Fiber optic connector

DOEpatents

Rajic, Slobodan; Muhs, Jeffrey D.

1996-01-01

A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled.

Optical contact micrometer

DOEpatents

Jacobson, Steven D.

2014-08-19

Certain examples provide optical contact micrometers and methods of use. An example optical contact micrometer includes a pair of opposable lenses to receive an object and immobilize the object in a position. The example optical contact micrometer includes a pair of opposable mirrors positioned with respect to the pair of lenses to facilitate viewing of the object through the lenses. The example optical contact micrometer includes a microscope to facilitate viewing of the object through the lenses via the mirrors; and an interferometer to obtain one or more measurements of the object.

Skull optical clearing for assessing to cerebral hemodynamics with high contrast and resolution (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zhu, Dan

2017-03-01

The tissue optical clearing technique could significantly enhance the biomedical optical imaging depth, but current investigations are mainly limited to in vitro studies. In vivo tissue optical clearing method should be enough rapid, transparent and safe, which makes it more difficult, especially, for hard tissue. During the past years, we developed skull optical clearing methods for in vivo cortical imaging. This presentation will report recent progress in skull optical clearing method, including their efficacy, safety, and applications. The skull optical clearing method is proved to be effective for adult mice ages in different month and permit various imaging techniques to monitor cortical blood flow, blood oxygen, and vascular with high resolution and contrast, not only for local cortex, but also for whole cortex. The long-term and short-term observation show that there is no obvious effect on cortical vascular function when laser speckle contrast imaging and hyperspectral imaging are used to repeatedly image the cortical blood flow, blood oxygen. Finally, we will demonstrate some applications for physiological or pathological situation, including monitoring the anoxia, drug-induced cortical response, et al.

Micro-optical-mechanical system photoacoustic spectrometer

DOEpatents

Kotovsky, Jack; Benett, William J.; Tooker, Angela C.; Alameda, Jennifer B.

2013-01-01

All-optical photoacoustic spectrometer sensing systems (PASS system) and methods include all the hardware needed to analyze the presence of a large variety of materials (solid, liquid and gas). Some of the all-optical PASS systems require only two optical-fibers to communicate with the opto-electronic power and readout systems that exist outside of the material environment. Methods for improving the signal-to-noise are provided and enable mirco-scale systems and methods for operating such systems.

Spectroscopic quantification of extremely rare molecular species in the presence of interfering optical absorption

DOEpatents

Ognibene, Ted; Bench, Graham; McCartt, Alan Daniel; Turteltaub, Kenneth; Rella, Chris W.; Tan, Sze; Hoffnagle, John A.; Crosson, Eric

2017-05-09

Optical spectrometer apparatus, systems, and methods for analysis of carbon-14 including a resonant optical cavity configured to accept a sample gas including carbon-14, an optical source configured to deliver optical radiation to the resonant optical cavity, an optical detector configured to detect optical radiation emitted from the resonant cavity and to provide a detector signal; and a processor configured to compute a carbon-14 concentration from the detector signal, wherein computing the carbon-14 concentration from the detector signal includes fitting a spectroscopic model to a measured spectrogram, wherein the spectroscopic model accounts for contributions from one or more interfering species that spectroscopically interfere with carbon-14.

Method and system for compact, multi-pass pulsed laser amplifier

DOEpatents

Erlandson, Alvin Charles

2014-11-25

A laser amplifier includes an input aperture operable to receive laser radiation having a first polarization, an output aperture coupled to the input aperture by an optical path, and a polarizer disposed along an optical path. A transmission axis of the polarizer is aligned with the first polarization. The laser amplifier also includes n optical switch disposed along the optical path. The optical switch is operable to pass the laser radiation when operated in a first state and to reflect the laser radiation when operated in a second state. The laser amplifier further includes an optical gain element disposed along the optical path and a polarization rotation device disposed along the optical path.

Diffractive optics in industry and research: novel components for optical security systems

NASA Astrophysics Data System (ADS)

Laakkonen, Pasi; Turunen, Jari; Pietarinen, Juha; Siitonen, Samuli; Laukkanen, Janne; Jefimovs, Konstantins; Orava, Joni; Ritala, Mikko; Pilvi, Tero; Tuovinen, Hemmo; Ventola, Kalle; Vallius, Tuomas; Kaipiainen, Matti; Kuittinen, Markku

2005-09-01

Design and manufacturing of diffractive optical elements (DOEs) are presented. Mass replication methods for DOEs are explained including UV-replication, micro-injection moulding and reel-to-reel production. Novel applications of diffractive optics including spectroscopic surface relief gratings, antireflection surfaces, infrared light rejection gratings, light incoupling into thin waveguides, and additive diffractive colour mixing are presented.

Fiber optic connector

DOEpatents

Rajic, S.; Muhs, J.D.

1996-10-22

A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded are disclosed. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled. 3 figs.

Optical metrology at the Optical Sciences Center: an historical review

NASA Astrophysics Data System (ADS)

Creath, Katherine; Parks, Robert E.

2014-10-01

The Optical Sciences Center (OSC) begun as a graduate-level applied optics teaching institution to support the US space effort. The making of optics representative of those used in other space programs was deemed essential. This led to the need for optical metrology: at first Hartmann tests, but almost immediately to interferometric tests using the newly invented HeNe laser. Not only were new types of interferometers needed, but the whole infrastructure that went with testing, fringe location methods, aberration removal software and contour map generation to aid the opticians during polishing needed to be developed. Over the last half century more rapid and precise methods of interferogram data reduction, surface roughness measurement, and methods of instrument calibration to separate errors from those in the optic have been pioneered at OSC. Other areas of research included null lens design and the writing of lens design software that led into the design of computer generated holograms for asphere testing. More recently work has been done on the reduction of speckle noise in interferograms, methods to test large convex aspheres, and a return to slope measuring tests to increase the dynamic range of the types of aspheric surfaces amenable to optical testing including free-form surfaces. This paper documents the history of the development of optical testing projects at OSC and highlights the contributions some of the individuals associated with new methods of testing and the infrastructure needed to support the testing. We conclude with comments about the future trends optical metrology.

Apparatus and method for creating a photonic densely-accumulated ray-point

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

2012-01-01

An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

Optical profile determining apparatus and associated methods including the use of a plurality of wavelengths in the reference beam and a plurality of wavelengths in a reflective transit beam

NASA Technical Reports Server (NTRS)

Montgomery, Robert M. (Inventor)

2006-01-01

An optical profile determining apparatus includes an optical detector and an optical source. The optical source generates a transmit beam including a plurality of wavelengths, and generates a reference beam including the plurality of wavelengths. Optical elements direct the transmit beam to a target, direct a resulting reflected transmit beam back from the target to the optical detector, and combine the reference beam with the reflected transmit beam so that a profile of the target is based upon fringe contrast produced by the plurality of wavelengths in the reference beam and the plurality of wavelengths in the reflected transmit beam.

Measurement of chalcogenide glass optical dispersion using a mid-infrared prism coupler

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

Qiao, Hong; Anheier, Norman C.; Musgraves, Jonathan D.

2011-05-01

Physical properties of chalcogenide glass, including broadband infrared transparency, high refractive index, low glass transition temperature, and nonlinear properties, make them attractive candidates for advanced mid-infrared (3 to 12 {micro}m) optical designs. Efforts focused at developing new chalcogenide glass formulations and processing methods require rapid quantitative evaluation of their optical contents to guide the materials research. However, characterization of important optical parameters such as optical dispersion remains a slow and costly process, generally with limited accuracy. The recent development of a prism coupler at the Pacific Northwest National Laboratory (PNNL) now enables rapid, high precision measurement of refractive indices atmore » discrete wavelengths from the visible to the mid-infrared. Optical dispersion data of several chalcogenide glass families were collected using this method. Variations in the optical dispersion were correlated to glass composition and compared against measurements using other methods. While this work has been focused on facilitating chalcogenide glass synthesis, mid-infrared prism coupler analysis has broader applications to other mid-infrared optical material development efforts, including oxide glasses and crystalline materials.« less

Method and device for detecting impact events on a security barrier which includes a hollow rebar allowing insertion and removal of an optical fiber

DOEpatents

Pies, Ross E.

2016-03-29

A method and device for the detection of impact events on a security barrier. A hollow rebar is farmed within a security barrier, whereby the hollow rebar is completely surrounded by the security barrier. An optical fiber passes through the interior of the hollow rebar. An optical transmitter and an optical receiver are both optically connected to the optical fiber and connected to optical electronics. The optical electronics are configured to provide notification upon the detection of an impact event at the security barrier based on the detection of disturbances within the optical fiber.

Contrast enhancing solution for use in confocal microscopy

DOEpatents

Tannous, Zeina; Torres, Abel; Gonzalez, Salvador

2006-10-31

A method of optically detecting a tumor during surgery. The method includes imaging at least one test point defined on the tumor using a first optical imaging system to provide a first tumor image. The method further includes excising a first predetermined layer of the tumor for forming an in-vivo defect area. A predetermined contrast enhancing solution is disposed on the in-vivo defect area, which is adapted to interact with at least one cell anomaly, such as basal cell carcinoma, located on the in-vivo defect area for optically enhancing the cell anomaly. Thereafter the defect area can be optically imaged to provide a clear and bright representation of the cell anomaly to aid a surgeon while surgically removing the cell anomaly.

The Optics of Bruising

NASA Astrophysics Data System (ADS)

Randeberg, Lise Lyngsnes; Skallerud, Bjørn; Langlois, Neil E. I.; Haugen, Olav Anton; Svaasand, Lars Othar

Forensic medicine is a field of medicine where technology plays an increasingly important role in securing and evaluating evidence in, for example, child abuse cases and cases of domestic violence. Methods from chemistry and biological sciences have found a wide application within forensic medicine. Optical technologies like microscopy are also widely used. Despite this, in vivo or post mortem optical diagnostics by spectroscopy have traditionally not had an important role in clinical or forensic examinations. Forensic medical optics as a field might include all kinds of optical analysis for use within forensic science. This includes everything from microscopic techniques to methods for examination of evidence from a crime scene. This chapter will, however, focus on the use of optical diagnostics for examining skin, with a focus on identification, characterization and age determination of minor traumatic injuries like skin bruises.

Development and applications of optical interferometric micrometrology in the Angstrom and subangstrom range

NASA Technical Reports Server (NTRS)

Lauer, James L.; Abel, Phillip B.

1988-01-01

The characteristics of the scanning tunneling microscope and atomic force microscope (AFM) are briefly reviewed, and optical methods, mainly interferometry, of sufficient resolution to measure AFM deflections are discussed. The methods include optical resonators, laser interferometry, multiple-beam interferometry, and evanescent wave detection. Experimental results using AFM are reviewed.

