a power series is added on the coordinate transformation functions. The series coefficients were calculated to reduce the deviations in Cauchy-Riemann equations, which, when satisfied, result in both conformal transformations and isotropic media. We also present a mathematical treatment for the special case of transformation optics to design waveguides. To demonstrate the proposed technique a waveguide with a 30° of bend and with a 50% of increase in its output width was designed. The results show that our technique is simultaneously straightforward to be implement and effective in reducing the anisotropy of the transformation for an extremely low value close to zero.

  12. Testing of flat optical surfaces by the quantitative Foucault method.

    PubMed

    Simon, M C; Simon, J M

    1978-01-01

    The complete theory of measurement of optical flat mirrors of circular or elliptical shape using the quantitative Foucault method is described here. It has been used in Córdoba since 1939 in a partially intuitive but correct form. The surface, not yet flat and, at times, astigmatic, is assimilated to the sum of a spherical plus a cylindrical dome. The errors of the three possible ways of reckoning are calculated.

  13. Optical methods for the detection of heavy metal ions

    NASA Astrophysics Data System (ADS)

    Uglov, A. N.; Bessmertnykh-Lemeune, A.; Guilard, R.; Averin, A. D.; Beletskaya, I. P.

    2014-03-01

    The review covers an important area of the modern chemistry, namely, the detection of heavy metal ions using optical molecular detectors. The role of this method in metal ion detection and the physicochemical grounds of operation of chemosensors are discussed, and examples of detection of most abundant heavy metal ions and synthetic approaches to molecular detectors are presented. The immobilization of molecular detectors on solid substrates for the design of analytical sensor devices is described. The bibliography includes 178 references.

  14. Transformation-optics simulation method for stimulated Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Zecca, Roberto; Bowen, Patrick T.; Smith, David R.; Larouche, Stéphane

    2016-12-01

    We develop an approach to enable the full-wave simulation of stimulated Brillouin scattering and related phenomena in a frequency-domain, finite-element environment. The method uses transformation-optics techniques to implement a time-harmonic coordinate transform that reconciles the different frames of reference used by electromagnetic and mechanical finite-element solvers. We show how this strategy can be successfully applied to bulk and guided systems, comparing the results with the predictions of established theory.

  15. Optical Sensors and Methods for Underwater 3D Reconstruction

    PubMed Central

    Massot-Campos, Miquel; Oliver-Codina, Gabriel

    2015-01-01

    This paper presents a survey on optical sensors and methods for 3D reconstruction in underwater environments. The techniques to obtain range data have been listed and explained, together with the different sensor hardware that makes them possible. The literature has been reviewed, and a classification has been proposed for the existing solutions. New developments, commercial solutions and previous reviews in this topic have also been gathered and considered. PMID:26694389

  16. An image reconstruction method (IRBis) for optical/infrared interferometry

    NASA Astrophysics Data System (ADS)

    Hofmann, K.-H.; Weigelt, G.; Schertl, D.

    2014-05-01

    Aims: We present an image reconstruction method for optical/infrared long-baseline interferometry called IRBis (image reconstruction software using the bispectrum). We describe the theory and present applications to computer-simulated interferograms. Methods: The IRBis method can reconstruct an image from measured visibilities and closure phases. The applied optimization routine ASA_CG is based on conjugate gradients. The method allows the user to implement different regularizers, apply residual ratios as an additional metric for goodness-of-fit, and use previous iteration results as a prior to force convergence. Results: We present the theory of the IRBis method and several applications of the method to computer-simulated interferograms. The image reconstruction results show the dependence of the reconstructed image on the noise in the interferograms (e.g., for ten electron read-out noise and 139 to 1219 detected photons per interferogram), the regularization method, the angular resolution, and the reconstruction parameters applied. Furthermore, we present the IRBis reconstructions submitted to the interferometric imaging beauty contest 2012 initiated by the IAU Working Group on Optical/IR Interferometry and describe the performed data processing steps.

  17. Image Retrieval Method for Multiscale Objects from Optical Colonoscopy Images

    PubMed Central

    Sakanashi, Hidenori; Takahashi, Eiichi; Murakawa, Masahiro; Aoki, Hiroshi; Takeuchi, Ken; Suzuki, Yasuo

    2017-01-01

    Optical colonoscopy is the most common approach to diagnosing bowel diseases through direct colon and rectum inspections. Periodic optical colonoscopy examinations are particularly important for detecting cancers at early stages while still treatable. However, diagnostic accuracy is highly dependent on both the experience and knowledge of the medical doctor. Moreover, it is extremely difficult, even for specialist doctors, to detect the early stages of cancer when obscured by inflammations of the colonic mucosa due to intractable inflammatory bowel diseases, such as ulcerative colitis. Thus, to assist the UC diagnosis, it is necessary to develop a new technology that can retrieve similar cases of diagnostic target image from cases in the past that stored the diagnosed images with various symptoms of colonic mucosa. In order to assist diagnoses with optical colonoscopy, this paper proposes a retrieval method for colonoscopy images that can cope with multiscale objects. The proposed method can retrieve similar colonoscopy images despite varying visible sizes of the target objects. Through three experiments conducted with real clinical colonoscopy images, we demonstrate that the method is able to retrieve objects of any visible size and any location at a high level of accuracy. PMID:28255295

  18. Fourier transform methods applied to an optical heterodyne profilometer

    NASA Astrophysics Data System (ADS)

    Beltrán-González, A.; García-Torales, G.; Martínez-Ponce, G.

    2013-11-01

    In this work, theory and experiment describe the performance of a surface profile measurement device based on optical heterodyne interferometry are presented. The object and reference beams propagating through the interferometer are obtained by single-pass through an acousto-optic modulator. The diffraction orders 0 and the Doppler-shifted +1 (object and reference beams, respectively) are manipulated to propagate collinearly towards the interferometer output where a fast photodetector is placed to collect the irradiance. The modulated optical signal is Fourier transformed using a data acquisition card and RF communications software. The peak centered at the acousto-optic frequency in the power spectrum is filtered and averaged. The irregularities on the surface of the reflective sample are proportional to the height of this peak. The profile of a reflective blazed grating has been sketched by translating laterally the sample using a nanopositioning system. Experimental results are compared to the measurement done with a scanning electron microscope. There has been found a good agreement between both methods.

  19. Alignment method of off-axis RC reflective optical system

    NASA Astrophysics Data System (ADS)

    Xue-min, Zhang; Xing, Song; Zhi-jun, Zhang; Hou, Xiao-hua

    2016-10-01

    Off-axis optical system has a wide application in space optics and remote detective area. The high surface shape accuracy can be ensured with the development of advanced manufacture technique. So the only condition which limits the wide application of off-axis optical system is how to realize the precise alignment of it. Based on a RC reflective optical system whose diameter is 400mm, the alignment method which combines the high resolution initial placement and computer-aided alignment is introduced. By designing a system which can measure the off-axis fabrication and off-axis angle precisely, the high resolution initial placement of off-axis mirror can be ensured with a measurement accuracy of +/-0.05mm and +/-10". The good initial placement can give a good initial state, so the computer-aided model can be converged well. The experiment shows that a system which has a good initial placement could have a good wave aberration of 0.04λ after three times iteration adjustment.

  20. Neurophotonics: optical methods to study and control the brain

    NASA Astrophysics Data System (ADS)

    Doronina-Amitonova, L. V.; Fedotov, I. V.; Fedotov, A. B.; Anokhin, K. V.; Zheltikov, A. M.

    2015-04-01

    Methods of optical physics offer unique opportunities for the investigation of brain and higher nervous activity. The integration of cutting-edge laser technologies and advanced neurobiology opens a new cross-disciplinary area of natural sciences - neurophotonics - focusing on the development of a vast arsenal of tools for functional brain diagnostics, stimulation of individual neurons and neural networks, and the molecular engineering of brain cells aimed at the diagnosis and therapy of neurodegenerative and psychic diseases. Optical fibers help to confront the most challenging problems in brain research, including the analysis of molecular-cellular mechanisms of the formation of memory and behavior. New generation optical fibers provide new solutions for the development of fundamentally new, unique tools for neurophotonics and laser neuroengineering - fiber-optic neuroendoscopes and neurointerfaces. These instruments broaden research horizons when investigating the most complex brain functions, enabling a long-term multiplex detection of fluorescent protein markers, as well as photostimulation of neuronal activity in deep brain areas in living, freely moving animals with an unprecedented spatial resolution and minimal invasiveness. This emerging technology opens new horizons for understanding learning and long-term memory through experiments with living, freely moving mammals. Here, we present a brief review of this rapidly growing field of research.

  1. Residual Stress Analysis Based on Acoustic and Optical Methods

    PubMed Central

    Yoshida, Sanichiro; Sasaki, Tomohiro; Usui, Masaru; Sakamoto, Shuichi; Gurney, David; Park, Ik-Keun

    2016-01-01

    Co-application of acoustoelasticity and optical interferometry to residual stress analysis is discussed. The underlying idea is to combine the advantages of both methods. Acoustoelasticity is capable of evaluating a residual stress absolutely but it is a single point measurement. Optical interferometry is able to measure deformation yielding two-dimensional, full-field data, but it is not suitable for absolute evaluation of residual stresses. By theoretically relating the deformation data to residual stresses, and calibrating it with absolute residual stress evaluated at a reference point, it is possible to measure residual stresses quantitatively, nondestructively and two-dimensionally. The feasibility of the idea has been tested with a butt-jointed dissimilar plate specimen. A steel plate 18.5 mm wide, 50 mm long and 3.37 mm thick is braze-jointed to a cemented carbide plate of the same dimension along the 18.5 mm-side. Acoustoelasticity evaluates the elastic modulus at reference points via acoustic velocity measurement. A tensile load is applied to the specimen at a constant pulling rate in a stress range substantially lower than the yield stress. Optical interferometry measures the resulting acceleration field. Based on the theory of harmonic oscillation, the acceleration field is correlated to compressive and tensile residual stresses qualitatively. The acoustic and optical results show reasonable agreement in the compressive and tensile residual stresses, indicating the feasibility of the idea. PMID:28787912

  2. Optical system and method for gas detection and monitoring

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A. (Inventor); Korman, Valentin (Inventor); Witherow, William K. (Inventor); Hendrickson, Adam Gail (Inventor); Sinko, John Elihu (Inventor)

    2011-01-01

    A free-space optical path of an optical interferometer is disposed in an environment of interest. A light beam is guided to the optical interferometer using a single-mode optical fiber. The light beam traverses the interferometer's optical path. The light beam guided to the optical path is combined with the light beam at the end of the optical path to define an output light. A temporal history of the output light is recorded.

  3. Method for the continuous processing of hermetic fiber optic components and the resultant fiber optic-to-metal components

    DOEpatents

    Kramer, Daniel P.

    1994-08-09

    Hermetic fiber optic-to-metal components and method for making hermetic fiber optic-to-metal components by assembling and fixturing elements comprising a metal shell, a glass preform, and a metal-coated fiber optic into desired relative positions and then sealing said fixtured elements preferably using a continuous heating process. The resultant hermetic fiber optic-to-metal components exhibit high hermeticity and durability despite the large differences in thermal coefficients of expansion among the various elements.

  4. Fabrication Method for LOBSTER-Eye Optics in <110> Silicon

    NASA Technical Reports Server (NTRS)

    Chervenak, James; Collier, Michael; Mateo, Jennette

    2013-01-01

    Soft x-ray optics can use narrow slots to direct x-rays into a desirable pattern on a focal plane. While square-pack, square-pore, slumped optics exist for this purpose, they are costly. Silicon (Si) is being examined as a possible low-cost replacement. A fabrication method was developed for narrow slots in <110> Si demonstrating the feasibility of stacked slot optics to replace micropores. Current micropore optics exist that have 20-micron-square pores on 26-micron pitch in glass with a depth of 1 mm and an extent of several square centimeters. Among several proposals to emulate the square pore optics are stacked slot chips with etched vertical slots. When the slots in the stack are positioned orthogonally to each other, the component will approach the soft x-ray focusing observed in the micropore optics. A specific improvement Si provides is that it can have narrower sidewalls between slots to permit greater throughput of x-rays through the optics. In general, Si can have more variation in slot geometry (width, length). Further, the sidewalls can be coated with high-Z materials to enhance reflection and potentially reduce the surface roughness of the reflecting surface. Narrow, close-packed deep slots in <110> Si have been produced using potassium hydroxide (KOH) etching and a patterned silicon nitride (SiN) mask. The achieved slot geometries have sufficient wall smoothness, as observed through scanning electron microscope (SEM) imaging, to enable evaluation of these slot plates as an optical element for soft x-rays. Etches of different angles to the crystal plane of Si were evaluated to identify a specific range of etch angles that will enable low undercut slots in the Si <110> material. These slots with the narrow sidewalls are demonstrated to several hundred microns in depth, and a technical path to 500-micron deep slots in a precision geometry of narrow, closepacked slots is feasible. Although intrinsic stress in ultrathin wall Si is observed, slots with

  5. New method for lightning location using optical ground wire

    NASA Astrophysics Data System (ADS)

    Qin, Zhaoyu; Cheng, Zhaogu; Zhang, Zhiping; Zhu, Jianqiang; Li, Feng

    2006-12-01

    A new technology of lightning location is described, which is based on detecting the state of polarization (SOP) fluctuation of the laser light in the optic ground wire (OPGW). Compared with the conventional lightning location method, the new method is more accurate, more stable, and cheaper. Theories of Stokes parameters and Poincare sphere are introduced to analyze the SOP at the lightning strike point. It can be concluded that although the initial points of SOP on the Poincare sphere are random, the SOP fluctuation generated by lightning strike can still be accurately identified by detecting the velocity of polarization motion. A new algorithm to quantify the velocity is also introduced.

  6. Calculation method of the Strehl Definition for decentral optical systems

    NASA Astrophysics Data System (ADS)

    Zhuang, Songlin; Chen, Huai'an

    1991-01-01

    A new method is proposed to calculate the Strehi Definition for optical systems lacking rotational symmetry. The Strehi Definition(S. D) is one of the commonly used criterion for evaluating the quality of an optical system especially for the microscopic objectives. It is will known that the S. D is defined as follows S. D 7-2 J1J1exp[-27riW(x y)dxdy I 2 (1) Where w(x y) is wave aberrations and (x y) is the coordinate of the pupil plane. For a high quality optical system S. D can be expressed as S. D 1 (2)2[W2(x W(x y) 2j (2) In order to calculate the S. D of the decentral optical system precisely both lateral and longitudinal defocus should be considered simultaneously. The corresponding aberration coefficients are C C01 (along y-direction) and C0 (along x-direction). Owing to the optical systems lacking relational symmetry the asymmetrical aberrations central astigmatism C21 and central coma C should be added in the wave aberration function i. e. the wave aberration for the system lacking symmetry is W(x y) C(x+ y) + C(x + y)2 + C(x + y)3 + C(x + + C02y2+ C22(x2 +y)y + C42(x+?)Y + C62(x+?)3? + Cy4 + C24(x2 + y)y4 + C + y)2y4 + C(x2 + + C41(x2 + y2)2y + C61(x2 + y)3y + Cd + C + y2)y3 +C43(x2+y2)+C01y+C1 x+Cx2+C1 (x2+?)x (3) After tedious but straightforward integral calculation equation

  7. Innovative methods to promote optics at school level

    NASA Astrophysics Data System (ADS)

    Garg, Amit; Bharadwaj, Sadashiv Raj; Kachru, Priyanka; Dutta, Subhajit Kumar; Singh, Shatakshi

    2016-09-01

    The conventional pedagogical techniques in Indian schools are predominantly limited to coursework and involve just necessary laboratory work. It lacks in inculcating the aptitude for practical applications relevant to the coursework amongst the students. This results in a major setback for the students as their mental approach remains constrained to books, where on the contrary, the future depends only on technologies and applications. Considering this, under Optics Outreach Education Program 2014, University of Delhi at Acharya Narendra Dev College SPIE Student Chapter conducted workshops in 22 schools of Delhi including various Government schools as well. The workshop zeroed into the concepts of optics and various innovative techniques developed by our Student chapter members to embark a new method of teaching.

  8. Optical center alignment technique based on inner profile measurement method

    NASA Astrophysics Data System (ADS)

    Wakayama, Toshitaka; Yoshizawa, Toru

    2014-05-01

    Center alignment is important technique to tune up the spindle of various precision machines in manufacturing industry. Conventionally such a tool as a dial indicator has been used to adjust and to position the axis by manual operations of a technical worker. However, it is not easy to precisely control its axis. In this paper, we developed the optical center alignment technique based on inner profile measurement using a ring beam device. In this case, the center position of the cylinder hole can be determined from circular profile detected by optical sectioning method using a ring beam device. In our trials, the resolution of the center position is proved less than 10 micrometers in extreme cases. This technique is available for practical applications in machine tool industry.

  9. Optical methods for hydrogen degassing monitoring in urban conditions

    NASA Astrophysics Data System (ADS)

    Timchenko, E. V.; Timchenko, P. E.; Zherdeva, L. A.; Tregub, N. V.; Selezneva, E. A.; Yakovlev, V. N.

    2015-12-01

    Results of a study of variations in optical parameters of bioindicators that grow in the regions of hydrogen degassing in Samara are presented. Raman spectroscopy and confocal fluorescence microscopy were used as the main methods of the study. Features of Raman spectra of plants that grow in zones with presence/ absence of deep hydrogen emissions have been ascertained. The main variations have been recorded at wavenumbers of 1380, 1522, 1547, and 1600 cm-1, which are responsible for stretching vibrations in lignin and β-carotene and chlorophyll a and cellulose in plant leaves. Confocal fluorescence microscopy showed an increase in the chloroplasts in leaves of plants which grow at hydrogen degassing territories. An optical coefficient was introduced, on the basis of which the Samara region was monitored.

  10. Comparison of three optical methods to study erythrocyte aggregation.

    PubMed

    Zhao, H; Wang, X; Stoltz, J F

    1999-01-01

    The aim of this work was to evaluate three optical methods designed to determine erythrocyte aggregation: Erythroaggregometer (EA; Regulest, France), Laser-assisted Optical Rotational Cell Analyzer (LORCA; Mechatronics, Netherlands) and Fully Automatic Erythrocyte Aggregometer (FAEA; Myrenne, GmbH, Germany). Blood samples were taken from fifty donors (26 males and 24 females). The aggregation of normal red blood cell (RBC) and RBCs suspended in three normo- and hyperaggregating suspending media was studied. The results revealed some significant correlations between parameters measured by these instruments, in particular, between the indexes of aggregation of EA and LORCA. Further, RBC aggregation of multiple myeloma patients was also studied and a hyper erythrocyte aggregation state was found by EA and LORCA.

  11. Structural, optical and nonlinear optical studies of AZO thin film prepared by SILAR method for electro-optic applications

    NASA Astrophysics Data System (ADS)

    Edison, D. Joseph; Nirmala, W.; Kumar, K. Deva Arun; Valanarasu, S.; Ganesh, V.; Shkir, Mohd.; AlFaify, S.

    2017-10-01

    Aluminium doped (i.e. 3 at%) zinc oxide (AZO) thin films were prepared by simple successive ionic layer adsorption and reaction (SILAR) method with different dipping cycles. The structural and surface morphology of AZO thin films were studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical parameters such as, transmittance, band gap, refractive index, extinction coefficient, dielectric constant and nonlinear optical properties of AZO films were investigated. XRD pattern revealed the formation of hexagonal phase ZnO and the intensity of the film was found to increase with increasing dipping cycle. The crystallite size was found to be in the range of 29-37 nm. Scanning Electron Microscope (SEM) images show the presence of small sized grains, revealing that the smoothest surface was obtained at all the films. The EDAX spectrum of AZO conforms the presence of Zn, O and Al. The optical transmittance in the visible region is high 87% and the band gap value is 3.23 eV. The optical transmittance is decreased with respect to dipping cycles. The room temperature PL studies revealed that the AZO films prepared at (30 cycles) has good film quality with lesser defect density. The third order nonlinear optical parameters were also studied using Z-scan technique to know the applications of deposited films in nonlinear devices. The third order nonlinear susceptibility value is found to be 1.69 × 10-7, 3.34 × 10-8, 1.33 × 10-7and 2.52 × 10-7 for AZO films deposited after 15, 20, 25 and 30 dipping cycles.

  12. Sparse identification for nonlinear optical communication systems: SINO method.

    PubMed

    Sorokina, Mariia; Sygletos, Stylianos; Turitsyn, Sergei

    2016-12-26

    We introduce low complexity machine learning method method (based on lasso regression, which promotes sparsity, to identify the interaction between symbols in different time slots and to select the minimum number relevant perturbation terms that are employed) for nonlinearity mitigation. The immense intricacy of the problem calls for the development of "smart" methodology, simplifying the analysis without losing the key features that are important for recovery of transmitted data. The proposed sparse identification method for optical systems (SINO) allows to determine the minimal (optimal) number of degrees of freedom required for adaptive mitigation of detrimental nonlinear effects. We demonstrate successful application of the SINO method both for standard fiber communication links (over 3 dB gain) and for few-mode spatial-division-multiplexing systems.

  13. Method and apparatus of highly linear optical modulation

    DOEpatents

    DeRose, Christopher; Watts, Michael R.

    2016-05-03

    In a new optical intensity modulator, a nonlinear change in refractive index is used to balance the nonlinearities in the optical transfer function in a way that leads to highly linear optical intensity modulation.

  14. Application of optical non-invasive methods in skin physiology

    NASA Astrophysics Data System (ADS)

    Lademann, J.; Patzelt, A.; Darvin, M.; Richter, H.; Antoniou, C.; Sterry, W.; Koch, S.

    2008-05-01

    In the present paper the application of optical non-invasive methods in dermatology and cosmetology is discussed. Laser scanning microscopy (LSM) and optical coherent tomography (OCT) are the most promising methods for this application. Using these methods, the analysis of different skin parameters like dryness and oiliness of the skin, the barrier function and the structure of furrows and wrinkles are discussed. Additionally the homogeneity of distribution of topically applied creams, as well as their penetration into the skin were investigated. It is shown that these methods are highly valuable in dermatology for diagnostic and therapy control and for basic research, for instance in the field of structure analysis of hair follicles and sweat glands. The vertical images of the tissue produced by OCT can be easily compared with histological sections. Unfortunately, the resolution of the OCT technique is not high enough to carry out measurements on a cellular level, as is possible by LSM. LSM has the advantage that it can be used for the investigation of penetration and storage processes of topically applied substances, if these substances have fluorescent properties or if they are fluorescent-labelled.

  15. Test methods for optical disk media characteristics (for 356 mm ruggedized magneto-optic media)

    NASA Technical Reports Server (NTRS)

    Podio, Fernando L.

    1991-01-01

    Standard test methods for computer storage media characteristics are essential and allow for conformance to media interchange standards. The test methods were developed for 356 mm two-sided laminated glass substrate with a magneto-optic active layer media technology. These test methods may be used for testing other media types, but in each case their applicability must be evaluated. Test methods are included for a series of different media characteristics, including operational, nonoperational, and storage environments; mechanical and physical characteristics; and substrate, recording layer, and preformat characteristics. Tests for environmental qualification and media lifetimes are also included. The best methods include testing conditions, testing procedures, a description of the testing setup, and the required calibration procedures.

  16. Optical methods for determining the shock Hugoniot of Solids

    NASA Astrophysics Data System (ADS)

    Svingala, Forrest; Hargather, Michael; Settles, Gary

    2013-06-01

    Traditionally, the shock Hugoniot is measured on a point-bypoint basis by a series of high-velocity impact experiments. Observations are typically confined to pointwise pressure or velocity measurements at the free-surfaces of the sample. In this work, shock waves are initiated in transparent polyurethane and opaque polyurea samples using exploding bridgewires, aluminum ballistic projectiles, and gram-scale explosive charges. Shock waves and material motion are observed optically by shadowgraphy using a high-speed-digital camera recording at up to 106 frames/s. Ballistic impact, producing a constant-strength shock wave, is combined with these optical techniques to obtain a single shock Hugoniot point per test. A gram-scale explosive charge produces a shock wave in the material sample that is initially strong, but attenuates as it transits the polymer sample. With optical access to the entire sample, multiple shock and particle velocity combinations may be observed in a single test, allowing the measurement of a shock Hugoniot curve in fewer experiments than by traditional methods. These techniques produce data in general agreement with an extrapolation of published Hugoniot data for polyurethane and polyurea. Work funded by the Office of Naval Research.

  17. Method for optical coherence elastography of the cornea

    PubMed Central

    Ford, Matthew R.; Dupps, William J.; Rollins, Andrew M.; Roy, Abhijit Sinha; Hu, Zhilin

    2011-01-01

    The material properties of the cornea are important determinants of corneal shape and refractive power. Corneal ectatic diseases, such as keratoconus, are characterized by material property abnormalities, are associated with progressive thinning and distortion of the cornea, and represent a leading indication for corneal transplantation. We describe a corneal elastography technique based on optical coherence tomography (OCT) imaging, in which displacement of intracorneal optical features is tracked with a 2-D cross-correlation algorithm as a step toward nondestructive estimation of local and directional corneal material properties. Phantom experiments are performed to measure the effects of image noise and out-of-plane displacement on effectiveness of displacement tracking and demonstrated accuracy within the tolerance of a micromechanical translation stage. Tissue experiments demonstrate the ability to produce 2-D maps of heterogeneous intracorneal displacement with OCT. The ability of a nondestructive optical method to assess tissue under in situ mechanical conditions with physiologic-range stress levels provides a framework for in vivo quantification of 3-D corneal elastic and viscoelastic resistance, including analogs of shear deformation and Poisson’s ratio that may be relevant in the early diagnosis of corneal ectatic disease. PMID:21280911

  18. Method for optical coherence elastography of the cornea

    NASA Astrophysics Data System (ADS)

    Ford, Matthew R.; Dupps, William J.; Rollins, Andrew M.; Roy, Abhijit Sinha; Hu, Zhilin

    2011-01-01

    The material properties of the cornea are important determinants of corneal shape and refractive power. Corneal ectatic diseases, such as keratoconus, are characterized by material property abnormalities, are associated with progressive thinning and distortion of the cornea, and represent a leading indication for corneal transplantation. We describe a corneal elastography technique based on optical coherence tomography (OCT) imaging, in which displacement of intracorneal optical features is tracked with a 2-D cross-correlation algorithm as a step toward nondestructive estimation of local and directional corneal material properties. Phantom experiments are performed to measure the effects of image noise and out-of-plane displacement on effectiveness of displacement tracking and demonstrated accuracy within the tolerance of a micromechanical translation stage. Tissue experiments demonstrate the ability to produce 2-D maps of heterogeneous intracorneal displacement with OCT. The ability of a nondestructive optical method to assess tissue under in situ mechanical conditions with physiologic-range stress levels provides a framework for in vivo quantification of 3-D corneal elastic and viscoelastic resistance, including analogs of shear deformation and Poisson's ratio that may be relevant in the early diagnosis of corneal ectatic disease.

  19. Optic disc segmentation: level set methods and blood vessels inpainting

    NASA Astrophysics Data System (ADS)

    Almazroa, A.; Sun, Weiwei; Alodhayb, Sami; Raahemifar, Kaamran; Lakshminarayanan, Vasudevan

    2017-03-01

    Segmenting the optic disc (OD) is an important and essential step in creating a frame of reference for diagnosing optic nerve head (ONH) pathology such as glaucoma. Therefore, a reliable OD segmentation technique is necessary for automatic screening of ONH abnormalities. The main contribution of this paper is in presenting a novel OD segmentation algorithm based on applying a level set method on a localized OD image. To prevent the blood vessels from interfering with the level set process, an inpainting technique is applied. The algorithm is evaluated using a new retinal fundus image dataset called RIGA (Retinal Images for Glaucoma Analysis). In the case of low quality images, a double level set is applied in which the first level set is considered to be a localization for the OD. Five hundred and fifty images are used to test the algorithm accuracy as well as its agreement with manual markings by six ophthalmologists. The accuracy of the algorithm in marking the optic disc area and centroid is 83.9%, and the best agreement is observed between the results of the algorithm and manual markings in 379 images.

  20. New optical method for noninvasive blood glucose measurement by optical ultrasonic modulation

    NASA Astrophysics Data System (ADS)

    Zhu, Lili; Lin, Jieqing; Xie, Wenming; Li, Hui

    2010-11-01

    A new optical technique for continuous, noninvasive monitoring of blood glucose levels based on ultrasonic modulation of scattering light is proposed. The ultrasound-modulated scattered light has an accurate separation of scattering and absorption changes in tissue. And the optical scattering and absorbing coefficient of tissue depend on the concentration of glucose in the extracellular fluid. As the glucose induced to scattering and absorption changes, the ultrasoundmodulated light also changes. In this paper, a correlation is observed between ultrasound-modulated light intensity as well as its modulation depth and blood glucose concentration in phantom experiments. In addition, some researches about ultrasound-modulated signal affected by the temperature of glucose aqueous solution are done. Preliminary experiments find that this method is a promising noninvasive blood glucose measurement.

  1. Experimental methods of molecular matter-wave optics.

    PubMed

    Juffmann, Thomas; Ulbricht, Hendrik; Arndt, Markus

    2013-08-01

    We describe the state of the art in preparing, manipulating and detecting coherent molecular matter. We focus on experimental methods for handling the quantum motion of compound systems from diatomic molecules to clusters or biomolecules.Molecular quantum optics offers many challenges and innovative prospects: already the combination of two atoms into one molecule takes several well-established methods from atomic physics, such as for instance laser cooling, to their limits. The enormous internal complexity that arises when hundreds or thousands of atoms are bound in a single organic molecule, cluster or nanocrystal provides a richness that can only be tackled by combining methods from atomic physics, chemistry, cluster physics, nanotechnology and the life sciences.We review various molecular beam sources and their suitability for matter-wave experiments. We discuss numerous molecular detection schemes and give an overview over diffraction and interference experiments that have already been performed with molecules or clusters.Applications of de Broglie studies with composite systems range from fundamental tests of physics up to quantum-enhanced metrology in physical chemistry, biophysics and the surface sciences.Nanoparticle quantum optics is a growing field, which will intrigue researchers still for many years to come. This review can, therefore, only be a snapshot of a very dynamical process.

  2. Experimental methods of molecular matter-wave optics

    NASA Astrophysics Data System (ADS)

    Juffmann, Thomas; Ulbricht, Hendrik; Arndt, Markus

    2013-08-01

    We describe the state of the art in preparing, manipulating and detecting coherent molecular matter. We focus on experimental methods for handling the quantum motion of compound systems from diatomic molecules to clusters or biomolecules. Molecular quantum optics offers many challenges and innovative prospects: already the combination of two atoms into one molecule takes several well-established methods from atomic physics, such as for instance laser cooling, to their limits. The enormous internal complexity that arises when hundreds or thousands of atoms are bound in a single organic molecule, cluster or nanocrystal provides a richness that can only be tackled by combining methods from atomic physics, chemistry, cluster physics, nanotechnology and the life sciences. We review various molecular beam sources and their suitability for matter-wave experiments. We discuss numerous molecular detection schemes and give an overview over diffraction and interference experiments that have already been performed with molecules or clusters. Applications of de Broglie studies with composite systems range from fundamental tests of physics up to quantum-enhanced metrology in physical chemistry, biophysics and the surface sciences. Nanoparticle quantum optics is a growing field, which will intrigue researchers still for many years to come. This review can, therefore, only be a snapshot of a very dynamical process.

  3. Fiber optic liquid mass flow sensor and method

    NASA Technical Reports Server (NTRS)

    Korman, Valentin (Inventor); Gregory, Don Allen (Inventor); Wiley, John T. (Inventor); Pedersen, Kevin W. (Inventor)

    2010-01-01

    A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.

  4. Optical model methods of predicting nuclide production from spallation reactions.

    PubMed

    Ramsey, C R; Townsend, L W; Tripathi, R K; Cucinotta, F A

    1998-02-01

    Quantum mechanical optical model methods for calculating isotope production cross sections from the spallation of heavy nuclei by high-energy protons are developed from a modified abrasion-ablation collision formalism. The abrasion step is treated quantum-mechanically as a knockout process which leaves the residual prefragment nucleus in an excited state. In ablation the prefragment deexcites to produce the final fragment. The excitation energies of the prefragments are estimated from a combination of liquid drop and frictional-spectator interaction considerations. Estimates of elemental and isotopic production cross sections are in good agreement with recently published cross section measurements.

  5. Method for quick thermal tolerancing of optical systems

    NASA Astrophysics Data System (ADS)

    Werschnik, J.; Uhlendorf, K.

    2016-09-01

    Optical systems for lithography (projection lens), inspection (micro-objectives) or laser material processing usually have tight specifications regarding focus and wave-front stability. The same is true regarding the field dependent properties. Especially projection lenses have tight specifications on field curvature, magnification and distortion. Unwanted heating either from internal or external sources lead to undesired changes of the above properties. In this work we show an elegant and fast method to analyze the thermal sensitivity using ZEMAX. The key point of this method is using the thermal changes of the lens data from the multi-configuration editor as starting point for a (standard) tolerance analysis. Knowing the sensitivity we can either define requirements on the environment or use it to systematically improve the thermal behavior of the lens. We demonstrate this method for a typical projection lens for which we optimized the thermal field curvature to a minimum.

  6. Diffuse optical methods for assessing breast cancer chemotherapy

    NASA Astrophysics Data System (ADS)

    Tromberg, Bruce J.

    2014-03-01

    In his talk, "Diffuse Optical Methods for Assessing Breast Cancer Chemotherapy," SPIE Fellow Bruce Tromberg (Beckman Laser Institute and Medical Clinic) describes a method combining frequency domain photon migration, essentially a method of tracking photon motion in tissue, with a NIR spectroscopy technique using 850nm LEDs. The result is a scatter corrected absorption spectra. The technique takes advantage of elevated blood and water levels and decreased lipid levels in the presence of tumors to provide a more accurate mapping of the breast, allowing more effective treatment. Tromberg's team recently completed their first full mapping of the breast and have taken the instrument from a standalone unit to a portable one suitable for travel. In addition to providing feedback to enhance breast cancer treatment, Tromberg expects that this technique will be applicable in treating other forms of cancer as well.

  7. Recurrent methods of the minimization of optical multilayer structures for fiber-optic communication facilities

    NASA Astrophysics Data System (ADS)

    Bagmanov, Valeriy H.; Kostrov, Sergey V.; Sultanov, Albert H.

    2008-12-01

    Optical multilayer selective mirror (OMSM) are widely used in different applications of fiber optic telecommunications. In this paper we represent the solution for synthesis of OMSM for constructing wavelength division multiplexing (WDM) optical filter used in add/drop multiplexers.

  8. Fast integral methods for integrated optical systems simulations: a review

    NASA Astrophysics Data System (ADS)

    Kleemann, Bernd H.

    2015-09-01

    Boundary integral equation methods (BIM) or simply integral methods (IM) in the context of optical design and simulation are rigorous electromagnetic methods solving Helmholtz or Maxwell equations on the boundary (surface or interface of the structures between two materials) for scattering or/and diffraction purposes. This work is mainly restricted to integral methods for diffracting structures such as gratings, kinoforms, diffractive optical elements (DOEs), micro Fresnel lenses, computer generated holograms (CGHs), holographic or digital phase holograms, periodic lithographic structures, and the like. In most cases all of the mentioned structures have dimensions of thousands of wavelengths in diameter. Therefore, the basic methods necessary for the numerical treatment are locally applied electromagnetic grating diffraction algorithms. Interestingly, integral methods belong to the first electromagnetic methods investigated for grating diffraction. The development started in the mid 1960ies for gratings with infinite conductivity and it was mainly due to the good convergence of the integral methods especially for TM polarization. The first integral equation methods (IEM) for finite conductivity were the methods by D. Maystre at Fresnel Institute in Marseille: in 1972/74 for dielectric, and metallic gratings, and later for multiprofile, and other types of gratings and for photonic crystals. Other methods such as differential and modal methods suffered from unstable behaviour and slow convergence compared to BIMs for metallic gratings in TM polarization from the beginning to the mid 1990ies. The first BIM for gratings using a parametrization of the profile was developed at Karl-Weierstrass Institute in Berlin under a contract with Carl Zeiss Jena works in 1984-1986 by A. Pomp, J. Creutziger, and the author. Due to the parametrization, this method was able to deal with any kind of surface grating from the beginning: whether profiles with edges, overhanging non

  9. Recent developments in optical detection methods for microchip separations.

    PubMed

    Götz, Sebastian; Karst, Uwe

    2007-01-01

    This paper summarizes the features and performances of optical detection systems currently applied in order to monitor separations on microchip devices. Fluorescence detection, which delivers very high sensitivity and selectivity, is still the most widely applied method of detection. Instruments utilizing laser-induced fluorescence (LIF) and lamp-based fluorescence along with recent applications of light-emitting diodes (LED) as excitation sources are also covered in this paper. Since chemiluminescence detection can be achieved using extremely simple devices which no longer require light sources and optical components for focusing and collimation, interesting approaches based on this technique are presented, too. Although UV/vis absorbance is a detection method that is commonly used in standard desktop electrophoresis and liquid chromatography instruments, it has not yet reached the same level of popularity for microchip applications. Current applications of UV/vis absorbance detection to microchip separations and innovative approaches that increase sensitivity are described. This article, which contains 85 references, focuses on developments and applications published within the last three years, points out exciting new approaches, and provides future perspectives on this field.

  10. Turbulence profiling methods applied to ESO's adaptive optics facility

    NASA Astrophysics Data System (ADS)

    Valenzuela, Javier; Béchet, Clémentine; Garcia-Rissmann, Aurea; Gonté, Frédéric; Kolb, Johann; Le Louarn, Miska; Neichel, Benoît; Madec, Pierre-Yves; Guesalaga, Andrés.

    2014-07-01

    Two algorithms were recently studied for C2n profiling from wide-field Adaptive Optics (AO) measurements on GeMS (Gemini Multi-Conjugate AO system). They both rely on the Slope Detection and Ranging (SLODAR) approach, using spatial covariances of the measurements issued from various wavefront sensors. The first algorithm estimates the C2n profile by applying the truncated least-squares inverse of a matrix modeling the response of slopes covariances to various turbulent layer heights. In the second method, the profile is estimated by deconvolution of these spatial cross-covariances of slopes. We compare these methods in the new configuration of ESO Adaptive Optics Facility (AOF), a high-order multiple laser system under integration. For this, we use measurements simulated by the AO cluster of ESO. The impact of the measurement noise and of the outer scale of the atmospheric turbulence is analyzed. The important influence of the outer scale on the results leads to the development of a new step for outer scale fitting included in each algorithm. This increases the reliability and robustness of the turbulence strength and profile estimations.

  11. Optical bandgap of semiconductor nanostructures: Methods for experimental data analysis

    NASA Astrophysics Data System (ADS)

    Raciti, R.; Bahariqushchi, R.; Summonte, C.; Aydinli, A.; Terrasi, A.; Mirabella, S.

    2017-06-01

    Determination of the optical bandgap (Eg) in semiconductor nanostructures is a key issue in understanding the extent of quantum confinement effects (QCE) on electronic properties and it usually involves some analytical approximation in experimental data reduction and modeling of the light absorption processes. Here, we compare some of the analytical procedures frequently used to evaluate the optical bandgap from reflectance (R) and transmittance (T) spectra. Ge quantum wells and quantum dots embedded in SiO2 were produced by plasma enhanced chemical vapor deposition, and light absorption was characterized by UV-Vis/NIR spectrophotometry. R&T elaboration to extract the absorption spectra was conducted by two approximated methods (single or double pass approximation, single pass analysis, and double pass analysis, respectively) followed by Eg evaluation through linear fit of Tauc or Cody plots. Direct fitting of R&T spectra through a Tauc-Lorentz oscillator model is used as comparison. Methods and data are discussed also in terms of the light absorption process in the presence of QCE. The reported data show that, despite the approximation, the DPA approach joined with Tauc plot gives reliable results, with clear advantages in terms of computational efforts and understanding of QCE.

  12. Reliable chromatic dispersion measurement method for installed optical fibers.

    PubMed

    Zong, Liangjia

    2015-09-10

    We propose and experimentally demonstrate a reliable chromatic dispersion measurement method for installed optical fibers. This technique is based on a modified Sagnac interferometer which is polarization-independent, hence no polarization controller device is needed to control the polarization state of the light entering into the interferometer during measurement. In our proposed system, the polarization mode dispersion (PMD) of the test fiber is compensated by employing a Faraday rotator mirror at one end of the fiber, so that the measured dispersion results will not be affected by any external perturbations on the test fiber. In addition, our method is single-ended, rapid (<1  s), and accurate. Experimental results show the differences for dispersion and dispersion slope of only 0.17% and 1.24%, respectively, compared with that of a commercial instrument. All characteristics indicate that our approach is indeed suitable for in-field dispersion measurement of installed fibers.

  13. System and method for optically locating microchannel positions

    SciTech Connect

    Brewer, Laurence R.; Kimbrough, Joseph; Balch, Joseph; Davidson, J. Courtney

    2001-01-01

    A system and method is disclosed for optically locating a microchannel position. A laser source generates a primary laser beam which is directed at a microchannel plate. The microchannel plates include microchannels at various locations. A back-reflectance beam detector receives a back-reflected beam from the plate. The back-reflected beam is generated when the primary beam reflects off of the plate. A photodiode circuit generates a trigger signal when the back-reflected beam exceeds a predetermined threshold, indicating a presence of the microchannel. The method of the present invention includes the steps of generating a primary beam, directing the primary beam to a plate containing a microchannel, receiving from the plate a back-reflected beam generated in response to the primary beam, and generating a trigger signal when the back-reflected beam exceeds a predetermined threshold which corresponds to a presence of the microchannel.

  14. Optical methods in tempera-on-wood painting restoration

    NASA Astrophysics Data System (ADS)

    Maracineanu, Walter; Coman, Victor; Striber, Joakim

    2004-10-01

    The present study refers to an application of optical techniques in restoration of icons. These are, technically speaking, paintings on wood panel using pigments mixed with egg yolk. Making a section through the layers that compose an icon, they appear in the following order: a support made of wood panel; a preparation made from a mixture of an organic glue and a substance for volume (most frequently used are CaSO4 or CaCO3 in natural spread forms of crystallization; a layer of paint and gold or silver sheets and the final almost transparent layer which consists in a natural resin also known as varnish. During the classic intervention, the specialist is assisted by modern optoelectronic devices. The cleaning process is based on the laser beam next to conventional methods. Cleaning with solvents or with scalpeds is less accurate than cleaning with laser and the precision of the later method is requested in fine art restoration.

  15. Boundary element method for surface nonlinear optics of nanoparticles.

    PubMed

    Mäkitalo, Jouni; Suuriniemi, Saku; Kauranen, Martti

    2011-11-07

    We present the frequency-domain boundary element formulation for solving surface second-harmonic generation from nanoparticles of virtually arbitrary shape and material. We use the Rao-Wilton-Glisson basis functions and Galerkin's testing, which leads to very accurate solutions for both near and far fields. This is verified by a comparison to a solution obtained via multipole expansion for the case of a spherical particle. The frequency-domain formulation allows the use of experimentally measured linear and nonlinear material parameters or the use of parameters obtained using ab-initio principles. As an example, the method is applied to a non-centrosymmetric L-shaped gold nanoparticle to illustrate the formation of surface nonlinear polarization and the second-harmonic radiation properties of the particle. This method provides a theoretically well-founded approach for modelling nonlinear optical phenomena in nanoparticles.

  16. Composite method for precise freeform optical beam shaping.

    PubMed

    Feng, Zexin; Froese, Brittany D; Liang, Rongguang

    2015-11-01

    We present a composite freeform surface construction method for creating a high-accuracy irradiance distribution from a given incident beam under the influence of diffraction. The main idea is that we first determine a fully continuous freeform surface estimate by solving a standard Monge-Ampère equation and then refine it using an iterative Fourier-transform algorithm associated with over-compensation. Although this method can only be implemented in the paraxial approximation, it can significantly simplify the design and is applicable to many examples that fulfill this restriction. The resulting optical surface, unwrapped from the final phase, is an unusual discontinuous freeform surface that can produce very promising performances in terms of surface roughness and irradiance accuracy.

  17. Optical and Physical Methods for Mapping Flooding with Satellite Imagery

    NASA Technical Reports Server (NTRS)

    Fayne, Jessica Fayne; Bolten, John; Lakshmi, Venkat; Ahamed, Aakash

    2016-01-01

    Flood and surface water mapping is becoming increasingly necessary, as extreme flooding events worldwide can damage crop yields and contribute to billions of dollars economic damages as well as social effects including fatalities and destroyed communities (Xaio et al. 2004; Kwak et al. 2015; Mueller et al. 2016).Utilizing earth observing satellite data to map standing water from space is indispensable to flood mapping for disaster response, mitigation, prevention, and warning (McFeeters 1996; Brakenridge and Anderson 2006). Since the early 1970s(Landsat, USGS 2013), researchers have been able to remotely sense surface processes such as extreme flood events to help offset some of these problems. Researchers have demonstrated countless methods and modifications of those methods to help increase knowledge of areas at risk and areas that are flooded using remote sensing data from optical and radar systems, as well as free publically available and costly commercial datasets.

  18. Spectroscopic Methods for Label-Free Optical Nanoscopy

    NASA Astrophysics Data System (ADS)

    Chandler, John E.

    It is becoming increasingly evident that the nanoscale organization and structure of macromolecules play a significant role in determining the function and properties of biological systems. To understand the relationships between biological structure and function at nanometer length scales, there is a need for methods which enable imaging of intact nanoscale biological structure. An ideal technique for these applications is sensitive to nanoscale structure below the resolution limit of conventional optical microscopy ( 200 nm), achieves label-free contrast, is non-perturbing to biological samples, is quantitative, is capable of molecular specificity, is high-throughput, and finally is simple, enabling widespread utilization. Existing techniques meet some of these criteria, but all have limitations. For example, super-resolution optical microscopy methods achieve molecular-specific nanoscale resolution well below the resolution limit of conventional optical microscopes, however, they rely on fluorescent labels often at high densities that can be toxic and can often require potentially damaging illumination intensities for imaging. As a result, there remains a need for label-free optical techniques to study the nanoscale structural properties of cells. To address this need, the development of instrumentation and algorithms for Partial Wave Spectroscopic (PWS) microscopy will be described. PWS is a spectroscopic, label-free, nanoscale sensitive microscope which, senses rather than resolves structure below the resolution limit of conventional microscopes ( 200nm). First, PWS has shown utility as a diagnostic screening tool for cancer due to nanoscale structural alterations that occur in cells as part of the earliest stages of carcinogenesis. Instrumentation and algorithms developed to enable high-throughput cancer screening applications will be described. Further enhancement of data acquisition and analysis speed will then be described through the development of new

  19. Method and apparatus for optical phase error correction

    DOEpatents

    DeRose, Christopher; Bender, Daniel A.

    2014-09-02

    The phase value of a phase-sensitive optical device, which includes an optical transport region, is modified by laser processing. At least a portion of the optical transport region is exposed to a laser beam such that the phase value is changed from a first phase value to a second phase value, where the second phase value is different from the first phase value. The portion of the optical transport region that is exposed to the laser beam can be a surface of the optical transport region or a portion of the volume of the optical transport region. In an embodiment of the invention, the phase value of the optical device is corrected by laser processing. At least a portion of the optical transport region is exposed to a laser beam until the phase value of the optical device is within a specified tolerance of a target phase value.

  20. Human psychophysiological activity monitoring methods using fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Zyczkowski, M.; Uzieblo-Zyczkowska, B.

    2010-10-01

    The paper presents the concept of fiber optic sensor system for human psycho-physical activity detection. A fiber optic sensor that utilizes optical phase interferometry or intensity in modalmetric to monitor a patient's vital signs such as respiration cardiac activity, blood pressure and body's physical movements. The sensor, which is non-invasive, comprises an optical fiber interferometer that includes an optical fiber proximately situated to the patient so that time varying acusto-mechanical signals from the patient are coupled into the optical fiber. The system can be implemented in embodiments ranging form a low cost in-home to a high end product for in hospital use.

  1. Analysis of a digital microstrip optical switch: a novel method.

    PubMed

    Al-Ruwaihi, K M; Hindy, M A

    1997-02-20

    A time domain analysis of an optically controlled digital microstrip switch for microwave integrated circuits on Si substrates is studied. A new model for high-frequency pulse propagation on a microstrip optical switch for different optical parameters is presented. A frequency-dependent macromodel for a microstrip line with a gap is implemented in Spice 3, taking into consideration high-frequency pulse dispersion, conductor and dielectric losses, metallization thickness, gap length, and different optical parameters such as optical energy, surface recombination velocities, and diffusion of generated carriers. In addition, the developed model has been used to optimize the switching frequency, gap length, level of optical power, and suitable substrate material parameters.

  2. Optical and Transport Properties of Organic Molecules: Methods and Applications

    NASA Astrophysics Data System (ADS)

    Strubbe, David Alan

    Organic molecules are versatile and tunable building blocks for technology, in nanoscale and bulk devices. In this dissertation, I will consider some important applications for organic molecules involving optical and transport properties, and develop methods and software appropriate for theoretical calculations of these properties. Specifically, we will consider second-harmonic generation, a nonlinear optical process; photoisomerization, in which absorption of light leads to mechanical motion; charge transport in junctions formed of single molecules; and optical excitations in pentacene, an organic semiconductor with applications in photovoltaics, optoelectronics, and flexible electronics. In the Introduction (Chapter 1), I will give an overview of some phenomenology about organic molecules and these application areas, and discuss the basics of the theoretical methodology I will use: density-functional theory (DFT), time-dependent density-functional theory (TDDFT), and many-body perturbation theory based on the GW approximation. In the subsequent chapters, I will further discuss, develop, and apply this methodology. 2. I will give a pedagogical derivation of the methods for calculating response properties in TDDFT, with particular focus on the Sternheimer equation, as will be used in subsequent chapters. I will review the many different response properties that can be calculated (dynamic and static) and the appropriate perturbations used to calculate them. 3. Standard techniques for calculating response use either integer occupations (as appropriate for a system with an energy gap) or fractional occupations due to a smearing function, used to improve convergence for metallic systems. I will present a generalization which can be used to compute response for a system with arbitrary fractional occupations. 4. Chloroform (CHCl3) is a small molecule commonly used as a solvent in measurements of nonlinear optics. I computed its hyperpolarizability for second

  3. Fabrication of optically active nanostructures by chemical methods

    NASA Astrophysics Data System (ADS)

    Moran, Cristin Erin

    A new method of fabricating long-range, planar arrays of discrete, submicron metal structures on glass or SiO2/Si surfaces has been developed without the use of resist masks or chemical etching. The approach combines microcontact printing and electroless plating for the controlled deposition of islands or lines of gold or silver. The metallic structures are varied in size, separation and shape by using a variety of commercial diffraction gratings to mold the polydimethylsiloxane (PDMS) elastomer stamps. An assortment of distinct geometrical patterns have been fabricated and imaged on a range of length scales using scanning probe, scanning electron, and optical microscopies. Additionally, the same chemical techniques can be used to pattern surfaces with biomolecules and ordered arrays of metal nanoshells. These arrays of metal nanostructures support surface plasmon propagation and also show plasmon-plasmon interactions dependent on the geometry of the metal features. These structures were used to investigate the effects of molecular functionalization on the excitation and propagation properties of the surface plasmons that are supported by this geometry. Distinct variations in the dispersion and energy gaps of surface plasmons on these structures due to chemical functionalization of the metal structures is observed. A second type of optically active structure, rare-earth doped silica particles, has been synthesized using wet chemistry. The polydispersity of the particles can be controlled by changing the concentration of dopant salt. These particles may be useful for microlaser or display technologies.

  4. Method of making and structure for monolithic optical circuits

    NASA Technical Reports Server (NTRS)

    Evanchuk, Vincent L. (Inventor)

    1983-01-01

    A method for making monolithic optical circuits, with related optical devices as required or desired, on a supporting surface (10) consists of coating the supporting surface with reflecting metal or cladding resin, spreading a layer of liquid radiation senstivie plastic (12) on the surface, exposing the liquid plastic with a mask (14) to cure it in a desired pattern of light conductors (16, 18, 20), washing away the unexposed liquid plastic, and coating the conductors thus formed with reflective metal or cladding resin. The index of refraction for the cladding (22) is selected to be lower than for the conductors so that light in the conductors will be reflected by the interface with the cladding. For multiple level conductors, as where one conductor must cross over another, the process may be repeated to fabricate a bridge with columns (24, 26) of conductors to the next level, and conductor (28) between the columns. For more efficient transfer of energy over the bridge, faces at 45.degree. may be formed to reflect light up and across the bridge.

  5. Apparatus and method for characterizing ultrafast polarization varying optical pulses

    DOEpatents

    Smirl, Arthur; Trebino, Rick P.

    1999-08-10

    Practical techniques are described for characterizing ultrafast potentially ultraweak, ultrashort optical pulses. The techniques are particularly suited to the measurement of signals from nonlinear optical materials characterization experiments, whose signals are generally too weak for full characterization using conventional techniques.

  6. Method of forming a sharp edge on an optical device

    NASA Technical Reports Server (NTRS)

    Fleetwood, C. M.; Rice, S. H.

    1980-01-01

    A sharp edge is formed on an optical device by placing the optical device in a holding mechanism; grinding one surface so that it and a surface of the holding mechanism are co-planar; and polishing both the surface of the optical device and the surface of the holding mechanism with felt until an edge on the surface of the optical device adjacent to the surface of the holding mechanism obtains a desired sharpness.

  7. Optical Spatial integration methods for ambiguity function generation

    NASA Technical Reports Server (NTRS)

    Tamura, P. N.; Rebholz, J. J.; Daehlin, O. T.; Lee, T. C.

    1981-01-01

    A coherent optical spatial integration approach to ambiguity function generation is described. It uses one dimensional acousto-optic Bragg cells as input tranducers in conjunction with a space variant linear phase shifter, a passive optical element, to generate the two dimensional ambiguity function in one exposure. Results of a real time implementation of this system are shown.

  8. Method and apparatus for two-dimensional absolute optical encoding

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B. (Inventor)

    2004-01-01

    This invention presents a two-dimensional absolute optical encoder and a method for determining position of an object in accordance with information from the encoder. The encoder of the present invention comprises a scale having a pattern being predetermined to indicate an absolute location on the scale, means for illuminating the scale, means for forming an image of the pattern; and detector means for outputting signals derived from the portion of the image of the pattern which lies within a field of view of the detector means, the field of view defining an image reference coordinate system, and analyzing means, receiving the signals from the detector means, for determining the absolute location of the object. There are two types of scale patterns presented in this invention: grid type and starfield type.

  9. Method for the continuous processing of hermetic fiber optic components and the resultant fiber optic-to-metal components

    DOEpatents

    Kramer, D.P.

    1994-08-09

    Hermetic fiber optic-to-metal components and method for making hermetic fiber optic-to-metal components by assembling and fixturing elements comprising a metal shell, a glass preform, and a metal-coated fiber optic into desired relative positions and then sealing said fixtured elements preferably using a continuous heating process is disclosed. The resultant hermetic fiber optic-to-metal components exhibit high hermeticity and durability despite the large differences in thermal coefficients of expansion among the various elements. 3 figs.

  10. Optical geometry calibration method for free-form digital tomosynthesis

    NASA Astrophysics Data System (ADS)

    Chtcheprov, Pavel; Hartman, Allison; Shan, Jing; Lee, Yueh Z.; Zhou, Otto; Lu, Jianping

    2016-03-01

    Digital tomosynthesis is a type of limited angle tomography that allows 3D information to be reconstructed from a set of x-ray projection images taken at various angles using an x-ray tube, a mechanical arm to rotate the tube about the object, and a digital detector. Tomosynthesis reconstruction requires the precise location of the detector with respect to each x-ray source, forcing all current clinical tomosynthesis systems to use a physically coupled source and detector so the geometry is always known and is always the same. This limits the imaging geometries and its large size is impractical for mobile or field operations. To counter this, we have developed a free form tomosynthesis with a decoupled, free-moving source and detector that uses a novel optical method for accurate and real-time geometry calibration to allow for manual, hand-held tomosynthesis and even CT imaging. We accomplish this by using a camera, attached to the source, to track the motion of the source relative to the detector. Attached to the detector is an optical pattern and the image captured by the camera is then used to determine the relative camera/pattern position and orientation by analyzing the pattern distortion and calculating the source positions for each projection, necessary for 3D reconstruction. This allows for portable imaging in the field and also as an inexpensive upgrade to existing 2D systems, such as in developing countries, to provide 3D image data. Here we report the first feasibility demonstrations of free form digital tomosynthesis systems using the method.

  11. Chemical Sensors Based On Oxygen Detection By Optical Methods

    NASA Astrophysics Data System (ADS)

    Parker, Jennifer W.; Cox, M. E.; Dunn, Bruce S.

    1986-08-01

    Fluorescence quenching is shown to be a viable method of measuring oxygen concentration. Two oxygen/optical transducers based on fluorescence quenching have been developed and characterized: one is hydrophobic and the other is hydrophilic. The development of both transducers provides great flexibility in the application of fluorescence to oxygen measurement. One transducer is produced by entrapping a fluorophor, 9,10-diphenyl anthracene, in poly(dimethyl siloxane) to yield a homogeneous composite polymer matrix. The resulting matrix is hydrophobic. This transducer is extremely sensitive to PO2 as a result of oxygen quenching the fluorescence of 9,10-diphenyl anthracene. This quenching is utilized in the novel method employed to measure the transport properties of oxygen within Ulf 2matrix. Results show large values for the diffusion coefficient at 25°C, D = 3.5 x 10-5 cm /s. The fluorescence intensity varies inversely with P02. The second oxygen transducer is fabricated by entrapping 9,10-diphenyl anthracene in poly(hydroxy ethyl methacrylate). Free radical, room temperature polymerization is employed. This transducer is hydrophilic, and contains 37% water. The transport properties of oxygen within this transducer are compared with those of the hydrophobic transducer. The feasibility of generalizing the oxygen transducers to a wider class of chemical sensors through coupling to other chemistries is proposed. An example of such coupling is given in a glucose/oxygen transducer. The glucose transducer is produced by entrapping an enzyme, glucose oxidase, in the composite matrix of the hydrophilic oxygen transducer. Glucose oxidase catalyzes a reaction between glucose and oxygen, thereby lowering the local oxygen concentration. This transducer yields a glucose modified optical oxygen signal. The operation of this transducer and preliminary results of its characterization are presented.

  12. Methods of making composite optical devices employing polymer liquid crystal

    DOEpatents

    Jacobs, Stephen D.; Marshall, Kenneth L.; Cerqua, Kathleen A.

    1991-01-01

    Composite optical devices using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T.sub.g) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device.

  13. Methods of making composite optical devices employing polymer liquid crystal

    DOEpatents

    Jacobs, S.D.; Marshall, K.L.; Cerqua, K.A.

    1991-10-08

    Composite optical devices are disclosed using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T[sub g]) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device. 7 figures.

  14. Method And Apparatus For Coupling Optical Elements To Optoelectronic Devices For Manufacturing Optical Transceiver Modules

    DOEpatents

    Anderson, Gene R.; Armendariz, Marcelino G.; Bryan, Robert P.; Carson, Richard F.; Chu, Dahwey; Duckett, III, Edwin B.; Giunta, Rachel Knudsen; Mitchell, Robert T.; McCormick, Frederick B.; Peterson, David W.; Rising, Merideth A.; Reber, Cathleen A.; Reysen, Bill H.

    2005-06-14

    A process is provided for aligning and connecting at least one optical fiber to at least one optoelectronic device so as to couple light between at least one optical fiber and at least one optoelectronic device. One embodiment of this process comprises the following steps: (1) holding at least one optical element close to at least one optoelectronic device, at least one optical element having at least a first end; (2) aligning at least one optical element with at least one optoelectronic device; (3) depositing a first non-opaque material on a first end of at least one optoelectronic device; and (4) bringing the first end of at least one optical element proximate to the first end of at least one optoelectronic device in such a manner that the first non-opaque material contacts the first end of at least one optoelectronic device and the first end of at least one optical element. The optical element may be an optical fiber, and the optoelectronic device may be a vertical cavity surface emitting laser. The first non-opaque material may be a UV optical adhesive that provides an optical path and mechanical stability. In another embodiment of the alignment process, the first end of at least one optical element is brought proximate to the first end of at least one optoelectronic device in such a manner that an interstitial space exists between the first end of at least one optoelectronic device and the first end of at least one optical element.

  15. Study on manufacturing method of optical surface with high precision in angle and surface

    NASA Astrophysics Data System (ADS)

    Yu, Xin; Li, Xin; Yu, Ze; Zhao, Bin; Zhang, Xuebin; Sun, Lipeng; Tong, Yi

    2016-10-01

    This paper studied a manufacturing processing of optical surface with high precision in angel and surface. By theoretical analysis of the relationships between the angel precision and surface, the measurement conversion of the technical indicators, optical-cement method application, the optical-cement tooling design, the experiment has been finished successfully, the processing method has been verified, which can be also used in the manufacturing of the optical surface with similar high precision in angle and surface.

  16. Integrated resonant micro-optical gyroscope and method of fabrication

    DOEpatents

    Vawter, G. Allen; Zubrzycki, Walter J.; Guo, Junpeng; Sullivan, Charles T.

    2006-09-12

    An integrated optic gyroscope is disclosed which is based on a photonic integrated circuit (PIC) having a bidirectional laser source, a pair of optical waveguide phase modulators and a pair of waveguide photodetectors. The PIC can be connected to a passive ring resonator formed either as a coil of optical fiber or as a coiled optical waveguide. The lasing output from each end of the bidirectional laser source is phase modulated and directed around the passive ring resonator in two counterpropagating directions, with a portion of the lasing output then being detected to determine a rotation rate for the integrated optical gyroscope. The coiled optical waveguide can be formed on a silicon, glass or quartz substrate with a silicon nitride core and a silica cladding, while the PIC includes a plurality of III V compound semiconductor layers including one or more quantum well layers which are disordered in the phase modulators and to form passive optical waveguides.

  17. Accurate optical CD profiler based on specialized finite element method

    NASA Astrophysics Data System (ADS)

    Carrero, Jesus; Perçin, Gökhan

    2012-03-01

    As the semiconductor industry is moving to very low-k1 patterning solutions, the metrology problems facing process engineers are becoming much more complex. Choosing the right optical critical dimension (OCD) metrology technique is essential for bridging the metrology gap and achieving the required manufacturing volume throughput. The critical dimension scanning electron microscope (CD-SEM) measurement is usually distorted by the high aspect ratio of the photoresist and hard mask layers. CD-SEM measurements cease to correlate with complex three-dimensional profiles, such as the cases for double patterning and FinFETs, thus necessitating sophisticated, accurate and fast computational methods to bridge the gap. In this work, a suite of computational methods that complement advanced OCD equipment, and enabling them to operate at higher accuracies, are developed. In this article, a novel method for accurately modeling OCD profiles is presented. A finite element formulation in primal form is used to discretize the equations. The implementation uses specialized finite element spaces to solve Maxwell equations in two dimensions.

  18. Response Surface Methods for Spatially-Resolved Optical Measurement Techniques

    NASA Technical Reports Server (NTRS)

    Danehy, P. M.; Dorrington, A. A.; Cutler, A. D.; DeLoach, R.

    2003-01-01

    Response surface methods (or methodology), RSM, have been applied to improve data quality for two vastly different spatial ly-re solved optical measurement techniques. In the first application, modern design of experiments (MDOE) methods, including RSM, are employed to map the temperature field in a direct-connect supersonic combustion test facility at NASA Langley Research Center. The laser-based measurement technique known as coherent anti-Stokes Raman spectroscopy (CARS) is used to measure temperature at various locations in the combustor. RSM is then used to develop temperature maps of the flow. Even though the temperature fluctuations at a single point in the flowfield have a standard deviation on the order of 300 K, RSM provides analytic fits to the data having 95% confidence interval half width uncertainties in the fit as low as +/-30 K. Methods of optimizing future CARS experiments are explored. The second application of RSM is to quantify the shape of a 5-meter diameter, ultra-light, inflatable space antenna at NASA Langley Research Center.

  19. Optical Calibration Process Developed for Neural-Network-Based Optical Nondestructive Evaluation Method

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.

    2004-01-01

    A completely optical calibration process has been developed at Glenn for calibrating a neural-network-based nondestructive evaluation (NDE) method. The NDE method itself detects very small changes in the characteristic patterns or vibration mode shapes of vibrating structures as discussed in many references. The mode shapes or characteristic patterns are recorded using television or electronic holography and change when a structure experiences, for example, cracking, debonds, or variations in fastener properties. An artificial neural network can be trained to be very sensitive to changes in the mode shapes, but quantifying or calibrating that sensitivity in a consistent, meaningful, and deliverable manner has been challenging. The standard calibration approach has been difficult to implement, where the response to damage of the trained neural network is compared with the responses of vibration-measurement sensors. In particular, the vibration-measurement sensors are intrusive, insufficiently sensitive, and not numerous enough. In response to these difficulties, a completely optical alternative to the standard calibration approach was proposed and tested successfully. Specifically, the vibration mode to be monitored for structural damage was intentionally contaminated with known amounts of another mode, and the response of the trained neural network was measured as a function of the peak-to-peak amplitude of the contaminating mode. The neural network calibration technique essentially uses the vibration mode shapes of the undamaged structure as standards against which the changed mode shapes are compared. The published response of the network can be made nearly independent of the contaminating mode, if enough vibration modes are used to train the net. The sensitivity of the neural network can be adjusted for the environment in which the test is to be conducted. The response of a neural network trained with measured vibration patterns for use on a vibration isolation

  20. Optical Calibration Process Developed for Neural-Network-Based Optical Nondestructive Evaluation Method

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.

    2004-01-01

    A completely optical calibration process has been developed at Glenn for calibrating a neural-network-based nondestructive evaluation (NDE) method. The NDE method itself detects very small changes in the characteristic patterns or vibration mode shapes of vibrating structures as discussed in many references. The mode shapes or characteristic patterns are recorded using television or electronic holography and change when a structure experiences, for example, cracking, debonds, or variations in fastener properties. An artificial neural network can be trained to be very sensitive to changes in the mode shapes, but quantifying or calibrating that sensitivity in a consistent, meaningful, and deliverable manner has been challenging. The standard calibration approach has been difficult to implement, where the response to damage of the trained neural network is compared with the responses of vibration-measurement sensors. In particular, the vibration-measurement sensors are intrusive, insufficiently sensitive, and not numerous enough. In response to these difficulties, a completely optical alternative to the standard calibration approach was proposed and tested successfully. Specifically, the vibration mode to be monitored for structural damage was intentionally contaminated with known amounts of another mode, and the response of the trained neural network was measured as a function of the peak-to-peak amplitude of the contaminating mode. The neural network calibration technique essentially uses the vibration mode shapes of the undamaged structure as standards against which the changed mode shapes are compared. The published response of the network can be made nearly independent of the contaminating mode, if enough vibration modes are used to train the net. The sensitivity of the neural network can be adjusted for the environment in which the test is to be conducted. The response of a neural network trained with measured vibration patterns for use on a vibration isolation

  1. Electro-optical and Magneto-optical Sensing Apparatus and Method for Characterizing Free-space Electromagnetic Radiation

    DOEpatents

    Zhang, Xi-Cheng; Riordan, Jenifer Ann; Sun, Feng-Guo

    2000-08-29

    Apparatus and methods for characterizing free-space electromagnetic energy, and in particular, apparatus/method suitable for real-time two-dimensional far-infrared imaging applications are presented. The sensing technique is based on a non-linear coupling between a low-frequency electric (or magnetic) field and a laser beam in an electro-optic (or magnetic-optic) crystal. In addition to a practical counter-propagating sensing technique, a co-linear approach is described which provides longer radiated field-optical beam interaction length, thereby making imaging applications practical.

  2. Method for removing tilt control in adaptive optics systems

    DOEpatents

    Salmon, Joseph Thaddeus

    1998-01-01

    A new adaptive optics system and method of operation, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation: G'=(I-X(X.sup.T X).sup.-1 X.sup.T)G(I-A)

  3. Method for removing tilt control in adaptive optics systems

    DOEpatents

    Salmon, J.T.

    1998-04-28

    A new adaptive optics system and method of operation are disclosed, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation: G{prime} = (I{minus}X(X{sup T} X){sup {minus}1}X{sup T})G(I{minus}A). 3 figs.

  4. Generalized spectral method for near-field optical microscopy

    SciTech Connect

    Jiang, B.-Y.; Zhang, L. M.; Basov, D. N.; Fogler, M. M.; Castro Neto, A. H.

    2016-02-07

    Electromagnetic interaction between a sub-wavelength particle (the “probe”) and a material surface (the “sample”) is studied theoretically. The interaction is shown to be governed by a series of resonances corresponding to surface polariton modes localized near the probe. The resonance parameters depend on the dielectric function and geometry of the probe as well as on the surface reflectivity of the material. Calculation of such resonances is carried out for several types of axisymmetric probes: spherical, spheroidal, and pear-shaped. For spheroids, an efficient numerical method is developed, capable of handling cases of large or strongly momentum-dependent surface reflectivity. Application of the method to highly resonant materials, such as aluminum oxide (by itself or covered with graphene), reveals a rich structure of multi-peak spectra and nonmonotonic approach curves, i.e., the probe-sample distance dependence. These features also strongly depend on the probe shape and optical constants of the model. For less resonant materials such as silicon oxide, the dependence is weak, so that the spheroidal model is reliable. The calculations are done within the quasistatic approximation with radiative damping included perturbatively.

  5. Generalized spectral method for near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Jiang, B.-Y.; Zhang, L. M.; Castro Neto, A. H.; Basov, D. N.; Fogler, M. M.

    2016-02-01

    Electromagnetic interaction between a sub-wavelength particle (the "probe") and a material surface (the "sample") is studied theoretically. The interaction is shown to be governed by a series of resonances corresponding to surface polariton modes localized near the probe. The resonance parameters depend on the dielectric function and geometry of the probe as well as on the surface reflectivity of the material. Calculation of such resonances is carried out for several types of axisymmetric probes: spherical, spheroidal, and pear-shaped. For spheroids, an efficient numerical method is developed, capable of handling cases of large or strongly momentum-dependent surface reflectivity. Application of the method to highly resonant materials, such as aluminum oxide (by itself or covered with graphene), reveals a rich structure of multi-peak spectra and nonmonotonic approach curves, i.e., the probe-sample distance dependence. These features also strongly depend on the probe shape and optical constants of the model. For less resonant materials such as silicon oxide, the dependence is weak, so that the spheroidal model is reliable. The calculations are done within the quasistatic approximation with radiative damping included perturbatively.

  6. Fiber optics interface for a dye laser oscillator and method

    DOEpatents

    Johnson, Steve A.; Seppala, Lynn G.

    1986-01-01

    A dye laser oscillator in which one light beam is used to pump a continuous tream of dye within a cooperating dye chamber for producing a second, different beam is generally disclosed herein along with a specific arrangement including an optical fiber and a fiber optics interface for directing the pumping beam into the dye chamber. The specific fiber optics interface illustrated includes three cooperating lenses which together image one particular dimension of the pumping beam into the dye chamber from the output end of the optical fiber in order to insure that the dye chamber is properly illuminated by the pumping beam.

  7. Fiber optics interface for a dye laser oscillator and method

    DOEpatents

    Johnson, S.A.; Seppala, L.G.