New generation all-silica based optical elements for high power laser systems

NASA Astrophysics Data System (ADS)

Tolenis, T.; GrinevičiÅ«tÄ--, L.; Melninkaitis, A.; Selskis, A.; Buzelis, R.; MažulÄ--, L.; Drazdys, R.

2017-08-01

Laser resistance of optical elements is one of the major topics in photonics. Various routes have been taken to improve optical coatings, including, but not limited by, materials engineering and optimisation of electric field distribution in multilayers. During the decades of research, it was found, that high band-gap materials, such as silica, are highly resistant to laser light. Unfortunately, only the production of anti-reflection coatings of all-silica materials are presented to this day. A novel route will be presented in materials engineering, capable to manufacture high reflection optical elements using only SiO2 material and GLancing Angle Deposition (GLAD) method. The technique involves the deposition of columnar structure and tailoring the refractive index of silica material throughout the coating thickness. A numerous analysis indicate the superior properties of GLAD coatings when compared with standard methods for Bragg mirrors production. Several groups of optical components are presented including anti-reflection coatings and Bragg mirrors. Structural and optical characterisation of the method have been performed and compared with standard methods. All researches indicate the possibility of new generation coatings for high power laser systems.

Non-invasive neuroimaging using near-infrared light

NASA Technical Reports Server (NTRS)

Strangman, Gary; Boas, David A.; Sutton, Jeffrey P.

2002-01-01

This article reviews diffuse optical brain imaging, a technique that employs near-infrared light to non-invasively probe the brain for changes in parameters relating to brain function. We describe the general methodology, including types of measurements and instrumentation (including the tradeoffs inherent in the various instrument components), and the basic theory required to interpret the recorded data. A brief review of diffuse optical applications is included, with an emphasis on research that has been done with psychiatric populations. Finally, we discuss some practical issues and limitations that are relevant when conducting diffuse optical experiments. We find that, while diffuse optics can provide substantial advantages to the psychiatric researcher relative to the alternative brain imaging methods, the method remains substantially underutilized in this field.

Method and apparatus for acoustic imaging of objects in water

DOEpatents

Deason, Vance A.; Telschow, Kenneth L.

2005-01-25

A method, system and underwater camera for acoustic imaging of objects in water or other liquids includes an acoustic source for generating an acoustic wavefront for reflecting from a target object as a reflected wavefront. The reflected acoustic wavefront deforms a screen on an acoustic side and correspondingly deforms the opposing optical side of the screen. An optical processing system is optically coupled to the optical side of the screen and converts the deformations on the optical side of the screen into an optical intensity image of the target object.

Sighting optics including an optical element having a first focal length and a second focal length and methods for sighting

DOEpatents

Crandall, David Lynn

2011-08-16

Sighting optics include a front sight and a rear sight positioned in a spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus for a user images of the front sight and the target.

Quantum Optical Realization of Arbitrary Linear Transformations Allowing for Loss and Gain

NASA Astrophysics Data System (ADS)

Tischler, N.; Rockstuhl, C.; Słowik, K.

2018-04-01

Unitary transformations are routinely modeled and implemented in the field of quantum optics. In contrast, nonunitary transformations, which can involve loss and gain, require a different approach. In this work, we present a universal method to deal with nonunitary networks. An input to the method is an arbitrary linear transformation matrix of optical modes that does not need to adhere to bosonic commutation relations. The method constructs a transformation that includes the network of interest and accounts for full quantum optical effects related to loss and gain. Furthermore, through a decomposition in terms of simple building blocks, it provides a step-by-step implementation recipe, in a manner similar to the decomposition by Reck et al. [Experimental Realization of Any Discrete Unitary Operator, Phys. Rev. Lett. 73, 58 (1994), 10.1103/PhysRevLett.73.58] but applicable to nonunitary transformations. Applications of the method include the implementation of positive-operator-valued measures and the design of probabilistic optical quantum information protocols.

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

Kang, Hyeonggon; Attota, Ravikiran, E-mail: ravikiran.attota@nist.gov; Tondare, Vipin

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 ismore » 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.« less

Device-packaging method and apparatus for optoelectronic circuits

DOEpatents

Zortman, William A.; Henry, Michael David; Jarecki, Jr., Robert L.

2017-04-25

An optoelectronic device package and a method for its fabrication are provided. The device package includes a lid die and an active die that is sealed or sealable to the lid die and in which one or more optical waveguides are integrally defined. The active die includes one or more active device regions, i.e. integral optoelectronic devices or etched cavities for placement of discrete optoelectronic devices. Optical waveguides terminate at active device regions so that they can be coupled to them. Slots are defined in peripheral parts of the active dies. At least some of the slots are aligned with the ends of integral optical waveguides so that optical fibers or optoelectronic devices inserted in the slots can optically couple to the waveguides.

Limitations and Tolerances in Optical Devices

NASA Astrophysics Data System (ADS)

Jackman, Neil Allan

The performance of optical systems is limited by the imperfections of their components. Many of the devices in optical systems including optical fiber amplifiers, multimode transmission lines and multilayered media such as mirrors, windows and filters, are modeled by coupled line equations. This investigation includes: (i) a study of the limitations imposed on a wavelength multiplexed unidirectional ring by the non-uniformities of the gain spectra of Erbium-doped optical fiber amplifiers. We find numerical solutions for non-linear coupled power differential equations and use these solutions to compare the signal -to-noise ratios and signal levels at different nodes. (ii) An analytical study of the tolerances of imperfect multimode media which support forward traveling modes. The complex mode amplitudes are related by linear coupled differential equations. We use analytical methods to derive extended equations for the expected mode powers and give heuristic limits for their regions of validity. These results compare favorably to exact solutions found for a special case. (iii) A study of the tolerances of multilayered media in the presence of optical thickness imperfections. We use analytical methods including Kronecker producers, to calculate the reflection and transmission statistics of the media. Monte Carlo simulations compare well to our analytical method.

Method and system for homogenizing diode laser pump arrays

DOEpatents

Bayramian, Andrew James

2016-05-03

An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

Method and system for homogenizing diode laser pump arrays

DOEpatents

Bayramian, Andy J

2013-10-01

An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

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.

Optical system design, analysis, and production; Proceedings of the Meeting, Geneva, Switzerland, April 19-22, 1983

NASA Astrophysics Data System (ADS)

Rogers, P. J.; Fischer, R. E.

1983-01-01

Topics considered include: optical system requirements, analysis, and system engineering; optical system design using microcomputers and minicomputers; optical design theory and computer programs; optical design methods and computer programs; optical design methods and philosophy; unconventional optical design; diffractive and gradient index optical system design; optical production and system integration; and optical systems engineering. Particular attention is given to: stray light control as an integral part of optical design; current and future directions of lens design software; thin-film technology in the design and production of optical systems; aspherical lenses in optical scanning systems; the application of volume phase holograms to avionic displays; the effect of lens defects on thermal imager performance; and a wide angle zoom for the Space Shuttle.

Optimized achromatic phase-matching system and method

DOEpatents

Trebino, R.; DeLong, K.; Hayden, C.

1997-07-15

An optical system for efficiently directing a large bandwidth light (e.g., a femtosecond laser pulse) onto a nonlinear optical medium includes a plurality of optical elements for directing an input light pulse onto a nonlinear optical medium arranged such that the angle {theta}{sub in} which the light pulse directed onto the nonlinear optical medium is substantially independent of a position x of the light beam entering the optical system. The optical system is also constructed such that the group velocity dispersion of light pulses passing through the system can be tuned to a desired value including negative group velocity dispersion. 15 figs.

Optimized achromatic phase-matching system and method

DOEpatents

Trebino, Rick; DeLong, Ken; Hayden, Carl

1997-01-01

An optical system for efficiently directing a large bandwidth light (e.g., a femtosecond laser pulse) onto a nonlinear optical medium includes a plurality of optical elements for directing an input light pulse onto a nonlinear optical medium arranged such that the angle .theta..sub.in which the light pulse directed onto the nonlinear optical medium is substantially independent of a position x of the light beam entering the optical system. The optical system is also constructed such that the group velocity dispersion of light pulses passing through the system can be tuned to a desired value including negative group velocity dispersion.

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.

New Methods for Design and Computation of Freeform Optics

DTIC Science & Technology

2015-07-09

338, Springer-Verlag Berlin Heidelberg, 2009. [18] R. Winston , J. C. Miñano, and P. Beńıtez, with contributions by N. Shatz and J. Bortz, Nonimaging Optics , Elsevier Academic Press, Amsterdam, 2005. 8 ...AFRL-OSR-VA-TR-2015-0160 New Methods for Design and Computation of Free-form Optics Vladimir Oliker EMORY UNIVERSITY Final Report 07/09/2015...Include area code) 01-07-2015 Final Technical Report May 01, 2012 - April 30, 2015 New Methods for Design and Computation of Freeform Optics FA9550-12--1

New teaching methods in use at UC Irvine's optical engineering and instrument design programs

NASA Astrophysics Data System (ADS)

Silberman, Donn M.; Rowe, T. Scott; Jo, Joshua; Dimas, David

2012-10-01

New teaching methods reach geographically dispersed students with advances in Distance Education. Capabilities include a new "Hybrid" teaching method with an instructor in a classroom and a live WebEx simulcast for remote students. Our Distance Education Geometric and Physical Optics courses include Hands-On Optics experiments. Low cost laboratory kits have been developed and YouTube type video recordings of the instructor using these tools guide the students through their labs. A weekly "Office Hour" has been developed using WebEx and a Live Webcam the instructor uses to display his live writings from his notebook for answering students' questions.

Methods and apparatus for optical switching using electrically movable optical fibers

DOEpatents

Peterson, Kenneth A [Albuquerque, NM

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.

Athermalization of resonant optical devices via thermo-mechanical feedback

DOEpatents

Rakich, Peter; Nielson, Gregory N.; Lentine, Anthony L.

2016-01-19

A passively athermal photonic system including a photonic circuit having a substrate and an optical cavity defined on the substrate, and passive temperature-responsive provisions for inducing strain in the optical cavity of the photonic circuit to compensate for a thermo-optic effect resulting from a temperature change in the optical cavity of the photonic circuit. Also disclosed is a method of passively compensating for a temperature dependent thermo-optic effect resulting on an optical cavity of a photonic circuit including the step of passively inducing strain in the optical cavity as a function of a temperature change of the optical cavity thereby producing an elasto-optic effect in the optical cavity to compensate for the thermo-optic effect resulting on an optical cavity due to the temperature change.

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.

Optical Interconnection Via Computer-Generated Holograms

NASA Technical Reports Server (NTRS)

Liu, Hua-Kuang; Zhou, Shaomin

1995-01-01

Method of free-space optical interconnection developed for data-processing applications like parallel optical computing, neural-network computing, and switching in optical communication networks. In method, multiple optical connections between multiple sources of light in one array and multiple photodetectors in another array made via computer-generated holograms in electrically addressed spatial light modulators (ESLMs). Offers potential advantages of massive parallelism, high space-bandwidth product, high time-bandwidth product, low power consumption, low cross talk, and low time skew. Also offers advantage of programmability with flexibility of reconfiguration, including variation of strengths of optical connections in real time.