    1984-06-13

    A dye laser oscillator in which one light beam is used to pump a continuous stream of dye within a cooperating dye chamber for producing a second, different beam is generally disclosed herein along with a specific arrangement including an optical fiber and a fiber optics interface for directing the pumping beam into the dye chamber. The specific fiber optics interface illustrated includes three cooperating lenses which together image one particular dimension of the pumping beam into the dye chamber from the output end of the optical fiber in order to insure that the dye chamber is properly illuminated by the pumping beam.

  8. Method and device for remotely monitoring an area using a low peak power optical pump

    DOEpatents

    Woodruff, Steven D.; Mcintyre, Dustin L.; Jain, Jinesh C.

    2014-07-22

    A method and device for remotely monitoring an area using a low peak power optical pump comprising one or more pumping sources, one or more lasers; and an optical response analyzer. Each pumping source creates a pumping energy. The lasers each comprise a high reflectivity mirror, a laser media, an output coupler, and an output lens. Each laser media is made of a material that emits a lasing power when exposed to pumping energy. Each laser media is optically connected to and positioned between a corresponding high reflectivity mirror and output coupler along a pumping axis. Each output coupler is optically connected to a corresponding output lens along the pumping axis. The high reflectivity mirror of each laser is optically connected to an optical pumping source from the one or more optical pumping sources via an optical connection comprising one or more first optical fibers.

  9. Methods of biomedical optical imaging: from subcellular structures to tissues and organs

    NASA Astrophysics Data System (ADS)

    Turchin, I. V.

    2016-05-01

    Optical bioimaging methods have a wide range of applications in the life sciences, most notably including the molecular resolution study of subcellular structures, small animal molecular imaging, and structural and functional clinical diagnostics of tissue layers and organs. We review fluorescent microscopy, fluorescent macroscopy, optical coherence tomography, optoacoustic tomography, and optical diffuse spectroscopy and tomography from the standpoint of physical fundamentals, applications, and progress.

  10. Self-referenced and single-ended method to measure Brillouin gain in monomode optical fibers.

    PubMed

    Lanticq, Vincent; Jiang, Shifeng; Gabet, Renaud; Jaouën, Yves; Taillade, Frédéric; Moreau, Gautier; Agrawal, Govind P

    2009-04-01

    We present a new self-referenced and single-ended method to measure the Brillouin-gain coefficient in monomode optical fibers accurately with high reliability. Our comparative measurements on several different fibers show that a fiber with a smaller optical effective mode area can nevertheless have a higher Brillouin threshold, thus confirming the significance of acousto-optic effective mode area.

  11. Simple in-line method to measure the dispersion of an optical system

    NASA Technical Reports Server (NTRS)

    Yao, X. S.; Feinberg, Jack

    1993-01-01

    We describe a simple in-line method to measure the dispersion of an optical system. The light beam passing through the optical system interferes with a reference beam in a spectrometer, and the resulting spectrum yields the quadratic and cubic dispersion terms of the system. We demonstrate this technique on an optical system made of grating pairs.

  12. Response Surface Methods For Spatially-Resolved Optical Measurement Techniques

    NASA Technical Reports Server (NTRS)

    Danehy, P. M.; Dorrington, A. A.; Cutler, A. D.; DeLoach, R.

    2003-01-01

    Response surface methods (or methodology), RSM, have been applied to improve data quality for two vastly different spatially-resolved optical measurement techniques. In the first application, modern design of experiments (MDOE) methods, including RSM, are employed to map the temperature field in a direct-connect supersonic combustion test facility at NASA Langley Research Center. The laser-based measurement technique known as coherent anti-Stokes Raman spectroscopy (CARS) is used to measure temperature at various locations in the combustor. RSM is then used to develop temperature maps of the flow. Even though the temperature fluctuations at a single point in the flowfield have a standard deviation on the order of 300 K, RSM provides analytic fits to the data having 95% confidence interval half width uncertainties in the fit as low as +/- 30 K. Methods of optimizing future CARS experiments are explored. The second application of RSM is to quantify the shape of a 5-meter diameter, ultra-lightweight, inflatable space antenna at NASA Langley Research Center. Photogrammetry is used to simultaneously measure the shape of the antenna at approximately 500 discrete spatial locations. RSM allows an analytic model to be developed that describes the shape of the majority of the antenna with an uncertainty of 0.4 mm, with 95% confidence. This model would allow a quantitative comparison between the actual shape of the antenna and the original design shape. Accurately determining this shape also allows confident interpolation between the measured points. Such a model could, for example, be used for ray tracing of radio-frequency waves up to 95 GHz. to predict the performance of the antenna.

  13. Response Surface Methods For Spatially-Resolved Optical Measurement Techniques

    NASA Technical Reports Server (NTRS)

    Danehy, P. M.; Dorrington, A. A.; Cutler, A. D.; DeLoach, R.

    2003-01-01

    Response surface methods (or methodology), RSM, have been applied to improve data quality for two vastly different spatially-resolved optical measurement techniques. In the first application, modern design of experiments (MDOE) methods, including RSM, are employed to map the temperature field in a direct-connect supersonic combustion test facility at NASA Langley Research Center. The laser-based measurement technique known as coherent anti-Stokes Raman spectroscopy (CARS) is used to measure temperature at various locations in the combustor. RSM is then used to develop temperature maps of the flow. Even though the temperature fluctuations at a single point in the flowfield have a standard deviation on the order of 300 K, RSM provides analytic fits to the data having 95% confidence interval half width uncertainties in the fit as low as +/- 30 K. Methods of optimizing future CARS experiments are explored. The second application of RSM is to quantify the shape of a 5-meter diameter, ultra-lightweight, inflatable space antenna at NASA Langley Research Center. Photogrammetry is used to simultaneously measure the shape of the antenna at approximately 500 discrete spatial locations. RSM allows an analytic model to be developed that describes the shape of the majority of the antenna with an uncertainty of 0.4 mm, with 95% confidence. This model would allow a quantitative comparison between the actual shape of the antenna and the original design shape. Accurately determining this shape also allows confident interpolation between the measured points. Such a model could, for example, be used for ray tracing of radio-frequency waves up to 95 GHz. to predict the performance of the antenna.

  14. A Simple Optical Coherence Tomography Quantification Method for Choroidal Neovascularization

    PubMed Central

    Sulaiman, Rania S.; Quigley, Judith; Qi, Xiaoping; O'Hare, Michael N.; Grant, Maria B.; Boulton, Michael E.

    2015-01-01

    Abstract Purpose: Therapeutic efficacy is routinely assessed by measurement of lesion size using flatmounted choroids and confocal microscopy in the laser-induced choroidal neovascularization (L-CNV) rodent model. We investigated whether optical coherence tomography (OCT) quantification, using an ellipsoid volume measurement, was comparable to standard ex vivo evaluation methods for this model and whether this approach could be used to monitor treatment-related lesion changes. Methods: Bruch's membrane was ruptured by argon laser in the dilated eyes of C57BL/6J mice, followed by intravitreal injections of anti-VEGF164 or vehicle, or no injection. In vivo OCT images were acquired using Micron III or InVivoVue systems at 7, 10, and/or 14 days post-laser and neovascular lesion volume was calculated as an ellipsoid. Subsequently, lesion volume was compared to that calculated from confocal Z-stack images of agglutinin-stained choroidal flatmounts. Results: Ellipsoid volume measurement of orthogonal 2-dimensional OCT images obtained from different imaging systems correlated with ex vivo lesion volumes for L-CNV (Spearman's ρ=0.82, 0.75, and 0.82 at days 7, 10, and 14, respectively). Ellipsoid volume calculation allowed temporal monitoring and evaluation of CNV lesions in response to antivascular endothelial growth factor treatment. Conclusions: Ellipsoid volume measurements allow rapid, quantitative use of OCT for the assessment of CNV lesions in vivo. This novel method can be used with different OCT imaging systems with sensitivity to distinguish between treatment conditions. It may serve as a useful adjunct to the standard ex vivo confocal quantification, to assess therapeutic efficacy in preclinical models of CNV, and in models of other ocular diseases. PMID:26060878

  15. Universal method for constructing N-port non-blocking optical router based on 2 × 2 optical switch for photonic networks-on-chip.

    PubMed

    Chen, Qiaoshan; Zhang, Fanfan; Ji, Ruiqiang; Zhang, Lei; Yang, Lin

    2014-05-19

    We propose a universal method for constructing N-port non-blocking optical router for photonic networks-on-chip, in which all microring (MR) optical switches or Mach-Zehnder (M-Z) optical switches behave as 2 × 2 optical switches. The optical router constructed by the proposed method has minimum optical switches, in which the number of the optical switches is reduced about 50% compared to the reported optical routers based on MR optical switches and more than 30% compared to the reported optical routers based on M-Z optical switches, and therefore is more compact in footprint and more power-efficient. We also present a strict mathematical proof of the non-blocking routing of the proposed N-port optical router.

  16. Apparatus and method for characterizing ultrafast polarization varying optical pulses

    DOEpatents

    Smirl, A.; Trebino, R.P.

    1999-08-10

    Practical techniques are described for characterizing ultrafast potentially ultraweak, ultrashort optical pulses. The techniques are particularly suited to the measurement of signals from nonlinear optical materials characterization experiments, whose signals are generally too weak for full characterization using conventional techniques. 2 figs.

  17. EVALUATION OF OPTICAL DETECTION METHODS FOR WATERBORNE SUSPENSIONS

    EPA Science Inventory

    Turbidimeters and optical paricle counters (OPCs) are used to monitor particulate matter in water. The response from these instruments is governed by the optical properties of the suspension and the instrument design. The recommended design criteria for turbidimeters allows for l...

  18. EVALUATION OF OPTICAL DETECTION METHODS FOR WATERBORNE SUSPENSIONS

    EPA Science Inventory

    Turbidimeters and optical paricle counters (OPCs) are used to monitor particulate matter in water. The response from these instruments is governed by the optical properties of the suspension and the instrument design. The recommended design criteria for turbidimeters allows for l...

  19. Analytical theory and method for longitudinal magneto-optical Kerr effect of optically anisotropic magnetic film

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Lian, Jie; Li, Ping; Xu, XiJin; Li, MengMeng

    2017-01-01

    The Fresnel equations are solved to analyze the reflection and propagation properties of the ordinary and extraordinary light of the optically anisotropic magnetic film. Using the boundary and propagation matrix, the longitudinal magneto-optical Kerr rotation expression is derived. After that, simulations are performed on optically anisotropic and isotropic Co/SiO2 film. Results show that for Co material in the thin-film limit, the anisotropic Co can provide larger max rotations than the isotropic Co in the visible region. This is because that the refractive index discrepancy of optically anisotropic Co film reduces the Fresnel reflective coefficient rpp, which improves the Kerr rotation. This makes the optically anisotropic Co film more effective in magneto optical sensor design and device fabrication.

  20. Modern methods of production of large-sized multicomponent optical systems

    NASA Astrophysics Data System (ADS)

    Galyavov, Igor R.; Belousov, Sergey P.; Ignatov, Aleksandr N.; Ponin, Oleg V.; Sharov, Aleksandr A.; Domnin, Aleksandr V.

    2016-10-01

    The article describes the technology of production of large-sized multicomponent optical systems of different function. All stages of a production cycle are considered: assembly of separate units of optical components, including aspherical and off-axis mirrors; preliminary assembly and adjustment of all system; final adjustment of optical system. Modern computer-controlled methods of testings and adjustment of multicomponent optical systems, using the examples of production of such systems at JSC LZOS, are described.

  1. Optical method for determining the mechanical properties of a material

    DOEpatents

    Maris, Humphrey J.; Stoner, Robert J.

    1998-01-01

    Disclosed is a method for characterizing a sample, comprising the steps of: (a) acquiring data from the sample using at least one probe beam wavelength to measure, for times less than a few nanoseconds, a change in the reflectivity of the sample induced by a pump beam; (b) analyzing the data to determine at least one material property by comparing a background signal component of the data with data obtained for a similar delay time range from one or more samples prepared under conditions known to give rise to certain physical and chemical material properties; and (c) analyzing a component of the measured time dependent reflectivity caused by ultrasonic waves generated by the pump beam using the at least one determined material property. The first step of analyzing may include a step of interpolating between reference samples to obtain an intermediate set of material properties. The material properties may include sound velocity, density, and optical constants. In one embodiment, only a correlation is made with the background signal, and at least one of the structural phase, grain orientation, and stoichiometry is determined.

  2. Optical method for determining the mechanical properties of a material

    DOEpatents

    Maris, H.J.; Stoner, R.J.

    1998-12-01

    Disclosed is a method for characterizing a sample, comprising the steps of: (a) acquiring data from the sample using at least one probe beam wavelength to measure, for times less than a few nanoseconds, a change in the reflectivity of the sample induced by a pump beam; (b) analyzing the data to determine at least one material property by comparing a background signal component of the data with data obtained for a similar delay time range from one or more samples prepared under conditions known to give rise to certain physical and chemical material properties; and (c) analyzing a component of the measured time dependent reflectivity caused by ultrasonic waves generated by the pump beam using the at least one determined material property. The first step of analyzing may include a step of interpolating between reference samples to obtain an intermediate set of material properties. The material properties may include sound velocity, density, and optical constants. In one embodiment, only a correlation is made with the background signal, and at least one of the structural phase, grain orientation, and stoichiometry is determined. 14 figs.

  3. Fiber optic assembly and method of making same

    DOEpatents

    Kramer, Daniel P.; Beckman, Thomas M.

    1997-09-02

    There is provided an assembly having a light guiding medium sealed to a her. Preferably the holder is a metal shell and a light guiding medium is an optical fiber of glass or sapphire whisker. The assembly includes a sealing medium which sealingly engages the metal holder to the fiber. In the formation of the assembly, the seal is essentially hermetic having a capability of minimizing leakage having a helium leak rate of less than 1.times.10.sup.-8 cubic centimeters per second and high strength having a capability of withstanding pressures of 100,000 psi or greater. The features of the assembly are obtained by a specific preparation method and by selection of specific starting materials. The fiber is selected to have a sufficiently high coefficient of thermal expansion which minimizes strains in the component during fabrication, as a result of fabrication, and during use. The other components are selected to be of a material having compatible coefficients of thermal expansion (TEC) where the TEC of the holder is greater than or equal to the TEC of the sealing material. The TEC of the sealing material is in turn greater than or equal to the TEC of the fiber. It is preferred that the materials be selected so that their respective coefficients of thermal expansion are as close as possible to one another and they may all be equal.

  4. Flexible multi-dimensional modulation method for elastic optical networks

    NASA Astrophysics Data System (ADS)

    He, Zilong; Liu, Wentao; Shi, Sheping; Shen, Bailin; Chen, Xue; Gao, Xiqing; Zhang, Qi; Shang, Dongdong; Ji, Yongning; Liu, Yingfeng

    2016-01-01

    We demonstrate a flexible multi-dimensional modulation method for elastic optical networks. We compare the flexible multi-dimensional modulation formats PM-kSC-mQAM with traditional modulation formats PM-mQAM using numerical simulations in back-to-back and wavelength division multiplexed (WDM) transmission (50 GHz-spaced) scenarios at the same symbol rate of 32 Gbaud. The simulation results show that PM-kSC-QPSK and PM-kSC-16QAM can achieve obvious back-to-back sensitivity gain with respect to PM-QPSK and PM-16QAM at the expense of spectral efficiency reduction. And the WDM transmission simulation results show that PM-2SC-QPSK can achieve 57.5% increase in transmission reach compared to PM-QPSK, and 48.5% increase for PM-2SC-16QAM over PM-16QAM. Furthermore, we also experimentally investigate the back to back performance of PM-2SC-QPSK, PM-4SC-QPSK, PM-2SC-16QAM and PM-3SC-16QAM, and the experimental results agree well with the numerical simulations.

  5. Methods for Monitoring Erosion Using Optical Coherence Tomography

    PubMed Central

    Chan, Kenneth H.; Chan, Andrew C.; Darling, Cynthia L.; Fried, Daniel

    2013-01-01

    Since optical coherence tomography is well suited for measuring small dimensional changes on tooth surfaces it has great potential for monitoring tooth erosion. The purpose of this study was to explore different approaches for monitoring the erosion of enamel. Application of an acid resistant varnish to protect the tooth surface from erosion has proven effective for providing a reference surface for in vitro studies but has limited potential for in vivo studies. Two approaches which can potentially be used in vivo were investigated. The first approach is to measure the remaining enamel thickness, namely the distance from the tooth surface to the dentinal-enamel junction (DEJ). The second more novel approach is to irradiate the surface with a carbon dioxide laser to create a reference layer which resists erosion. Measuring the remaining enamel thickness proved challenging since the surface roughening and subsurface demineralization that commonly occurs during the erosion process can prevent resolution of the underlying DEJ. The areas irradiated by the laser manifested lower rates of erosion compared to the non-irradiated areas and this method appears promising but it is highly dependent on the severity of the acid challenge. PMID:24465117

  6. Methods for monitoring erosion using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Chan, Kenneth H.; Chan, Andrew C.; Darling, Cynthia L.; Fried, Daniel

    Since optical coherence tomography is well suited for measuring small dimensional changes on tooth surfaces it has great potential for monitoring tooth erosion. The purpose of this study was to explore different approaches for monitoring the erosion of enamel. Application of an acid resistant varnish to protect the tooth surface from erosion has proven effective for providing a reference surface for in vitro studies but has limited potential for in vivo studies. Two approaches which can potentially be used in vivo were investigated. The first approach is to measure the remaining enamel thickness, namely the distance from the tooth surface to the dentinal-enamel junction (DEJ). The second more novel approach is to irradiate the surface with a carbon dioxide laser to create a reference layer which resists erosion. Measuring the remaining enamel thickness proved challenging since the surface roughening and subsurface demineralization that commonly occurs during the erosion process can prevent resolution of the underlying DEJ. The areas irradiated by the laser manifested lower rates of erosion compared to the non-irradiated areas and this method appears promising but it is highly dependent on the severity of the acid challenge.

  7. Fiber optic assembly and method of making same

    DOEpatents

    Kramer, D.P.; Beckman, T.M.

    1997-09-02

    There is provided an assembly having a light guiding medium sealed to a holder. Preferably the holder is a metal shell and a light guiding medium is an optical fiber of glass or sapphire whisker. The assembly includes a sealing medium which sealingly engages the metal holder to the fiber. In the formation of the assembly, the seal is essentially hermetic having a capability of minimizing leakage having a helium leak rate of less than 1{times}10{sup {minus}8} cubic centimeters per second and high strength having a capability of withstanding pressures of 100,000 psi or greater. The features of the assembly are obtained by a specific preparation method and by selection of specific starting materials. The fiber is selected to have a sufficiently high coefficient of thermal expansion which minimizes strains in the component during fabrication, as a result of fabrication, and during use. The other components are selected to be of a material having compatible coefficients of thermal expansion (TEC) where the TEC of the holder is greater than or equal to the TEC of the sealing material. The TEC of the sealing material is in turn greater than or equal to the TEC of the fiber. It is preferred that the materials be selected so that their respective coefficients of thermal expansion are as close as possible to one another and they may all be equal. 4 figs.

  8. Determination of petrophysical properties of sedimentary rocks by optical methods

    NASA Astrophysics Data System (ADS)

    Korte, D.; Kaukler, D.; Fanetti, M.; Cabrera, H.; Daubront, E.; Franko, M.

    2017-04-01

    Petrophysical properties of rocks (thermal diffusivity and conductivity, porosity and density) as well as the correlation between them are of great importance for many geoscientific applications. The porosity of the reservoir rocks and their permeability are the most fundamental physical properties with respect to the storage and transmission of fluids, mainly oil characterization. Accurate knowledge of these parameters for any hydrocarbon reservoir is required for efficient development, management, and prediction of future performance of the oilfield. Thus, the porosity and permeability, as well as the chemical composition must be quantified as precisely as possible. This should be done along with the thermal properties, density, conductivity, diffusivity and effusivity that are intimately related with them. For this reason, photothermal Beam Deflection Spectrometry (BDS) technique for determination of materials' thermal properties together with other methods such as Energy Dispersive X-ray Scanning Electron Microscopy (SEM-EDX) for determining the chemical composition and sample structure, as well as optical microscopy to determine the particles size, were applied for characterization of sedimentary rocks. The rocks were obtained from the Andes south flank in the Venezuela's western basin. The validation of BDS applicability for determination of petrophysical properties of three sedimentary rocks of different texture and composition (all from Late Cretaceous associated with the Luna, Capacho and Colón-Mito Juan geological formations) was performed. The rocks' thermal properties were correlated to the microstructures and chemical composition of the examined samples.

  9. An Optical Streaking Method for Measuring Femtosecond Electron Bunches

    SciTech Connect

    Ding, Yuantao; Bane, Karl L.F.; Huang, Zhirong; /SLAC

    2011-12-14

    The measurement of the ultra-short electron bunch length on the femtosecond time scale constitutes a very challenging problem. In the x-ray free electron laser facilities such as the Linac Coherent Light Source, generation of a sub-ten femtoseconds electron beam with 20pC charge is possible, but direct measurements are very difficult due to the resolution limit of the present diagnostics. We propose a new method here based on the measurement of the electron beam energy modulation induced from laser-electron interaction in a short wiggler. A typical optical streaking method requires a laser wavelength much longer than the electron bunch length. In this paper a laser with its wavelength shorter than the electron bunch length has been adopted, while the slope on the laser intensity envelope is used to distinguish the different periods. With this technique it is possible to reconstruct the bunch longitudinal profile from a single shot measurement. Generation of ultrashort x-ray pulses at femtoseconds (fs) scale is of great interest within synchrotron radiation and free electron laser (FEL) user community. One of the simple methods is to operate the FEL facility at low charge. At the Linac Coherent Light Source (LCLS), we have demonstrated the capability of generating ultrashort electron-beam (e-beam) with a duration of less than 10 fs fwhm using 20 pC charge. The x-ray pulses have been delivered to the x-ray users with a similar or even shorter pulse duration. However, The measurement of such short electron or x-ray pulse length at the fs time-scale constitutes a challenging problem. A standard method using an S-band radio-frequency (rf) transverse deflector has been established at LCLS, which works like a streak camera for electrons and is capable of resolving bunch lengths as short as 25 fs fwhm. With this device, the electrons are transversely deflected by the high-frequency time-variation of the deflecting fields. Increasing the deflecting voltage and rf frequency

  10. Co-validation of three methods for optical characterization of point-focus concentrators

    SciTech Connect

    Wendelin, T.J.; Grossman, J.W.

    1994-10-01

    Three different methods for characterizing point-focus solar concentrator optical performance have been developed for specific applications. These methods include a laser ray trace technique called the Scanning Hartmann Optical Test, a video imaging process called the 2f Technique and actual on-sun testing in conjunction with optical computer modeling. Three concentrator test articles, each of a different design, were characterized using at least two of the methods and, in one case, all three. The results of these tests are compared in order to validate the methods. Excellent agreement is observed in the results, suggesting that the techniques provide consistent and accurate characterizations of solar concentrator optics.

  11. A method to determine the number of nanoparticles in a cluster using conventional optical microscopes

    SciTech Connect

    Kang, Hyeonggon; Attota, Ravikiran Tondare, Vipin; Vladár, András E.; Kavuri, Premsagar

    2015-09-07

    We present a method that uses conventional optical microscopes to determine the number of nanoparticles in a cluster, which is typically not possible using traditional image-based optical methods due to the diffraction limit. The method, called through-focus scanning optical microscopy (TSOM), uses a series of optical images taken at varying focus levels to achieve this. The optical images cannot directly resolve the individual nanoparticles, but contain information related to the number of particles. The TSOM method makes use of this information to determine the number of nanoparticles in a cluster. Initial good agreement between the simulations and the measurements is also presented. The TSOM method can be applied to fluorescent and non-fluorescent as well as metallic and non-metallic nano-scale materials, including soft materials, making it attractive for tag-less, high-speed, optical analysis of nanoparticles down to 45 nm diameter.

  12. A novel method of developing all-optical frequency encoded memory unit exploiting nonlinear switching character of semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Kumar Garai, Sisir; Mukhopadhyay, Sourangshu

    2010-10-01

    The very fast running optical memory and optical logic gates are the basic building blocks for any optical computing data processing system. Realization of a very fast memory-cell in the optical domain is very challenging. In the last two decades many methods of implementing all-optical flip-flops have been proposed. Most of these suffer from speed limitation because of low switching response of the active devices. In our present communication the authors propose a method of developing a frequency encoded memory unit based on the switching action of semiconductor optical amplifier (SOA). Nonlinear polarization rotation characters of SOA and 'SOA based Mach-Zehnder Interferometer' switch, i.e. 'SOA-MZI' switch, are exploited for the purpose of some switching action with least switching power (<-3 dB m) and high switching contrast ratio (20 dB). Here two logic states ('0' state and '1' state) of the memory is encoded by two different frequencies, which will remain unchanged throughout the data communication irrespective of loss of light energy due to reflection, refraction, attenuation, etc. Though the SOA based switch runs with the operational speed 100 Gb/s, still due to the presence of the other optical components in the memory unit, the overall speed of the proposed system will come down to 10 Gb/s.

  13. System and method for reproducibly mounting an optical element

    DOEpatents

    Eisenbies, Stephen; Haney, Steven

    2005-05-31

    The present invention provides a two-piece apparatus for holding and aligning the MEMS deformable mirror. The two-piece apparatus comprises a holding plate for fixedly holding an adaptive optics element in an overall optical system and a base spatially fixed with respect to the optical system and adapted for mounting and containing the holding plate. The invention further relates to a means for configuring the holding plate through adjustments to each of a number of off-set pads touching each of three orthogonal plane surfaces on the base, wherein through the adjustments the orientation of the holding plate, and the adaptive optics element attached thereto, can be aligned with respect to the optical system with six degrees of freedom when aligning the plane surface of the optical element. The mounting system thus described also enables an operator to repeatedly remove and restore the adaptive element in the optical system without the need to realign the system once that element has been aligned.

  14. Optical frequency-domain chromatic dispersion measurement method for higher-order modes in an optical fiber.

    PubMed

    Ahn, Tae-Jung; Jung, Yongmin; Oh, Kyunghwan; Kim, Dug Young

    2005-12-12

    We propose a new chromatic dispersion measurement method for the higher-order modes of an optical fiber using optical frequency modulated continuous-wave (FMCW) interferometry. An optical fiber which supports few excited modes was prepared for our experiments. Three different guiding modes of the fiber were identified by using far-field spatial beam profile measurements and confirmed with numerical mode analysis. By using the principle of a conventional FMWC interferometry with a tunable external cavity laser, we have demonstrated that the chromatic dispersion of a few-mode optical fiber can be obtained directly and quantitatively as well as qualitatively. We have also compared our measurement results with those of conventional modulation phase-shift method.

  15. Combined application of optical methods to increase the information content of optical coherent tomography in diagnostics of neoplastic processes

    SciTech Connect

    Kuranov, R V; Sapozhnikova, V V; Shakhova, N M; Gelikonov, V M; Zagainova, E V; Petrova, S A

    2002-11-30

    A combined application of optical methods [optical coherent tomography (OCT), cross-polarisation optical coherent tomography, and fluorescence spectroscopy] is proposed for obtaining information on morphological and biochemical changes occurring in tissues in norm and pathology. It is shown that neoplastic and scar changes in esophagus can be distinguished using a combination of polarisation and standard OCT due to the difference between the depolarising properties of the tissues caused by the structural properties of collagenic fibres in stroma. It is shown that OCT combined with fluorescence spectroscopy with the use of 5-aminolevulinic acid is promising for determining the boundaries of carcinoma of the uterine cervix and vulva. It is found that the tumour boundary detected by optical methods coincides with the morphological boundary and extends beyond colposcopically determined boundary by about 2 mm. (laser biology and medicine)

  16. Probing high quality pentacene monolayers by optical methods

    NASA Astrophysics Data System (ADS)

    He, Rui; Tassi, Nancy G.; Blanchet, Graciela B.; Pinczuk, Aron

    2006-05-01

    We report optical studies of pentacene monolayers grown on poly-alpha-methyl-styrene (PAMS) substrates of high uniformity that reaches into the micron length-scale in the lateral dimension. Raman scattering intensities from a two-monolayer pentacene film exhibit large resonance enhancements when incoming and outgoing photon energies overlap the free exciton measured in optical emission. The incoming and outgoing resonance enhancements are of about the same strength. The free exciton optical emission band is sharp and intense, and it blue-shifts by about 85 meV from that of the pentacene single crystal.

  17. All-optical flip-flop and control methods thereof

    DOEpatents

    Maywar, Drew; Agrawal, Govind P.

    2010-03-23

    Embodiments of the invention pertain to remote optical control of holding beam-type, optical flip-flop devices, as well as to the devices themselves. All-optical SET and RE-SET control signals operate on a cw holding beam in a remote manner to vary the power of the holding beam between threshold switching values to enable flip-flop operation. Cross-gain modulation and cross-polarization modulation processes can be used to change the power of the holding beam.

  18. Analytical study of acousto/optical holography-interfacing methods for acoustical and optical holography NDT research

    NASA Technical Reports Server (NTRS)

    El-Sum, H. M. A.

    1976-01-01

    The international status of the art of acousto optical imaging techniques adaptable to nondestructive testing and, interfacing methods for acoustical and optical holography in nondestructive testing research are studied. Evaluation of 20 different techniques encompassed investigation of varieties of detectors and detection schemes, all of which are described and summarized. Related investigation is reported in an Appendix. Important remarks on image quality, factors to be considered in designing a particular system, and conclusions and recommendations are presented. Three bibliographies are included.

  19. Method and apparatus for optical communication by frequency modulation

    DOEpatents

    Priatko, Gordon J.

    1988-01-01

    Laser optical communication according to this invention is carried out by producing multi-frequency laser beams having different frequencies, splitting one or more of these constituent beams into reference and signal beams, encoding information on the signal beams by frequency modulation and detecting the encoded information by heterodyne techniques. Much more information can be transmitted over optical paths according to the present invention than with the use of only one path as done previously.

  20. Method and apparatus for optical communication by frequency modulation

    SciTech Connect

    Priatko, G.J.

    1988-12-13

    Laser optical communication according to this invention is carried out by producing multi-frequency laser beams having different frequencies, splitting one or more of these constituent beams into reference and signal beams, encoding information on the signal beams by frequency modulation and detecting the encoded information by heterodyne techniques. Much more information can be transmitted over optical paths according to the present invention than with the use of only one path as done previously.

  1. Fiber optic transmission line stabilization apparatus and method

    NASA Technical Reports Server (NTRS)

    Lutes, G. F., Jr.; Lau, K. Y. (Inventor)

    1981-01-01

    A reference signal of RF frequency modulates a 0.85 micrometer wavelength optical transmitter. The output of which passes through a first optical filter and a voltage-controller phase shifter. The output of the phase shifter is provided to the fiber optic transmission line. At the receiving end of the transmission line, the signal is demodulated and used to modulate a 1.06 micrometer optical transmitter. The signal from the transmitter is provided to the fiber optic transmission line and passes through the voltage-controlled phase shifter to a phase error detector. The phase of the modulation of the 1.06 micrometer wavelength signal is compared to the phase of the reference signal by the phase error detector. A phase control signal related to the phase difference is provided to the voltage controlled phase shifter which alters the phase of both optical signals until a predetermined phase relationship between modulation on the 1.06 micrometer signal and the reference signal is obtained.

  2. Adhesive Bubble Removal Method and Apparatus for Fiber Optic Applications

    NASA Technical Reports Server (NTRS)

    Kolasinski, John R. (Inventor)

    2001-01-01

    An assembly for supporting a fiber optic termination or connector in a centrifuge and comprising a cylindrical body member having a top portion adapted to receive the ferrule body portion of a fiber optic termination or connector and a bottom portion for receiving a cylindrical piston/sealing unit is presented. The piston portion of the piston/sealing unit includes a compressible tip which is adapted to a butt up against the outer end of the ferrule body portion of the fiber optic termination or connector. A cylindrical end cap fits over the upper end of the body member for holding the fiber optic termination in place on the body member and causing a seal to be formed between the termination or connector and the upper portion of the body member adjacent the compressible tip of the plunger. The parts, when fitted together, are placed in a centrifuge which is operated for a predetermined spin cycle, so as to cause any bubbles in the uncured liquid adhesive to be vented outwardly from the termination through the end cap. Subsequent removal of the fiber optic termination or connector from the centrifuge and assembly is "bubble free" and ready to be joined with an optical fiber which is inserted in the ferrule end of the termination or connector.

  3. Study of 3D printing method for GRIN micro-optics devices

    NASA Astrophysics Data System (ADS)

    Wang, P. J.; Yeh, J. A.; Hsu, W. Y.; Cheng, Y. C.; Lee, W.; Wu, N. H.; Wu, C. Y.

    2016-03-01

    Conventional optical elements are based on either refractive or reflective optics theory to fulfill the design specifications via optics performance data. In refractive optical lenses, the refractive index of materials and radius of curvature of element surfaces determine the optical power and wavefront aberrations so that optical performance can be further optimized iteratively. Although gradient index (GRIN) phenomenon in optical materials is well studied for more than a half century, the optics theory in lens design via GRIN materials is still yet to be comprehensively investigated before realistic GRIN lenses are manufactured. In this paper, 3D printing method for manufacture of micro-optics devices with special features has been studied based on methods reported in the literatures. Due to the additive nature of the method, GRIN lenses in micro-optics devices seem to be readily achievable if a design methodology is available. First, derivation of ray-tracing formulae is introduced for all possible structures in GRIN lenses. Optics simulation program is employed for characterization of GRIN lenses with performance data given by aberration coefficients in Zernike polynomial. Finally, a proposed structure of 3D printing machine is described with conceptual illustration.

  4. Nonlinear optical methods for cellular imaging and localization.

    PubMed

    McVey, A; Crain, J

    2014-07-01

    Of all the ways in which complex materials (including many biological systems) can be explored, imaging is perhaps the most powerful because delivering high information content directly. This is particular relevant in aspects of cellular localization where the physical proximity of molecules is crucial in biochemical processes. A great deal of effort in imaging has been spent on enabling chemically selective imaging so that only specific features are revealed. This is almost always achieved by adding fluorescent chemical labels to specific molecules. Under appropriate illumination conditions only the molecules (via their labels) will be visible. The technique is simple and elegant but does suffer from fundamental limitations: (1) the fluorescent labels may fade when illuminated (a phenomenon called photobleaching) thereby constantly decreasing signal contrast over the course of image acquisition. To combat photobleaching one must reduce observation times or apply unfavourably low excitation levels all of which reduce the information content of images; (2) the fluorescent species may be deactivated by various environmental factors (the general term is fluorescence quenching); (3) the presence of fluorescent labels may introduce unexpected complications or may interfere with processes of interest (4) Some molecules of interest cannot be labelled. In these circumstances we require a fundamentally different strategy. One of the most promising alternative is based on a technique called Coherent Anti-Stokes Raman scattering (CARS). CARS is a fundamentally more complex process than is fluorescence and the experimental procedures and optical systems required to deliver high quality CARS images are intricate. However, the rewards are correspondingly very high: CARS probes the chemically distinct vibrations of the constituent molecules in a complex system and is therefore also chemically selective as are fluorescence-based methods. Moreover,the potentially severe problems of

  5. Computer-aided alignment method of optical lens with high accuracy

    NASA Astrophysics Data System (ADS)

    Xing, Song; Hou, Xiao-hua; Zhang, Xue-min; Ji, Bin-dong

    2016-09-01

    With the development of space and aviation industry, the optical systems with high resolution and better imaging quality are required. According to the alignment technical process, the factors of every step which have big influence to the imaging quality are analyzed. It is detected that the micro-stress assembly of the optical unit and the high co-axial precision of the entire optical system are the two important factors which are supposed to determine how well the imaging quality of the optical system is; also the technical methods are discussed to ensure these two factors from the engineering view. The reflective interference testing method to measure the surface figure and the transitive interference testing method to measure the wave aberration of the optical unit are combined to ensure the micro-stress assembly of the optical unit, so it will not bring astigmatism to the whole system imaging quality. Optical alignment machining and precision alignment are combined to ensure the high co-axial precision of the optical system. An optical lens of high accuracy is assembled by using these methods; the final wave aberration of optical lens is 0.022λ.