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

He, Liping; Zhu, Fulong, E-mail: zhufulong@hust.edu.cn; Duan, Ke

Ultrasonic waves are widely used, with applications including the medical, military, and chemical fields. However, there are currently no effective methods for ultrasonic power measurement. Previously, ultrasonic power measurement has been reliant on mechanical methods such as hydrophones and radiation force balances. This paper deals with ultrasonic power measurement based on an unconventional method: acousto-optic interaction. Compared with mechanical methods, the optical method has a greater ability to resist interference and also has reduced environmental requirements. Therefore, this paper begins with an experimental determination of the acoustic power in water contained in a glass tank using a set of opticalmore » devices. Because the light intensity of the diffraction image generated by acousto-optic interaction contains the required ultrasonic power information, specific software was written to extract the light intensity information from the image through a combination of filtering, binarization, contour extraction, and other image processing operations. The power value can then be obtained rapidly by processing the diffraction image using a computer. The results of this work show that the optical method offers advantages that include accuracy, speed, and a noncontact measurement method.« less

Optical Brain Imaging: A Powerful Tool for Neuroscience.

PubMed

Zhu, Xinpei; Xia, Yanfang; Wang, Xuecen; Si, Ke; Gong, Wei

2017-02-01

As the control center of organisms, the brain remains little understood due to its complexity. Taking advantage of imaging methods, scientists have found an accessible approach to unraveling the mystery of neuroscience. Among these methods, optical imaging techniques are widely used due to their high molecular specificity and single-molecule sensitivity. Here, we overview several optical imaging techniques in neuroscience of recent years, including brain clearing, the micro-optical sectioning tomography system, and deep tissue imaging.

Method and system for suppression of stimulated Raman scattering in laser materials

DOEpatents

Caird, John A; Bayramian, Andrew J; Ebbers, Christopher A

2013-11-19

A composition of matter is provided having the general chemical formula K(H,D).sub.2P(.sup.16O.sub.x,.sup.18O.sub.y).sub.4, where x<0.998 or y>0.002, and x+y.apprxeq.1. Additionally, a method of fabricating an optical material by growth from solution is provided. The method includes providing a solution including a predetermined percentage of (H,D).sub.2.sup.16O and a predetermined percentage of (H,D).sub.2.sup.18O, providing a seed crystal, and supporting the seed crystal on a platform. The method also includes immersing the seed crystal in the solution and forming the optical material. The optical material has the general chemical formula K(H,D).sub.2P(.sup.16O.sub.x,.sup.18O.sub.y).sub.4, where x<0.998 or y>0.002, and x+y.apprxeq.1.

Method and system for suppression of stimulated Raman scattering in laser materials

DOEpatents

Caird, John A.; Bayramian, Andrew J.; Ebbers, Christopher A.

2015-07-14

A composition of matter is provided having the general chemical formula K(H,D).sub.2P(.sup.16O.sub.x,.sup.18O.sub.y).sub.4, where x<0.998 or y>0.002, and x+y.apprxeq.1. Additionally, a method of fabricating an optical material by growth from solution is provided. The method includes providing a solution including a predetermined percentage of (H,D).sub.2.sup.16O and a predetermined percentage of (H,D).sub.2.sup.18O, providing a seed crystal, and supporting the seed crystal on a platform. The method also includes immersing the seed crystal in the solution and forming the optical material. The optical material has the general chemical formula K(H,D).sub.2P(.sup.16O.sub.x,.sup.18O.sub.y).sub.4, where x<0.998 or y>0.002, and x+y.apprxeq.1.

Method of Making Lightweight, Single Crystal Mirror

NASA Technical Reports Server (NTRS)

Bly, Vincent T. (Inventor)

2015-01-01

A method of making a mirror from a single crystal blank may include fine grinding top and bottom surfaces of the blank to be parallel. The blank may then be heat treated to near its melting temperature. An optical surface may be created on an optical side of the blank. A protector may be bonded to the optical surface. With the protector in place, the blank may be light weighted by grinding a non-optical surface of the blank using computer controlled grinding. The light weighting may include creating a structure having a substantially minimum mass necessary to maintain distortion of the mirror within a preset limit. A damaged layer of the non-optical surface caused by light weighting may be removed with an isotropic etch and/or repaired by heat treatment. If an oxide layer is present, the entire blank may then be etched using, for example, hydrofluoric acid. A reflecting coating may be deposited on the optical surface.

Front lighted optical tooling method and apparatus

DOEpatents

Stone, W.J.

1983-06-30

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.

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.

A comparative review of optical surface contamination assessment techniques

NASA Technical Reports Server (NTRS)

Heaney, James B.

1987-01-01

This paper will review the relative sensitivities and practicalities of the common surface analytical methods that are used to detect and identify unwelcome adsorbants on optical surfaces. The compared methods include visual inspection, simple reflectometry and transmissiometry, ellipsometry, infrared absorption and attenuated total reflectance spectroscopy (ATR), Auger electron spectroscopy (AES), scanning electron microscopy (SEM), secondary ion mass spectrometry (SIMS), and mass accretion determined by quartz crystal microbalance (QCM). The discussion is biased toward those methods that apply optical thin film analytical techniques to spacecraft optical contamination problems. Examples are cited from both ground based and in-orbit experiments.

Method and system for compact efficient laser architecture

DOEpatents

Bayramian, Andrew James; Erlandson, Alvin Charles; Manes, Kenneth Rene; Spaeth, Mary Louis; Caird, John Allyn; Deri, Robert J.

2015-09-15

A laser amplifier module having an enclosure includes an input window, a mirror optically coupled to the input window and disposed in a first plane, and a first amplifier head disposed along an optical amplification path adjacent a first end of the enclosure. The laser amplifier module also includes a second amplifier head disposed along the optical amplification path adjacent a second end of the enclosure and a cavity mirror disposed along the optical amplification path.

Spectroelectrochemistry: The Combination of Optical and Electrochemical Techniques.

ERIC Educational Resources Information Center

Heineman, William R.

1983-01-01

Two different techniques, electrochemistry and spectroscopy, can be combined for studying the redox chemistry of inorganic, organic, and biological molecules. Several commonly used spectroelectrochemical methods and their applications are described. Includes discussions of optically transparent electrodes, optical absorption/fluorescence…

Extraction film for optical waveguide and method of producing same

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

Tarsa, Eric J.; Durkee, John W.

2017-05-16

An optical waveguide includes a waveguide body and a film disposed on a surface of the waveguide body. The film includes a base and a plurality of undercut light extraction elements disposed between the base and the surface.

Reconfigurable optical-to-optical frequency conversion method and apparatus

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

Zortman, William A.; Lentine, Anthony L.

A photonic device is provided for impressing a modulation pattern on an optical carrier. The device includes a unit in which a photodetector and an optical microresonator are monolithically integrated. The device further includes an optical waveguide evanescently coupled to the optical microresonator and having at least an upstream portion configured to carry at least one optical carrier toward the microresonator. The optical microresonator is tunable so as to resonate with the optical carrier frequency. The optical microresonator and the photodetector are mutually coupled such that in operation, charge carriers photogenerated in the photodetector are injected into the microresonator, wheremore » the photocurrent changes the resonant conditions. In some embodiments the device is operable as an optical-to-optical frequency converter. In other embodiments the device is operable as an oscillator.« less

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.

Transfer of non-Gaussian quantum states of mechanical oscillator to light

NASA Astrophysics Data System (ADS)

Filip, Radim; Rakhubovsky, Andrey A.

2015-11-01

Non-Gaussian quantum states are key resources for quantum optics with continuous-variable oscillators. The non-Gaussian states can be deterministically prepared by a continuous evolution of the mechanical oscillator isolated in a nonlinear potential. We propose feasible and deterministic transfer of non-Gaussian quantum states of mechanical oscillators to a traveling light beam, using purely all-optical methods. The method relies on only basic feasible and high-quality elements of quantum optics: squeezed states of light, linear optics, homodyne detection, and electro-optical feedforward control of light. By this method, a wide range of novel non-Gaussian states of light can be produced in the future from the mechanical states of levitating particles in optical tweezers, including states necessary for the implementation of an important cubic phase gate.

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.

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.

Multipass optical device and process for gas and analyte determination

DOEpatents

Bernacki, Bruce E [Kennewick, WA

2011-01-25

A torus multipass optical device and method are described that provide for trace level determination of gases and gas-phase analytes. The torus device includes an optical cavity defined by at least one ring mirror. The mirror delivers optical power in at least a radial and axial direction and propagates light in a multipass optical path of a predefined path length.

Spatial Light Modulators as Optical Crossbar Switches

NASA Technical Reports Server (NTRS)

Juday, Richard

2003-01-01

A proposed method of implementing cross connections in an optical communication network is based on the use of a spatial light modulator (SLM) to form controlled diffraction patterns that connect inputs (light sources) and outputs (light sinks). Sources would typically include optical fibers and/or light-emitting diodes; sinks would typically include optical fibers and/or photodetectors. The sources and/or sinks could be distributed in two dimensions; that is, on planes. Alternatively or in addition, sources and/or sinks could be distributed in three dimensions -- for example, on curved surfaces or in more complex (including random) three-dimensional patterns.

Silicon photonics thermal phase shifter with reduced temperature range

DOEpatents

Lentine, Anthony L; Kekatpure, Rohan D; DeRose, Christopher; Davids, Paul; Watts, Michael R

2013-12-17

Optical devices, phased array systems and methods of phase-shifting an input signal are provided. An optical device includes a microresonator and a waveguide for receiving an input optical signal. The waveguide includes a segment coupled to the microresonator with a coupling coefficient such that the waveguide is overcoupled to the microresonator. The microresonator received the input optical signal via the waveguide and phase-shifts the input optical signal to form an output optical signal. The output optical signal is coupled into the waveguide via the microresonator and transmitted by the waveguide. At an operating point of the optical device, the coupling coefficient is selected to reduce a change in an amplitude of the output optical signal and to increase a change in a phase of the output optical signal, relative to the input optical signal.

WGM resonators for studying orbital angular momentum of a photon, and methods

NASA Technical Reports Server (NTRS)

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

2009-01-01

An optical system, device, and method that are capable of generating high-order Bessel beams and determining the orbital angular momentum of at least one of the photons of a Bessel beam are provided. The optical system and device include a tapered waveguide having an outer surface defined by a diameter that varies along a longitudinal axis of the waveguide from a first end to an opposing second end. The optical system and device include a resonator that is arranged in optical communication with the first end of the tapered waveguide such that an evanescent field emitted from (i) the waveguide can be coupled with the resonator, or (ii) the resonator can be coupled with the waveguide.