  6. PMD test method in the fiber link with optical amplifier

    NASA Astrophysics Data System (ADS)

    Li, Tangjun; Wang, Muguang; Gong, Xiangfeng; Diao, Cao; Tong, Zhi; Wei, Hui; Jian, Shuisheng

    2005-02-01

    To learn the surrounding conditions in the fiber link and its effect on PMD, and to provide the first-hand design basis, we have carried out the data observation of PMD in a fiber link for a long time. We have tested the first-order and second-order PMD. The fiber tested is the G652 fiber produced by Corning Co. of USA, and the testing distance is 1000km; n segments of same fibers are linked into one, and n equals to 40, that is to say, the length of every segment is 25km; for the requirement of dispersion compensation in the high-speed and long distance fiber optical communication system, one fiber grating dispersion compensator is added in the place of every 200km, and there are five compensators; one EDFA is added in the place of every 100km, and there are eleven EDFA. The result suggests that, with the increase of length of fiber link, the distribution of PMD intends to be stable, that is, with the number n increasing, the relative error of PMD becomes less. The testing methods are the Jones matrix eigenanalysis technique and interference technique. HP8509B fiber polarization analyzer of Agilent in USA is used for measuring instrument of the Jones matrix eigenanalysis technique; FPMD-5600 Femtosecond PMD Analyzer of EXFO in Canada is used for measuring instrument of interference technique. The difference between these two testing methods is analyzed. With the Jones matrix eigenanalysis technique, fibers of 1000km are inspected through 48 hours, and the result suggests that, at nine o'clock in the morning, PMD reaches the maximum, at nine o'clock in the evening, it reaches the minimum, during other time, its change is very little. So it can be concluded that, PMD in the long distance fiber link is affected by temperature of the lab. Stress testing is carried in the ultra-short fiber (less than one meter). PMD has no obvious change in the range of stress which can be endured by the fiber.

  7. Study of GaInNAs Epilayers Using Optical Methods

    NASA Astrophysics Data System (ADS)

    Tsai, Yutsung

    Photovoltaic devices that convert sun's energy into electricity have the potential to influence energy needs on a global scale. A major limitation of single junction solar cells is that only photons with energy slightly above the bandgap are absorbed efficiently. One of the methods is to split the energy of the incoming spectrum into multiple bands each of which is absorbed separately for more efficient collection. That is why multijunction solar cells formed from III-V compound semiconductors are the highest efficiency photovoltaic devices today. To achieve this goal, researchers stack a number of junctions made of different materials with the highest gap material at the top and the lowest at the bottom since each material is transparent to photons with energy smaller than its bandgap. Kurtz [1] predicted an improvement in the performance of multijunction solar cells if a fourth material with bandgap in the 1.0eV-1.05eV range is included between the GaAs (bandgap = 1.42 eV) and Ge (bandgap = 0.67 eV) in the solar cell. In order for this fourth material to be easily incorporated into the GaInP/ GaAs/Ge triple junction device, it must also be lattice matched to germanium. Since it is preferred to grow multijunction solar cells monolithically lattice matching is required making the options for the 1 eV material rather limited. The most promising material for the fourth junction is currently GaInNAs. This is the reason why this thesis concentrates on the study of this material. In this thesis, we have conducted PL, optical pumping, magneto-PL, reflectance and transmission spectroscopic studies of undoped and p-type doped GaInNAs epilayers. The objective of these studies is to investigate the following phenomena in our samples: (a) Localized excitons and free excitons at low temperatures in GaInNAs epilayers: The exciton localization at low temperatures in undoped GaInNAs epilayers results in the S-shape of the PL peaks versus temperature plot. On the other hand, the

  8. Method and system for processing optical materials for high power laser systems

    SciTech Connect

    Demos, Stavros G; Raman, Rajesh; Negres, Raluca A

    2015-02-03

    A method of determining conditioning pulse parameters for an optical element includes directing a pump pulse to impinge on the optical element and directing a probe pulse to impinge on the optical element. The method also includes determining a first time associated with an onset of electronic excitation leading to formation of an absorbing region of the optical element and determining a second time associated with expansion of the absorbing region of the optical element. The method further includes defining a turn-off time for a conditioning pulse between the first time and the second time. According to embodiments of the present invention, pulse shaping of the conditioning pulse enables laser conditioning of optical elements to achieve improvements in their laser induced damage threshold.

  9. Method and apparatus for efficient operation of optically pumped laser

    NASA Technical Reports Server (NTRS)

    Sipes, Jr., Donald L. (Inventor)

    1987-01-01

    An optically pumped single mode laser, e.g., Nd:YAG crystal (20) with planoconcave mirrors is increased in efficiency by an order of magnitude to about 8% by optics (25, 27) for focusing the high power multimode output of laser diode arrays (21, 22) into the mode volume (20') of the laser medium (20). A plurality of these optically pumped single mode lasers (1-4) may be cascaded in a ring with dichroic mirrors (M.sub.1 -M.sub.4) at the corners for coupling in the laser diode arrays, each having its own means for spatially tailoring its beam to concentrate pump distribution inside the lasing mode volume of the medium. An InGaAlAs pump diode (30) with its wavelength the same as the lasing medium makes the ring unidirectional.

  10. High efficiency replicated x-ray optics and fabrication method

    DOEpatents

    Barbee, Jr., Troy W.; Lane, Stephen M.; Hoffman, Donald E.

    2001-01-01

    Replicated x-ray optics are fabricated by sputter deposition of reflecting layers on a super-polished reusable mandrel. The reflecting layers are strengthened by a supporting multilayer that results in stronger stress-relieved reflecting surfaces that do not deform during separation from the mandrel. The supporting multilayer enhances the ability to part the replica from the mandrel without degradation in surface roughness. The reflecting surfaces are comparable in smoothness to the mandrel surface. An outer layer is electrodeposited on the supporting multilayer. A parting layer may be deposited directly on the mandrel before the reflecting surface to facilitate removal of the layered, tubular optic device from the mandrel without deformation. The inner reflecting surface of the shell can be a single layer grazing reflection mirror or a resonant multilayer mirror. The resulting optics can be used in a wide variety of applications, including lithography, microscopy, radiography, tomography, and crystallography.

  11. Low-cost method for producing extreme ultraviolet lithography optics

    DOEpatents

    Folta, James A.; Montcalm, Claude; Taylor, John S.; Spiller, Eberhard A.

    2003-11-21

    Spherical and non-spherical optical elements produced by standard optical figuring and polishing techniques are extremely expensive. Such surfaces can be cheaply produced by diamond turning; however, the roughness in the diamond turned surface prevent their use for EUV lithography. These ripples are smoothed with a coating of polyimide before applying a 60 period Mo/Si multilayer to reflect a wavelength of 134 .ANG. and have obtained peak reflectivities close to 63%. The savings in cost are about a factor of 100.

  12. Fibre Optic Connections And Method For Using Same

    DOEpatents

    Chan, Benson; Cohen, Mitchell S.; Fortier, Paul F.; Freitag, Ladd W.; Hall, Richard R.; Johnson, Glen W.; Lin, How Tzu; Sherman, John H.

    2004-03-30

    A package is described that couples a twelve channel wide fiber optic cable to a twelve channel Vertical Cavity Surface Emitting Laser (VCSEL) transmitter and a multiple channel Perpendicularly Aligned Integrated Die (PAID) receiver. The package allows for reduction in the height of the assembly package by vertically orienting certain dies parallel to the fiber optic cable and horizontally orienting certain other dies. The assembly allows the vertically oriented optoelectronic dies to be perpendicularly attached to the horizontally oriented laminate via a flexible circuit.

  13. Influence of model order reduction methods on dynamical-optical simulations

    NASA Astrophysics Data System (ADS)

    Störkle, Johannes; Eberhard, Peter

    2017-04-01

    In this work, the influence of model order reduction (MOR) methods on optical aberrations is analyzed within a dynamical-optical simulation of a high precision optomechanical system. Therefore, an integrated modeling process and new methods have to be introduced for the computation and investigation of the overall dynamical-optical behavior. For instance, this optical system can be a telescope optic or a lithographic objective. In order to derive a simplified mechanical model for transient time simulations with low computational cost, the method of elastic multibody systems in combination with MOR methods can be used. For this, software tools and interfaces are defined and created. Furthermore, mechanical and optical simulation models are derived and implemented. With these, on the one hand, the mechanical sensitivity can be investigated for arbitrary external excitations and on the other hand, the related optical behavior can be predicted. In order to clarify these methods, academic examples are chosen and the influences of the MOR methods and simulation strategies are analyzed. Finally, the systems are investigated with respect to the mechanical-optical frequency responses, and in conclusion, some recommendations for the application of reduction methods are given.

  14. Shapes, spectra and new methods in nonlinear spatial optics

    NASA Astrophysics Data System (ADS)

    Sun, Can

    For a myriad of optical applications, the quality of the light source is poor and the beam is inherently spatially partially-coherent. For this broad class of systems, wave dynamics depends not only on the wave intensity, but also on its distribution of spatial frequencies. Unfortunately, this entire spectrum of problems has often been overlooked - for reasons of theoretical ease or experimental difficulties. Here, we remedy this by demonstrating a novel experimental setup which, for the first time, allows arbitrarily modulation of the spatial spectra of light to obtain any distribution of interest. Using modulation instability as an example, we isolate the effect of different spectral shapes and observe distinct beam dynamics. Next, we turn to a thermodynamic description of the long-term evolution of statistical fields. For quantum systems, a major consequence is Bose-Einstein Condensation. However, recent theoretical studies have suggested that quantum mechanics is not necessary for the condensation process: classical waves with random phases can also self-organize into a coherent state. Starting from a random ensemble, nonlinear interactions can lead to a turbulent energy cascade towards longer spatial scales. In complete analogy with the kinetics of a gas system, there is a statistical dynamics of waves in which particle velocities map to wavepacket k-vectors while collisions are mimicked by four-wave mixing. As with collisions, each wave interaction is formally reversible, yet entropy principles mandate that the ensemble evolves towards an equilibrium state of maximum disorder. The result is an equipartition of energy, in the form of a Rayleigh-Jeans spectrum, with information about the condensation process recorded in small-scale fluctuations. Here, we give the first experimental observation of the condensation of classical waves in any media. Using classical light in a self-defocusing photorefractive, we observe all aspects of the condensation process

  15. An endoscopic diffuse optical tomographic method with high resolution based on the improved FOCUSS method

    NASA Astrophysics Data System (ADS)

    Qin, Zhuanping; Ma, Wenjuan; Ren, Shuyan; Geng, Liqing; Li, Jing; Yang, Ying; Qin, Yingmei

    2017-02-01

    Endoscopic DOT has the potential to apply to cancer-related imaging in tubular organs. Although the DOT has relatively large tissue penetration depth, the endoscopic DOT is limited by the narrow space of the internal tubular tissue, so as to the relatively small penetration depth. Because some adenocarcinomas including cervical adenocarcinoma are located in deep canal, it is necessary to improve the imaging resolution under the limited measurement condition. To improve the resolution, a new FOCUSS algorithm along with the image reconstruction algorithm based on the effective detection range (EDR) is developed. This algorithm is based on the region of interest (ROI) to reduce the dimensions of the matrix. The shrinking method cuts down the computation burden. To reduce the computational complexity, double conjugate gradient method is used in the matrix inversion. For a typical inner size and optical properties of the cervix-like tubular tissue, reconstructed images from the simulation data demonstrate that the proposed method achieves equivalent image quality to that obtained from the method based on EDR when the target is close the inner boundary of the model, and with higher spatial resolution and quantitative ratio when the targets are far from the inner boundary of the model. The quantitative ratio of reconstructed absorption and reduced scattering coefficient can be up to 70% and 80% under 5mm depth, respectively. Furthermore, the two close targets with different depths can be separated from each other. The proposed method will be useful to the development of endoscopic DOT technologies in tubular organs.

  16. Method for systematically designing polarization optics to maximize sensitivity of electrooptic sensors

    NASA Astrophysics Data System (ADS)

    Sasaki, Ai-ichiro; Furuya, Akinori; Hirata, Akihiko; Morimura, Hiroki; Kodate, Junichi

    2017-09-01

    A systematic design method is considered for maximizing the sensitivity of electrooptic sensors used for electric-field detection. The design method can be reduced to a routine procedure that includes matrix manipulation and differentiation. By applying the design method, the maximum sensitivity is realized with fewer optical components than in conventional electrooptic sensing systems. Since the proposed method shows a wide generality, it can be applied to designing sensors including various optical crystals.

  17. A novel method of developing all optical frequency encoded Fredkin gates

    NASA Astrophysics Data System (ADS)

    Garai, Sisir Kumar

    2014-02-01

    All optical reversible logic gates have significant applications in the field of optics and optoelectronics for developing different sequential and combinational circuits of optical computing, optical signal processing and in multi-valued logic operations and quantum computing. Here the author proposes a method for developing all optical three-input-output Fredkin gate and modified Fredkin gate using frequency encoded data. For this purpose the author has exploited the properties of efficient frequency conversion and faster switching speed of semiconductor optical amplifiers. Simulation results of the three input-output Fredkin gate testifies to the feasibility of the proposed scheme. These Fredkin gates are universal logic gates, and can be used to develop different all-optical logic and data processors in communication network.

  18. Optics Demonstration with Student Eyeglasses Using the Inquiry Method

    ERIC Educational Resources Information Center

    James, Mark C.

    2011-01-01

    A favorite qualitative optics demonstration I perform in introductory physics classes makes use of students' eyeglasses to introduce converging and diverging lenses. Taking on the persona of a magician, I walk to the back of the classroom and approach a student wearing glasses. The top part of Fig. 1 shows a glasses-wearing student who is…

  19. Activities Using Headsticks and Optical Pointers: A Description of Methods.

    ERIC Educational Resources Information Center

    Eriksson, Britt-Marie; And Others

    A variety of head-mounted aids have been developed in the past decade to fill in the functional gaps of children and adults unable to use their hands at standard capacity. For those with speech difficulties, the optical pointer, headstick and mouthstick also provide communication alternatives. This handbook discusses the characteristics of several…

  20. Optics Demonstration with Student Eyeglasses Using the Inquiry Method

    ERIC Educational Resources Information Center

    James, Mark C.

    2011-01-01

    A favorite qualitative optics demonstration I perform in introductory physics classes makes use of students' eyeglasses to introduce converging and diverging lenses. Taking on the persona of a magician, I walk to the back of the classroom and approach a student wearing glasses. The top part of Fig. 1 shows a glasses-wearing student who is…

  1. Methods of restoring spatial phase distribution of complex optical fields

    NASA Astrophysics Data System (ADS)

    Gorsky, M. P.; Ryabyi, P. A.; Angelsky, P. O.

    2016-09-01

    The paper presents principal approaches to diagnosing the structure forming skeleton of the complex optical field. It is shown that intensity distribution smoothing and bicubic spline simulation allow to bring much closer the solution of the phase problem of localization speckle-field special points.

  2. Method based on video imaging to correct the consistency of multi-optical axes

    NASA Astrophysics Data System (ADS)

    Wang, Ning; Li, Ya-can; Fan, Jing-fan; Jiang, Yu-hua; Fan, Fan; Jin, Wei-qi; Wang, Xia

    2010-10-01

    The multi-sensor photoelectric systems, which collect laser ranging, laser-guided radiation, visible light imaging and thermal imaging as a whole, are widely used at modern weaponry platform. The consistency detection of optical axis has become a key to measure these systems' functions. According to the multi-optic-axis consistency detection's requirements, this paper puts forward a new method based on video imaging to correct the consistency of multi-optical axes. This method abandons the traditional methods based on the numerous refractions and reflections between many optical components. It takes laser axis as the base and obtains the exposure point of laser beam in the scene through video imaging technology. Then, by contrasting the exposure point and the TV's optical axis reticle, the TV's optical axis and the laser axis can be adjusted and kept in consistency in the form of electric reticle. According to this method, a set of portable imaging detector prototype that can be used to detect the consistency of multi-optical axes in the outfield has been made. This prototype can achieve the consistency detection of CCD imaging system and thermal imaging system by adjusting them with the laser range finder axis/laser irradiation axis separately. This prototype makes it simple and straightforward to adjust the optical axes by the way of imaging. With easy operation, environmental adaptability and compact structure, this system is suitable for the outfield testing and expected to be used for multi-optic-axis consistency detection online.

  3. A New Method for Determining the Optical Constants of Highly Transparent Solids.

    PubMed

    Li, Xingcan; Wang, Chengchao; Zhao, Junming; Liu, Linhua

    2017-01-01

    Highly transparent substrates are of interest for a variety of applications, but it is difficult to measure their optical constants precisely, especially the absorption index in the transparent spectral region. In this paper, a combination technique (DOPTM-EM) using both the double optical pathlength transmission method (DOPTM) and the ellipsometry method (EM) is presented to obtain the optical constants of highly transparent substrates, which overcomes the deficiencies of both the two methods. The EM cannot give accurate result of optical constants when the absorption index is very weak. The DOPTM is suitable to retrieve the weak absorption index; however, two sets of solutions exist for the retrieved refractive index and absorption index, and only one is the true value that needs to be identified. In the DOPTM-EM, the optical constants are measured first by using the EM and set as the initial value in the gradient-based inverse method used in the DOPTM, which ensures only the true optical constants are retrieved. The new method simultaneously obtains the refractive index and the absorption index of highly transparent substrate without relying on the Kramers-Kronig relation. The optical constants of three highly transparent substrates (polycrystalline BaF2, CaF2, and MgF2) were experimentally determined within wavelength range from ultraviolet to infrared regions (0.2-14 µm). The presented method will facilitate the measurement of optical constants for highly transparent materials.

  4. Single-step method for fiber-optic probe-based full-range spectral domain optical coherence tomography.

    PubMed

    Min, Eun Jung; Shin, Jun Geun; Lee, Jae Hwi; Yasuno, Yoshiaki; Lee, Byeong Ha

    2013-07-20

    We propose a single-step method appropriated for a fiber-optic probe-based full-range spectral domain optical coherence tomography (OCT). The fiber-optic probe was scanned over a sample with a magnetically driven actuator. In the reference arm, a phase shift of π/2 was applied during two neighbor axial scanning, from which the complex spectral interferogram was directly reconstructed. Since the complex-conjugate-free OCT image is obtained by doing just one Fourier transform on the complex interferogram, obtaining the full-range image is simple in algorithm and effective in computation time. Some full-range images of biological samples created with the proposed method are presented and the processing time is analyzed.

  5. "METHOD": A tool for mechanical, electrical, thermal, and optical characterization of single lens module design

    NASA Astrophysics Data System (ADS)

    Besson, Pierre; Dominguez, Cesar; Voarino, Philippe; Garcia-Linares, Pablo; Weick, Clement; Lemiti, Mustapha; Baudrit, Mathieu

    2015-09-01

    The optical characterization and electrical performance evaluation are essential in the design and optimization of a concentrator photovoltaic system. The geometry, materials, and size of concentrator optics are diverse and different environmental conditions impact their performance. CEA has developed a new concentrator photovoltaic system characterization bench, METHOD, which enables multi-physics optimization studies. The lens and cell temperatures are controlled independently with the METHOD to study their isolated effects on the electrical and optical performance of the system. These influences can be studied in terms of their effect on optical efficiency, focal distance, spectral sensitivity, electrical efficiency, or cell current matching. Furthermore, the irradiance map of a concentrator optic can be mapped to study its variations versus the focal length or the lens temperature. The present work shows this application to analyze the performance of a Fresnel lens linking temperature to optical and electrical performance.

  6. THUNDER Piezoelectric Actuators as a Method of Stretch-Tuning an Optical Fiber Grating

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Fox, Robert L.; Froggatt, Mark E.; Childers, Brooks A.

    2000-01-01

    A method of stretching optical fiber holds interest for measuring strain in smart structures where the physical displacement may be used to tune optical fiber lasers. A small, light weight, low power tunable fiber laser is ideal for demodulating strain in optical fiber Bragg gratings attached to smart structures such as the re-usable launch vehicle that is being developed by NASA. A method is presented for stretching optical fibers using the THUNDER piezoelectric actuators invented at NASA Langley Research Center. THUNDER actuators use a piezoelectric layer bonded to a metal backing to enable the actuators to produce displacements larger than the unbonded piezoelectric material. The shift in reflected optical wavelength resulting from stretching the fiber Bragg grating is presented. Means of adapting THUNDER actuators for stretching optical fibers is discussed, including ferrules, ferrule clamp blocks, and plastic hinges made with stereo lithography.

  7. Spatial-light-modulator-based adaptive optical system for the use of multiple phase retrieval methods.

    PubMed

    Lingel, Christian; Haist, Tobias; Osten, Wolfgang

    2016-12-20

    We propose an adaptive optical setup using a spatial light modulator (SLM), which is suitable to perform different phase retrieval methods with varying optical features and without mechanical movement. By this approach, it is possible to test many different phase retrieval methods and their parameters (optical and algorithmic) using one stable setup and without hardware adaption. We show exemplary results for the well-known transport of intensity equation (TIE) method and a new iterative adaptive phase retrieval method, where the object phase is canceled by an inverse phase written into part of the SLM. The measurement results are compared to white light interferometric measurements.

  8. Optical caries diagnostics: comparison of laser spectroscopic PNC method with method of laser integral fluorescence

    NASA Astrophysics Data System (ADS)

    Masychev, Victor I.

    2000-11-01

    In this research we present the results of approbation of two methods of optical caries diagnostics: PNC-spectral diagnostics and caries detection by laser integral fluorescence. The research was conducted in a dental clinic. PNC-method analyses parameters of probing laser radiation and PNC-spectrums of stimulated secondary radiations: backscattering and endogenous fluorescence of caries-involved bacterias. He-Ne-laser ((lambda) =632,8 nm, 1-2mW) was used as a source of probing (stimulated) radiation. For registration of signals, received from intact and pathological teeth PDA-detector was applied. PNC-spectrums were processed by special algorithms, and were displayed on PC monitor. The method of laser integral fluorescence was used for comparison. In this case integral power of fluorescence of human teeth was measured. As a source of probing (stimulated) radiation diode lasers ((lambda) =655 nm, 0.1 mW and 630nm, 1mW) and He-Ne laser were applied. For registration of signals Si-photodetector was used. Integral power was shown in a digital indicator. Advantages and disadvantages of these methods are described in this research. It is disclosed that the method of laser integral power of fluorescence has the following characteristics: simplicity of construction and schema-technical decisions. However the method of PNC-spectral diagnostics are characterized by considerably more sensitivity in diagnostics of initial caries and capability to differentiate pathologies of various stages (for example, calculus/initial caries). Estimation of spectral characteristics of PNC-signals allows eliminating a number of drawbacks, which are character for detection by method of laser integral fluorescence (for instance, detection of fluorescent fillings, plagues, calculus, discolorations generally, amalgam, gold fillings as if it were caries.

  9. Method and means for detecting optically transmitted signals and establishing optical interference pattern between electrodes

    DOEpatents

    Kostenbauder, Adnah G.

    1988-01-01

    A photodetector for detecting signal pulses transmitted in an optical carrier signal relies on the generation of electron-hole pairs and the diffusion of the generated electrons and holes to the electrodes on the surface of the semiconductor detector body for generating photovoltaic pulses. The detector utilizes the interference of optical waves for generating an electron-hole grating within the semiconductor body, and, by establishing an electron-hole pair maximum at one electrode and a minimum at the other electrode, a detectable voltaic pulse is generated across the electrode.

  10. Method and means for detecting optically transmitted signals and establishing optical interference pattern between electrodes

    DOEpatents

    Kostenbauder, A.G.

    1988-06-28

    A photodetector for detecting signal pulses transmitted in an optical carrier signal relies on the generation of electron-hole pairs and the diffusion of the generated electrons and holes to the electrodes on the surface of the semiconductor detector body for generating photovoltaic pulses. The detector utilizes the interference of optical waves for generating an electron-hole grating within the semiconductor body, and, by establishing an electron-hole pair maximum at one electrode and a minimum at the other electrode, a detectable voltaic pulse is generated across the electrode. 4 figs.

  11. Multiscale optical simulation settings: challenging applications handled with an iterative ray-tracing FDTD interface method.

    PubMed

    Leiner, Claude; Nemitz, Wolfgang; Schweitzer, Susanne; Kuna, Ladislav; Wenzl, Franz P; Hartmann, Paul; Satzinger, Valentin; Sommer, Christian

    2016-03-20

    We show that with an appropriate combination of two optical simulation techniques-classical ray-tracing and the finite difference time domain method-an optical device containing multiple diffractive and refractive optical elements can be accurately simulated in an iterative simulation approach. We compare the simulation results with experimental measurements of the device to discuss the applicability and accuracy of our iterative simulation procedure.

  12. Apparatus and Method for Elimination of Polarization-Induced Fading in Fiber-optic Sensor System

    NASA Technical Reports Server (NTRS)

    Chan, Hon Man (Inventor); Parker, Jr., Allen R. (Inventor)

    2015-01-01

    The invention is an apparatus and method of eliminating polarization-induced fading in interferometric fiber-optic sensor system having a wavelength-swept laser optical signal. The interferometric return signal from the sensor arms are combined and provided to a multi-optical path detector assembly and ultimately to a data acquisition and processing unit by way of a switch that is time synchronized with the laser scan sweep cycle.

  13. Photogrammetry and optical methods in structural dynamics - A review

    NASA Astrophysics Data System (ADS)

    Baqersad, Javad; Poozesh, Peyman; Niezrecki, Christopher; Avitabile, Peter

    2017-03-01

    In the last few decades, there has been a surge of research in the area of non-contact measurement techniques. Photogrammetry has received considerable attention due to its ability to achieve full-field measurement and its robustness to work in testing environments and on testing articles in which using other measurement techniques may not be practical. More recently, researchers have used this technique to study transient phenomena and to perform measurements on vibrating structures. The current paper reviews the most current trends in the photogrammetry technique (point tracking, digital image correlation, and target-less approaches) and compares the applications of photogrammetry to other measurement techniques used in structural dynamics (e.g. laser Doppler vibrometry and interferometry techniques). The paper does not present the theoretical background of the optical techniques, but instead presents the general principles of each approach and highlights the novel structural dynamic measurement concepts and applications that are enhanced by utilizing optical techniques.

  14. Method for the protection of extreme ultraviolet lithography optics

    DOEpatents

    Grunow, Philip A.; Clift, Wayne M.; Klebanoff, Leonard E.

    2010-06-22

    A coating for the protection of optical surfaces exposed to a high energy erosive plasma. A gas that can be decomposed by the high energy plasma, such as the xenon plasma used for extreme ultraviolet lithography (EUVL), is injected into the EUVL machine. The decomposition products coat the optical surfaces with a protective coating maintained at less than about 100 .ANG. thick by periodic injections of the gas. Gases that can be used include hydrocarbon gases, particularly methane, PH.sub.3 and H.sub.2S. The use of PH.sub.3 and H.sub.2S is particularly advantageous since films of the plasma-induced decomposition products S and P cannot grow to greater than 10 .ANG. thick in a vacuum atmosphere such as found in an EUVL machine.

  15. Optical efficiency enhancement methods for terahertz receiving photoconductive switches

    NASA Astrophysics Data System (ADS)

    Heshmat, Barmak; Pahlevaninezhad, Hamid; Darcie, Thomas Edward

    2013-12-01

    We improve the efficiency of THz receiving photoconductive switches by improving the conversion of the optical pump to signal current. This is achieved by both optimizing the incident excitation beam polarization and spatial profile of excitation. Due to boundary conditions of the electric field at the electrode edge, a nanometer-sized polarization-dependent shadow is created in the substrate at the electrode edge where most picosecond lifetime photocarriers are collected. This edge effect is further harnessed by elongating the excitation beam next to the stripline electrode. The effects of excitation beam polarization and spatial profile were experimented with InGaAs/InAlAs quantum-well-based photoconductive switch. In both cases notable enhancement in the signal is observed-30% with polarization optimization and up to 100% with beam elongation. Both techniques preserve the pulse quality and are applicable with readily available optical elements.

  16. New Methods for Design and Computation of Freeform Optics

    DTIC Science & Technology

    2015-07-09

    as a partial differential equation(PDE) of second order with nonstandard boundary conditions. The solution to this PDE problem is a scalar function...the exact solution with any a priori given accuracy. By contrast with other approaches the solution obtained with our approach does not depend on ad hoc...strategy for constructing weak solutions to nonlinear partial differential equations arising in design problems involving freeform optical surfaces[10

  17. Optics Demonstration with Student Eyeglasses Using the Inquiry Method

    NASA Astrophysics Data System (ADS)

    James, Mark C.

    2011-09-01

    A favorite qualitative optics demonstration I perform in introductory physics classes makes use of students' eyeglasses to introduce converging and diverging lenses. Taking on the persona of a magician, I walk to the back of the classroom and approach a student wearing glasses. The top part of Fig. 1 shows a glasses-wearing student who is farsighted in her left eye and has a slight astigmatism in her right eye.

  18. The study of plant tissue by optical coherent microscopy method

    NASA Astrophysics Data System (ADS)

    Chirskaya, V. V.; Margaryants, N. B.; Zhukova, E. V.

    2016-08-01

    The article presents the results of application of the optical coherent microscopy technique using a high-resolution automatic Linnik interference microscope to study the structure of plant tissues exemplified by surface periderm layers of a tuberous nightshade (solánum tuberosum) bulb. The results of 3D visualization of the structure of the sample under examination are provided. Scanning depth was 32 µm, with axial and lateral resolution of the device 1 µm.

  19. Applying fiber optical methods for toxicological testing in vitro

    NASA Astrophysics Data System (ADS)

    Maerz, Holger K.; Buchholz, Rainer; Emmrich, Frank; Fink, Frank; Geddes, Clive L.; Pfeifer, Lutz; Raabe, Ferdinand; Scheper, Thomas-Helmut; Ulrich, Elizabeth; Marx, Uwe

    1999-04-01

    The new medical developments, e.g. immune therapy, patient oriented chemotherapy or even gene therapy, create a questionable doubt to the further requirement of animal test. Instead the call for humanitarian reproductive in vitro models becomes increasingly louder. Pharmaceutical usage of in vitro has a long proven history. In cancer research and therapy, the effect of chemostatica in vitro in the so-called oncobiogram is being tested; but the assays do not always correlate with in vivo-like drug resistance and sensitivity. We developed a drug test system in vitro, feasible for therapeutic drug monitoring by the combination of tissue cultivation in hollow fiber bioreactors and fiber optic sensors for monitoring the pharmaceutical effect. Using two fiber optic sensors - an optical oxygen sensor and a metabolism detecting Laserfluoroscope, we were able to successfully monitor the biological status of tissue culture and the drug or toxic effects of in vitro pharmaceutical testing. Furthermore, we developed and patented a system for monitoring the effect of minor toxic compounds which can induce Sick Building Syndrome.

  20. Advanced scanning methods with tracking optical coherence tomography

    PubMed Central

    Ferguson, R. Daniel; Iftimia, Nicusor V.; Ustun, Teoman; Wollstein, Gadi; Ishikawa, Hiroshi; Gabriele, Michelle L.; Dilworth, William D.; Kagemann, Larry; Schuman, Joel S.

    2013-01-01

    An upgraded optical coherence tomography system with integrated retinal tracker (TOCT) was developed. The upgraded system uses improved components to extend the tracking bandwidth, fully integrates the tracking hardware into the optical head of the clinical OCT system, and operates from a single software platform. The system was able to achieve transverse scan registration with sub-pixel accuracy (~10 μm). We demonstrate several advanced scan sequences with the TOCT, including composite scans averaged (co-added) from multiple B-scans taken consecutively and several hours apart, en face images collected by summing the A-scans of circular, line, and raster scans, and three-dimensional (3D) retinal maps of the fovea and optic disc. The new system achieves highly accurate OCT scan registration yielding composite images with significantly improved spatial resolution, increased signal-to-noise ratio, and reduced speckle while maintaining well-defined boundaries and sharp fine structure compared to single scans. Precise re-registration of multiple scans over separate imaging sessions demonstrates TOCT utility for longitudinal studies. En face images and 3D data cubes generated from these data reveal high fidelity image registration with tracking, despite scan durations of more than one minute. PMID:19498823

  1. Improved Method for Laser Damage Testing Coated Optics

    SciTech Connect

    Borden, M R; Folta, J A; Stolz, C J; Taylor, J R; Wolfe, J E; Griffin, A J; Thomas, M D

    2005-10-25

    The damage test procedure for qualifying a coating run of anti-reflection coated optics consists of scanning a pulsed 1064 nm laser over a 1 cm x 1 cm area on a test sample to illuminate approximately 2400 sites. Scans are repeated at 3 J/cm{sup 2} increments until the fluence specification for the optic is reached. In the past, initiation of 1 or more damage sites was classified as a failed coating run, requiring the production optics in the corresponding coating lot be reworked and recoated. Recent laser damage growth tests of 300 repetitive pulses performed on numerous damage sites revealed that all were stable up to 20 J/cm{sup 2}. Therefore the acceptance criteria has been modified to allow a moderate number of damage sites, as long as they are smaller than the allowed dig size and are stable (do not grow). Consequently many coating runs that previously would have been rejected are now accepted, resulting in higher yield, lower cost, and improved delivery schedule. The new test also provides assurance that initiated damage sites are stable during long term operation.

  2. Effects of fiber manipulation methods on optical fiber properties

    NASA Astrophysics Data System (ADS)

    Reynolds, Robert O.; Bechter, Andrew; Crass, Jonathan

    2016-07-01

    Optical fibers are routinely used to couple high-resolution spectrographs to modern telescopes, enabling important advantages in areas such as the search for extrasolar planets using spectroscopic radial velocity measurements of candidate stars. Optical fibers partially scramble the input illumination, and this feature enables a fiber feed to provide more uniform illumination to the spectrograph optics, thereby reducing systematic errors in radial velocity measurements. However fibers suffer from focal ratio degradation (FRD), a spreading of the beam at the output of the fiber with respect to that at the fiber input, which results in losses in throughput and resolution. Modal noise, a measurement uncertainty caused by inherent fiber properties and evident as a varying spatial intensity at the fiber exit plane, reduces the signal to noise ratio in the data. Devices such as double scramblers are often used to improve scrambling, and better fiber end preparation can mitigate FRD. Many instruments agitate the fiber during an observation to reduce modal noise, and stretching the fiber during use has been shown to offer a greater reduction in that noise. But effects of agitation and stretching on fiber parameters such as total transmission and focal ratio degradation have not been adequately studied. In this paper we present measurements of transmission loss and focal ratio degradation for both agitated and stretched fibers.

  3. Detection and laser ranging of orbital objects using optical methods

    NASA Astrophysics Data System (ADS)

    Wagner, P.; Hampf, D.; Sproll, F.; Hasenohr, T.; Humbert, L.; Rodmann, J.; Riede, W.

    2016-09-01

    Laser ranging to satellites (SLR) in earth orbit is an established technology used for geodesy, fundamental science and precise orbit determination. A combined active and passive optical measurement system using a single telescope mount is presented which performs precise ranging measurements of retro reflector equipped objects in low earth orbit (LEO). The German Aerospace Center (DLR) runs an observatory in Stuttgart where a system has been assembled completely from commercial off-the-shelf (COTS) components. The visible light directed to the tracking camera is used to perform angular measurements of objects under investigation. This is done astrometrically by comparing the apparent target position with cataloged star positions. First successful satellite laser ranging was demonstrated recently using an optical fiber directing laser pulses onto the astronomical mount. The transmitter operates at a wavelength of 1064 nm with a repetition rate of 3 kHz and pulse energy of 25 μJ. A motorized tip/tilt mount allows beam steering of the collimated beam with μrad accuracy. The returning photons reflected from the object in space are captured with the tracking telescope. A special low aberration beam splitter unit was designed to separate the infrared from visible light. This allows passive optical closed loop tracking and operation of a single photon detector for time of flight measurements at a single telescope simultaneously. The presented innovative design yields to a compact and cost effective but very precise ranging system which allows orbit determination.

  4. Light, sound, chemistry… action: state of the art optical methods for animal imaging.

    PubMed

    Ripoll, Jorge; Ntziachristos, Vasilis

    2011-01-01

    During recent years, macroscopic optical methods have been promoted from backstage to main actors in biological imaging. Many possible forms of energy conservation have been explored that involve light, including fluorescence emission, sound generated through absorption and bioluminescence, that is light generated through a chemical reaction. These physicochemical approaches for contrast generation have resulted in optical imaging methods that come with potent performance characteristics over simple epi-illumination optical imaging approaches of the past, and can play a central role in imaging applications in vivo as it pertains to modern biological and drug discovery, pre-clinical imaging and clinical applications. This review focuses on state of the art optical and opto-acoustic (photo-acoustic) imaging methods and discusses key performance characteristics that convert optical imaging from a qualitative modality to a powerful high-resolution and quantitative volumetric interrogation tool for operation through several millimeters of tissue depth.: © 2011 Elsevier Ltd . All rights reserved.

  5. Improved retrievals of the optical properties of cirrus clouds by a combination of lidar methods.

    PubMed

    Cadet, Bertrand; Giraud, Vincent; Haeffelin, Martial; Keckhut, Philippe; Rechou, Anne; Baldy, Serge

    2005-03-20

    We focus on improvement of the retrieval of optical properties of cirrus clouds by combining two lidar methods. We retrieve the cloud's optical depth by using independently the molecular backscattering profile below and above the cloud [molecular integration (MI) method] and the backscattering profile inside the cloud with an a priori effective lidar ratio [particle integration (PI) method]. When the MI method is reliable, the combined MI-PI method allows us to retrieve the optimal effective lidar ratio. We compare these results with Raman lidar retrievals. We then use the derived optimal effective lidar ratio for retrieval with the PI method for situations in which the MI method cannot be applied.

  6. Electro-optical deflectors as a method of beam smoothing for Inertial Confinement Fusion

    SciTech Connect

    Rothenberg, J.E.

    1997-01-01

    The electro-optic deflector is analyzed and compared to smoothing by spectral dispersion for efficacy as a beam smoothing method for ICF. It is found that the electro-optic deflector is inherently somewhat less efficient when compared either on the basis of equal peak phase modulation or equal generated bandwidth.

  7. An Auto-Focusing Method in a Microscopic Testbed for Optical Discs.

    PubMed

    Tang, X; L'Hostis, P; Xiao, Y

    2000-01-01

    An auto-focusing method in a digital image system is demonstrated that uses a standard deviation of pixel gray levels as a feedback signal. In this system, an optical microscope and a charge coupled device (CCD) camera are used to create clear pit images of optical discs. A dynamic focusing scheme is designed in the system-control software, which is able to eliminate environmental disturbances and other noises so that a fast and stable focus can be achieved. The method shows an excellent focusing accuracy. The performance and possible applications of this method are discussed. The test results for optical discs are given in this paper.

  8. Simulation method of spatial laser field for arbitrary distance optical transmission with carbon nanotube

    NASA Astrophysics Data System (ADS)

    Wang, Jianmin; Bai, Rumeng; Zhou, Ye; Zhao, Guang

    2017-06-01

    In this paper, an arbitrary distance optical transmission simulation method for free-space optical communication system is presented. Based on this method, direct point-to-point performance tests between two optical terminals can be realized in the laboratory, and the test results are equivalent to those on-orbit. A theoretical analysis of this method is presented in this paper. Verification experiments showed that there is a good linearity between the incoming power density and output photocurrent of the carbon nanotube (CNT); the relative power difference between the CNT and the charge-coupled device (CCD) camera is 4.75%, which can be ignored compared with the link redundancy.

  9. Optical Device, System, and Method of Generating High Angular Momentum Beams

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy A. (Inventor); Matsko, Andrey B. (Inventor); Strekalov, Dmitry V. (Inventor); Grudinin, Ivan S. (Inventor); Maleki, Lute (Inventor)

    2009-01-01

    An optical device, optical system, and method of generating optical beams having high angular momenta are provided. The optical device includes a whispering gallery mode resonator defining a resonator radius and an elongated wavegWde having a length defined between a first end and a second end of the waveguide. The waveguide defines a waveguide radius which increases at least along a portion of the length of the waveguide in a direction from the first end to the second end. The waveguide radius at the first end of the waveguide is smaller than the resonator radius and the resonator is integrally formed with the first end of the waveguide.

  10. Evaluating optical aberrations using fluorescent microspheres: methods, analysis, and corrective actions.

    PubMed

    Goodwin, Paul C

    2013-01-01

    Obtaining optimal performance from a microscopy system requires careful evaluation of the entire optics train of the imaging system. This evaluation starts with a fundamental evaluation of the optical components in the microscope. Concise and visual methods are provided for understanding the optical performance of the microscope as a system using subdiffraction fluorescent microspheres to evaluate both monochromatic and polychromatic aberrations. Further practical guides are given to troubleshooting optical problems and final comments are made on optimizing sample preparation. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Cryogenic fiber optic temperature sensor and method of manufacturing the same

    NASA Technical Reports Server (NTRS)

    Kochergin, Vladimir (Inventor)

    2012-01-01

    This invention teaches the fiber optic sensors temperature sensors for cryogenic temperature range with improved sensitivity and resolution, and method of making said sensors. In more detail, the present invention is related to enhancement of temperature sensitivity of fiber optic temperature sensors at cryogenic temperatures by utilizing nanomaterials with a thermal expansion coefficient that is smaller than the thermal expansion coefficient of the optical fiber but larger in absolute value than the thermal expansion coefficient of the optical fiber at least over a range of temperatures.

  12. Method to adjust multilayer film stress induced deformation of optics

    DOEpatents

    Spiller, Eberhard A.; Mirkarimi, Paul B.; Montcalm, Claude; Bajt, Sasa; Folta, James A.

    2000-01-01

    Stress compensating systems that reduces/compensates stress in a multilayer without loss in reflectivity, while reducing total film thickness compared to the earlier buffer-layer approach. The stress free multilayer systems contain multilayer systems with two different material combinations of opposite stress, where both systems give good reflectivity at the design wavelengths. The main advantage of the multilayer system design is that stress reduction does not require the deposition of any additional layers, as in the buffer layer approach. If the optical performance of the two systems at the design wavelength differ, the system with the poorer performance is deposited first, and then the system with better performance last, thus forming the top of the multilayer system. The components for the stress reducing layer are chosen among materials that have opposite stress to that of the preferred multilayer reflecting stack and simultaneously have optical constants that allow one to get good reflectivity at the design wavelength. For a wavelength of 13.4 nm, the wavelength presently used for extreme ultraviolet (EUV) lithography, Si and Be have practically the same optical constants, but the Mo/Si multilayer has opposite stress than the Mo/Be multilayer. Multilayer systems of these materials have practically identical reflectivity curves. For example, stress free multilayers can be formed on a substrate using Mo/Be multilayers in the bottom of the stack and Mo/Si multilayers at the top of the stack, with the switch-over point selected to obtain zero stress. In this multilayer system, the switch-over point is at about the half point of the total thickness of the stack, and for the Mo/Be--Mo/Si system, there may be 25 deposition periods Mo/Be to 20 deposition periods Mo/Si.

  13. Comparison of Three Optical Methods for Measuring Model Deformation

    NASA Technical Reports Server (NTRS)

    Burner, A. W.; Fleming, G. A.; Hoppe, J. C.

    2000-01-01

    The objective of this paper is to compare the current state-of-the-art of the following three optical techniques under study by NASA for measuring model deformation in wind tunnels: (1) video photogrammetry, (2) projection moire interferometry, and (3) the commercially available Optotrak system. An objective comparison of these three techniques should enable the selection of the best technique for a particular test undertaken at various NASA facilities. As might be expected, no one technique is best for all applications. The techniques are also not necessarily mutually exclusive and in some cases can be complementary to one another.

  14. One step geometrical calibration method for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Díaz Díaz, Jesús; Stritzel, Jenny; Rahlves, Maik; Majdani, Omid; Reithmeier, Eduard; Ortmaier, Tobias; Roth, Bernhard

    2016-01-01

    We present a novel one-step calibration methodology for geometrical distortion correction for optical coherence tomography (OCT). A calibration standard especially designed for OCT is introduced, which consists of an array of inverse pyramidal structures. The use of multiple landmarks situated on four different height levels on the pyramids allow performing a 3D geometrical calibration. The calibration procedure itself is based on a parametric model of the OCT beam propagation. It is validated by experimental results and enables the reduction of systematic errors by more than one order of magnitude. In future, our results can improve OCT image reconstruction and interpretation for medical applications such as real time monitoring of surgery.

  15. Method and apparatus for optical encoding with compressible imaging

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B. (Inventor)

    2006-01-01

    The present invention presents an optical encoder with increased conversion rates. Improvement in the conversion rate is a result of combining changes in the pattern recognition encoder's scale pattern with an image sensor readout technique which takes full advantage of those changes, and lends itself to operation by modern, high-speed, ultra-compact microprocessors and digital signal processors (DSP) or field programmable gate array (FPGA) logic elements which can process encoder scale images at the highest speeds. Through these improvements, all three components of conversion time (reciprocal conversion rate)--namely exposure time, image readout time, and image processing time--are minimized.

  16. System and method for optical monitoring of a combustion flame

    DOEpatents

    Brown, Dale M; Sandvik, Peter M; Fedison, Jeffrey B; Matocha, Kevin S; Johnson, Thomas E

    2006-09-26

    An optical spectrometer for combustion flame temperature determination includes at least two photodetectors positioned for receiving light from a combustion flame, each of the at least two photodetectors having a different, overlapping bandwidth for detecting a respective output signal in an ultraviolet emission band; and a computer for subtracting a respective output signal of a first one of the at least two photodetectors from a respective output signal of a second one of the at least two photodetectors to obtain a segment signal, and using the segment signal to determine the combustion flame temperature.

  17. Method of forming silicon structures with selectable optical characteristics

    NASA Technical Reports Server (NTRS)

    Fathauer, Robert W. (Inventor); Schowalter, Leo (Inventor)

    1993-01-01

    Silicon and metal are coevaporated onto a silicon substrate in a molecular beam epitaxy system with a larger than stoichiometric amount of silicon so as to epitaxially grow particles of metal silicide embedded in a matrix of single crystal epitaxially grown silicon. The particles interact with incident photons by resonant optical absorption at the surface plasmon resonance frequency. Controlling the substrate temperature and deposition rate and time allows the aspect ratio of the particles to be tailored to desired wavelength photons and polarizations. The plasmon energy may decay as excited charge carriers or phonons, either of which can be monitored to indicate the amount of incident radiation at the selected frequency and polarization.

  18. Optical-diffraction method for determining crystal orientation

    DOEpatents

    Sopori, B.L.

    1982-05-07

    Disclosed is an optical diffraction technique for characterizing the three-dimensional orientation of a crystal sample. An arbitrary surface of the crystal sample is texture etched so as to generate a pseudo-periodic diffraction grating on the surface. A laser light beam is then directed onto the etched surface, and the reflected light forms a farfield diffraction pattern in reflection. Parameters of the diffraction pattern, such as the geometry and angular dispersion of the diffracted beam are then related to grating shape of the etched surface which is in turn related to crystal orientation. This technique may be used for examining polycrystalline silicon for use in solar cells.

  19. Fiber-optic delay-line stabilization of heterodyne optical signal generator and method using same

    NASA Technical Reports Server (NTRS)

    Logan, Ronald T. (Inventor)

    1997-01-01

    The present invention is a laser heterodyne frequency generator system with a stabilizer for use in the microwave and millimeter-wave frequency ranges utilizing a photonic mixer as a photonic phase detector in a stable optical fiber delay-line. Phase and frequency fluctuations of the heterodyne laser signal generators are stabilized at microwave and millimeter wave frequencies by a delay line system operating as a frequency discriminator. The present invention is free from amplifier and mixer 1/.function. noise at microwave and millimeter-wave frequencies that typically limit phase noise performance in electronic cavity stabilized electronic oscillators. Thus, 1/.function. noise due to conventional mixers is eliminated and stable optical heterodyne generation of electrical signals is achieved.

  20. Optical near-field analysis of spherical metals: Application of the FDTD method combined with the ADE method.

    PubMed

    Yamaguchi, Takashi; Hinata, Takashi

    2007-09-03

    The time-average energy density of the optical near-field generated around a metallic sphere is computed using the finite-difference time-domain method. To check the accuracy, the numerical results are compared with the rigorous solutions by Mie theory. The Lorentz-Drude model, which is coupled with Maxwell's equation via motion equations of an electron, is applied to simulate the dispersion relation of metallic materials. The distributions of the optical near-filed generated around a metallic hemisphere and a metallic spheroid are also computed, and strong optical near-fields are obtained at the rim of them.

  1. Evaluation of a time-resolved stress detection method to determine tissue optical properties

    NASA Astrophysics Data System (ADS)

    Vijverberg, Helene; Thomsen, Sharon L.; Jacques, Steven L.; Oraevsky, Alexander A.

    1995-01-01

    A new method to determine optical properties of biological tissue, time-resolved stress detection (TRSD), was tested on albino rat skin, heated in vitro. The TRSD method is based on the detection of pressure waves that are generated by short laser pulses. The pressure waves carry information about the optical properties (absorption and effective attenuation coefficients) of the medium. The evaluation was done in a systematic way by comparing the results of the TRSD method with results obtained using an integrating sphere. Measurements for both methods were performed on the same skin samples to minimize biological variations. The TRSD method proved to be reasonably successful to determine optical properties of tissue for the used wavelength of 355 nm: (1) The effective attenuation coefficients of both methods agreed very well; (2) The TRSD method gave absorption coefficients of a factor 2 + 0.5 times higher than the integrating sphere method; and (3) The reduced scattering coefficients were sensitive to error.

  2. Optics-Only Calibration of a Neural-Net Based Optical NDE Method for Structural Health Monitoring

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.

    2004-01-01

    A calibration process is presented that uses optical measurements alone to calibrate a neural-net based NDE method. The method itself detects small changes in the vibration mode shapes of structures. The optics-only calibration process confirms previous work that the sensitivity to vibration-amplitude changes can be as small as 10 nanometers. A more practical value in an NDE service laboratory is shown to be 50 nanometers. Both model-generated and experimental calibrations are demonstrated using two implementations of the calibration technique. The implementations are based on previously published demonstrations of the NDE method and an alternative calibration procedure that depends on comparing neural-net and point sensor measurements. The optics-only calibration method, unlike the alternative method, does not require modifications of the structure being tested or the creation of calibration objects. The calibration process can be used to test improvements in the NDE process and to develop a vibration-mode-independence of damagedetection sensitivity. The calibration effort was intended to support NASA s objective to promote safety in the operations of ground test facilities or aviation safety, in general, by allowing the detection of the gradual onset of structural changes and damage.

  3. Research on the Calculation Method of Optical Path Difference of the Shanghai Tian Ma Telescope

    NASA Astrophysics Data System (ADS)

    Dong, J.; Fu, L.; Jiang, Y. B.; Liu, Q. H.; Gou, W.; Yan, F.

    2016-03-01

    Based on the Shanghai Tian Ma Telescope (TM), an optical path difference calculation method of the shaped Cassegrain antenna is presented in the paper. Firstly, the mathematical model of the TM optics is established based on the antenna reciprocity theorem. Secondly, the TM sub-reflector and main reflector are fitted by the Non-Uniform Rational B-Splines (NURBS). Finally, the method of optical path difference calculation is implemented, and the expanding application of the Ruze optical path difference formulas in the TM is researched. The method can be used to calculate the optical path difference distributions across the aperture field of the TM due to misalignment like the axial and lateral displacements of the feed and sub-reflector, or the tilt of the sub-reflector. When the misalignment quantity is small, the expanding Ruze optical path difference formulas can be used to calculate the optical path difference quickly. The paper supports the real-time measurement and adjustment of the TM structure. The research has universality, and can provide reference for the optical path difference calculation of other radio telescopes with shaped surfaces.

  4. Methods for Manipulating CaF Using Optical Polychromatic Forces

    NASA Astrophysics Data System (ADS)

    Eyler, Edward E.; Galica, Scott E.; Aldridge, Leland M.

    2013-06-01

    We are undertaking theoretical and experimental studies of laser deceleration and cooling of molecules using coherent multi-frequency optical forces. A primary objective is to reduce radiative loss into dark states when a pure two-level cycling transition is unavailable. The optical bichromatic force (BCF) can multiply the available velocity change for a given number of radiative cycles, by employing alternating cycles of excitation and stimulated emission from opposing directions. Tests in atomic helium show that when the BCF is combined with frequency chirping, very large decelerations are achieved. We report numerical studies of variations intended to further optimize deceleration, including a 4-color version. We describe progress on experimental tests using the 531 nm B ^2Σ^+leftrightarrow X ^2Σ^+ transition in CaF. We also describe low-cost lasers and electronics developed for these experiments. Several versatile new instruments are based on 32-bit microcontrollers, interfaced to an Android tablet that provides a touch-screen graphical interface. These include a timing/ramp generator, a PZT driver, a temperature controller, and even a phase-synchronized dual 35-4000 MHz rf synthesizer that fits on a 2 1/4" × 4 3/4" board. This research is supported by the National Science Foundation. M.A. Chieda and E.E. Eyler, Phys. Rev. A 86, 053415 (2012); also Phys. Rev. A 84, 063401 (2011).

  5. Cell death monitoring using quantitative optical coherence tomography methods

    NASA Astrophysics Data System (ADS)

    Farhat, Golnaz; Yang, Victor X. D.; Kolios, Michael C.; Czarnota, Gregory J.

    2011-03-01

    Cell death is characterized by a series of predictable morphological changes, which modify the light scattering properties of cells. We present a multi-parametric approach to detecting changes in subcellular morphology related to cell death using optical coherence tomography (OCT). Optical coherence tomography data were acquired from acute myeloid leukemia (AML) cells undergoing apoptosis over a period of 48 hours. Integrated backscatter (IB) and spectral slope (SS) were computed from OCT backscatter spectra and statistical parameters were extracted from a generalized gamma (GG) distribution fit to OCT signal intensity histograms. The IB increased by 2-fold over 48 hours with significant increases observed as early as 4 hours. The SS increased in steepness by 2.5-fold with significant changes at 12 hours, while the GG parameters were sensitive to apoptotic changes at 24 to 48 hours. Histology slides indicated nuclear condensation and fragmentation at 24 hours, suggesting the late scattering changes could be related to nuclear structure. A second series of measurements from AML cells treated with cisplatin, colchicine or ionizing radiation suggested that the GG parameters could potentially differentiate between modes of cell death. Distinct cellular morphology was observed in histology slides obtained from cells treated under each condition.

  6. The optical method for investigation of the peritonitis progressing process

    NASA Astrophysics Data System (ADS)

    Guminetskiy, S. H.; Ushenko, O. G.; Polyanskiy, I. P.; Motrych, A. V.; Grynchuk, F. V.

    2008-05-01

    There have been given the results of the spectrophotometric examination of the dogs' and rats' venous and whole blood plasma taken in the process of the peritonitis progressing within the spectral interval λ = 220 - 320 nm (for plasma) and λ = 350 - 610 nm (for the whole blood). It has been defined that D-optical density values in the field of the long-waved maximum of plasma absorption intensity of the venous blood at λ = 280 nm depend upon the intensity of the inflammatory process and also upon the circumstances against the background of which it started to progress. It was found out that the dynamics of D= values changes for λ = 540 (or 570) nm in the process of the peritonitis progressing in case of the whole blood taken from a portal vein is a mirror symmetrical if to compare to the same dynamics for the blood from cava inferior. The defined conformities with regularities may have a diagnostic meaning. It was also found out that the biggest influence upon the dynamics of D-values at λ = 280nm of the venous blood plasma has the content of the circulating immune complexes, necrosis factor of α-tumors and interleukin - 2, the changes of which explain for almost on 100% the distribution of the optical density parameters and what proves a possible immunologic explanation of its changes.

  7. Optical methods for quantitative and label-free sensing in living human tissues: principles, techniques, and applications.

    PubMed

    Wilson, Robert H; Vishwanath, Karthik; Mycek, Mary-Ann

    2016-01-01

    We present an overview of quantitative and label-free optical methods used to characterize living biological tissues, with an emphasis on emerging applications in clinical tissue diagnostics. Specifically, this review focuses on diffuse optical spectroscopy, imaging, and tomography, optical coherence-based techniques, and non-linear optical methods for molecular imaging. The potential for non- or minimally-invasive assessment, quantitative diagnostics, and continuous monitoring enabled by these tissue-optics technologies provides significant promise for continued clinical translation.

  8. An Optical Fiber Lateral Displacement Measurement Method and Experiments Based on Reflective Grating Panel

    PubMed Central

    Li, Yuhe; Guan, Kaisen; Hu, Zhaohui; Chen, Yanxiang

    2016-01-01

    An optical fiber sensing method based on a reflective grating panel is demonstrated for lateral displacement measurement. The reflective panel is a homemade grating with a periodic variation of its refractive index, which is used to modulate the reflected light intensity. The system structure and operation principle are illustrated in detail. The intensity calculation and simulation of the optical path are carried out to theoretically analyze the measurement performance. A distinctive fiber optic grating ruler with a special fiber optic measuring probe and reflective grating panel is set up. Experiments with different grating pitches are conducted, and long-distance measurements are executed to accomplish the functions of counting optical signals, subdivision, and discerning direction. Experimental results show that the proposed measurement method can be used to detect lateral displacement, especially for applications in working environments with high temperatures. PMID:27271624

  9. An Optical Fiber Lateral Displacement Measurement Method and Experiments Based on Reflective Grating Panel.

    PubMed

    Li, Yuhe; Guan, Kaisen; Hu, Zhaohui; Chen, Yanxiang

    2016-06-02

    An optical fiber sensing method based on a reflective grating panel is demonstrated for lateral displacement measurement. The reflective panel is a homemade grating with a periodic variation of its refractive index, which is used to modulate the reflected light intensity. The system structure and operation principle are illustrated in detail. The intensity calculation and simulation of the optical path are carried out to theoretically analyze the measurement performance. A distinctive fiber optic grating ruler with a special fiber optic measuring probe and reflective grating panel is set up. Experiments with different grating pitches are conducted, and long-distance measurements are executed to accomplish the functions of counting optical signals, subdivision, and discerning direction. Experimental results show that the proposed measurement method can be used to detect lateral displacement, especially for applications in working environments with high temperatures.

  10. SiPM electro-optical detection system noise suppression method

    NASA Astrophysics Data System (ADS)

    Bi, Xiangli; Yang, Suhui; Hu, Tao; Song, Yiheng

    2014-11-01

    In this paper, the single photon detection principle of Silicon Photomultipliers (SiPM) device is introduced. The main noise factors that infect the sensitivity of the electro-optical detection system are analyzed, including background light noise, detector dark noise, preamplifier noise and signal light noise etc. The Optical, electrical and thermodynamic methods are used to suppress the SiPM electro-optical detection system noise, which improved the response sensitivity of the detector. Using SiPM optoelectronic detector with a even high sensitivity, together with small field large aperture optical system, high cutoff narrow bandwidth filters, low-noise operational amplifier circuit, the modular design of functional circuit, semiconductor refrigeration technology, greatly improved the sensitivity of optical detection system, reduced system noise and achieved long-range detection of weak laser radiation signal. Theoretical analysis and experimental results show that the proposed methods are reasonable and efficient.

  11. Multispeed rewritable optical-recording method with an initialization-free phase-change disk.

    PubMed

    Miao, Xiang Shui; Shi, Lu Ping; Tan, Pik Kee; Li, Jian Ming; Lim, Kian Guan; Hu, Xiang; Chong, Tow Chong

    2004-02-10

    A new method of multispeed rewritable optical recording is presented. An initialization-free phase-change optical disk is proposed as a candidate for multispeed rewritable optical recording. The simulated results of the initialization-free disk at different linear velocities show that the cooling rate increases from approximately 18.69% to 37.96%. A model that combines the crystallization acceleration effect due to the additional layers and the rapid cooling rate due to the initialization-free disk structure is proposed as the physical mechanism of the multispeed recording method with an initialization-free disk. The dynamic optical-recording properties of the initialization-free DVD-RAM disk at different recording speeds shows that the initialization-free phase-change optical-recording disk is compatible with a broad range of recording speeds from 3.49 to 12.21 m/s.

  12. New method for the improvement of data link dependency of fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Lau, Matthias; Renschen, Claus P.

    1993-03-01

    In the field of optic sensors, in most applications, the measurement of intensity is of main interest. There are many sensors, which by means of fiber optic evanescent spectroscopy are used to measure the temperature, concentration of methane or carbon dioxide in fiber optic transmission cells and glucose or other important substances. Using these sensors, the compensation of the influence at the data link dependencies is problematic. There are several proposals to compensate these influences. Among them there are the utilization of two or more wavelengths, the earliest possible digital conversion and the application of optical bridges. However, these methods are circumstantial and problems cannot be solved in general. A new method for the compensation of fiber optical connectors is presented.

  13. All-optical beam deflection method for simultaneous thermal conductivity and thermo-optic coefficient ( d n / d T ) measurements

    NASA Astrophysics Data System (ADS)

    Putnam, Shawn A.; Fairchild, Steven B.; Arends, Armando A.; Urbas, Augustine M.

    2016-05-01

    This work describes an all-optical beam deflection method to simultaneously measure the thermal conductivity ( Λ) and thermo-optic coefficient ( d n / d T ) of materials that are absorbing at λ = 10.6 μm and are transparent to semi-transparent at λ = 632.8 nm. The technique is based on the principle of measuring the beam deflection of a probe beam (632.8 nm) in the frequency-domain due to a spatially and temporally varying index gradient that is thermally induced by 50:50 split pump beam from a CO2 laser (10.6 μm). The technique and analysis methods are validated with measurements of 10 different optical materials having Λ and d n / d T properties ranging between 0.7 W/m K ≲ Λ ≲ 33.5 W/m K and -12 × 10-6 K-1 ≲ d n / d T ≲ 14 × 10-6 K-1, respectively. The described beam deflection technique is highly related to other well-established, all-optical materials characterization methods, namely, thermal lensing and photothermal deflection spectroscopy. Likewise, due to its all-optical, pump-probe nature, it is applicable to materials characterization in extreme environments with minimal errors due to black-body radiation. In addition, the measurement principle can be extended over a broad range of electromagnetic wavelengths (e.g., ultraviolet to THz) provided the required sources, detectors, and focusing elements are available.

  14. [A reflection interference method for determining optical constants and thickness of a thin solid film].

    PubMed

    Yang, P; Xu, Z; Xu, L

    2000-06-01

    In this paper we report a simple method for deducing optical constants and thickness from the reflection interference spectrum of a thin transparent film which is on a substrate of high reflection coefficient. When a light beam is incident on the surface of the film, the reflection light beams at the front and rear faces are coherent. We calculated the optical constants and thickness of the film from the reflection spectrum. This simple method makes a directly programmable calculation possible.

  15. Method of bundling rods so as to form an optical fiber preform

    DOEpatents

    Kliner, Dahv A. V.; Koplow, Jeffery P.

    2004-03-30

    The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

  16. Method of optical coherence tomography with parallel depth-resolved signal reception and fibre-optic phase modulators

    SciTech Connect

    Morozov, A N; Turchin, I V

    2013-12-31

    The method of optical coherence tomography with the scheme of parallel reception of the interference signal (P-OCT) is developed on the basis of spatial paralleling of the reference wave by means of a phase diffraction grating producing the appropriate time delay in the Mach–Zehnder interferometer. The absence of mechanical variation of the optical path difference in the interferometer essentially reduces the time required for 2D imaging of the object internal structure, as compared to the classical OCT that uses the time-domain method of the image construction, the sensitivity and the dynamic range being comparable in both approaches. For the resulting field of the interfering object and reference waves an analytical expression is derived that allows the calculation of the autocorrelation function in the plane of photodetectors. For the first time a method of linear phase modulation by 2π is proposed for P-OCT systems, which allows the use of compact high-frequency (a few hundred kHz) piezoelectric cell-based modulators. For the demonstration of the P-OCT method an experimental setup was created, using which the images of the inner structure of biological objects at the depth up to 1 mm with the axial spatial resolution of 12 μm were obtained. (optical coherence tomography)

  17. A surface irregularity compensation alignment method for all-reflective optical system

    NASA Astrophysics Data System (ADS)

    Li, Lian; Zhang, Ming; Ma, TianMeng

    2016-09-01

    Surface irregularity of optical elements is one of the errors caused in manufacturing process, which has a bad influence on optical system image quality. This image quality deterioration can't be neglected especially in some all-reflective optical systems. A method by rotating the mirrors for compensating the surface irregularity is put forward in the paper. Firstly, the surface irregularity of all the mirrors is analyzed and the most closely matched mirrors are chosen for one set of system alignment. Then, the wavefront characteristic of optical system and the surface irregularity of each mirror represented by Zernike polynomial are studied, and the relationship between them is analyzed. The calculation of the rotate angle is described in detail. A numerical simulation of the method has been performed for two sets of three-mirror optical system to verify the ability and accuracy of the method. The results show that the astigmatism of the optical system caused by the surface irregularity can be decreased and the image quality of both the two systems can be improved effectively. The method is especially suitable for multiple sets of optical systems alignment.

  18. Power-efficient method for IM-DD optical transmission of multiple OFDM signals.

    PubMed

    Effenberger, Frank; Liu, Xiang

    2015-05-18

    We propose a power-efficient method for transmitting multiple frequency-division multiplexed (FDM) orthogonal frequency-division multiplexing (OFDM) signals in intensity-modulation direct-detection (IM-DD) optical systems. This method is based on quadratic soft clipping in combination with odd-only channel mapping. We show, both analytically and experimentally, that the proposed approach is capable of improving the power efficiency by about 3 dB as compared to conventional FDM OFDM signals under practical bias conditions, making it a viable solution in applications such as optical fiber-wireless integrated systems where both IM-DD optical transmission and OFDM signaling are important.

  19. A review on self-reference wavefront methods in optical testing

    NASA Astrophysics Data System (ADS)

    Cornejo-Rodríguez, Alejandro; Granados-Agustín, Fermín. S.

    2013-11-01

    For the testing of components and optical systems, there are diverse methods with different characteristics each one; in the presentation will be done a review of some of them, that can be classified as optical testing techniques, using a self-reference wavefront. Some examples are the lateral shearing interferometers (Bates, Ronchi, Murty), point diffraction interferometer (Linnik), Burch's scattering interferometer, and the knife edge interferometer. Some advantages of such self-reference methods is the fact that are not necessary optical reference surfaces; and usually the light interfering beams have common paths, that implies that the set up is not affected by environment vibrations and other effects.

  20. Methods and optical fibers that decrease pulse degradation resulting from random chromatic dispersion

    DOEpatents

    Chertkov, Michael; Gabitov, Ildar

    2004-03-02

    The present invention provides methods and optical fibers for periodically pinning an actual (random) accumulated chromatic dispersion of an optical fiber to a predicted accumulated dispersion of the fiber through relatively simple modifications of fiber-optic manufacturing methods or retrofitting of existing fibers. If the pinning occurs with sufficient frequency (at a distance less than or are equal to a correlation scale), pulse degradation resulting from random chromatic dispersion is minimized. Alternatively, pinning may occur quasi-periodically, i.e., the pinning distance is distributed between approximately zero and approximately two to three times the correlation scale.

  1. CHRONICLE: Fourth Scientific and Technical Conference on Optical Methods for Flow Diagnostics

    NASA Astrophysics Data System (ADS)

    Zubov, Vladimir A.; Rinkevichius, Bronyus S.

    1997-12-01

    A review is given of the papers presented at the Fourth Scientific and Technical Conference on Optical Methods for Flow Diagnostics. This conference was concerned with research and applications in the field of flow diagnostics and with related physical and technical topics, such as determination and visualisation of optical and dynamic characteristics of media, creation and monitoring of local directional precision displacements, local measurements and determination of the spatial distribution of optical inhomogeneities in transparent media, as well as a number of practical applications of new methods and techniques.

  2. Simple wide-range method for angle measurement with a point fiber-optic output.

    PubMed

    Ilev, I; Kumagai, H; Toyoda, K

    1997-01-01

    We propose a simple optical method for precise, wide-range angle measurement based on the use of a single-mode optical fiber as a registration scheme output. Because of its micrometric core dimensions, the fiber serves as a point receiver that is highly sensitive to angular displacements of focused laser emission. The method allows the independent photoelectric measurement of both rotation and spatial angles of various optical elements, combining a wide angular dynamic range (from 0 degrees to 360 degrees ) with high accuracy (exceeding 3 arcsec).

  3. Practical Methods for Molecular In Vivo Optical Imaging.

    PubMed

    Chen, Hannah; Thorne, Stephen H

    2012-01-01

    Traditional approaches for translating observations of molecular events into the context of a living organism have suffered from the requirements for either sacrificing animals at multiple time points prior to labor-intensive analyses of multiple tissues, or have relied on subjective observations or measurements of the animals over time. Recently an explosion of dedicated animal imaging modalities and the release of modified clinical imaging devices dedicated for animal imaging have allowed for the design of quantitative real time experiments incorporating fewer animals and providing whole animal analyses. Of these modalities, optical imaging (bioluminescence and fluorescence) has emerged as a powerful research tool, allowing investigators with limited whole animal imaging expertise to rapidly and inexpensively translate models produced in cellular assays into the context of a living animal. Here we will outline the steps necessary for translation of models established in culture systems into rodents.

  4. Brain metastasis detection by resonant Raman optical biopsy method

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Liu, Cheng-hui; Cheng, Gangge; Zhou, Lixin; Zhang, Chunyuan; Pu, Yang; Li, Zhongwu; Liu, Yulong; Li, Qingbo; Wang, Wei; Alfano, Robert R.

    2014-03-01

    Resonant Raman (RR) spectroscopy provides an effective way to enhance Raman signal from particular bonds associated with key molecules due to changes on a molecular level. In this study, RR is used for detection of human brain metastases of five kinds of primary organs of lung, breast, kidney, rectal and orbital in ex-vivo. The RR spectra of brain metastases cancerous tissues were measured and compared with those of normal brain tissues and the corresponding primary cancer tissues. The differences of five types of brain metastases tissues in key bio-components of carotene, tryptophan, lactate, alanine and methyl/methylene group were investigated. The SVM-KNN classifier was used to categorize a set of RR spectra data of brain metastasis of lung cancerous tissues from normal brain tissue, yielding diagnostic sensitivity and specificity at 100% and 75%, respectively. The RR spectroscopy may provide new moleculebased optical probe tools for diagnosis and classification of brain metastatic of cancers.

  5. Optical method for the screening of doping substances

    NASA Astrophysics Data System (ADS)

    Lademann, J.; Shevtsova, J.; Patzelt, A.; Richter, H.; Gladkowa, N. D.; Gelikonov, V. M.; Gonchukov, S. A.; Sterry, W.; Blume-Peytavi, U.

    2008-12-01

    During the last years, an increased misuse of doping substances in sport has been observed. The action of doping substances characterized by the stimulation of blood flow and metabolic processes is also reflected in the hair structure. In the present study it was demonstrated that optical coherent tomography is well suited for the analysis of hair parameters influenced by doping. Analyzing 20 patients, systemically treated with steroids which also represent doping substances, it was found that in all cases a significant increase in the cross-section of the hairs could be detected. The results obtained in the study are not only important for the screening of doping substances but also for medical diagnostics and control of compliance of patients.