Optical Biopsy: A New Frontier in Endoscopic Detection and Diagnosis

PubMed Central

WANG, THOMAS D.; VAN DAM, JACQUES

2007-01-01

Endoscopic diagnosis currently relies on the ability of the operator to visualize abnormal patterns in the image created by light reflected from the mucosal surface of the gastrointestinal tract. Advances in fiber optics, light sources, detectors, and molecular biology have led to the development of several novel methods for tissue evaluation in situ. The term “optical biopsy” refers to methods that use the properties of light to enable the operator to make an instant diagnosis at endoscopy, previously possible only by using histological or cytological analysis. Promising imaging techniques include fluorescence endoscopy, optical coherence tomography, confocal microendoscopy, and molecular imaging. Point detection schemes under development include light scattering and Raman spectroscopy. Such advanced diagnostic methods go beyond standard endoscopic techniques by offering improved image resolution, contrast, and tissue penetration and providing biochemical and molecular information about mucosal disease. This review describes the basic biophysics of light-tissue interactions, assesses the strengths and weaknesses of each method, and examines clinical and preclinical evidence for each approach. PMID:15354274

Mini-lidar sensor for the remote stand-off sensing of chemical/biological substances and method for sensing same

DOEpatents

Ray, Mark D.; Sedlacek, Arthur J.

2003-08-19

A method and apparatus for remote, stand-off, and high efficiency spectroscopic detection of biological and chemical substances. The apparatus including an optical beam transmitter which transmits a beam having an axis of transmission to a target, the beam comprising at least a laser emission. An optical detector having an optical detection path to the target is provided for gathering optical information. The optical detection path has an axis of optical detection. A beam alignment device fixes the transmitter proximal to the detector and directs the beam to the target along the optical detection path such that the axis of transmission is within the optical detection path. Optical information gathered by the optical detector is analyzed by an analyzer which is operatively connected to the detector.

Parametric instability in the high power era of Advanced LIGO

NASA Astrophysics Data System (ADS)

Hardwick, Terra; Blair, Carl; Kennedy, Ross; Evans, Matthew; Fritschel, Peter; LIGO Virgo Scientific Collaboration

2017-01-01

After the first direct detections of gravitational waves, Advanced LIGO aims to increase its detection rate during the upcoming science runs through a series of detector improvements, including increased optical power. Higher circulating power increases the likelihood for three-mode parametric instabilities (PIs), in which mechanical modes of the mirrors scatter light into higher-order optical modes in the cavity and the resulting optical modes reinforce the mechanical modes via radiation pressure. Currently, LIGO uses two PI mitigation methods: thermal tuning to change the cavity g-factor and effectively decrease the frequency overlap between mechanical and optical modes, and active damping of mechanical modes with electrostatic actuation. While the combined methods provide stability at the current operating power, there is evidence that these will be insufficient for the next planned power increase; future suppression methods including acoustic mode dampers and dynamic g-factor modulation are discussed.

Optical filter including a sub-wavelength periodic structure and method of making

DOEpatents

Kaushik, Sumanth; Stallard, Brian R.

1998-01-01

An optical filter includes a dielectric layer formed within a resonant optical cavity, with the dielectric layer having formed therein a sub-wavelength periodic structure to define, at least in part, a wavelength for transmission of light through the resonant optical cavity. The sub-wavelength periodic structure can be formed either by removing material from the dielectric layer (e.g. by etching through an electron-beam defined mask), or by altering the composition of the layer (e.g. by ion implantation). Different portions of the dielectric layer can be patterned to form one or more optical interference filter elements having different light transmission wavelengths so that the optical filter can filter incident light according to wavelength and/or polarization. For some embodiments, the optical filter can include a detector element in optical alignment with each optical interference filter element to quantify or measure the filtered light for analysis thereof. The optical filter has applications to spectrometry, colorimetry, and chemical sensing.

Optical filter including a sub-wavelength periodic structure and method of making

DOEpatents

Kaushik, S.; Stallard, B.R.

1998-03-10

An optical filter includes a dielectric layer formed within a resonant optical cavity, with the dielectric layer having formed therein a sub-wavelength periodic structure to define, at least in part, a wavelength for transmission of light through the resonant optical cavity. The sub-wavelength periodic structure can be formed either by removing material from the dielectric layer (e.g. by etching through an electron-beam defined mask), or by altering the composition of the layer (e.g. by ion implantation). Different portions of the dielectric layer can be patterned to form one or more optical interference filter elements having different light transmission wavelengths so that the optical filter can filter incident light according to wavelength and/or polarization. For some embodiments, the optical filter can include a detector element in optical alignment with each optical interference filter element to quantify or measure the filtered light for analysis thereof. The optical filter has applications to spectrometry, colorimetry, and chemical sensing. 17 figs.

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.

Apparatus, system, and method for laser-induced breakdown spectroscopy

DOEpatents

Effenberger, Jr., Andrew J; Scott, Jill R; McJunkin, Timothy R

2014-11-18

In laser-induced breakdown spectroscopy (LIBS), an apparatus includes a pulsed laser configured to generate a pulsed laser signal toward a sample, a constructive interference object and an optical element, each located in a path of light from the sample. The constructive interference object is configured to generate constructive interference patterns of the light. The optical element is configured to disperse the light. A LIBS system includes a first and a second optical element, and a data acquisition module. The data acquisition module is configured to determine an isotope measurement based, at least in part, on light received by an image sensor from the first and second optical elements. A method for performing LIBS includes generating a pulsed laser on a sample to generate light from a plasma, generating constructive interference patterns of the light, and dispersing the light into a plurality of wavelengths.

Method and system for communicating with a laser power driver

DOEpatents

Telford, Steven

2017-07-18

A system for controlling a plurality of laser diodes includes an optical transmitter coupled to the laser diode driver for each laser diode. An optical signal including bi-phase encoded data is provided to each laser diode driver. The optical signal includes current level and pulse duration information at which each of the diodes is to be driven. Upon receiving a trigger signal, the laser diode drivers operate the laser diodes using the current level and pulse duration information to output a laser beam.

Advances in thickness measurements and dynamic visualization of the tear film using non-invasive optical approaches.

PubMed

Bai, Yuqiang; Nichols, Jason J

2017-05-01

The thickness of tear film has been investigated under both invasive and non-invasive methods. While invasive methods are largely historical, more recent noninvasive methods are generally based on optical approaches that provide accurate, precise, and rapid measures. Optical microscopy, interferometry, and optical coherence tomography (OCT) have been developed to characterize the thickness of tear film or certain aspects of the tear film (e.g., the lipid layer). This review provides an in-depth overview on contemporary optical techniques used in studying the tear film, including both advantages and limitations of these approaches. It is anticipated that further developments of high-resolution OCT and other interferometric methods will enable a more accurate and precise measurement of the thickness of the tear film and its related dynamic properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-scale theory-assisted nano-engineering of plasmonic-organic hybrid electro-optic device performance

NASA Astrophysics Data System (ADS)

Elder, Delwin L.; Johnson, Lewis E.; Tillack, Andreas F.; Robinson, Bruce H.; Haffner, Christian; Heni, Wolfgang; Hoessbacher, Claudia; Fedoryshyn, Yuriy; Salamin, Yannick; Baeuerle, Benedikt; Josten, Arne; Ayata, Masafumi; Koch, Ueli; Leuthold, Juerg; Dalton, Larry R.

2018-02-01

Multi-scale (correlated quantum and statistical mechanics) modeling methods have been advanced and employed to guide the improvement of organic electro-optic (OEO) materials, including by analyzing electric field poling induced electro-optic activity in nanoscopic plasmonic-organic hybrid (POH) waveguide devices. The analysis of in-device electro-optic activity emphasizes the importance of considering both the details of intermolecular interactions within organic electro-optic materials and interactions at interfaces between OEO materials and device architectures. Dramatic improvement in electro-optic device performance-including voltage-length performance, bandwidth, energy efficiency, and lower optical losses have been realized. These improvements are critical to applications in telecommunications, computing, sensor technology, and metrology. Multi-scale modeling methods illustrate the complexity of improving the electro-optic activity of organic materials, including the necessity of considering the trade-off between improving poling-induced acentric order through chromophore modification and the reduction of chromophore number density associated with such modification. Computational simulations also emphasize the importance of developing chromophore modifications that serve multiple purposes including matrix hardening for enhanced thermal and photochemical stability, control of matrix dimensionality, influence on material viscoelasticity, improvement of chromophore molecular hyperpolarizability, control of material dielectric permittivity and index of refraction properties, and control of material conductance. Consideration of new device architectures is critical to the implementation of chipscale integration of electronics and photonics and achieving the high bandwidths for applications such as next generation (e.g., 5G) telecommunications.

Laser ablation system, and method of decontaminating surfaces

DOEpatents

Ferguson, Russell L.; Edelson, Martin C.; Pang, Ho-ming

1998-07-14

A laser ablation system comprising a laser head providing a laser output; a flexible fiber optic cable optically coupled to the laser output and transmitting laser light; an output optics assembly including a nozzle through which laser light passes; an exhaust tube in communication with the nozzle; and a blower generating a vacuum on the exhaust tube. A method of decontaminating a surface comprising the following steps: providing an acousto-optic, Q-switched Nd:YAG laser light ablation system having a fiber optically coupled output optics assembly; and operating the laser light ablation system to produce an irradiance greater than 1.times.10.sup.7 W/cm.sup.2, and a pulse width between 80 and 170 ns.

Multiplane optical microscope

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

Li, Tongcang; Ota, Sadao; Kim, Jeongmin

This disclosure provides systems, methods, and apparatus related to optical microscopy. In one aspect, an apparatus includes a sample holder, a first objective lens, a plurality of optical components, a second objective lens, and a mirror. The apparatus may directly image a cross-section of a sample oblique to or parallel to the optical axis of the first objective lens, without scanning.

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.

Optical contrast for identifying the thickness of two-dimensional materials

NASA Astrophysics Data System (ADS)

Bing, Dan; Wang, Yingying; Bai, Jing; Du, Ruxia; Wu, Guoqing; Liu, Liyan

2018-01-01

One of the most intriguing properties of two-dimensional (2D) materials is their thickness dependent properties. A quick and precise technique to identify the layer number of 2D materials is therefore highly desirable. In this review, we will introduce the basic principle of using optical contrast to determine the thickness of 2D material and also its advantage as compared to other modern techniques. Different 2D materials, including graphene, graphene oxide, transitional metal dichalcogenides, black phosphorus, boron nitride, have been used as examples to demonstrate the capability of optical contrast methods. A simple and more efficient optical contrast image technique is also emphasized, which is suitable for quick and large-scale thickness identification. We have also discussed the factors that could affect the experimental results of optical contrast, including incident light angle, anisotropic nature of materials, and also the twisted angle between 2D layers. Finally, we give perspectives on future development of optical contrast methods for the study and application of 2D materials.