  6. Anti-aliasing optical method for Shack Hartmann WFSs

    NASA Astrophysics Data System (ADS)

    Herriot, Glen; Véran, Jean-Pierre

    2016-07-01

    Measurement errors due to aliasing in a Shack-Hartmann WFS are typically 40% larger in variance than the fitting error of an AO system. On bright stars, aliasing is the dominant error within the control radius of the deformable mirror. Wavefront spatial frequencies beyond the WFS' Nyquist frequency corrupt measurements below this frequency. A common misconception is to think that aliasing primarily affects the higher spatial frequency measurements. But in fact aliasing propagates to the lowest order modes, and corrupts even tip/tilt. There are many examples including the observation that the temporal power spectrum of measured tip/tilt from a WFS does not correspond to Kolmogorov theory. We propose a simple optical modification to a SH WFS (borrowed from the digital video camera industry), and present simulation results showing that the aliasing errors are reduced.

  7. Method of making an integral window hermetic fiber optic component

    DOEpatents

    Dalton, R.D.; Kramer, D.P.; Massey, R.T.; Waker, D.A.

    1996-11-12

    In the fabrication of igniters, actuators, detonators, and other pyrotechnic devices to be activated by a laser beam, an integral optical glass window is formed by placing a preform in the structural member of the device and then melting the glass and sealing it in place by heating at a temperature between the ceramming temperature of the glass and the melting point of the metal, followed by rapid furnace cooling to avoid devitrification. No other sealing material is needed to achieve hermeticity. A preferred embodiment of this type of device is fabricated by allowing the molten glass to flow further and form a plano-convex lens integral with and at the bottom of the window. The lens functions to decrease the beam divergence caused by refraction of the laser light passing through the window when the device is fired by means of a laser beam. 9 figs.

  8. Method of making an integral window hermetic fiber optic component

    DOEpatents

    Dalton, Rick D.; Kramer, Daniel P.; Massey, Richard T.; Waker, Damon A.

    1996-11-12

    In the fabrication of igniters, actuators, detonators, and other pyrotechnic devices to be activated by a laser beam, an integral optical glass window is formed by placing a preform in the structural member of the device and then melting the glass and sealing it in place by heating at a temperature between the ceramming temperature of the glass and the melting point of the metal, followed by rapid furnace cooling to avoid devitrification. No other sealing material is needed to achieve hermeticity. A preferred embodiment of this type of device is fabricated by allowing the molten glass to flow further and form a plano-convex lens integral with and at the bottom of the window. The lens functions to decrease the beam divergence caused by refraction of the laser light passing through the window when the device is fired by means of a laser beam.

  9. Optical measurement methods to study dynamic behavior in MEMS

    NASA Astrophysics Data System (ADS)

    Rembe, Christian; Kant, Rishi; Muller, Richard S.

    2001-10-01

    The maturing designs of moving microelectromechanical systems (MEMS) make it more-and-more important to have precise measurements and visual means to characterize dynamic microstructures. The Berkeley Sensor&Actuator Center (BSAC) has a forefront project aimed at developing these capabilities and at providing high-speed Internet (Supernet) access for remote use of its facilities. Already in operation are three optical-characterization tools: a stroboscopic-interferometer system, a computer-microvision system, and a laser-Doppler vibrometer. This paper describes precision and limitations of these systems and discusses their further development. In addition, we describe the results of experimental studies on the different MEMS devices, and give an overview about high-speed visualization of rapidly moving MEMS structures.

  10. Temperature Monitoring by Optical Methods in Laser Processing

    NASA Astrophysics Data System (ADS)

    Smurov, I.; Doubenskaia, M.

    Diverse optical diagnostic tools were applied for monitoring high temperature heat and mass transfer in a number of laser-based technologies . A set of pyrometers was developed and applied for surface temperature monitoring in pulsed periodic Nd-YAG laser welding and surface treatment, deep penetration welding by CO2 and Nd:YAG lasers, laser cladding (LC) with lateral and coaxial powder injection, and selective laser melting (SLM). Particle-in-flight parameters in LC were measured by CCD camera-based diagnostic system. Infrared camera was applied for process visualization in laser welding, cladding, and SLM. Process monitoring was carried out at different temporal and spatial scales and in different spectral bands. True temperature was restored in pulsed laser surface treatment and in pulsed periodic (PP) LC.

  11. Automatic optical inspection method for soft contact lenses

    NASA Astrophysics Data System (ADS)

    Chang, Chun-Li; Wu, Wen-Hong; Hwang, Chi-Chun

    2015-07-01

    In general, the manufacture of contact lenses is conventionally labor intensive, requiring manual handling and inspection of the cast lens during production. This paper is to build an AOI (automatic optical inspection) system, which include suitable light source, camera and image processing algorithms, for contact lenses defect inspection. The mainly defect type are missing lens and surface defect on the contact lenses. An illumination system with fixed focal lens and charge coupled device (CCD) is used to capture the images of contact lenses. After images are captured, an algorithm is employed to check if there are flaws showed on the images. Five kinds of defect can be detected by the designed algorithm. A prototype of the AOI system for contact lenses inspection is implemented. The experimental result shows that the proposed system is robust for in-line inspection.

  12. Non-Intrusive Optical Diagnostic Methods for Flowfield Characterization

    NASA Technical Reports Server (NTRS)

    Tabibi, Bagher M.; Terrell, Charles A.; Spraggins, Darrell; Lee, Ja. H.; Weinstein, Leonard M.

    1997-01-01

    Non-intrusive optical diagnostic techniques such as Electron Beam Fluorescence (EBF), Laser-Induced Fluorescence (LIF), and Focusing Schlieren (FS) have been setup for high-speed flow characterization and large flowfield visualization, respectively. Fluorescence emission from the First Negative band of N2(+) with the (0,0) vibration transition (at lambda =391.44 nm) was obtained using the EBF technique and a quenching rate of N2(+)* molecules by argon gas was reported. A very high sensitivity FS system was built and applied in the High-Speed Flow Generator (HFG) at NASA LaRC. A LIF system is available at the Advanced Propulsion Laboratory (APL) on campus and a plume exhaust velocity measurement, measuring the Doppler shift from lambda = 728.7 nm of argon gas, is under way.

  13. Practical Methods for Molecular In Vivo Optical Imaging

    PubMed Central

    Chen, Hannah; Thorne, Stephen H

    2011-01-01

    Traditional approaches for translating observations of molecular events into the context of a living organism have suffered from the requirements for either sacrificing animals at multiple time points prior to labor-intensive analyses of multiple tissues, or have relied on subjective observations or measurements of the animals over time. Recently an explosion of dedicated animal imaging modalities and the release of modified clinical imaging devices dedicated for animal imaging have allowed for the design of quantitative real time experiments incorporating fewer animals and providing whole animal analyses. Of these modalities, optical imaging (bioluminescence and fluorescence) has emerged as a powerful research tool, allowing investigators with limited whole animal imaging expertise to rapidly and inexpensively translate models produced in cellular assays into the context of a living animal. Here we will outline the steps necessary for translation of models established in culture systems into rodents. PMID:25419262

  14. A testing method of optical axes parallelism of shipboard photoelectrical theodolite

    NASA Astrophysics Data System (ADS)

    Zou, Hui-hui; Wu, Hong-bing; Zhou, Lu-jun

    2016-09-01

    A testing method of optical axes parallelism of shipboard photoelectrical theodolite (short for theodolite) was proposed which based on image processing by comparing disadvantages of the conventional method. Owing to the application of this method, the testing process of optical axes parallelism of theodolite was optimized as well as the adaptability of the testing method was enhanced. The trial result indicated that this method could improve the efficiency and accuracy, and it also could reduce the human vision which is the main factor affected the detection results and had some actual application values.

  15. Optical Method for Detecting Displacements and Strains at Ultra-High Temperatures During Thermo-Mechanical Testing

    NASA Technical Reports Server (NTRS)

    Smith, Russell W. (Inventor); Rivers, H. Kevin (Inventor); Sikora, Joseph G. (Inventor); Roth, Mark C. (Inventor); Johnston, William M. (Inventor)

    2016-01-01

    An ultra-high temperature optical method incorporates speckle optics for sensing displacement and strain measurements well above conventional measurement techniques. High temperature pattern materials are used which can endure experimental high temperature environments while simultaneously having a minimum optical aberration. A purge medium is used to reduce or eliminate optical distortions and to reduce, and/or eliminate oxidation of the target specimen.

  16. Application of optical methods in the monitoring of traumatic brain injury: A review

    PubMed Central

    Milej, Daniel; Janusek, Dariusz; Wojtkiewicz, Stanisław; Sawosz, Piotr; Kacprzak, Michał; Gerega, Anna; Maniewski, Roman; Liebert, Adam

    2016-01-01

    We present an overview of the wide range of potential applications of optical methods for monitoring traumatic brain injury. The MEDLINE database was electronically searched with the following search terms: “traumatic brain injury,” “head injury,” or “head trauma,” and “optical methods,” “NIRS,” “near-infrared spectroscopy,” “cerebral oxygenation,” or “cerebral oximetry.” Original reports concerning human subjects published from January 1980 to June 2015 in English were analyzed. Fifty-four studies met our inclusion criteria. Optical methods have been tested for detection of intracranial lesions, monitoring brain oxygenation, assessment of brain perfusion, and evaluation of cerebral autoregulation or intracellular metabolic processes in the brain. Some studies have also examined the applicability of optical methods during the recovery phase of traumatic brain injury . The limitations of currently available optical methods and promising directions of future development are described in this review. Considering the outstanding technical challenges, the limited number of patients studied, and the mixed results and opinions gathered from other reviews on this subject, we believe that optical methods must remain primarily research tools for the present. More studies are needed to gain confidence in the use of these techniques for neuromonitoring of traumatic brain injury patients. PMID:27604312

  17. Application of optical methods in the monitoring of traumatic brain injury: A review.

    PubMed

    Weigl, Wojciech; Milej, Daniel; Janusek, Dariusz; Wojtkiewicz, Stanisław; Sawosz, Piotr; Kacprzak, Michał; Gerega, Anna; Maniewski, Roman; Liebert, Adam

    2016-11-01

    We present an overview of the wide range of potential applications of optical methods for monitoring traumatic brain injury. The MEDLINE database was electronically searched with the following search terms: "traumatic brain injury," "head injury," or "head trauma," and "optical methods," "NIRS," "near-infrared spectroscopy," "cerebral oxygenation," or "cerebral oximetry." Original reports concerning human subjects published from January 1980 to June 2015 in English were analyzed. Fifty-four studies met our inclusion criteria. Optical methods have been tested for detection of intracranial lesions, monitoring brain oxygenation, assessment of brain perfusion, and evaluation of cerebral autoregulation or intracellular metabolic processes in the brain. Some studies have also examined the applicability of optical methods during the recovery phase of traumatic brain injury . The limitations of currently available optical methods and promising directions of future development are described in this review. Considering the outstanding technical challenges, the limited number of patients studied, and the mixed results and opinions gathered from other reviews on this subject, we believe that optical methods must remain primarily research tools for the present. More studies are needed to gain confidence in the use of these techniques for neuromonitoring of traumatic brain injury patients. © The Author(s) 2016.

  18. A polarization measurement method for the quantification of retardation in optic nerve fiber layer

    NASA Astrophysics Data System (ADS)

    Fukuma, Yasufumi; Okazaki, Yoshio; Shioiri, Takashi; Iida, Yukio; Kikuta, Hisao; Ohnuma, Kazuhiko

    2008-02-01

    The thickness measurement of the optic nerve fiber layer is one of the most important evaluations for carrying out glaucoma diagnosis. Because the optic nerve fiber layer has birefringence, the thickness can be measured by illuminating eye optics with circular polarized light and analyzing the elliptical rate of the detected polarized light reflected from the optic nerve fiber layer. In this method, the scattering light from the background and the retardation caused by the cornea disturbs the precise measurement. If the Stokes vector expressing the whole state of polarization can be detected, we can eliminate numerically the influence of the background scattering and of the retardation caused by the cornea. Because the retardation process of the eye optics can be represented by a numerical equation using the retardation matrix of each component and also the nonpolarized background scattering light, it can be calculated by using the Stokes vector. We applied a polarization analysis system that can detect the Stokes vector onto the fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a micro phase plate array, and a circularly polarized light illumination unit. With this simply constructed system, we can calculate the retardation caused only by the optic nerve fiber layer and it can predict the thickness of the optic nerve fiber layer. We report the method and the results graphically showing the retardation of the optic nerve fiber layer without the retardation of the cornea.

  19. A FrFT based method for measuring chromatic dispersion and SPM in optical fibers

    NASA Astrophysics Data System (ADS)

    Yang, Aiying; Liu, Xiang; Chen, Xiaoyu

    2017-03-01

    A fractional Fourier transformation based method is proposed to blindly estimate the chromatic dispersion and self phase modulation in optical fibers. The experimental results demonstrate that up to 20,000 ps/nm accumulative chromatic dispersion of a fiber link is measured with the error less than 0.8%. If the chromatic dispersion is compensated by multiplying an opposite chromatic dispersion function in frequency domain, the 1st order chirp parameter caused by SPM in an optical fiber communication system can be measured by fractional Fourier transformation based method, i.e. the accumulative SPM of a fiber link can be quantitatively measured. The results of equalizing chromatic dispersion and self phase modulation in an optical fiber communication system demonstrated that the FrFT based method is promising to blindly monitor and equalize the chromatic dispersion and SPM of the fiber link in an optical network with dynamical routing function.

  20. Evaluating the Accuracy of Optic Nerve Detections in Retina Imaging Using Complementary Methods

    SciTech Connect

    Karnowski, Thomas Paul; Aykac, Deniz; Chaum, Edward; Giancardo, Luca; Tobin Jr, Kenneth William

    2009-01-01

    The detection of the optic nerve in retina images is a key element of detecting the anatomical structure of the retina. In this work we report on the fusion of two complementary optic nerve detection methods. The methods are complementary in the sense that they use different fundamental queues for locating the optic nerve. By fusing the methods through applying simple distance-based threshold, a confidence level may be assigned to the quality of the optic nerve detection. In a practical screening system this metric can be used to determine if the images should be immediately reviewed by a physician or if further automatic processing is feasible. We report on the results for two different data sets and show that the use of the threshold improves detection quality.

  1. Weak scratch detection and defect classification methods for a large-aperture optical element

    NASA Astrophysics Data System (ADS)

    Tao, Xian; Xu, De; Zhang, Zheng-Tao; Zhang, Feng; Liu, Xi-Long; Zhang, Da-Peng

    2017-03-01

    Surface defects on optics cause optic failure and heavy loss to the optical system. Therefore, surface defects on optics must be carefully inspected. This paper proposes a coarse-to-fine detection strategy of weak scratches in complicated dark-field images. First, all possible scratches are detected based on bionic vision. Then, each possible scratch is precisely positioned and connected to a complete scratch by the LSD and a priori knowledge. Finally, multiple scratches with various types can be detected in dark-field images. To classify defects and pollutants, a classification method based on GIST features is proposed. This paper uses many real dark-field images as experimental images. The results show that this method can detect multiple types of weak scratches in complex images and that the defects can be correctly distinguished with interference. This method satisfies the real-time and accurate detection requirements of surface defects.

  2. 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.

  3. Optical inspection methods and their applications in the manufactured industrial sector: knowledge transfer to Panamanian industry

    NASA Astrophysics Data System (ADS)

    Pino, Abdiel O.; Pladellorens, Josep

    2014-07-01

    A means of facilitating the transfer of Optical inspection methods knowledge and skills from academic institutions and their research partners into Panama optics and optical research groups is described. The process involves the creation of an Integrated Knowledge Group Research (IKGR), a partnership led by Polytechnic University of Panama with the support of the SENACYT and Optics and Optometry Department, Polytechnic University of Catalonia. This paper describes the development of the Project for knowledge transfer "Implementation of a method of optical inspection of low cost for improving the surface quality of rolled material of metallic and nonmetallic industrial use", this project will develop a method for measuring the surface quality using texture analysis speckle pattern formed on the surface to be characterized. The project is designed to address the shortage of key skills in the field of precision engineering for optical applications. The main issues encountered during the development of the knowledge transfer teaching and learning are discussed, and the outcomes from the first four months of knowledge transfer activities are described. In overall summary, the results demonstrate how the Integrated Knowledge Group Research and new approach to knowledge transfer has been effective in addressing the engineering skills gap in precision optics for manufactured industrial sector.

  4. Investigation of light propagation methods used to calculate wave-optical PSF

    NASA Astrophysics Data System (ADS)

    Horiuchi, Shuma; Yoshida, Shuhei; Yamamoto, Manabu

    2015-09-01

    In this study, we investigated the suitability of various light propagation methods and their usefulness in terms of calculating the wave-optical point spread function (PSF) of an optical imaging system. To analyze an aberration in an optical imaging system in order to obtain its PSF, light propagation methods are widely used to obtain the light intensity distribution on the observation plane. Both the Fresnel-Kirchhoff and Rayleigh-Sommerfeld diffraction formulae are commonly used in light propagation simulations. Recently, there have been many reports concerning light propagation methods in the field of digital holography. These methods are based on the Rayleigh-Sommerfeld diffraction formula and use discrete Fourier transformation. These methods are referred to as the angular spectrum and Fresnel diffraction methods. In this study, these propagation methods are evaluated in terms of the degree of accuracy offered and their associated calculation costs. In order to demonstrate and investigate the features of these propagation methods, we employed a Tessar lens system, which is composed of four lenses. The wavefront aberration of the lens system is obtained by a ray tracing simulation and is used to generate the generalized pupil function. Next, the Rayleigh- Sommerfeld diffraction formula and the light propagation method based on this formula are used to calculate the waveoptical PSF using the pupil function. We applied these simulation methods to various recently proposed propagation methods and discussed the suitability of the various light propagation methods under consideration for calculating the wave-optical PSF.

  5. Efficient numerical method for analyzing optical bistability in photonic crystal microcavities.

    PubMed

    Yuan, Lijun; Lu, Ya Yan

    2013-05-20

    Nonlinear optical effects can be enhanced by photonic crystal microcavities and be used to develop practical ultra-compact optical devices with low power requirements. The finite-difference time-domain method is the standard numerical method for simulating nonlinear optical devices, but it has limitations in terms of accuracy and efficiency. In this paper, a rigorous and efficient frequency-domain numerical method is developed for analyzing nonlinear optical devices where the nonlinear effect is concentrated in the microcavities. The method replaces the linear problem outside the microcavities by a rigorous and numerically computed boundary condition, then solves the nonlinear problem iteratively in a small region around the microcavities. Convergence of the iterative method is much easier to achieve since the size of the problem is significantly reduced. The method is presented for a specific two-dimensional photonic crystal waveguide-cavity system with a Kerr nonlinearity, using numerical methods that can take advantage of the geometric features of the structure. The method is able to calculate multiple solutions exhibiting the optical bistability phenomenon in the strongly nonlinear regime.

  6. Atmospheric pollution measurement by optical cross correlation methods - A concept

    NASA Technical Reports Server (NTRS)

    Fisher, M. J.; Krause, F. R.

    1971-01-01

    Method combines standard spectroscopy with statistical cross correlation analysis of two narrow light beams for remote sensing to detect foreign matter of given particulate size and consistency. Method is applicable in studies of generation and motion of clouds, nuclear debris, ozone, and radiation belts.

  7. An improved image reconstruction method for optical intensity correlation Imaging

    NASA Astrophysics Data System (ADS)

    Gao, Xin; Feng, Lingjie; Li, Xiyu

    2016-12-01

    The intensity correlation imaging method is a novel kind of interference imaging and it has favorable prospects in deep space recognition. However, restricted by the low detecting signal-to-noise ratio (SNR), it's usually very difficult to obtain high-quality image of deep space object like high-Earth-orbit (HEO) satellite with existing phase retrieval methods. In this paper, based on the priori intensity statistical distribution model of the object and characteristics of measurement noise distribution, an improved method of Prior Information Optimization (PIO) is proposed to reduce the ambiguous images and accelerate the phase retrieval procedure thus realizing fine image reconstruction. As the simulations and experiments show, compared to previous methods, our method could acquire higher-resolution images with less error in low SNR condition.

  8. All-optical recognition method of double two-dimensional optical orthogonal codes-based labels using four-wave mixing

    NASA Astrophysics Data System (ADS)

    Zhang, Chongfu; Wang, Leyang; Perumal, Sathishkumar; Qiu, Kun; Zhou, Heng

    2011-08-01

    A novel all-optical label recognition method is proposed and demonstrated experimentally which is based on fiber Bragg gratings (FBGs)-based encoder/decoder and semiconductor optical amplifier (SOA). In this scheme, the optical label is firstly decoded properly, the decoded signal then generates the 1st and the 2nd order four-wave mixing (FWM) effect in different SOA, any of the frequencies achieved by the 2nd order FWM is extracted to recognize the optical label. The proposed solution can favor hardware simplicity over bandwidth efficiency in order to achieve the double two-dimensional optical orthogonal codes (2D-OOCs)-based optical label recognition in an optical packet switching (OPS) system where the bandwidth efficiency can be improved by FWM effect in SOA to achieve optical label processing and reasonable spacing of wavelengths for the payloads and optical label. The feasibility of the proposed method is validated by two experiments of the double 2D-OOCs-based optical label generation and recognition, the effect of the optical label on the payloads is also considered. These results show that the proposed method can (1) reduce effectively the code auto-correlation /cross-correlation requirements of the optical label identification and remove the cross-correlation pulses after optical decoding, (2) increase greatly the coding capacity and the number of the available optical labels, (3) improve the reliability and bandwidth efficiency of the optical label identification. The experimental results also show that the optical label has a high extinction ratio and can be operated easily.

  9. Comparing optical test methods for a lightweight primary mirror of a space-borne Cassegrain telescope

    NASA Astrophysics Data System (ADS)

    Lin, Wei-Cheng; Chang, Shenq-Tsong; Yu, Zong-Ru; Lin, Yu-Chuan; Ho, Cheng-Fong; Huang, Ting-Ming; Chen, Cheng-Huan

    2014-09-01

    A Cassegrain telescope with a 450 mm clear aperture was developed for use in a spaceborne optical remote-sensing instrument. Self-weight deformation and thermal distortion were considered: to this end, Zerodur was used to manufacture the primary mirror. The lightweight scheme adopted a hexagonal cell structure yielding a lightweight ratio of 50%. In general, optical testing on a lightweight mirror is a critical technique during both the manufacturing and assembly processes. To prevent unexpected measurement errors that cause erroneous judgment, this paper proposes a novel and reliable analytical method for optical testing, called the bench test. The proposed algorithm was used to distinguish the manufacturing form error from surface deformation caused by the mounting, supporter and gravity effects for the optical testing. The performance of the proposed bench test was compared with a conventional vertical setup for optical testing during the manufacturing process of the lightweight mirror.

  10. Signal digitizing system and method based on amplitude-to-time optical mapping

    DOEpatents

    Chou, Jason; Bennett, Corey V; Hernandez, Vince

    2015-01-13

    A signal digitizing system and method based on analog-to-time optical mapping, optically maps amplitude information of an analog signal of interest first into wavelength information using an amplitude tunable filter (ATF) to impress spectral changes induced by the amplitude of the analog signal onto a carrier signal, i.e. a train of optical pulses, and next from wavelength information to temporal information using a dispersive element so that temporal information representing the amplitude information is encoded in the time domain in the carrier signal. Optical-to-electrical conversion of the optical pulses into voltage waveforms and subsequently digitizing the voltage waveforms into a digital image enables the temporal information to be resolved and quantized in the time domain. The digital image may them be digital signal processed to digitally reconstruct the analog signal based on the temporal information with high fidelity.

  11. White-Light Whispering Gallery Mode Optical Resonator System and Method

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey B. (Inventor); Savchenkov, Anatoliy A. (Inventor); Maleki, Lute (Inventor)

    2009-01-01

    An optical resonator system and method that includes a whispering-gallery mode (WGM) optical resonator that is capable of resonating across a broad, continuous swath of frequencies is provided. The optical resonator of the system is shaped to support at least one whispering gallery mode and includes a top surface, a bottom surface, a side wall, and a first curved transition region extending between the side wall and the top surface. The system further includes a coupler having a coupling surface which is arranged to face the transition region of the optical resonator and in the vicinity thereof such that an evanescent field emitted from the coupler is capable of being coupled into the optical resonator through the first curved transition region

  12. PREFACE: I International Scientific School Methods of Digital Image Processing in Optics and Photonics

    NASA Astrophysics Data System (ADS)

    Gurov, I. P.; Kozlov, S. A.

    2014-09-01

    The first international scientific school "Methods of Digital Image Processing in Optics and Photonics" was held with a view to develop cooperation between world-class experts, young scientists, students and post-graduate students, and to exchange information on the current status and directions of research in the field of digital image processing in optics and photonics. The International Scientific School was managed by: Saint Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University) - Saint Petersburg (Russia) Chernyshevsky Saratov State University - Saratov (Russia) National research nuclear University "MEPHI" (NRNU MEPhI) - Moscow (Russia) The school was held with the participation of the local chapters of Optical Society of America (OSA), the Society of Photo-Optical Instrumentation Engineers (SPIE) and IEEE Photonics Society. Further details, including topics, committees and conference photos are available in the PDF

  13. In vivo optical imaging and dynamic contrast methods for biomedical research

    PubMed Central

    Hillman, Elizabeth M. C.; Amoozegar, Cyrus B.; Wang, Tracy; McCaslin, Addason F. H.; Bouchard, Matthew B.; Mansfield, James; Levenson, Richard M.

    2011-01-01

    This paper provides an overview of optical imaging methods commonly applied to basic research applications. Optical imaging is well suited for non-clinical use, since it can exploit an enormous range of endogenous and exogenous forms of contrast that provide information about the structure and function of tissues ranging from single cells to entire organisms. An additional benefit of optical imaging that is often under-exploited is its ability to acquire data at high speeds; a feature that enables it to not only observe static distributions of contrast, but to probe and characterize dynamic events related to physiology, disease progression and acute interventions in real time. The benefits and limitations of in vivo optical imaging for biomedical research applications are described, followed by a perspective on future applications of optical imaging for basic research centred on a recently introduced real-time imaging technique called dynamic contrast-enhanced small animal molecular imaging (DyCE). PMID:22006910

  14. Using DFT Methods to Study Activators in Optical Materials

    SciTech Connect

    Du, Mao-Hua

    2015-08-17

    Density functional theory (DFT) calculations of various activators (ranging from transition metal ions, rare-earth ions, ns2 ions, to self-trapped and dopant-bound excitons) in phosphors and scintillators are reviewed. As a single-particle ground-state theory, DFT calculations cannot reproduce the experimentally observed optical spectra, which involve transitions between multi-electronic states. However, DFT calculations can generally provide sufficiently accurate structural relaxation and distinguish different hybridization strengths between an activator and its ligands in different host compounds. This is important because the activator-ligand interaction often governs the trends in luminescence properties in phosphors and scintillators, and can be used to search for new materials. DFT calculations of the electronic structure of the host compound and the positions of the activator levels relative to the host band edges in scintillators are also important for finding optimal host-activator combinations for high light yields and fast scintillation response. Mn4+ activated red phosphors, scintillators activated by Ce3+, Eu2+, Tl+, and excitons are shown as examples of using DFT calculations in phosphor and scintillator research.

  15. Using DFT Methods to Study Activators in Optical Materials

    DOE PAGES

    Du, Mao-Hua

    2015-08-17

    Density functional theory (DFT) calculations of various activators (ranging from transition metal ions, rare-earth ions, ns2 ions, to self-trapped and dopant-bound excitons) in phosphors and scintillators are reviewed. As a single-particle ground-state theory, DFT calculations cannot reproduce the experimentally observed optical spectra, which involve transitions between multi-electronic states. However, DFT calculations can generally provide sufficiently accurate structural relaxation and distinguish different hybridization strengths between an activator and its ligands in different host compounds. This is important because the activator-ligand interaction often governs the trends in luminescence properties in phosphors and scintillators, and can be used to search for new materials.more » DFT calculations of the electronic structure of the host compound and the positions of the activator levels relative to the host band edges in scintillators are also important for finding optimal host-activator combinations for high light yields and fast scintillation response. Mn4+ activated red phosphors, scintillators activated by Ce3+, Eu2+, Tl+, and excitons are shown as examples of using DFT calculations in phosphor and scintillator research.« less

  16. Soft tissue strain measurement using an optical method

    NASA Astrophysics Data System (ADS)

    Toh, Siew Lok; Tay, Cho Jui; Goh, Cho Hong James

    2008-11-01

    Digital image correlation (DIC) is a non-contact optical technique that allows the full-field estimation of strains on a surface under an applied deformation. In this project, the application of an optimized DIC technique is applied, which can achieve efficiency and accuracy in the measurement of two-dimensional deformation fields in soft tissue. This technique relies on matching the random patterns recorded in images to directly obtain surface displacements and to get displacement gradients from which the strain field can be determined. Digital image correlation is a well developed technique that has numerous and varied engineering applications, including the application in soft and hard tissue biomechanics. Chicken drumstick ligaments were harvested and used during the experiments. The surface of the ligament was speckled with black paint to allow for correlation to be done. Results show that the stress-strain curve exhibits a bi-linear behavior i.e. a "toe region" and a "linear elastic region". The Young's modulus obtained for the toe region is about 92 MPa and the modulus for the linear elastic region is about 230 MPa. The results are within the values for mammalian anterior cruciate ligaments of 150-300 MPa.

  17. Method to adjust multilayer film stress induced deformation of optics

    DOEpatents

    Mirkarimi, Paul B.; Montcalm, Claude

    2000-01-01

    A buffer-layer located between a substrate and a multilayer for counteracting stress in the multilayer. Depositing a buffer-layer having a stress of sufficient magnitude and opposite in sign reduces or cancels out deformation in the substrate due to the stress in the multilayer. By providing a buffer-layer between the substrate and the multilayer, a tunable, near-zero net stress results, and hence results in little or no deformation of the substrate, such as an optic for an extreme ultraviolet (EUV) lithography tool. Buffer-layers have been deposited, for example, between Mo/Si and Mo/Be multilayer films and their associated substrate reducing significantly the stress, wherein the magnitude of the stress is less than 100 MPa and respectively near-normal incidence (5.degree.) reflectance of over 60% is obtained at 13.4 nm and 11.4 nm. The present invention is applicable to crystalline and non-crystalline materials, and can be used at ambient temperatures.

  18. Near-infrared optical mammography: Imaging methods and human pilot studies

    NASA Astrophysics Data System (ADS)

    Liu, Ning

    Optical breast imaging uses near-infrared light, utilizes intrinsic optical absorption signatures of tissue chromophores such as hemoglobin, and localizes optical inhomogeneities including subsurface blood vessel structures and breast lesions that have increased vascular density. The different optical absorption signatures of oxy- and deoxy-hemoglobin can be exploited to yield some physiological information of the optical inhomogeneities such as tissue oxygenation. The advantages of optical mammography include the lack of ionizing radiation, its non-invasiveness, the relatively compact instrumentation, and its cost-effectiveness. More importantly, it has the potential to distinguish malignant tumors from benign lesions or normal tissue non-invasively. The primary limitation of optical breast imaging is the relatively poor spatial resolution compared with conventional techniques such as x-ray mammography. Another challenge is how to exploit its potential for quantitative and absolute measurements of oxygenation. In this work we show some strategies to improve the spatial resolution and to estimate the absolute oxygen saturation of breast tumors from a collinear tandem scan of source and detector in a planar geometry optical mammography. In particular we designed and constructed a hybrid continuous-wave/frequency-domain optical breast imaging system capable of taking one full breast image in 5 minutes or less. We developed a three-element phased-array approach to enhance spatial resolution and achieve depth discrimination, and a paired-wavelength spectral approach for quantitative and absolute oxygenation measurement. The theoretical analysis and experimental results have demonstrated the efficiency of the methods. The initial results in health breasts demonstrate the practical feasibility of our imaging method and its implementation into a clinical instrumentation. A whole-breast oxygenation map has been obtained, which, to the best of our knowledge, is so far the

  19. Fired Cartridge Case Identification Using Optical Images and the Congruent Matching Cells (CMC) Method

    PubMed Central

    Tong, Mingsi; Song, John; Chu, Wei; Thompson, Robert M

    2014-01-01

    The Congruent Matching Cells (CMC) method for ballistics identification was invented at the National Institute of Standards and Technology (NIST). The CMC method is based on the correlation of pairs of small correlation cells instead of the correlation of entire images. Four identification parameters – TCCF, Tθ, Tx and Ty are proposed for identifying correlated cell pairs originating from the same firearm. The correlation conclusion (matching or non-matching) is determined by whether the number of CMC is ≥ 6. This method has been previously validated using a set of 780 pair-wise 3D topography images. However, most ballistic images stored in current local and national databases are in an optical intensity (grayscale) format. As a result, the reliability of applying the CMC method on optical intensity images is an important issue. In this paper, optical intensity images of breech face impressions captured on the same set of 40 cartridge cases are correlated and analyzed for the validation test of CMC method using optical images. This includes correlations of 63 pairs of matching images and 717 pairs of non-matching images under top ring lighting. Tests of the method do not produce any false identification (false positive) or false exclusion (false negative) results, which support the CMC method and the proposed identification criterion, C = 6, for firearm breech face identifications using optical intensity images. PMID:26601045

  20. Cleaning Verification Monitor Technique Based on Infrared Optical Methods

    DTIC Science & Technology

    2004-10-01

    Cleaning Verification Techniques.” Real-time methods to provide both qualitative and quantitative assessments of surface cleanliness are needed for a...detection VCPI method offer a wide range of complementary capabilities in real-time surface cleanliness verification. Introduction Currently...also has great potential to reduce or eliminate premature failures of surface coatings caused by a lack of surface cleanliness . Additional

  1. Structural Properties of Potexvirus Coat Proteins Detected by Optical Methods.

    PubMed

    Semenyuk, P I; Karpova, O V; Ksenofontov, A L; Kalinina, N O; Dobrov, E N; Makarov, V V

    2016-12-01

    It has been shown by X-ray analysis that cores of coat proteins (CPs) from three potexviruses, flexible helical RNA-containing plant viruses, have similar α-helical structure. However, this similarity cannot explain structural lability of potexvirus virions, which is believed to determine their biological activity. Here, we used circular dichroism (CD) spectroscopy in the far UV region to compare optical properties of CPs from three potexviruses with the same morphology and similar structure. CPs from Alternanthera mosaic virus (AltMV), potato aucuba mosaic virus (PAMV), and potato virus X (PVX) have been studied in a free state and in virions. The CD spectrum of AltMV virions was similar to the previously obtained CD spectrum of papaya mosaic virus (PapMV) virions, but differed significantly from the CD spectrum of PAMV virions. The CD spectrum of PAMV virions resembled in its basic characteristics the CD spectrum of PVX virions characterized by molar ellipticity that is abnormally low for α-helical proteins. Homology modeling of the CP structures in AltMV, PAMV, and PVX virions was based on the known high-resolution structures of CPs from papaya mosaic virus and bamboo mosaic virus and confirmed that the structures of the CP cores in all three viruses were nearly identical. Comparison of amino acid sequences of different potexvirus CPs and prediction of unstructured regions in these proteins revealed a possible correlation between specific features in the virion CD spectra and the presence of disordered N-terminal segments in the CPs.