Overview of Optical and Thermal Laser-Tissue Interaction and Nomenclature

NASA Astrophysics Data System (ADS)

Welch, Ashley J.; van Gemert, Martin J. C.

The development of a unified theory for the optical and thermal response of tissue to laser radiation is no longer in its infancy, though it is still not fully developed. This book describes our current understanding of the physical events that can occur when light interacts with tissue, particularly the sequence of formulations that estimate the optical and thermal responses of tissue to laser radiation. This overview is followed by an important chapter that describes the basic interactions of light with tissue. Part I considers basic tissue optics. Tissue is treated as an absorbing and scattering medium and methods are presented for calculating and measuring light propagation, including polarized light. Also, methods for estimating tissue optical properties from measurements of reflection and transmission are discussed. Part II concerns the thermal response of tissue owing to absorbed light, and rate reactions are presented for predicting the extent of laser induced thermal damage. Methods for measuring temperature, thermal properties, rate constants, pulsed ablation and laser tissue interactions are detailed. Part III is devoted to examples that use the theory presented in Parts I and II to analyze various medical applications of lasers. Discussions of Optical Coherence Tomography (OCT), forensic optics, and light stimulation of nerves are also included.

Method and apparatus for determining the physical properties of materials using dynamic light scattering techniques

NASA Technical Reports Server (NTRS)

Dhadwal, Harbans S. (Inventor)

1992-01-01

A system for determining the physical properties of materials through the use of dynamic light scattering is disclosed. The system includes a probe, a laser source for directing a laser beam into the probe, and a photodetector for converting scattered light detected by the probe into electrical signals. The probe includes at least one optical fiber connected to the laser source and a second optical fiber connected to the photodetector. Each of the fibers may adjoin a gradient index microlens which is capable of providing a collimated laser beam into a scattering medium. The position of the second optical fiber with respect to the optical axis of the probe determines whether homodyne or self-beating detection is provided. Self-beating detection may be provided without a gradient index microlens. This allows a very small probe to be constructed which is insertable through a hypodermic needle or the like into a droplet extending from such a needle. A method of detecting scattered light through the use of a collimated, Gaussian laser beam is also provided. A method for controlling the waist and divergence of the optical field emanating from the free end of an optical fiber is also provided.

Optical methods for noninvasive determination of carotenoids in human and animal skin

NASA Astrophysics Data System (ADS)

Darvin, Maxim E.; Meinke, Martina C.; Sterry, Wolfram; Lademann, Juergen

2013-06-01

Carotenoids are important substances for human skin due to their powerful antioxidant properties in reaction of neutralization of free radicals and especially reactive oxygen species, including singlet oxygen. Concentration of carotenoids in the skin could mirror the current redox status of the skin and should be investigated in vivo. Optical methods are ideally suited for determination of carotenoids in mammalian skin in vivo as they are both noninvasive and quick. Four different optical methods could be used for in vivo measurement of carotenoids in the human or animal skin: (1) resonance Raman spectroscopy; (2) Raman microscopy; (3) reflection spectroscopy; (4) skin color measurements. The advantages, shortcomings, and limitations of the above-mentioned optical methods are discussed.

Optical methods for noninvasive determination of carotenoids in human and animal skin.

PubMed

Darvin, Maxim E; Meinke, Martina C; Sterry, Wolfram; Lademann, Juergen

2013-06-01

Carotenoids are important substances for human skin due to their powerful antioxidant properties in reaction of neutralization of free radicals and especially reactive oxygen species, including singlet oxygen. Concentration of carotenoids in the skin could mirror the current redox status of the skin and should be investigated in vivo. Optical methods are ideally suited for determination of carotenoids in mammalian skin in vivo as they are both noninvasive and quick. Four different optical methods could be used for in vivo measurement of carotenoids in the human or animal skin: (1) resonance Raman spectroscopy; (2) Raman microscopy; (3) reflection spectroscopy; (4) skin color measurements. The advantages, shortcomings, and limitations of the above-mentioned optical methods are discussed.

Optical control of multi-stage thin film solar cell production

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

Li, Jian; Levi, Dean H.; Contreras, Miguel A.

2016-05-17

Embodiments include methods of depositing and controlling the deposition of a film in multiple stages. The disclosed deposition and deposition control methods include the optical monitoring of a deposition matrix to determine a time when at least one transition point occurs. In certain embodiments, the transition point or transition points are a stoichiometry point. Methods may also include controlling the length of time in which material is deposited during a deposition stage or controlling the amount of the first, second or subsequent materials deposited during any deposition stage in response to a determination of the time when a selected transitionmore » point occurs.« less

Tunable pulsed narrow bandwidth light source

DOEpatents

Powers, Peter E.; Kulp, Thomas J.

2002-01-01

A tunable pulsed narrow bandwidth light source and a method of operating a light source are provided. The light source includes a pump laser, first and second non-linear optical crystals, a tunable filter, and light pulse directing optics. The method includes the steps of operating the pump laser to generate a pulsed pump beam characterized by a nanosecond pulse duration and arranging the light pulse directing optics so as to (i) split the pulsed pump beam into primary and secondary pump beams; (ii) direct the primary pump beam through an input face of the first non-linear optical crystal such that a primary output beam exits from an output face of the first non-linear optical crystal; (iii) direct the primary output beam through the tunable filter to generate a sculpted seed beam; and direct the sculpted seed beam and the secondary pump beam through an input face of the second non-linear optical crystal such that a secondary output beam characterized by at least one spectral bandwidth on the order of about 0.1 cm.sup.-1 and below exits from an output face of the second non-linear optical crystal.

Optical 1's and 2's complement devices using lithium-niobate-based waveguide

NASA Astrophysics Data System (ADS)

Pal, Amrindra; Kumar, Santosh; Sharma, Sandeep

2016-12-01

Optical 1's and 2's complement devices are proposed with the help of lithium-niobate-based Mach-Zehnder interferometers. It has a powerful capability of switching an optical signal from one port to the other port with the help of an electrical control signal. The paper includes the optical conversion scheme using sets of optical switches. 2's complement is common in computer systems and is used in binary subtraction and logical manipulation. The operation of the circuits is studied theoretically and analyzed through numerical simulations. The truth table of these complement methods is verified with the beam propagation method and MATLAB® simulation results.

Method and device for measuring single-shot transient signals

DOEpatents

Yin, Yan

2004-05-18

Methods, apparatus, and systems, including computer program products, implementing and using techniques for measuring multi-channel single-shot transient signals. A signal acquisition unit receives one or more single-shot pulses from a multi-channel source. An optical-fiber recirculating loop reproduces the one or more received single-shot optical pulses to form a first multi-channel pulse train for circulation in the recirculating loop, and a second multi-channel pulse train for display on a display device. The optical-fiber recirculating loop also optically amplifies the first circulating pulse train to compensate for signal losses and performs optical multi-channel noise filtration.

Lithographic manufacturing of adaptive optics components

NASA Astrophysics Data System (ADS)

Scott, R. Phillip; Jean, Madison; Johnson, Lee; Gatlin, Ridley; Bronson, Ryan; Milster, Tom; Hart, Michael

2017-09-01

Adaptive optics systems and their laboratory test environments call for a number of unusual optical components. Examples include lenslet arrays, pyramids, and Kolmogorov phase screens. Because of their specialized application, the availability of these parts is generally limited, with high cost and long lead time, which can also significantly drive optical system design. These concerns can be alleviated by a fast and inexpensive method of optical fabrication. To that end, we are exploring direct-write lithographic techniques to manufacture three different custom elements. We report results from a number of prototype devices including 1, 2, and 3 wave Multiple Order Diffractive (MOD) lenslet arrays with 0.75 mm pitch and phase screens with near Kolmogorov structure functions with a Fried length r0 around 1 mm. We also discuss plans to expand our research to include a diffractive pyramid that is smaller, lighter, and more easily manufactured than glass versions presently used in pyramid wavefront sensors. We describe how these components can be produced within the limited dynamic range of the lithographic process, and with a rapid prototyping and manufacturing cycle. We discuss exploratory manufacturing methods, including replication, and potential observing techniques enabled by the ready availability of custom components.

LAO web page

Science.gov Websites

of adaptive optics systems for the next generation of high resolution astronomy instrumentation. The largest telescopes in support of UC Astronomy, including those at the Keck, Gemini, and Lick Observatories optics for astronomy: MEMS and fiber lasers lead the way. In Adaptive Optics: Analysis, Methods and

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.

Plastic scintillators with high loading of one or more metal carboxylates

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

Cherepy, Nerine; Sanner, Robert Dean

According to one embodiment, a method includes incorporating a metal carboxylate complex into a polymeric matrix to form an optically transparent material. According to another embodiment, a material includes at least one metal carboxylate complex incorporated into a polymeric matrix, where the material is optically transparent.

Method and apparatus for use of III-nitride wide bandgap semiconductors in optical communications

DOEpatents

Hui, Rongqing [Lenexa, KS; Jiang, Hong-Xing [Manhattan, KS; Lin, Jing-Yu [Manhattan, KS

2008-03-18

The present disclosure relates to the use of III-nitride wide bandgap semiconductor materials for optical communications. In one embodiment, an optical device includes an optical waveguide device fabricated using a III-nitride semiconductor material. The III-nitride semiconductor material provides for an electrically controllable refractive index. The optical waveguide device provides for high speed optical communications in an infrared wavelength region. In one embodiment, an optical amplifier is provided using optical coatings at the facet ends of a waveguide formed of erbium-doped III-nitride semiconductor materials.

Study on High Resolution Membrane-Based Diffractive Optical Imaging on Geostationary Orbit

NASA Astrophysics Data System (ADS)

Jiao, J.; Wang, B.; Wang, C.; Zhang, Y.; Jin, J.; Liu, Z.; Su, Y.; Ruan, N.

2017-05-01

Diffractive optical imaging technology provides a new way to realize high resolution earth observation on geostationary orbit. There are a lot of benefits to use the membrane-based diffractive optical element in ultra-large aperture optical imaging system, including loose tolerance, light weight, easy folding and unfolding, which make it easy to realize high resolution earth observation on geostationary orbit. The implementation of this technology also faces some challenges, including the configuration of the diffractive primary lens, the development of high diffraction efficiency membrane-based diffractive optical elements, and the correction of the chromatic aberration of the diffractive optical elements. Aiming at the configuration of the diffractive primary lens, the "6+1" petal-type unfold scheme is proposed, which consider the compression ratio, the blocking rate and the development complexity. For high diffraction efficiency membrane-based diffractive optical element, a self-collimating method is proposed. The diffraction efficiency is more than 90 % of the theoretical value. For the chromatic aberration correction problem, an optimization method based on schupmann is proposed to make the imaging spectral bandwidth in visible light band reach 100 nm. The above conclusions have reference significance for the development of ultra-large aperture diffractive optical imaging system.