  2. A new method for acquiring the complex hologram in optical scanning holography

    NASA Astrophysics Data System (ADS)

    Zhu, Meijuan; Dai, Enwen; Liu, Liren; Sun, Jianfeng; Wu, Yapeng; Zhou, Yu; Yan, Aimin; Zhi, Yanan

    2011-09-01

    In this paper, we propose a new method that can acquire the complex hologram of a 3D object for optical scanning holography (OSH) by using polarized optical elements and a 90 degrees 2×4 optical hybrid. The 3D object is scanned by a wave front combined by a plane and spherical wave with orthogonal polarization. The transmitted/reflected signal light is divided into two beams by a polarized beamsplitter (PBS). Then after the polarization control, the two separated beams are heterodyne detected by a 90 degrees 2×4 optical hybrid with two balanced detectors. The 3D object can be reconstructed from the complex hologram acquired from the balanced detectors. Compared with the conventional OSH, the acousto-optic modulator and complex electronic system are not needed in this method. Another advantage of this method lies in its high efficiency since there is almost no energy loss in the generation of the scanning beam by using the polarized optical elements. This method should be used for 3D holographic microscopy and 3D holographic television.

  3. Comprehensive validation scheme for in situ fiber optics dissolution method for pharmaceutical drug product testing.

    PubMed

    Mirza, Tahseen; Liu, Qian Julie; Vivilecchia, Richard; Joshi, Yatindra

    2009-03-01

    There has been a growing interest during the past decade in the use of fiber optics dissolution testing. Use of this novel technology is mainly confined to research and development laboratories. It has not yet emerged as a tool for end product release testing despite its ability to generate in situ results and efficiency improvement. One potential reason may be the lack of clear validation guidelines that can be applied for the assessment of suitability of fiber optics. This article describes a comprehensive validation scheme and development of a reliable, robust, reproducible and cost-effective dissolution test using fiber optics technology. The test was successfully applied for characterizing the dissolution behavior of a 40-mg immediate-release tablet dosage form that is under development at Novartis Pharmaceuticals, East Hanover, New Jersey. The method was validated for the following parameters: linearity, precision, accuracy, specificity, and robustness. In particular, robustness was evaluated in terms of probe sampling depth and probe orientation. The in situ fiber optic method was found to be comparable to the existing manual sampling dissolution method. Finally, the fiber optic dissolution test was successfully performed by different operators on different days, to further enhance the validity of the method. The results demonstrate that the fiber optics technology can be successfully validated for end product dissolution/release testing.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Laser optical method of visualizing cutaneous blood vessels and its applications in biometry and photomedicine

    NASA Astrophysics Data System (ADS)

    Asimov, M. M.; Asimov, R. M.; Rubinov, A. N.

    2011-05-01

    We propose and examine a new approach to visualizing a local network of cutaneous blood vessels using laser optical methods for applications in biometry and photomedicine. Various optical schemes of the formation of biometrical information on the architecture of blood vessels of skin tissue are analyzed. We developed an optical model of the interaction of the laser radiation with the biological tissue and a mathematical algorithm of processing of measurement results. We show that, in medicine, the visualization of blood vessels makes it possible to calculate and determine regions of disturbance of blood microcirculation and to control tissue hypoxia, as well as to maintain the local concentration of oxygen at a level necessary for the normal cellular metabolism. We propose noninvasive optical methods for modern photomedicine and biometry for diagnostics and elimination of tissue hypoxia and for personality identification and verification via the pattern of cutaneous blood vessels.

  9. A simple method for characterizing and engineering thermal relaxation of an optical microcavity

    SciTech Connect

    Chen, Weijian; Zhu, Jiangang; Özdemir, Şahin Kaya; Peng, Bo; Yang, Lan

    2016-08-08

    Thermal properties of a photonic resonator are determined not only by intrinsic properties of materials, such as thermo-optic coefficient, but also by the geometry and structure of the resonator. Techniques for characterization and measurement of thermal properties of individual photonic resonator will benefit numerous applications. In this work, we demonstrate a method to optically measure the thermal relaxation time and effective thermal conductance of a whispering gallery mode microcavity using optothermal effect. Two nearby optical modes within the cavity are optically probed, which allows us to quantify the thermal relaxation process of the cavity by analyzing changes in the transmission spectra induced by optothermal effect. We show that the effective thermal conductance can be experimentally deduced from the thermal relaxation measurement, and it can be tailored by changing the geometric parameters of the cavity. The experimental observations are in good agreement with the proposed analytical modeling. This method can be applied to various resonators in different forms.

  10. INSTRUMENTS AND METHODS OF INVESTIGATION: Cladding modes of optical fibers: properties and applications

    NASA Astrophysics Data System (ADS)

    Ivanov, Oleg V.; Nikitov, Sergei A.; Gulyaev, Yurii V.

    2006-02-01

    One of the new methods of fiber optics uses cladding modes for controlling propagation of radiation in optical fibers. This paper reviews the results of studies on the propagation, excitation, and interaction of cladding modes in optical fibers. The resonance between core and cladding modes excited by means of fiber Bragg gratings, including tilted ones, is analyzed. Propagation of cladding modes in microstructured fibers is considered. The most frequently used method of exciting cladding modes is described, based on the application of long-period fiber gratings. Examples are presented of long-period gratings used as sensors and gain equalizers for fiber amplifiers, as well as devices for coupling light into and out of optical fibers.

  11. A method for calculating phase-space densities in ion-optical systems

    NASA Astrophysics Data System (ADS)

    Hanelt, E.; Schmidt, K.-H.

    1992-10-01

    A method for calculating the motion of an ensemble of beam particles through an ion-optical system is presented. The collective motion of the ensemble which covers a finite phase-space volume is described by an analytical transformation of the corresponding particle density distribution in phase space. This density distribution is represented by a convolution of generating functions. It is transformed by applying the ion-optical matrix formalism tto the generating functions. Physical effects acting on the particle ensemble on its way through the ion-optical system are taken into account by additional generating functions. This method allows to calculate rare processes in ion-optical systems with low computational effort.

  12. Practical method for evaluating optical image defects caused by center artifacts

    NASA Astrophysics Data System (ADS)

    Tanabe, Takao; Shibuya, Masato; Maehara, Kazuhisa

    2017-08-01

    In modern optical element manufacturing, center artifacts are a common problem. A center artifact is a shape error that is rotationally symmetrical, steep, and localized at the center. These properties cause characteristic image defects different from those caused by ordinary irregularities. However, tolerancing center artifacts has not been fully discussed or properly carried out. We propose a simple mathematical model for center artifacts using normal distribution function as a figure model and showing that this function can be represented by a polynomial including odd-order terms. Our method enables appropriate optical simulation and tolerancing for center artifacts using general optical design software.

  13. Confocal laser method for quantitative evaluation of critical optical properties of toric intraocular lenses.

    PubMed

    Walker, Bennett N; James, Robert H; Song, Samuel; Calogero, Don; Ilev, Ilko K

    2016-03-01

    To present a proof-of-concept study on the development and implementation of an innovative confocal laser method platform for precise quantitative evaluation of critical optical properties unique to toric intraocular lenses (IOLs). U.S. Food and Drug Administration, Optical Therapeutics and Medical Nanophotonics Laboratory, Silver Spring, Maryland, USA. Experimental study. The optical properties of hydrophobic toric IOLs were evaluated with a confocal laser method that was modified to isolate the 2 planes of focus that are observed with toric IOLs. The results show the confocal laser method has the potential to measure the orthogonally separated optical powers and then calculate them to the commonly referenced spherical equivalent and cylinder powers of toric IOLs with high accuracy (≤1 μm of focal length measurement). Furthermore, the proposed confocal laser method design includes a new component for precise differentiation of the 2 focal planes and isolation of the 2 focal points, and thus for accurate measurement of the anterior cylinder axis of toric IOLs. The modifications to the confocal laser method platform enabled the quantitative evaluation of optical properties attributed to toric IOLs. None of the authors has a financial or proprietary interest in any material or method mentioned. Published by Elsevier Inc.

  14. One step linear reconstruction method for continuous wave diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Ukhrowiyah, N.; Yasin, M.

    2017-09-01

    The method one step linear reconstruction method for continuous wave diffuse optical tomography is proposed and demonstrated for polyvinyl chloride based material and breast phantom. Approximation which used in this method is selecting regulation coefficient and evaluating the difference between two states that corresponding to the data acquired without and with a change in optical properties. This method is used to recovery of optical parameters from measured boundary data of light propagation in the object. The research is demonstrated by simulation and experimental data. Numerical object is used to produce simulation data. Chloride based material and breast phantom sample is used to produce experimental data. Comparisons of results between experiment and simulation data are conducted to validate the proposed method. The results of the reconstruction image which is produced by the one step linear reconstruction method show that the image reconstruction almost same as the original object. This approach provides a means of imaging that is sensitive to changes in optical properties, which may be particularly useful for functional imaging used continuous wave diffuse optical tomography of early diagnosis of breast cancer.

  15. Stability Characterization of Quinazoline Derivative BG1188 by Optical Methods

    NASA Astrophysics Data System (ADS)

    Militaru, Andra; Smarandache, Adriana; Mahamoud, Abdallah; Damian, Victor; Ganea, Paul; Alibert, Sandrine; Pagès, Jean-Marie; Pascu, Mihail-Lucian

    2011-08-01

    3-[2-(dimethylamino)ethyl]-6-nitroquinazolin-4(3H)-one, labeled BG1188, is a new synthesized compound, out of a series of quinazoline derivatives developed to fight the multidrug resistance of antibiotics acquired by bacteria. A characterization of the BG1188 powder was made using FTIR spectra in order to evidence the functional groups in the medicine's molecule. The ultraviolet-visible (UV-Vis) absorption spectra were used to study the stability of the BG1188 solutions in two solvents and at different temperatures. BG1188 concentration in ultrapure water was varied between 2×10-3 M (stock solution) and 10-6 M. The concentration recommended by higher activity on bacteria was 10-3 M. For the same reason, this was the utilized concentration of BG1188 in dimethyl sulfoxide (DMSO). Time stability was characterized by comparing the time evolution of the UV-Vis absorption spectra of the BG1188 solutions in ultrapure de-ionized water or in DMSO. The spectra were recorded daily for about 4 months after the preparation for the BG1188 solutions in ultrapure water. Generally, samples are stable within the experimental errors at concentrations higher than 10-5 M, but the stability time interval may vary from 119 days at 10-4 M to 34 days at 10-5 M. Time evolution of the absorption spectra at 10-3 M in ultrapure water shows reproducibility within the measuring errors (±1.045%) for time intervals up to 1032 hours (more than 40 days) after preparation. On the other hand, BG1188 solutions in DMSO may be considered unstable because the absorption spectra modify in terms of peak shapes and intensities, indicating that the samples exhibit modifications immediately after preparation. Regardless the solvent used, some aggregation phenomena took place and wire-like aggregates were observed in all the solutions with the naked eye. These aggregates were analyzed, tentatively, using optical microscopy and FTIR.

  16. Imaging photorefractive optical vibration measurement method and device

    DOEpatents

    Telschow, Kenneth L.; Deason, Vance A.; Hale, Thomas C.

    2000-01-01

    A method and apparatus are disclosed for characterizing a vibrating image of an object of interest. The method includes providing a sensing media having a detection resolution within a limited bandwidth and providing an object of interest having a vibrating medium. Two or more wavefronts are provided, with at least one of the wavefronts being modulated by interacting the one wavefront with the vibrating medium of the object of interest. The another wavefront is modulated such that the difference frequency between the one wavefront and the another wavefront is within a response range of the sensing media. The modulated one wavefront and another wavefront are combined in association with the sensing media to interfere and produce simultaneous vibration measurements that are distributed over the object so as to provide an image of the vibrating medium. The image has an output intensity that is substantially linear with small physical variations within the vibrating medium. Furthermore, the method includes detecting the image. In one implementation, the apparatus comprises a vibration spectrum analyzer having an emitter, a modulator, sensing media and a detector configured so as to realize such method. According to another implementation, the apparatus comprises a vibration imaging device.

  17. Using of methods of speckle optics for Chlamydia trachomatis typing

    NASA Astrophysics Data System (ADS)

    Ulyanov, Sergey S.; Zaytsev, Sergey S.; Ulianova, Onega V.; Saltykov, Yury V.; Feodorova, Valentina A.

    2017-03-01

    Specific method of transformation of nucleotide of gene into speckle pattern is suggested. Reference speckle pattern of omp1 gene of typical wild strains of Chlamydia trachomatis of genovars D, E, F, G, J and K and Chlamydia psittaci as well is generated. Perspectives of proposed technique in the gene identification and detection of natural genetic mutations as single nucleotide polymorphism (SNP) are demonstrated.

  18. Applicability of optical scanner method for fine root dynamics

    NASA Astrophysics Data System (ADS)

    Kume, Tomonori; Ohashi, Mizue; Makita, Naoki; Khoon Kho, Lip; Katayama, Ayumi; Matsumoto, Kazuho; Ikeno, Hidetoshi

    2016-04-01

    Fine root dynamics is one of the important components in forest carbon cycling, as ~60 % of tree photosynthetic production can be allocated to root growth and metabolic activities. Various techniques have been developed for monitoring fine root biomass, production, mortality in order to understand carbon pools and fluxes resulting from fine roots dynamics. The minirhizotron method is now a widely used technique, in which a transparent tube is inserted into the soil and researchers count an increase and decrease of roots along the tube using images taken by a minirhizotron camera or minirhizotron video camera inside the tube. This method allows us to observe root behavior directly without destruction, but has several weaknesses; e.g., the difficulty of scaling up the results to stand level because of the small observation windows. Also, most of the image analysis are performed manually, which may yield insufficient quantitative and objective data. Recently, scanner method has been proposed, which can produce much bigger-size images (A4-size) with lower cost than those of the minirhizotron methods. However, laborious and time-consuming image analysis still limits the applicability of this method. In this study, therefore, we aimed to develop a new protocol for scanner image analysis to extract root behavior in soil. We evaluated applicability of this method in two ways; 1) the impact of different observers including root-study professionals, semi- and non-professionals on the detected results of root dynamics such as abundance, growth, and decomposition, and 2) the impact of window size on the results using a random sampling basis exercise. We applied our new protocol to analyze temporal changes of root behavior from sequential scanner images derived from a Bornean tropical forests. The results detected by the six observers showed considerable concordance in temporal changes in the abundance and the growth of fine roots but less in the decomposition. We also examined

  19. Apparatus and Method for Measuring Strain in Optical Fibers using Rayleigh Scatter

    NASA Technical Reports Server (NTRS)

    Froggatt, Mark E. (Inventor); Moore, Jason P. (Inventor)

    2003-01-01

    An apparatus and method for measuring strain in an optical fiber using the spectral shift of Rayleigh scattered light. The interference pattern produced by an air gap reflector and backscattered radiation is measured. Using Fourier Transforms, the spectrum of any section of fiber can be extracted. Cross correlation with an unstrained measurement produces a correlation peak. The location of the correlation peak indicates the strain level in the selected portion of optical fiber.

  20. Method of bistable optical information storage using antiferroelectric phase PLZT ceramics

    DOEpatents

    Land, Cecil E.

    1990-01-01

    A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field.

  1. Method of bistable optical information storage using antiferroelectric phase PLZT ceramics

    DOEpatents

    Land, C.E.

    1990-07-31

    A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field. 8 figs.

  2. A new method for determining the plasma electron density using optical frequency comb interferometer

    SciTech Connect

    Arakawa, Hiroyuki Tojo, Hiroshi; Sasao, Hajime; Kawano, Yasunori; Itami, Kiyoshi

    2014-04-15

    A new method of plasma electron density measurement using interferometric phases (fractional fringes) of an optical frequency comb interferometer is proposed. Using the characteristics of the optical frequency comb laser, high density measurement can be achieved without fringe counting errors. Simulations show that the short wavelength and wide wavelength range of the laser source and low noise in interferometric phases measurements are effective to reduce ambiguity of measured density.

  3. Organic crystalline films for optical applications and related methods of fabrication

    NASA Technical Reports Server (NTRS)

    Leyderman, Alexander (Inventor); Cui, Yunlong (Inventor)

    2003-01-01

    The present invention provides organic single crystal films of less than 20 .mu.m, and devices and methods of making such films. The crystal films are useful in electro-optical applications and can be provided as part of an electro-optical device which provides strength, durability, and relative ease of manipulation of the mono-crystalline films during and after crystal growth.

  4. Direct optical band gap measurement in polycrystalline semiconductors: A critical look at the Tauc method

    SciTech Connect

    Dolgonos, Alex; Mason, Thomas O.; Poeppelmeier, Kenneth R.

    2016-08-15

    The direct optical band gap of semiconductors is traditionally measured by extrapolating the linear region of the square of the absorption curve to the x-axis, and a variation of this method, developed by Tauc, has also been widely used. The application of the Tauc method to crystalline materials is rooted in misconception–and traditional linear extrapolation methods are inappropriate for use on degenerate semiconductors, where the occupation of conduction band energy states cannot be ignored. A new method is proposed for extracting a direct optical band gap from absorption spectra of degenerately-doped bulk semiconductors. This method was applied to pseudo-absorption spectra of Sn-doped In{sub 2}O{sub 3} (ITO)—converted from diffuse-reflectance measurements on bulk specimens. The results of this analysis were corroborated by room-temperature photoluminescence excitation measurements, which yielded values of optical band gap and Burstein–Moss shift that are consistent with previous studies on In{sub 2}O{sub 3} single crystals and thin films. - Highlights: • The Tauc method of band gap measurement is re-evaluated for crystalline materials. • Graphical method proposed for extracting optical band gaps from absorption spectra. • The proposed method incorporates an energy broadening term for energy transitions. • Values for ITO were self-consistent between two different measurement methods.

  5. Optical methods in the study of protein-protein interactions.

    PubMed

    Masi, Alessio; Cicchi, Riccardo; Carloni, Adolfo; Pavone, Francesco Saverio; Arcangeli, Annarosa

    2010-01-01

    Förster (or Fluorescence) resonance energy transfer (FRET) is a physical process in which energy is transferred nonradiatively from an excited fluorophore, serving as a donor, to another chromophore (acceptor). Among the techniques related to fluorescence microscopy, FRET is unique in providing signals sensitive to intra- and intermolecular distances in the 1-10 nm range. Because of its potency, FRET is increasingly used to visualize and quantify the dynamics of protein-protein interaction in living cells, with high spatio-temporal resolution. Here we describe the physical bases of FRET, detailing the principal methods applied: (1) measurement of signal intensity and (2) analysis of fluorescence lifetime (FLIM). Although several technical complications must be carefully considered, both methods can be applied fruitfully to specific fields. For example, FRET based on intensity detection is more suitable to follow biological phenomena at a finely tuned spatial and temporal scale. Furthermore, a specific fluorescence signal occurring close to the plasma membrane (< or = 100 nm) can be obtained using a total internal reflection fluorescence (TIRF) microscopy system. When performing FRET experiments, care must be also taken to the method chosen for labeling interacting proteins. Two principal tools can be applied: (1) fluorophore tagged antibodies; (2) recombinant fluorescent fusion proteins. The latter method essentially takes advantage of the discovery and use of spontaneously fluorescent proteins, like the green fluorescent protein (GFP). Until now, FRET has been widely used to analyze the structural characteristics of several proteins, including integrins and ion channels. More recently, this method has been applied to clarify the interaction dynamics of these classes of membrane proteins with cytosolic signaling proteins. We report two examples in which the interaction dynamics between integrins and ion channels have been studied with FRET methods. Using

  6. Method for determiantion of the frequency-contrast characteristics of electronic-optic systems

    NASA Astrophysics Data System (ADS)

    Mardirossian, Garo; Zhekov, Zhivko

    The frequency-contrast characteristics is an important criterion to judge the quality of electronic-optic systems, which boast an increasing application in space research, astronomy, martial art etc. The paper provides a brief description of the methods for determining the frequency-contrast characteristics of optic systems, developed at the Space Research Institute of the Bulgarian Academy of Science. The suggested methods have been used to develop a couple of electronic-optic systems participated in the designed ground-based and aerospace scientific-research equipment. Based on the obtained practical results, the conclusion was made that the methods provide to obtain sufficiently precise data, which coincide well with the results, obtained when using other methods.

  7. Study of linear and nonlinear optical properties of dendrimers using density matrix renormalization group method

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Ramasesha, S.

    2009-08-01

    We have used the density matrix renormalization group (DMRG) method to study the linear and nonlinear optical responses of first generation nitrogen based dendrimers with donor acceptor groups. We have employed Pariser-Parr-Pople Hamiltonian to model the interacting π electrons in these systems. Within the DMRG method we have used an innovative scheme to target excited states with large transition dipole to the ground state. This method reproduces exact optical gaps and polarization in systems where exact diagonalization of the Hamiltonian is possible. We have used a correction vector method which tacitly takes into account the contribution of all excited states, to obtain the ground state polarizibility, first hyperpolarizibility, and two photon absorption cross sections. We find that the lowest optical excitations as well as the lowest excited triplet states are localized. It is interesting to note that the first hyperpolarizibility saturates more rapidly with system size compared to linear polarizibility unlike that of linear polyenes.

  8. Modeling hemoglobin at optical frequency using the unconditionally stable fundamental ADI-FDTD method.

    PubMed

    Heh, Ding Yu; Tan, Eng Leong

    2011-04-12

    This paper presents the modeling of hemoglobin at optical frequency (250 nm - 1000 nm) using the unconditionally stable fundamental alternating-direction-implicit finite-difference time-domain (FADI-FDTD) method. An accurate model based on complex conjugate pole-residue pairs is proposed to model the complex permittivity of hemoglobin at optical frequency. Two hemoglobin concentrations at 15 g/dL and 33 g/dL are considered. The model is then incorporated into the FADI-FDTD method for solving electromagnetic problems involving interaction of light with hemoglobin. The computation of transmission and reflection coefficients of a half space hemoglobin medium using the FADI-FDTD validates the accuracy of our model and method. The specific absorption rate (SAR) distribution of human capillary at optical frequency is also shown. While maintaining accuracy, the unconditionally stable FADI-FDTD method exhibits high efficiency in modeling hemoglobin.

  9. Modeling hemoglobin at optical frequency using the unconditionally stable fundamental ADI-FDTD method

    PubMed Central

    Heh, Ding Yu; Tan, Eng Leong

    2011-01-01

    This paper presents the modeling of hemoglobin at optical frequency (250 nm – 1000 nm) using the unconditionally stable fundamental alternating-direction-implicit finite-difference time-domain (FADI-FDTD) method. An accurate model based on complex conjugate pole-residue pairs is proposed to model the complex permittivity of hemoglobin at optical frequency. Two hemoglobin concentrations at 15 g/dL and 33 g/dL are considered. The model is then incorporated into the FADI-FDTD method for solving electromagnetic problems involving interaction of light with hemoglobin. The computation of transmission and reflection coefficients of a half space hemoglobin medium using the FADI-FDTD validates the accuracy of our model and method. The specific absorption rate (SAR) distribution of human capillary at optical frequency is also shown. While maintaining accuracy, the unconditionally stable FADI-FDTD method exhibits high efficiency in modeling hemoglobin. PMID:21559129

  10. A surface intrinsic feature based method (SIFBM) for the characterization of optical microstructure

    NASA Astrophysics Data System (ADS)

    Cheung, C. F.; Kong, L. B.; Lee, W. B.; To, S.

    2008-12-01

    Optical microstructures are small scale topologies which are generally classified as grooves, pyramids, microlens arrays, lenticulations, echells, etc. They are widely used in advanced optics applications. Currently, there is lack of methods for the characterization of surface quality for optical microstructures with sub-micromenter form accuracy and surface finish in the nanometer range. This paper presents a Surface Intrinsic Feature Based Method (SIFBM) which makes use of surface intrinsic properties such as curvatures, normal vectors, torsion, intrinsic frames, etc. They are mapped as special images and image processing techniques are then employed to conduct image registration or correspondences searching by some algorithms such as correlation functions. The surface matching is optimized by corresponding vectors deviations. In the present study, a prototype surface characterization system has been built based on the SIFBM. Primary experimental work has been conducted to validate the proposed method. The results demonstrate that the SIFBM has potential advantages over existing methods.

  11. Study of linear and nonlinear optical properties of dendrimers using density matrix renormalization group method.

    PubMed

    Mukhopadhyay, S; Ramasesha, S

    2009-08-21

    We have used the density matrix renormalization group (DMRG) method to study the linear and nonlinear optical responses of first generation nitrogen based dendrimers with donor acceptor groups. We have employed Pariser-Parr-Pople Hamiltonian to model the interacting pi electrons in these systems. Within the DMRG method we have used an innovative scheme to target excited states with large transition dipole to the ground state. This method reproduces exact optical gaps and polarization in systems where exact diagonalization of the Hamiltonian is possible. We have used a correction vector method which tacitly takes into account the contribution of all excited states, to obtain the ground state polarizibility, first hyperpolarizibility, and two photon absorption cross sections. We find that the lowest optical excitations as well as the lowest excited triplet states are localized. It is interesting to note that the first hyperpolarizibility saturates more rapidly with system size compared to linear polarizibility unlike that of linear polyenes.

  12. A method of rapidly evaluating image quality of NED optical system

    NASA Astrophysics Data System (ADS)

    Sun, Qi; Qiu, Chuankai; Yang, Huan

    2014-11-01

    In recent years, with the development of technology of micro-display, advanced optics and the software and hardware, near-to-eye display ( NED) optical system will have a wide range of potential applications in the fields of amusement and virtual reality. However, research on the evaluating image quality of this kind optical system is comparatively lagging behind. Although now there are some methods and equipment for evaluation, they can't be applied in commercial production because of their complex operation and inaccuracy. In this paper, an academic method is proposed and a Rapid Evaluation System (RES) is designed to evaluate the image of optical system rapidly and exactly. Firstly, a set of parameters that eyes are sensitive to and also express the quality of system should be extracted and quantized to be criterion, so the evaluation standards can be established. Then, some parameters can be detected by RES consisted of micro-display, CCD camera and computer and so on. By process of scaling, the measuring results of the RES are exact and creditable, relationship between object measurement, subjective evaluation and the RES will be established. After that, image quality of optical system can be evaluated just by detecting parameters of that. The RES is simple and the results of evaluation are exact and keeping with human vision. So the method can be used not only for optimizing design of optical system, but also for evaluation in commercial production.

  13. Reliable clarity automatic-evaluation method for optical remote sensing images

    NASA Astrophysics Data System (ADS)

    Qin, Bangyong; Shang, Ren; Li, Shengyang; Hei, Baoqin; Liu, Zhiwen

    2015-10-01

    Image clarity, which reflects the sharpness degree at the edge of objects in images, is an important quality evaluate index for optical remote sensing images. Scholars at home and abroad have done a lot of work on estimation of image clarity. At present, common clarity-estimation methods for digital images mainly include frequency-domain function methods, statistical parametric methods, gradient function methods and edge acutance methods. Frequency-domain function method is an accurate clarity-measure approach. However, its calculation process is complicate and cannot be carried out automatically. Statistical parametric methods and gradient function methods are both sensitive to clarity of images, while their results are easy to be affected by the complex degree of images. Edge acutance method is an effective approach for clarity estimate, while it needs picking out the edges manually. Due to the limits in accuracy, consistent or automation, these existing methods are not applicable to quality evaluation of optical remote sensing images. In this article, a new clarity-evaluation method, which is based on the principle of edge acutance algorithm, is proposed. In the new method, edge detection algorithm and gradient search algorithm are adopted to automatically search the object edges in images. Moreover, The calculation algorithm for edge sharpness has been improved. The new method has been tested with several groups of optical remote sensing images. Compared with the existing automatic evaluation methods, the new method perform better both in accuracy and consistency. Thus, the new method is an effective clarity evaluation method for optical remote sensing images.

  14. Non-focusing optics spectrophotometer, and methods of use

    DOEpatents

    Kramer, David M.; Sacksteder, Colette A.

    2004-11-02

    In one aspect, the present invention provides kinetic spectrophotometers that each comprise: (a) a light source; and (b) a compound parabolic concentrator disposed to receive light from the light source and configured to (1) intensify and diffuse the light received from the light source, and (2) direct the intensified and diffused light onto a sample. In other aspects, the present invention provides methods for measuring a photosynthetic parameter, the methods comprising the steps of: (a) illuminating a plant leaf until steady-state photosynthesis is achieved; (b) subjecting the illuminated plant leaf to a period of darkness; (c) using a kinetic spectrophotometer of the invention to collect spectral data from the plant leaf treated in accordance with steps (a) and (b); and (d) determining a value for a photosynthetic parameter from the spectral data.

  15. A novel method for large area graphene transfer on the polymer optical fiber.

    PubMed

    Kulkarni, Atul; Kim, Hyeongkeun; Amin, Rashid; Park, Sung Ha; Hong, Byung Hee; Kim, Taesung

    2012-05-01

    We develop two simple methods-the dip coat stamping and lift-off methods-to transfer large area, high quality graphene films onto the top and side faces of the polymer optical fiber. The graphene films can be synthesized using chemical vapor deposition method on large Cu foils. After synthesis, the graphene films are characterized by scanning electron microscopy, atomic force microscopy and Raman spectroscopy. The polymer optical fiber probe with the transferred graphene film can be used as a chemical sensor for the detection of various organic aerosols.

  16. A method for studying the effects of thermal deformations on optical systems for space application

    NASA Astrophysics Data System (ADS)

    Segato, Elisa; Da Deppo, Vania; Debei, Stefano; Cremonese, Gabriele

    2010-04-01

    Optical instruments for space missions work in hostile environment, it's thus necessary to accurately study the effects of ambient parameters variations on the equipment performance. In particular, optical instruments are very sensitive to ambient conditions, especially temperature. This variable can cause dilatation and misalignment of the optical elements, and can also lead to rise of dangerous stresses in the optics. Optical elements displacements and surface deformations degrade the quality of the sampled images. In this work a method for simulating and studying the effects of the thermal deformations, particularly the impact on the expected optical performance, is presented. Optical elements and their mountings are modelled and processed by a thermo-mechanical Finite Element Model (FEM) analysis, reproducing expected operative conditions. The FEM output is elaborated into a MATLAB optimisation code; a non-linear least square algorithm is used to determine the equation of the best fitting nth degree polynomial, or the spherical surface of the deformed lenses and mirrors; model accuracy is 10-8 m. The obtained mathematical surface representations are then directly imported into ZEMAX raytracing software for sequential raytrace analysis. The results are spot diagrams, chief ray coordinates on the detector, MTF curves and Diffraction Encircled Energy variations due to simulated thermal loads. This analysis helps to design and compare different optical housing systems for finding a feasible mounting solution. The described method has been applied successfully to the optics and mountings of a stereo-camera for the BepiColombo mission. Different types of lenses and prisms constraints have been designed and analysed. The results show the preferable use of kinematic constraints, instead of using glue, to correctly maintain the instrument focus in orbit around Mercury considering an operative temperature range between -20°C and +30°C.

  17. Robust, efficient computational methods for axially symmetric optical aspheres.

    PubMed

    Forbes, G W

    2010-09-13

    Whether in design or the various stages of fabrication and testing, an effective representation of an asphere's shape is critical. Some algorithms are given for implementing tailored polynomials that are ideally suited to these needs. With minimal coding, these results allow a recently introduced orthogonal polynomial basis to be employed to arbitrary orders. Interestingly, these robust and efficient methods are enabled by the introduction of an auxiliary polynomial basis.

  18. Design of diffractive optical surfaces within the nonimaging SMS design method

    NASA Astrophysics Data System (ADS)

    Mendes-Lopes, João.; Benítez, Pablo; Miñano, Juan C.

    2015-09-01

    The Simultaneous Multiple Surface (SMS) method was initially developed as a design method in Nonimaging Optics and later, the method was extended for designing Imaging Optics. We show an extension of the SMS method to diffractive surfaces. Using this method, diffractive kinoform surfaces are calculated simultaneously and through a direct method, i. e. it is not based in multi-parametric optimization techniques. Using the phase-shift properties of diffractive surfaces as an extra degree of freedom, only N/2 surfaces are needed to perfectly couple N one parameter wavefronts. Wavefronts of different wavelengths can also be coupled, hence chromatic aberration can be corrected in SMS-based systems. This method can be used by combining and calculating simultaneously both reflective, refractive and diffractive surfaces, through direct calculation of phase and refractive/reflective profiles. Representative diffractive systems designed by the SMS method are presented.

  19. Simply Scan—Optical Methods for Elemental Carbon Measurement in Diesel Exhaust Particulate

    PubMed Central

    Forder, James A.

    2014-01-01

    This article describes a performance assessment of three optical methods, a Magee Scientific OT21 Transmissometer, a Hach-Lange Microcolor II difference gloss meter, and a combination of an office scanner with Adobe Photoshop software. The optical methods measure filter staining as a proxy for elemental carbon in diesel exhaust particulate (DEP) exposure assessment and the suitability of each as a replacement for the existing Bosch meter optical method. Filters loaded with DEP were produced from air in a non-coal mine and the exhaust gases from a mobile crane. These were measured with each apparatus and then by combustion to obtain a reference elemental carbon value. The results from each apparatus were then plotted against both the Bosch number and reference elemental carbon values. The equations of the best fit lines for these plots were derived, and these gave functions for elemental carbon and Bosch number from the output of each new optical method. For each optical method, the range of DEP loadings which can be measured has been determined, and conversion equations for elemental carbon and Bosch number have been obtained. All three optical methods studied will effectively quantify blackness as a measure of elemental carbon. Of these the Magee Scientific OT21 transmissometer has the best performance. The Microcolor II and scanner/photoshop methods will in addition allow conversion to Bosch number which may be useful if historical Bosch data are available and functions for this are described. The scanner/photoshop method demonstrates a technique to obtain measurements of DEP exposure without the need to purchase specialized instrumentation. PMID:24939982

  20. Simply scan--optical methods for elemental carbon measurement in diesel exhaust particulate.

    PubMed

    Forder, James A

    2014-08-01

    This article describes a performance assessment of three optical methods, a Magee Scientific OT21 Transmissometer, a Hach-Lange Microcolor II difference gloss meter, and a combination of an office scanner with Adobe Photoshop software. The optical methods measure filter staining as a proxy for elemental carbon in diesel exhaust particulate (DEP) exposure assessment and the suitability of each as a replacement for the existing Bosch meter optical method. Filters loaded with DEP were produced from air in a non-coal mine and the exhaust gases from a mobile crane. These were measured with each apparatus and then by combustion to obtain a reference elemental carbon value. The results from each apparatus were then plotted against both the Bosch number and reference elemental carbon values. The equations of the best fit lines for these plots were derived, and these gave functions for elemental carbon and Bosch number from the output of each new optical method. For each optical method, the range of DEP loadings which can be measured has been determined, and conversion equations for elemental carbon and Bosch number have been obtained. All three optical methods studied will effectively quantify blackness as a measure of elemental carbon. Of these the Magee Scientific OT21 transmissometer has the best performance. The Microcolor II and scanner/photoshop methods will in addition allow conversion to Bosch number which may be useful if historical Bosch data are available and functions for this are described. The scanner/photoshop method demonstrates a technique to obtain measurements of DEP exposure without the need to purchase specialized instrumentation.

  1. Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

    DOEpatents

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2015-03-10

    A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

  2. Optical Methods For Transient Plasmas Studies By Multichannel TEA Nitrogen Laser

    NASA Astrophysics Data System (ADS)

    Ursu, Ioan; Popescu, Ion M.; Ivascu, M.; Baltog, I.; Mihut, L.; Zambreanu, V.; Zoita, V.

    1989-05-01

    A multichannel TEA nitrogen laser has been realized for some optical diagnostics. The following methods have been applied on the plasma focus device (PFD): interferometry, schlieren, shadowgraphy and a new combination of the last two. The background of these methods and some qualitative and quantitative results obtained in plasma focus (PF) studies are presented.

  3. Acousto-Optic Tunable Filter Hyperspectral Microscope Imaging Method for Characterizing Spectra from Foodborne Pathogens.

    USDA-ARS?s Scientific Manuscript database

    Hyperspectral microscope imaging (HMI) method, which provides both spatial and spectral characteristics of samples, can be effective for foodborne pathogen detection. The acousto-optic tunable filter (AOTF)-based HMI method can be used to characterize spectral properties of biofilms formed by Salmon...