Thermally-Resilient, Broadband Optical Absorber from UV-to-IR Derived from Carbon Nanostructures and Method of Making the Same

NASA Technical Reports Server (NTRS)

Kaul, Anupama B. (Inventor); Coles, James B. (Inventor)

2015-01-01

A monolithic optical absorber and methods of making same. The monolithic optical absorber uses an array of mutually aligned carbon nanotubes that are grown using a PECVD growth process and a structure that includes a conductive substrate, a refractory template layer and a nucleation layer. Monolithic optical absorbers made according to the described structure and method exhibit high absorptivity, high site densities (greater than 10.sup.9 nanotubes/cm.sup.2), very low reflectivity (below 1%), and high thermal stability in air (up to at least 400.degree. C.). The PECVD process allows the application of such absorbers in a wide variety of end uses.

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.

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.

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.

Simulating Optical Fibers.

ERIC Educational Resources Information Center

Edgar, Dale

1988-01-01

Described is a demonstration of Snell's law using a laser beam and an optical fiber. Provided are the set-up method of the demonstration apparatus and some practical suggestions including "index matching" technique using vaseline. (YP)

Research on distributed optical fiber sensing data processing method based on LabVIEW

NASA Astrophysics Data System (ADS)

Li, Zhonghu; Yang, Meifang; Wang, Luling; Wang, Jinming; Yan, Junhong; Zuo, Jing

2018-01-01

The pipeline leak detection and leak location problem have gotten extensive attention in the industry. In this paper, the distributed optical fiber sensing system is designed based on the heat supply pipeline. The data processing method of distributed optical fiber sensing based on LabVIEW is studied emphatically. The hardware system includes laser, sensing optical fiber, wavelength division multiplexer, photoelectric detector, data acquisition card and computer etc. The software system is developed using LabVIEW. The software system adopts wavelet denoising method to deal with the temperature information, which improved the SNR. By extracting the characteristic value of the fiber temperature information, the system can realize the functions of temperature measurement, leak location and measurement signal storage and inquiry etc. Compared with traditional negative pressure wave method or acoustic signal method, the distributed optical fiber temperature measuring system can measure several temperatures in one measurement and locate the leak point accurately. It has a broad application prospect.

Investigation on filter method for smoothing spiral phase plate

NASA Astrophysics Data System (ADS)

Zhang, Yuanhang; Wen, Shenglin; Luo, Zijian; Tang, Caixue; Yan, Hao; Yang, Chunlin; Liu, Mincai; Zhang, Qinghua; Wang, Jian

2018-03-01

Spiral phase plate (SPP) for generating vortex hollow beams has high efficiency in various applications. However, it is difficult to obtain an ideal spiral phase plate because of its continuous-varying helical phase and discontinued phase step. This paper describes the demonstration of continuous spiral phase plate using filter methods. The numerical simulations indicate that different filter method including spatial domain filter, frequency domain filter has unique impact on surface topography of SPP and optical vortex characteristics. The experimental results reveal that the spatial Gaussian filter method for smoothing SPP is suitable for Computer Controlled Optical Surfacing (CCOS) technique and obtains good optical properties.

Method for using polarization gating to measure a scattering sample

DOEpatents

Baba, Justin S.

2015-08-04

Described herein are systems, devices, and methods facilitating optical characterization of scattering samples. A polarized optical beam can be directed to pass through a sample to be tested. The optical beam exiting the sample can then be analyzed to determine its degree of polarization, from which other properties of the sample can be determined. In some cases, an apparatus can include a source of an optical beam, an input polarizer, a sample, an output polarizer, and a photodetector. In some cases, a signal from a photodetector can be processed through attenuation, variable offset, and variable gain.

Method and system for laser-based formation of micro-shapes in surfaces of optical elements

DOEpatents

Bass, Isaac Louis; Guss, Gabriel Mark

2013-03-05

A method of forming a surface feature extending into a sample includes providing a laser operable to emit an output beam and modulating the output beam to form a pulse train having a plurality of pulses. The method also includes a) directing the pulse train along an optical path intersecting an exposed portion of the sample at a position i and b) focusing a first portion of the plurality of pulses to impinge on the sample at the position i. Each of the plurality of pulses is characterized by a spot size at the sample. The method further includes c) ablating at least a portion of the sample at the position i to form a portion of the surface feature and d) incrementing counter i. The method includes e) repeating steps a) through d) to form the surface feature. The sample is free of a rim surrounding the surface feature.

The theoretical study of passive and active optical devices via planewave based transfer (scattering) matrix method and other approaches

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

Zhuo, Ye

2011-01-01

In this thesis, we theoretically study the electromagnetic wave propagation in several passive and active optical components and devices including 2-D photonic crystals, straight and curved waveguides, organic light emitting diodes (OLEDs), and etc. Several optical designs are also presented like organic photovoltaic (OPV) cells and solar concentrators. The first part of the thesis focuses on theoretical investigation. First, the plane-wave-based transfer (scattering) matrix method (TMM) is briefly described with a short review of photonic crystals and other numerical methods to study them (Chapter 1 and 2). Next TMM, the numerical method itself is investigated in details and developed inmore » advance to deal with more complex optical systems. In chapter 3, TMM is extended in curvilinear coordinates to study curved nanoribbon waveguides. The problem of a curved structure is transformed into an equivalent one of a straight structure with spatially dependent tensors of dielectric constant and magnetic permeability. In chapter 4, a new set of localized basis orbitals are introduced to locally represent electromagnetic field in photonic crystals as alternative to planewave basis. The second part of the thesis focuses on the design of optical devices. First, two examples of TMM applications are given. The first example is the design of metal grating structures as replacements of ITO to enhance the optical absorption in OPV cells (chapter 6). The second one is the design of the same structure as above to enhance the light extraction of OLEDs (chapter 7). Next, two design examples by ray tracing method are given, including applying a microlens array to enhance the light extraction of OLEDs (chapter 5) and an all-angle wide-wavelength design of solar concentrator (chapter 8). In summary, this dissertation has extended TMM which makes it capable of treating complex optical systems. Several optical designs by TMM and ray tracing method are also given as a full complement of this work.« less

The Community Cloud retrieval for CLimate (CC4CL) - Part 2: The optimal estimation approach

NASA Astrophysics Data System (ADS)

McGarragh, Gregory R.; Poulsen, Caroline A.; Thomas, Gareth E.; Povey, Adam C.; Sus, Oliver; Stapelberg, Stefan; Schlundt, Cornelia; Proud, Simon; Christensen, Matthew W.; Stengel, Martin; Hollmann, Rainer; Grainger, Roy G.

2018-06-01

The Community Cloud retrieval for Climate (CC4CL) is a cloud property retrieval system for satellite-based multispectral imagers and is an important component of the Cloud Climate Change Initiative (Cloud_cci) project. In this paper we discuss the optimal estimation retrieval of cloud optical thickness, effective radius and cloud top pressure based on the Optimal Retrieval of Aerosol and Cloud (ORAC) algorithm. Key to this method is the forward model, which includes the clear-sky model, the liquid water and ice cloud models, the surface model including a bidirectional reflectance distribution function (BRDF), and the "fast" radiative transfer solution (which includes a multiple scattering treatment). All of these components and their assumptions and limitations will be discussed in detail. The forward model provides the accuracy appropriate for our retrieval method. The errors are comparable to the instrument noise for cloud optical thicknesses greater than 10. At optical thicknesses less than 10 modeling errors become more significant. The retrieval method is then presented describing optimal estimation in general, the nonlinear inversion method employed, measurement and a priori inputs, the propagation of input uncertainties and the calculation of subsidiary quantities that are derived from the retrieval results. An evaluation of the retrieval was performed using measurements simulated with noise levels appropriate for the MODIS instrument. Results show errors less than 10 % for cloud optical thicknesses greater than 10. Results for clouds of optical thicknesses less than 10 have errors up to 20 %.

Parallel image logical operations using cross correlation

NASA Technical Reports Server (NTRS)

Strong, J. P., III

1972-01-01

Methods are presented for counting areas in an image in a parallel manner using noncoherent optical techniques. The techniques presented include the Levialdi algorithm for counting, optical techniques for binary operations, and cross-correlation.

Thin-film optical shutter. Final report

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

Matlow, S.L.

1981-02-01

A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

Direct-to-digital holography and holovision

DOEpatents

Thomas, Clarence E.; Baylor, Larry R.; Hanson, Gregory R.; Rasmussen, David A.; Voelkl, Edgar; Castracane, James; Simkulet, Michelle; Clow, Lawrence

2000-01-01

Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made.

Virtual mask digital electron beam lithography

DOEpatents

Baylor, L.R.; Thomas, C.E.; Voelkl, E.; Moore, J.A.; Simpson, M.L.; Paulus, M.J.

1999-04-06

Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made. 5 figs.

Objective measurement of the optical image quality in the human eye

NASA Astrophysics Data System (ADS)

Navarro, Rafael M.

2001-05-01

This communication reviews some recent studies on the optical performance of the human eye. Although the retinal image cannot be recorded directly, different objective methods have been developed, which permit to determine optical quality parameters, such as the Point Spread Function (PSF), the Modulation Transfer Function (MTF), the geometrical ray aberrations or the wavefront distortions, in the living human eye. These methods have been applied in both basic and applied research. This includes the measurement of the optical performance of the eye across visual field, the optical quality of eyes with intraocular lens implants, the aberrations induced by LASIK refractive surgery, or the manufacture of customized phase plates to compensate the wavefront aberration in the eye.

Virtual mask digital electron beam lithography

DOEpatents

Baylor, Larry R.; Thomas, Clarence E.; Voelkl, Edgar; Moore, James A.; Simpson, Michael L.; Paulus, Michael J.

1999-01-01

Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made.

Automated pupil remapping with binary optics

DOEpatents

Neal, Daniel R.; Mansell, Justin

1999-01-01

Methods and apparatuses for pupil remapping employing non-standard lenslet shapes in arrays; divergence of lenslet focal spots from on-axis arrangements; use of lenslet arrays to resize two-dimensional inputs to the array; and use of lenslet arrays to map an aperture shape to a different detector shape. Applications include wavefront sensing, astronomical applications, optical interconnects, keylocks, and other binary optics and diffractive optics applications.

Estimation of coupling efficiency of optical fiber by far-field method

NASA Astrophysics Data System (ADS)

Kataoka, Keiji

2010-09-01

Coupling efficiency to a single-mode optical fiber can be estimated with the field amplitudes at far-field of an incident beam and optical fiber mode. We call it the calculation by far-field method (FFM) in this paper. The coupling efficiency by FFM is formulated including effects of optical aberrations, vignetting of the incident beam, and misalignments of the optical fiber such as defocus, lateral displacements, and angle deviation in arrangement of the fiber. As the results, it is shown the coupling efficiency is proportional to the central intensity of the focused spot, i.e., Strehl intensity of a virtual beam determined by the incident beam and mode of the optical fiber. Using the FFM, a typical optics in which a laser beam is coupled to an optical fiber with a lens of finite numerical aperture (NA) is analyzed for several cases of amplitude distributions of the incident light.

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.

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.

FIBER OPTICS: Theoretical basis of the method for reducing drift of the zero level of the output signal of a fiber-optic gyroscope with the aid of a Lyot depolarizer

NASA Astrophysics Data System (ADS)

Alekseev, É. I.; Bazarov, E. N.

1992-09-01

A theoretical justification is given of the widely used method of stabilization of the output signal from a fiber-optic gyroscope with a broad-band radiation source by a Lyot depolarizer. Different variants of including a depolarizer in such a gyroscope are considered and the role of the dichroism and birefringence induced in the gyroscope system is discussed.

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

DOEpatents

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

1997-01-01

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

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

DOEpatents

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

1994-01-01

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

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

DOEpatents

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

1997-05-06

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

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

DOEpatents

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

1994-11-01

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

Double degree master program: Optical Design

NASA Astrophysics Data System (ADS)

Bakholdin, Alexey; Kujawinska, Malgorzata; Livshits, Irina; Styk, Adam; Voznesenskaya, Anna; Ezhova, Kseniia; Ermolayeva, Elena; Ivanova, Tatiana; Romanova, Galina; Tolstoba, Nadezhda

2015-10-01

Modern tendencies of higher education require development of master programs providing achievement of learning outcomes corresponding to quickly variable job market needs. ITMO University represented by Applied and Computer Optics Department and Optical Design and Testing Laboratory jointly with Warsaw University of Technology represented by the Institute of Micromechanics and Photonics at The Faculty of Mechatronics have developed a novel international master double-degree program "Optical Design" accumulating the expertise of both universities including experienced teaching staff, educational technologies, and experimental resources. The program presents studies targeting research and professional activities in high-tech fields connected with optical and optoelectronics devices, optical engineering, numerical methods and computer technologies. This master program deals with the design of optical systems of various types, assemblies and layouts using computer modeling means; investigation of light distribution phenomena; image modeling and formation; development of optical methods for image analysis and optical metrology including optical testing, materials characterization, NDT and industrial control and monitoring. The goal of this program is training a graduate capable to solve a wide range of research and engineering tasks in optical design and metrology leading to modern manufacturing and innovation. Variability of the program structure provides its flexibility and adoption according to current job market demands and personal learning paths for each student. In addition considerable proportion of internship and research expands practical skills. Some special features of the "Optical Design" program which implements the best practices of both Universities, the challenges and lessons learnt during its realization are presented in the paper.

Network analysis of mesoscale optical recordings to assess regional, functional connectivity.

PubMed

Lim, Diana H; LeDue, Jeffrey M; Murphy, Timothy H

2015-10-01

With modern optical imaging methods, it is possible to map structural and functional connectivity. Optical imaging studies that aim to describe large-scale neural connectivity often need to handle large and complex datasets. In order to interpret these datasets, new methods for analyzing structural and functional connectivity are being developed. Recently, network analysis, based on graph theory, has been used to describe and quantify brain connectivity in both experimental and clinical studies. We outline how to apply regional, functional network analysis to mesoscale optical imaging using voltage-sensitive-dye imaging and channelrhodopsin-2 stimulation in a mouse model. We include links to sample datasets and an analysis script. The analyses we employ can be applied to other types of fluorescence wide-field imaging, including genetically encoded calcium indicators, to assess network properties. We discuss the benefits and limitations of using network analysis for interpreting optical imaging data and define network properties that may be used to compare across preparations or other manipulations such as animal models of disease.

Adaptive imaging through far-field turbulence

NASA Astrophysics Data System (ADS)

Troxel, Steven E.; Welsh, Byron M.; Roggemann, Michael C.

1993-11-01

This paper presents a new method for calculating the field angle dependent average OTF of an adaptive optic system and compares this method to calculations based on geometric optics. Geometric optics calculations are shown to be inaccurate due to the diffraction effects created by far-field turbulence and the approximations made in the atmospheric parameters. Our analysis includes diffraction effects and properly accounts for the effect of the atmospheric turbulence scale sizes. We show that for any atmospheric C(superscript 2)(subscript n) profile, the actual OTF is always better than the OTF calculated using geometric optics. The magnitude of the difference between the calculation methods is shown to be dependent on the amount of far- field turbulence and the values of the outer scale dimension.

Improved measurement of vibration amplitude in dynamic optical coherence elastography

PubMed Central

Kennedy, Brendan F.; Wojtkowski, Maciej; Szkulmowski, Maciej; Kennedy, Kelsey M.; Karnowski, Karol; Sampson, David D.

2012-01-01

Abstract: Optical coherence elastography employs optical coherence tomography (OCT) to measure the displacement of tissues under load and, thus, maps the resulting strain into an image, known as an elastogram. We present a new improved method to measure vibration amplitude in dynamic optical coherence elastography. The tissue vibration amplitude caused by sinusoidal loading is measured from the spread of the Doppler spectrum, which is extracted using joint spectral and time domain signal processing. At low OCT signal-to-noise ratio (SNR), the method provides more accurate vibration amplitude measurements than the currently used phase-sensitive method. For measurements performed on a mirror at OCT SNR = 5 dB, our method introduces <3% error, compared to >20% using the phase-sensitive method. We present elastograms of a tissue-mimicking phantom and excised porcine tissue that demonstrate improvements, including a 50% increase in the depth range of reliable vibration amplitude measurement. PMID:23243565

Microscopy imaging device with advanced imaging properties

DOEpatents

Ghosh, Kunal; Burns, Laurie; El Gamal, Abbas; Schnitzer, Mark J.; Cocker, Eric; Ho, Tatt Wei

2015-11-24

Systems, methods and devices are implemented for microscope imaging solutions. One embodiment of the present disclosure is directed toward an epifluorescence microscope. The microscope includes an image capture circuit including an array of optical sensor. An optical arrangement is configured to direct excitation light of less than about 1 mW to a target object in a field of view of that is at least 0.5 mm.sup.2 and to direct epi-fluorescence emission caused by the excitation light to the array of optical sensors. The optical arrangement and array of optical sensors are each sufficiently close to the target object to provide at least 2.5 .mu.m resolution for an image of the field of view.

Method and apparatus of wide-angle optical beamsteering from a nanoantenna phased array

DOEpatents

Davids, Paul; DeRose, Christopher; Rakich, Peter Thomas

2015-08-11

An optical beam-steering apparatus is provided. The apparatus includes one or more optical waveguides and at least one row of metallic nanoantenna elements overlying and electromagnetically coupled to a respective waveguide. In each such row, individual nanoantenna elements are spaced apart along an optical propagation axis of the waveguide so that there is an optical propagation phase delay between successive pairs of nanoantenna elements along the row. The apparatus also includes a respective single electric heating element in thermal contact with each of the waveguides. Each heating element is arranged to heat, substantially uniformly, at least that portion of its waveguide that directly underlies the corresponding row of nanoantenna elements.

Microscopy imaging device with advanced imaging properties

DOEpatents

Ghosh, Kunal; Burns, Laurie; El Gamal, Abbas; Schnitzer, Mark J.; Cocker, Eric; Ho, Tatt Wei

2016-10-25

Systems, methods and devices are implemented for microscope imaging solutions. One embodiment of the present disclosure is directed toward an epifluorescence microscope. The microscope includes an image capture circuit including an array of optical sensor. An optical arrangement is configured to direct excitation light of less than about 1 mW to a target object in a field of view of that is at least 0.5 mm.sup.2 and to direct epi-fluorescence emission caused by the excitation light to the array of optical sensors. The optical arrangement and array of optical sensors are each sufficiently close to the target object to provide at least 2.5 .mu.m resolution for an image of the field of view.

Microscopy imaging device with advanced imaging properties

DOEpatents

Ghosh, Kunal; Burns, Laurie; El Gamal, Abbas; Schnitzer, Mark J.; Cocker, Eric; Ho, Tatt Wei

2016-11-22

Systems, methods and devices are implemented for microscope imaging solutions. One embodiment of the present disclosure is directed toward an epifluorescence microscope. The microscope includes an image capture circuit including an array of optical sensor. An optical arrangement is configured to direct excitation light of less than about 1 mW to a target object in a field of view of that is at least 0.5 mm.sup.2 and to direct epi-fluorescence emission caused by the excitation light to the array of optical sensors. The optical arrangement and array of optical sensors are each sufficiently close to the target object to provide at least 2.5 .mu.m resolution for an image of the field of view.

Microscopy imaging device with advanced imaging properties

DOEpatents

Ghosh, Kunal; Burns, Laurie; El Gamal, Abbas; Schnitzer, Mark J.; Cocker, Eric; Ho, Tatt Wei

2017-04-25

Systems, methods and devices are implemented for microscope imaging solutions. One embodiment of the present disclosure is directed toward an epifluorescence microscope. The microscope includes an image capture circuit including an array of optical sensor. An optical arrangement is configured to direct excitation light of less than about 1 mW to a target object in a field of view of that is at least 0.5 mm.sup.2 and to direct epi-fluorescence emission caused by the excitation light to the array of optical sensors. The optical arrangement and array of optical sensors are each sufficiently close to the target object to provide at least 2.5 .mu.m resolution for an image of the field of view.

Open-ended projects in undergraduate optics and lasers courses

NASA Astrophysics Data System (ADS)

Hoyt, Chad

This talk will describe the format and experience of undergraduate Lasers and Optics courses at Bethel University. The courses, which include a rigorous lecture portion, are built on open-ended research projects that have a novel aspect. They begin with four weeks of small student groups rotating between several standard laser and optics laboratory exercises. These may include, for example, alignment and characterization of a helium neon laser and measurements with a Michelson interferometer or a scanning Fabry-Pérot optical cavity. During the following seven weeks of the course, student groups (2-4 people) choose and pursue research questions in the lab. Their work culminates in a group manuscript typeset in and a twenty-minute presentation to the class. Projects in the spring, 2014 Optics course included experiments with ultracold lithium atoms in a magneto-optical trap, optical tweezers, digital holography and adaptive optics. Projects in the spring, 2015 Lasers course included ultrafast optics with a mode-locked erbium fiber laser, quantum optics, surface plasmon lasers (led by Nathan Lindquist) and a low-cost, near-infrared spectrometer. Several of these projects are related to larger scale, funded research in the physics department. The format and experience in Lasers and Optics is representative of other upper-level courses at Bethel, including Fluid Mechanics and Computer Methods. A physics education research group from the University of Colorado evaluated the spring, 2015 Lasers course. They focused on student experimental attitudes and measurements of student project ownership.

Systems and methods for enhancing optical information

DOEpatents

DeVore, Peter Thomas Setsuda; Chou, Jason T.