  4. Measurement of greenhouse gas emissions from agricultural sites using open-path optical remote sensing method.

    USDA-ARS?s Scientific Manuscript database

    Improved characterization of distributed emission sources of greenhouse gases such as methane from concentrated animal feeding operations require more accurate methods. One promising method is recently used by the USEPA. It employs a vertical radial plume mapping (VRPM) algorithm using optical remot...

  5. Optically-detected spin-echo method for relaxation times measurements in a Rb atomic vapor

    NASA Astrophysics Data System (ADS)

    Gharavipour, M.; Affolderbach, C.; Gruet, F.; Radojičić, I. S.; Krmpot, A. J.; Jelenković, B. M.; Mileti, G.

    2017-06-01

    We introduce and demonstrate an experimental method, optically-detected spin-echo (ODSE), to measure ground-state relaxation times of a rubidium (Rb) atomic vapor held in a glass cell with buffer-gas. The work is motivated by our studies on high-performance Rb atomic clocks, where both population and coherence relaxation times (T 1 and T 2, respectively) of the ‘clock transition’ (52S1/2 | {F}g = 1,{m}F=0> ≤ftrightarrow | {F}g=2,{m}F=0> ) are relevant. Our ODSE method is inspired by classical nuclear magnetic resonance spin-echo method, combined with optical detection. In contrast to other existing methods, like continuous-wave double-resonance (CW-DR) and Ramsey-DR, principles of the ODSE method allow suppression of decoherence arising from the inhomogeneity of the static magnetic field across the vapor cell, thus enabling measurements of intrinsic relaxation rates, as properties of the cell alone. Our experimental result for the coherence relaxation time, specific for the clock transition, measured with the ODSE method is in good agreement with the theoretical prediction, and the ODSE results are validated by comparison to those obtained with Franzen, CW-DR and Ramsey-DR methods. The method is of interest for a wide variety of quantum optics experiments with optical signal readout.

  6. Method for studying the phase function in tunable diffraction optical elements

    SciTech Connect

    Paranin, V D; Tukmakov, K N

    2014-04-28

    A method for studying the phase function in tunable diffraction optical elements is proposed, based on measurement of the transmission of interelectrode gaps. The mathematical description of the method, which is approved experimentally, is developed. The instrumental error effects are analysed. (laser applications and other topics in quantum electronics)

  7. Optical methods for molecular sensing: Supplementing imaging of tissue microstructure with molecular information

    NASA Astrophysics Data System (ADS)

    Winkler, Amy Marie

    More and more researchers and clinicians are looking to molecular sensing to predict how cells will behave, seeking the answers to questions like will these tumor cells become malignant? or how will these cells respond to chemotherapy? Optical methods are attractive for answering these questions because optical radiation is safer and less expensive than alternative methods, such as CT which uses X-ray radiation, PET/SPECT which use gamma radiation, or MRI which is expensive and only available in a hospital setting. In this dissertation, three distinct optical methods are explored to detect at the molecular level: optical coherence tomography (OCT), laser-induced fluorescence (LIF), and optical polarimetry. OCT has the capability to simultaneously capture anatomical information as well as molecular information using targeted contrast agents such as gold nanoshells. LIF is less useful for capturing anatomical information, but it can achieve significantly better molecular sensitivity with the use of targeted fluorescent dyes. Optical polarimetry has potential to detect the concentration of helical molecules, such as glucose. All of these methods are noninvasive or minimally invasive. The work is organized into four specific aims. The first is the design and implementation of a fast, high resolution, endoscopic OCT system to facilitate minimally invasive mouse colon imaging. The second aim is to demonstrate the utility of this system for automatically identifying tumor lesions based on tissue microstructure. The third is to demonstrate the use of contrast agents to detect molecular expression using OCT and LIF. The last aim is to demonstrate a new method based on optical polarimetry for noninvasive glucose sensing.

  8. Application of the linear muffin-tin-orbital band-structure method to calculate optical properties of solids

    NASA Astrophysics Data System (ADS)

    Zemach, R.; Ashkenazi, J.; Ehrenfreund, E.

    1989-01-01

    Optical matrix elements have been derived for crystals by applying the theory of optical transitions within the formalism of the linear muffin-tin-orbital band-structure method and using Racah algebra. A Brillouin-zone integration by the tetrahedron method allows straightforward numerical computation of the optical function ɛ2(ω) [or σ(ω)]. Other optical functions may be derived by using a Kramers-Kronig analysis.

  9. Measurement of Black (BC) and Elemental (EC) Carbon by an Optical and a Thermal- optical Method: An Intercomparison

    NASA Astrophysics Data System (ADS)

    Ahmed, T.; Dutkiewicz, V. A.; Khan, A. R.; Husain, L.

    2009-05-01

    Elemental or Black carbon (EC or BC) aerosol emitted into the atmosphere from incomplete combustion of fossil fuel, biomass and forest fires absorbs solar radiations and contributes to global warming. EC or BC is defined based on different analytical methods used for measuring the same fraction of carbonaceous aerosol. The different methods give different results which can vary widely. There is no accepted standard available to accurately quantify EC and therefore measurements between different methods need to be compared to reduce the bias. In this study intercomparison of data between two widely used techniques, BC obtained using optical method (non-destructive technique) and EC obtained using thermal-optical methods (destructive technique) are performed on aerosol samples collected on Whatman 41 filter paper from two rural sites, Whiteface Mountain (WFM) and Mayville, NY. Daily aerosol samples from six months at Mayville collected during 1998 and 2002 and fourteen months from WFM collected during 1996 and 2002 were analyzed using Sunset thermal-optical transmittance (TOT) elemental/organic carbon (EC/OC) analyzer and Magee Scientific Transmissiometer (Model OT-21). Total numbers of samples analyzed from the two sites were around 400. Transmissiometer used for BC measurement is based on optical attenuation of light and its working principle is similar to that of widely used Aethalometer. Whatman 41 filters are not suitable for direct EC measurement using EC/OC analyzer, so a pretreatment technique was developed and EC was subsequently transferred on 47 mm quartz filter paper. The total analysis time for individual sample using Transmissiometer is short (˜ 3-5 min) compared with ˜ 20-25 minutes for EC/OC analyzer excluding the time required for chemical pre-treatment (which can be up to 60 min). Reasonably good correlation, r2>0.8 and BC/EC slope close to 1 was obtained for concentrations up to 600 ngm- 3. For concentration >600 ngm-3 the relationship tends to

  10. Differentiated protection method in passive optical networks based on OPEX

    NASA Astrophysics Data System (ADS)

    Zhang, Zhicheng; Guo, Wei; Jin, Yaohui; Sun, Weiqiang; Hu, Weisheng

    2011-12-01

    Reliable service delivery becomes more significant due to increased dependency on electronic services all over society and the growing importance of reliable service delivery. As the capability of PON increasing, both residential and business customers may be included in a PON. Meanwhile, OPEX have been proven to be a very important factor of the total cost for a telecommunication operator. Thus, in this paper, we present the partial protection PON architecture and compare the operational expenditures (OPEX) of fully duplicated protection and partly duplicated protection for ONUs with different distributed fiber length, reliability requirement and penalty cost per hour. At last, we propose a differentiated protection method to minimize OPEX.

  11. Holographic optical grating and method for optimizing monochromator configuration

    DOEpatents

    Koike, Masato

    1999-01-01

    This invention comprises a novel apparatus for recording a holographic groove pattern on a diffraction grating blank. The recording apparatus is configured using newly developed groups of analytical equations. The invention further comprises the novel holographic diffraction grating made with the inventive recording apparatus. The invention additionally comprises monochromators and spectrometers equipped with the inventive holographic diffraction grating. Further, the invention comprises a monochromator configured to reduce aberrations using a newly developed group of analytical equations. Additionally, the invention comprises a method to reduce aberrations in monochromators and spectrometers using newly developed groups of analytical equations.

  12. Optical method of measuring angular displacement using a diffraction pattern.

    PubMed

    Ami, M; Sato, K; Yamamoto, S; Kamada, O; Shibanuma, H

    1987-10-01

    We investigate a method of measuring the angular displacement of an aperture when the diffraction pattern rotates. The data that are on a rectangular coordinate are transformed into the data on a polar coordinate. We calculate a cross-correlation function between the diffraction pattern that is rotated and the reference pattern. When the angular displacement is within +/-5 degrees , the error is <0.050. Then, we calculated the angular displacement of the pattern on a spherical coordinate system by personal computer simulation. Consequently, when the azimuth and the elevation of its rotation axis are within +/-6 degrees , the error is <0.1 degrees .

  13. Generalized method of eigenoscillations for near-field optical microscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Bor-Yuan; Zhang, Lingfeng; Castro Neto, Antonio; Basov, Dimitri; Fogler, Michael

    2015-03-01

    Electromagnetic interaction between a sub-wavelength particle (the ``probe'') and a material surface (the ``sample'') is studied theoretically. The interaction is shown to be governed by a series of resonances (eigenoscillations), corresponding to surface polariton modes localized near the probe. The resonance parameters depend on the dielectric function and geometry of the probe, as well as the surface reflectivity of the material. Calculation of such resonances is carried out for several axisymmetric particle shapes (spherical, spheroidal, and pear-shaped). For spheroids an efficient numerical method is proposed, capable of handling cases of large or strongly momentum-dependent surface reflectivity. The method is applied to modeling near-field spectroscopy studies of various materials. For highly resonant materials such as aluminum oxide (by itself or covered with graphene) a rich structure of the simulated signal is found, including multi-peak spectra and nonmonotonic approach curves. These features have a strong dependence on physical parameters, e.g., the probe shape. For less resonant materials such as silicon oxide the dependence is weaker, and the spheroid model is generally applicable.

  14. Method for optic nerve intensity characterization in mice from Mn2+ enhanced MR images

    NASA Astrophysics Data System (ADS)

    Xiao, D.; Ribic, J.; Butzkueven, H.; Fang, K.; Kilpatrick, T. J.; Egan, G. F.; Salvado, O.

    2009-02-01

    Investigating whether manganese transport is impaired in the optic nerve of small animal model is a new approach for evaluating optic neuritis. One needs to quantify signal intensity enhancement due to Mn2+ after intra-orbital injection, along the optic nerve from MR images. Quantification is very challenging as the optic nerve (ON) is not straight, its location does not correspond to standard slice orientation, the noise is substantial, and the signal is subject to inhomogeneity from the coil sensitivity. In this paper, we propose a semi-automatic method whereby 1) the retina point and the start of the chiasm in a mouse brain MR image are defined manually in a 3D visualization environment, 2) optic nerve in reformatted slices perpendicular to the optic nerve segment is semi-manually selected, 3) an automatic algorithm extracts the intensities along the optic nerve while correcting for intensity inhomogeneity, and 4) a model for the Mn2+ diffusion with a exponential decay function is fitted to the intensity profile. Results for the study of experimental autoimmune encephalomyelitis (EAE) are reported whereby statistically significant differences were found between the EAE and the control group.

  15. On convergence of the Horn and Schunck optical-flow estimation method.

    PubMed

    Mitiche, Amar; Mansouri, Abdol-Reza

    2004-06-01

    The purpose of this study is to prove convergence results for the Horn and Schunck optical-flow estimation method. Horn and Schunck stated optical-flow estimation as the minimization of a functional. When discretized, the corresponding Euler-Lagrange equations form a linear system of equations We write explicitly this system and order the equations in such a way that its matrix is symmetric positive definite. This property implies the convergence Gauss-Seidel iterative resolution method, but does not afford a conclusion on the convergence of the Jacobi method. However, we prove directly that this method also converges. We also show that the matrix of the linear system is block tridiagonal. The blockwise iterations corresponding to this block tridiagonal structure converge for both the Jacobi and the Gauss-Seidel methods, and the Gauss-Seidel method is faster than the (sequential) Jacobi method.

  16. Organic solid state optical switches and method for producing organic solid state optical switches

    DOEpatents

    Wasielewski, M.R.; Gaines, G.L.; Niemczyk, M.P.; Johnson, D.G.; Gosztola, D.J.; O`Neil, M.P.

    1993-01-01

    This invention consists of a light-intensity dependent molecular switch comprised of a compound which shuttles an electron or a plurality of electrons from a plurality of electron donors to an electron acceptor upon being stimulated with light of predetermined wavelengths, and a method for making said compound.

  17. Accurate core position control in polymer optical waveguides using the Mosquito method for three-dimensional optical wiring

    NASA Astrophysics Data System (ADS)

    Date, Kumi; Ishigure, Takaaki

    2017-02-01

    Polymer optical waveguides with graded-index (GI) circular cores are fabricated using the Mosquito method, in which the positions of parallel cores are accurately controlled. Such an accurate arrangement is of great importance for a high optical coupling efficiency with other optical components such as fiber ribbons. In the Mosquito method that we developed, a core monomer with a viscous liquid state is dispensed into another liquid state monomer for cladding via a syringe needle. Hence, the core positions are likely to shift during or after the dispensing process due to several factors. We investigate the factors, specifically affecting the core height. When the core and cladding monomers are selected appropriately, the effect of the gravity could be negligible, so the core height is maintained uniform, resulting in accurate core heights. The height variance is controlled in +/-2 micrometers for the 12 cores. Meanwhile, larger shift in the core height is observed when the needle-tip position is apart from the substrate surface. One of the possible reasons of the needle-tip height dependence is the asymmetric volume contraction during the monomer curing. We find a linear relationship between the original needle-tip height and the core-height observed. This relationship is implemented in the needle-scan program to stabilize the core height in different layers. Finally, the core heights are accurately controlled even if the cores are aligned on various heights. These results indicate that the Mosquito method enables to fabricate waveguides in which the cores are 3-dimensionally aligned with a high position accuracy.

  18. Systems and methods for correcting optical reflectance measurements

    NASA Technical Reports Server (NTRS)

    Yang, Ye (Inventor); Soller, Babs R. (Inventor); Soyemi, Olusola O. (Inventor); Shear, Michael A. (Inventor)

    2009-01-01

    We disclose measurement systems and methods for measuring analytes in target regions of samples that also include features overlying the target regions. The systems include: (a) a light source; (b) a detection system; (c) a set of at least first, second, and third light ports which transmit light from the light source to a sample and receive and direct light reflected from the sample to the detection system, generating a first set of data including information corresponding to both an internal target within the sample and features overlying the internal target, and a second set of data including information corresponding to features overlying the internal target; and (d) a processor configured to remove information characteristic of the overlying features from the first set of data using the first and second sets of data to produce corrected information representing the internal target.

  19. Systems and Methods for Correcting Optical Reflectance Measurements

    NASA Technical Reports Server (NTRS)

    Yang, Ye (Inventor); Soller, Babs R. (Inventor); Soyemi, Olusola O. (Inventor); Shear, Michael A. (Inventor)

    2014-01-01

    We disclose measurement systems and methods for measuring analytes in target regions of samples that also include features overlying the target regions. The systems include: (a) a light source; (b) a detection system; (c) a set of at least first, second, and third light ports which transmit light from the light source to a sample and receive and direct light reflected from the sample to the detection system, generating a first set of data including information corresponding to both an internal target within the sample and features overlying the internal target, and a second set of data including information corresponding to features overlying the internal target; and (d) a processor configured to remove information characteristic of the overlying features from the first set of data using the first and second sets of data to produce corrected information representing the internal target.

  20. Method and apparatus for fiber optic multiple scattering suppression

    NASA Technical Reports Server (NTRS)

    Ackerson, Bruce J. (Inventor)

    2000-01-01

    The instant invention provides a method and apparatus for use in laser induced dynamic light scattering which attenuates the multiple scattering component in favor of the single scattering component. The preferred apparatus utilizes two light detectors that are spatially and/or angularly separated and which simultaneously record the speckle pattern from a single sample. The recorded patterns from the two detectors are then cross correlated in time to produce one point on a composite single/multiple scattering function curve. By collecting and analyzing cross correlation measurements that have been taken at a plurality of different spatial/angular positions, the signal representative of single scattering may be differentiated from the signal representative of multiple scattering, and a near optimum detector separation angle for use in taking future measurements may be determined.

  1. Optical method for inspecting surface defects inside a small bore

    NASA Astrophysics Data System (ADS)

    Hong, En; Katz, Reuven; Hufnagel, Brian; Agapiou, John

    2010-01-01

    Most automotive powertrain parts made of castings have surface defects such as pores. However, detecting pores inside small diameter bores is a challenge because of the limited dimensional accessibility. Adding to this difficulty is the auto industry's desire to conduct the porosity inspection in-line, i.e. within the machining production cycle time of a part. A technique or equipment that meets these requirements currently does not exist. In order to meet these demands, it is necessary to develop an entire new methodology to inspect the inner surface of small diameter bores. This paper presents an innovative methodology to inspect the porosity of the inner surface of small bores and to provide their characteristics such as size and location. A prototype measurement system was built and tested in the lab. Experimental results showed the proposed method to be reliable and consistent.

  2. Advanced Motion Compensation Methods for Intravital Optical Microscopy

    PubMed Central

    Vinegoni, Claudio; Lee, Sungon; Feruglio, Paolo Fumene; Weissleder, Ralph

    2013-01-01

    Intravital microscopy has emerged in the recent decade as an indispensible imaging modality for the study of the micro-dynamics of biological processes in live animals. Technical advancements in imaging techniques and hardware components, combined with the development of novel targeted probes and new mice models, have enabled us to address long-standing questions in several biology areas such as oncology, cell biology, immunology and neuroscience. As the instrument resolution has increased, physiological motion activities have become a major obstacle that prevents imaging live animals at resolutions analogue to the ones obtained in vitro. Motion compensation techniques aim at reducing this gap and can effectively increase the in vivo resolution. This paper provides a technical review of some of the latest developments in motion compensation methods, providing organ specific solutions. PMID:24273405

  3. Fiber optic pressure sensing method based on Sagnac interferometer

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Zhuang, Zhi; Chen, Ying; Yang, Yuanhong

    2014-11-01

    Pressure method using polarization-maintaining photonic crystal fiber (PM-PCF) as sensing element based on Sagnac interferometer is proposed to monitor inter layer pressure in especial compact structure. Sensing model is analyzed and test system is set up, which is validated by experiment. The birefringence can be modified by the deformation of PM-PCF under transverse pressure, realizing pressure measurement by detecting the wavelength shift of one specific valley from output of the Sagnac interferometer. The experiment results show that the output interference fringes were shifted linearly with pressure. The dynamic range of 0 kN ~10kN, sensing precision of 2.6%, and pressure sensitivity of 0.4414nm/kN are achieved, and the strain relaxation phenomenon of cushion can be observed obviously. The sensor has better engineering practicability and capability to restrain interference brought up by fluctuation of environment temperature, which temperature sensitivity is -11.8pm/°C.

  4. New researches on teratogenic effects of singulair using optical methods

    NASA Astrophysics Data System (ADS)

    Valiulis, A.; Gaidelis, P.; Januskevicius, A.

    2005-11-01

    It was proved that singulair does not cause macroscopical and histological alterations on the animals, but it is not known its influence on the molecular level. The purpose of our work is to explore teratogenic effects of singulair on the animals by using our non-standard method (which is preciser than standard method, because it showes not only macroscopical, but also and molecular alterations in the damage tissue), hoping, that it would be the help for the pregnant women to decide can they take this drug or not. We injected singulair (25 mg/kg of rat) to one group of pregnant rats in rareripe period (from the first to the eight day) of embryogenesis. Another group of pregnant rats got injections of teratogenic substance ochratoxin A (25 pg/kg of rat) in the same period of embryogenesis. The third group got injections of physiological solution. There were taken 10 rats to everyone group. In the end of rareripe period we took a blood sample from each rat of the rats and wrote a spectrum of everyone sample by using spectrophotometer. We got, that spectra of solutions from the first and the third group were very similar (there were no statistical difference) and spectra of solutions from the second group were very similar (there were no statistical difference), but statistical difference was between the first and the third group together and the second group in the zone of 200-350 nm. At the twentieth day of pregnancy we made Caesarean section to all of the rats, compared embryos interpendent and did not find any defects in anyone of them through all the first and the third group, but everyone embryo from the second group had a lot of defects.

  5. Mixed Total Variation and L(1) Regularization Method for Optical Tomography Based on Radiative Transfer Equation.

    PubMed

    Tang, Jinping; Han, Bo; Han, Weimin; Bi, Bo; Li, Li

    2017-01-01

    Optical tomography is an emerging and important molecular imaging modality. The aim of optical tomography is to reconstruct optical properties of human tissues. In this paper, we focus on reconstructing the absorption coefficient based on the radiative transfer equation (RTE). It is an ill-posed parameter identification problem. Regularization methods have been broadly applied to reconstruct the optical coefficients, such as the total variation (TV) regularization and the L(1) regularization. In order to better reconstruct the piecewise constant and sparse coefficient distributions, TV and L(1) norms are combined as the regularization. The forward problem is discretized with the discontinuous Galerkin method on the spatial space and the finite element method on the angular space. The minimization problem is solved by a Jacobian-based Levenberg-Marquardt type method which is equipped with a split Bregman algorithms for the L(1) regularization. We use the adjoint method to compute the Jacobian matrix which dramatically improves the computation efficiency. By comparing with the other imaging reconstruction methods based on TV and L(1) regularizations, the simulation results show the validity and efficiency of the proposed method.

  6. Mixed Total Variation and L1 Regularization Method for Optical Tomography Based on Radiative Transfer Equation

    PubMed Central

    Bi, Bo; Li, Li

    2017-01-01

    Optical tomography is an emerging and important molecular imaging modality. The aim of optical tomography is to reconstruct optical properties of human tissues. In this paper, we focus on reconstructing the absorption coefficient based on the radiative transfer equation (RTE). It is an ill-posed parameter identification problem. Regularization methods have been broadly applied to reconstruct the optical coefficients, such as the total variation (TV) regularization and the L1 regularization. In order to better reconstruct the piecewise constant and sparse coefficient distributions, TV and L1 norms are combined as the regularization. The forward problem is discretized with the discontinuous Galerkin method on the spatial space and the finite element method on the angular space. The minimization problem is solved by a Jacobian-based Levenberg-Marquardt type method which is equipped with a split Bregman algorithms for the L1 regularization. We use the adjoint method to compute the Jacobian matrix which dramatically improves the computation efficiency. By comparing with the other imaging reconstruction methods based on TV and L1 regularizations, the simulation results show the validity and efficiency of the proposed method. PMID:28280517

  7. Method to Enhance the Operation of an Optical Inspection Instrument Using Spatial Light Modulators

    NASA Technical Reports Server (NTRS)

    Trolinger, James; Lal, Amit; Jo, Joshua; Kupiec, Stephen

    2012-01-01

    For many aspheric and freeform optical components, existing interferometric solutions require a custom computer-generated hologram (CGH) to characterize the part. The overall objective of this research is to develop hardware and a procedure to produce a combined, dynamic, Hartmann/ Digital Holographic interferometry inspection system for a wide range of advanced optical components, including aspheric and freeform optics. This new instrument would have greater versatility and dynamic range than currently available measurement systems. The method uses a spatial light modulator to pre-condition wavefronts for imaging, interferometry, and data processing to improve the resolution and versatility of an optical inspection instrument. Existing interferometers and Hartmann inspection systems have either too small a dynamic range or insufficient resolution to characterize conveniently unusual optical surfaces like aspherical and freeform optics. For interferometers, a specially produced, computer-generated holographic optical element is needed to transform the wavefront to within the range of the interferometer. A new hybrid wavefront sensor employs newly available spatial light modulators (SLMs) as programmable holographic optical elements (HOEs). The HOE is programmed to enable the same instrument to inspect an optical element in stages, first by a Hartmann measurement, which has a very large dynamic range but less resolution. The first measurement provides the information required to precondition a reference wave that avails the measurement process to the more precise phase shifting interferometry. The SLM preconditions a wavefront before it is used to inspect an optical component. This adds important features to an optical inspection system, enabling not just wavefront conditioning for null testing and dynamic range extension, but also the creation of hybrid measurement procedures. This, for example, allows the combination of dynamic digital holography and Hartmann

  8. Method of developing all-optical trinary JK, D-type, and T-type flip-flops using semiconductor optical amplifiers.

    PubMed

    Garai, Sisir Kumar

    2012-04-10

    To meet the demand of very fast and agile optical networks, the optical processors in a network system should have a very fast execution rate, large information handling, and large information storage capacities. Multivalued logic operations and multistate optical flip-flops are the basic building blocks for such fast running optical computing and data processing systems. In the past two decades, many methods of implementing all-optical flip-flops have been proposed. Most of these suffer from speed limitations because of the low switching response of active devices. The frequency encoding technique has been used because of its many advantages. It can preserve its identity throughout data communication irrespective of loss of light energy due to reflection, refraction, attenuation, etc. The action of polarization-rotation-based very fast switching of semiconductor optical amplifiers increases processing speed. At the same time, tristate optical flip-flops increase information handling capacity.

  9. Hybrid diversity method utilizing adaptive diversity function for recovering unknown aberrations in an optical system

    NASA Technical Reports Server (NTRS)

    Dean, Bruce H. (Inventor)

    2009-01-01

    A method of recovering unknown aberrations in an optical system includes collecting intensity data produced by the optical system, generating an initial estimate of a phase of the optical system, iteratively performing a phase retrieval on the intensity data to generate a phase estimate using an initial diversity function corresponding to the intensity data, generating a phase map from the phase retrieval phase estimate, decomposing the phase map to generate a decomposition vector, generating an updated diversity function by combining the initial diversity function with the decomposition vector, generating an updated estimate of the phase of the optical system by removing the initial diversity function from the phase map. The method may further include repeating the process beginning with iteratively performing a phase retrieval on the intensity data using the updated estimate of the phase of the optical system in place of the initial estimate of the phase of the optical system, and using the updated diversity function in place of the initial diversity function, until a predetermined convergence is achieved.

  10. Optical devices and methods employing nanoparticles, microcavities, and semicontinuous metal films

    NASA Technical Reports Server (NTRS)

    Armstrong, Robert L. (Inventor); Shalaev, Vladimir M. (Inventor); Smith, Harold V. (Inventor); Sarychev, Andrey K. (Inventor); Ying, Z. Charles (Inventor)

    2006-01-01

    An optical sensing enhancing material (and corresponding method of making) comprising: a medium, the medium comprising a plurality of aggregated nanoparticles comprising fractals; and a microcavity, wherein the medium is located in a vicinity of the microcavity. Also an optical sensor and sensing method comprising: providing a doped medium, the medium comprising a plurality of aggregated nanoparticles comprising fractals, with the material; locating the doped medium in the vicinity of a microcavity; exciting the doped medium with a light source; and detecting light reflected from the doped medium. Also an optical sensing enhancing material comprising a medium, the medium comprising a semicontinuous metal film of randomly distributed metal particles and their clusters at approximately their percolation threshold. The medium preferably additionally comprises a microcavity/microresonator. Also devices and methods employing such material.

  11. Caries Detection Methods Based on Changes in Optical Properties between Healthy and Carious Tissue

    PubMed Central

    Karlsson, Lena

    2010-01-01

    A conservative, noninvasive or minimally invasive approach to clinical management of dental caries requires diagnostic techniques capable of detecting and quantifying lesions at an early stage, when progression can be arrested or reversed. Objective evidence of initiation of the disease can be detected in the form of distinct changes in the optical properties of the affected tooth structure. Caries detection methods based on changes in a specific optical property are collectively referred to as optically based methods. This paper presents a simple overview of the feasibility of three such technologies for quantitative or semiquantitative assessment of caries lesions. Two of the techniques are well-established: quantitative light-induced fluorescence, which is used primarily in caries research, and laser-induced fluorescence, a commercially available method used in clinical dental practice. The third technique, based on near-infrared transillumination of dental enamel is in the developmental stages. PMID:20454579

  12. Automatic Detection of the Optic Disc of the Retina: A Fast Method

    PubMed Central

    Jamshidi, M.; Rabbani, H.; Amini, Z.; Kafieh, R.; Ommani, A.; Lakshminarayanan, V.

    2016-01-01

    Localizing the optic disc (OD) in retinal fundus images is of critical importance and many techniques have been developed for OD detection. In this paper, we present the results obtained from two fast methods, correlation and least square, to approximate the location of optic cup. These methods are simple and are not complex, while most of the OD detection algorithms are. The methods were tested on two groups of data (a total of 100 color fundus images) and were 98% successful in the detection of the optic cup. An algorithm using the vessel mask of fundus images is proposed to be run after correlation to ensure that the localization of OD in all images is successful. It was tested on 40 of the test images and had a 100% rate of success. PMID:27014613

  13. Hybrid freeform TIR optics construction in Cartesian coordinate system: a new composite ray mapping method

    NASA Astrophysics Data System (ADS)

    Ma, Donglin; Feng, Zexin; Wang, Chengliang; Liang, Rongguang

    2015-09-01

    In this paper, we propose a new composite ray mapping method to design freeform total internal reflective (TIR) optics for LED illumination. We sample the ray intensity distribution into rectangular grids which have the best topological match to those rectangular grids on the target surface. With the multiple-to-one mapping relationships between the source intensity distribution and target irradiance distribution, we can construct the freeform TIR surfaces and freeform refractive surface using Snell's law. Compared to our previous design using uv-θϕ composite ray mapping method, this design approach is expected to have much less surface error and improve the illumination uniformity further because of the better topological match. In addition, due to the overlapping mechanism by multiple-to-one (composite) ray mapping, the method could lead to a more robust freeform optics compared to traditional freeform optics designs.

  14. Method used to test the imaging consistency of binocular camera's left-right optical system

    NASA Astrophysics Data System (ADS)

    Liu, Meiying; Wang, Hu; Liu, Jie; Xue, Yaoke; Yang, Shaodong; Zhao, Hui

    2016-09-01

    To binocular camera, the consistency of optical parameters of the left and the right optical system is an important factor that will influence the overall imaging consistency. In conventional testing procedure of optical system, there lacks specifications suitable for evaluating imaging consistency. In this paper, considering the special requirements of binocular optical imaging system, a method used to measure the imaging consistency of binocular camera is presented. Based on this method, a measurement system which is composed of an integrating sphere, a rotary table and a CMOS camera has been established. First, let the left and the right optical system capture images in normal exposure time under the same condition. Second, a contour image is obtained based on the multiple threshold segmentation result and the boundary is determined using the slope of contour lines near the pseudo-contour line. Third, the constraint of gray level based on the corresponding coordinates of left-right images is established and the imaging consistency could be evaluated through standard deviation σ of the imaging grayscale difference D (x, y) between the left and right optical system. The experiments demonstrate that the method is suitable for carrying out the imaging consistency testing for binocular camera. When the standard deviation 3σ distribution of imaging gray difference D (x, y) between the left and right optical system of the binocular camera does not exceed 5%, it is believed that the design requirements have been achieved. This method could be used effectively and paves the way for the imaging consistency testing of the binocular camera.

  15. Effect of Sn on the optical band gap determined using absorption spectrum fitting method

    SciTech Connect

    Heera, Pawan; Kumar, Anup; Sharma, Raman

    2015-05-15

    We report the preparation and the optical studies on tellurium rich glasses thin films. The thin films of Se{sub 30}Te{sub 70-x} Sn{sub x} system for x= 0, 1.5, 2.5 and 4.5 glassy alloys prepared by melt quenching technique are deposited on the glass substrate using vacuum thermal evaporation technique. The analysis of absorption spectra in the spectral range 400nm–4000 nm at room temperature obtained from UV-VIS-NIR spectrophotometer [Perkin Elmer Lamda-750] helps us in the optical characterization of the thin films under study. The absorption spectrum fitting method is applied by using the Tauc’s model for estimating the optical band gap and the width of the band tail of the thin films. The optical band gap is calculated and is found to decrease with the Sn content.

  16. Effect of Sn on the optical band gap determined using absorption spectrum fitting method

    NASA Astrophysics Data System (ADS)

    Heera, Pawan; Kumar, Anup; Sharma, Raman

    2015-05-01

    We report the preparation and the optical studies on tellurium rich glasses thin films. The thin films of Se30Te70-x Snx system for x= 0, 1.5, 2.5 and 4.5 glassy alloys prepared by melt quenching technique are deposited on the glass substrate using vacuum thermal evaporation technique. The analysis of absorption spectra in the spectral range 400nm-4000 nm at room temperature obtained from UV-VIS-NIR spectrophotometer [Perkin Elmer Lamda-750] helps us in the optical characterization of the thin films under study. The absorption spectrum fitting method is applied by using the Tauc's model for estimating the optical band gap and the width of the band tail of the thin films. The optical band gap is calculated and is found to decrease with the Sn content.

  17. An all-optical method of developing data communication system with error detection circuit

    NASA Astrophysics Data System (ADS)

    Mandal, Sumana; Mandal, Dhoumendra; Garai, Sisir Kumar

    2014-03-01

    The basic criterion of data communication is that received data should exactly be the replica of the transmitting data. If any error is introduced in the received data, then data transmission should be stopped immediately. In this article the authors have developed an all-optical method of data communication system with error detection mechanism that works with frequency encoded data. Basic building blocks of the proposed data communication scheme are parity generator and parity checker which are developed from all optical XOR logic gates. Simulation results testify the feasibility of the proposed scheme. These logic gates are developed exploiting nonlinear polarization rotation based frequency conversion and switching character of semiconductor optical amplifiers. The scheme with frequency encoded data, high speed of frequency conversion and polarization switching action of semiconductor optical amplifier offers secure, error free, faster data communication network.

  18. Fiber-optic apparatus and method for measurement of luminescence and Raman scattering

    DOEpatents

    Myrick, M.L.; Angel, S.M.

    1993-03-16

    A dual fiber forward scattering optrode for Raman spectroscopy with the remote ends of the fibers in opposed, spaced relationship to each other to form a analyte sampling space therebetween and the method of measuring Raman spectra utilizing same are described. One optical fiber is for sending an exciting signal to the remote sampling space and, at its remote end, has a collimating microlens and an optical filter for filtering out background emissions generated in the fiber. The other optical fiber is for collecting the Raman scattering signal at the remote sampling space and, at its remote end, has a collimating microlens and an optical filter to prevent the exciting signal from the exciting fiber from entering the collection fiber and to thereby prevent the generation of background emissions in the collecting fiber.

  19. Fiber-optic apparatus and method for measurement of luminescence and raman scattering

    DOEpatents

    Myrick, Michael L.; Angel, Stanley M.

    1993-01-01

    A dual fiber forward scattering optrode for Raman spectroscopy with the remote ends of the fibers in opposed, spaced relationship to each other to form a analyte sampling space therebetween and the method of measuring Raman spectra utilizing same. One optical fiber is for sending an exciting signal to the remote sampling space and, at its remote end, has a collimating microlens and an optical filter for filtering out background emissions generated in the fiber. The other optical fiber is for collecting the Raman scattering signal at the remote sampling space and, at its remote end, has a collimating microlens and an optical filter to prevent the exciting signal from the exciting fiber from entering the collection fiber and to thereby prevent the generation of background emissions in the collecting fiber.

  20. Fabrication of double layer optical tissue phantom by spin coating method: mimicking epidermal and dermal layer

    NASA Astrophysics Data System (ADS)

    Park, Jihoon; Bae, Yunjin; Bae, Youngwoo; Kang, Heesung; Lee, Kyoung-Joung; Jung, Byungjo

    2013-02-01

    Methodologies to fabricate a solid optical tissue phantom (OTP) mimicking epidermal thin-layer have been developed for in vitro human skin experiment. However, there are cumbersome and time-consuming efforts in fabrication process such as a custom-made casting and calculation of solvent volume before curing process. In a previous study, we introduced a new methodology based on spin coating method (SCM) which is utilized to fabricate a thin-layer OTP analogous to epidermal thickness. In this study, a double layer solid OTP which has epidermal and dermal layers was fabricated to mimic the morphological and optical similarity of human tissue. The structural characteristic and optical properties of fabricated double layer OTP were measured using optical coherence tomography and inverse adding doubling algorithms, respectively. It is expected that the new methodology based on the SCM may be usefully used in the fabrication of double layer OTP.