2018-01-02

An Optical Information Transfer Enhancer System includes a first system for producing an information bearing first optical wave that is impressed with a first information having a first information strength wherein the first optical wave has a first shape. A second system produces a second optical wave. An information strength enhancer module receives the first and said second optical waves and impresses the first optical wave upon the second optical wave via cross-phase modulation (XPM) to produce an information-strength-enhanced second optical wave having a second information strength that is greater than the first information strength of the first optical wave. Following a center-wavelength changer by an Optical Information Transfer Enhancer System improves its performance.

Method and apparatus for wavefront sensing

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

Bahk, Seung-Whan

A method for performing optical wavefront sensing includes providing an amplitude transmission mask having a light input side, a light output side, and an optical transmission axis passing from the light input side to the light output side. The amplitude transmission mask is characterized by a checkerboard pattern having a square unit cell of size .LAMBDA.. The method also includes directing an incident light field having a wavelengthmore » $$ \\lamda $$ to be incident on the light input side and propagating the incident light field through the amplitude transmission mask. The method further includes producing a plurality of diffracted light fields on the light output side and detecting, at a detector disposed a distance L from the amplitude transmission mask, an interferogram associated with the plurality of diffracted light fields.« less

Dielectric waveguide gas-filled stark shift modulator

DOEpatents

Hutchinson, Donald P.; Richards, Roger K.

2003-07-22

An optical modulator includes a dielectric waveguide for receiving an optical beam and coupling energy of the optical beam into the waveguide. At least one Stark material is provided in the waveguide. A bias circuit generates a bias signal to produce an electrical field across the Stark material to shift at least one of the Stark absorption frequencies towards the frequency of the optical beam. A circuit for producing a time varying electric field across the Stark material modulates the optical beam. At least a portion of the bias field can be generated by an alternating bias signal, such as a square wave. A method of modulating optical signals includes the steps of providing a dielectric waveguide for receiving an optical beam and coupling energy of the optical beam into the waveguide, the waveguide having at least one Stark material disposed therein, and varying an electric field imposed across the Stark material.

Integrated resonant micro-optical gyroscope and method of fabrication

DOEpatents

Vawter, G Allen [Albuquerque, NM; Zubrzycki, Walter J [Sandia Park, NM; Guo, Junpeng [Albuquerque, NM; Sullivan, Charles T [Albuquerque, NM

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.

Laser And Nonlinear Optical Materials For Laser Remote Sensing

NASA Technical Reports Server (NTRS)

Barnes, Norman P.

2005-01-01

NASA remote sensing missions involving laser systems and their economic impact are outlined. Potential remote sensing missions include: green house gasses, tropospheric winds, ozone, water vapor, and ice cap thickness. Systems to perform these measurements use lanthanide series lasers and nonlinear devices including second harmonic generators and parametric oscillators. Demands these missions place on the laser and nonlinear optical materials are discussed from a materials point of view. Methods of designing new laser and nonlinear optical materials to meet these demands are presented.

Optical signal processing

NASA Technical Reports Server (NTRS)

Casasent, D.

1978-01-01

The article discusses several optical configurations used for signal processing. Electronic-to-optical transducers are outlined, noting fixed window transducers and moving window acousto-optic transducers. Folded spectrum techniques are considered, with reference to wideband RF signal analysis, fetal electroencephalogram analysis, engine vibration analysis, signal buried in noise, and spatial filtering. Various methods for radar signal processing are described, such as phased-array antennas, the optical processing of phased-array data, pulsed Doppler and FM radar systems, a multichannel one-dimensional optical correlator, correlations with long coded waveforms, and Doppler signal processing. Means for noncoherent optical signal processing are noted, including an optical correlator for speech recognition and a noncoherent optical correlator.

The Individual Virtual Eye: a Computer Model for Advanced Intraocular Lens Calculation

PubMed Central

Einighammer, Jens; Oltrup, Theo; Bende, Thomas; Jean, Benedikt

2010-01-01

Purpose To describe the individual virtual eye, a computer model of a human eye with respect to its optical properties. It is based on measurements of an individual person and one of its major application is calculating intraocular lenses (IOLs) for cataract surgery. Methods The model is constructed from an eye's geometry, including axial length and topographic measurements of the anterior corneal surface. All optical components of a pseudophakic eye are modeled with computer scientific methods. A spline-based interpolation method efficiently includes data from corneal topographic measurements. The geometrical optical properties, such as the wavefront aberration, are simulated with real ray-tracing using Snell's law. Optical components can be calculated using computer scientific optimization procedures. The geometry of customized aspheric IOLs was calculated for 32 eyes and the resulting wavefront aberration was investigated. Results The more complex the calculated IOL is, the lower the residual wavefront error is. Spherical IOLs are only able to correct for the defocus, while toric IOLs also eliminate astigmatism. Spherical aberration is additionally reduced by aspheric and toric aspheric IOLs. The efficient implementation of time-critical numerical ray-tracing and optimization procedures allows for short calculation times, which may lead to a practicable method integrated in some device. Conclusions The individual virtual eye allows for simulations and calculations regarding geometrical optics for individual persons. This leads to clinical applications like IOL calculation, with the potential to overcome the limitations of those current calculation methods that are based on paraxial optics, exemplary shown by calculating customized aspheric IOLs.

Automated pupil remapping with binary optics

DOEpatents

Neal, D.R.; Mansell, J.

1999-01-26

Methods and apparatuses are disclosed for pupil remapping employing non-standard lenslet shapes in arrays; divergence of lenslet focal spots from on-axis arrangements; use of lenslet arrays to resize two-dimensional inputs to the array; and use of lenslet arrays to map an aperture shape to a different detector shape. Applications include wavefront sensing, astronomical applications, optical interconnects, keylocks, and other binary optics and diffractive optics applications. 24 figs.

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.

Method and apparatus for passive optical dosimeter comprising caged dye molecules

DOEpatents

Sandison, David R.

2001-07-03

A new class of ultraviolet dosimeters is made possible by exposing caged dye molecules, which generate a dye molecule on exposure to ultraviolet radiation, to an exterior environment. Applications include sunburn monitors, characterizing the UV exposure history of UV-sensitive materials, especially including structural plastics, and use in disposable `one-use` optical equipment, especially medical devices.

Characterization of rock thermal conductivity by high-resolution optical scanning

USGS Publications Warehouse

Popov, Y.A.; Pribnow, D.F.C.; Sass, J.H.; Williams, C.F.; Burkhardt, H.

1999-01-01

We compared thress laboratory methods for thermal conductivity measurements: divided-bar, line-source and optical scanning. These methods are widely used in geothermal and petrophysical studies, particularly as applied to research on cores from deep scientific boreholes. The relatively new optical scanning method has recently been perfected and applied to geophysical problems. A comparison among these methods for determining the thermal conductivity tensor for anisotropic rocks is based on a representative collection of 80 crystalline rock samples from the KTB continental deep borehole (Germany). Despite substantial thermal inhomogeneity of rock thermal conductivity (up to 40-50% variation) and high anisotropy (with ratios of principal values attaining 2 and more), the results of measurements agree very well among the different methods. The discrepancy for measurements along the foliation is negligible (<1%). The component of thermal conductivity normal to the foliation reveals somewhat larger differences (3-4%). Optical scanning allowed us to characterize the thermal inhomogeneity of rocks and to identify a three-dimensional anisotropy in thermal conductivity of some gneiss samples. The merits of optical scanning include minor random errors (1.6%), the ability to record the variation of thermal conductivity along the sample, the ability to sample deeply using a slow scanning rate, freedom from constraints for sample size and shape, and quality of mechanical treatment of the sample surface, a contactless mode of measurement, high speed of operation, and the ability to measure on a cylindrical sample surface. More traditional methods remain superior for characterizing bulk conductivity at elevated temperature.Three laboratory methods including divided-bar, line-source and optical scanning are widely applied in geothermal and petrophysical studies. In this study, these three methods were compared for determining the thermal conductivity tensor for anisotropic rocks. For this study, a representative collection of 80 crystalline rock samples from the KTB continental deep borehole was used. Despite substantial thermal inhomogeneity of rock thermal conductivity and high anisotropy, measurement results were in excellent agreement among the three methods.

Developments in optical modeling methods for metrology

NASA Astrophysics Data System (ADS)

Davidson, Mark P.

1999-06-01

Despite the fact that in recent years the scanning electron microscope has come to dominate the linewidth measurement application for wafer manufacturing, there are still many applications for optical metrology and alignment. These include mask metrology, stepper alignment, and overlay metrology. Most advanced non-optical lithographic technologies are also considering using topics for alignment. In addition, there have been a number of in-situ technologies proposed which use optical measurements to control one aspect or another of the semiconductor process. So optics is definitely not dying out in the semiconductor industry. In this paper a description of recent advances in optical metrology and alignment modeling is presented. The theory of high numerical aperture image simulation for partially coherent illumination is discussed. The implications of telecentric optics on the image simulation is also presented. Reciprocity tests are proposed as an important measure of numerical accuracy. Diffraction efficiencies for chrome gratings on reticles are one good way to test Kirchoff's approximation as compared to rigorous calculations. We find significant differences between the predictions of Kirchoff's approximation and rigorous methods. The methods for simulating brightfield, confocal, and coherence probe microscope imags are outlined, as are methods for describing aberrations such as coma, spherical aberration, and illumination aperture decentering.

Micro spectrometer for parallel light and method of use

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

2011-01-01

A spectrometer system includes an optical assembly for collimating light, a micro-ring grating assembly having a plurality of coaxially-aligned ring gratings, an aperture device defining an aperture circumscribing a target focal point, and a photon detector. An electro-optical layer of the grating assembly may be electrically connected to an energy supply to change the refractive index of the electro-optical layer. Alternately, the gratings may be electrically connected to the energy supply and energized, e.g., with alternating voltages, to change the refractive index. A data recorder may record the predetermined spectral characteristic. A method of detecting a spectral characteristic of a predetermined wavelength of source light includes generating collimated light using an optical assembly, directing the collimated light onto the micro-ring grating assembly, and selectively energizing the micro-ring grating assembly to diffract the predetermined wavelength onto the target focal point, and detecting the spectral characteristic using a photon detector.

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.

Ground simulation of wide frequency band angular vibration for Lander's optic sensors

NASA Astrophysics Data System (ADS)

Xing, Zhigang; Xiang, Jianwei; Zheng, Gangtie

2017-11-01

To guide a lander of Moon or Mars exploration spacecraft during the stage of descent onto a desired place, optic sensors have been chosen to take the task, which include optic cameras and laser distance meters. However, such optic sensors are sensitive to vibrations, especially angular vibrations, from the lander. To reduce the risk of abnormal function and ensure the performance of optic sensors, ground simulations are necessary. More importantly, the simulations can be used as a method for examining the sensor performance and finding possible improvement on the sensor design. In the present paper, we proposed an angular vibration simulation method during the landing. This simulation method has been realized into product and applied to optic sensor tests for the moon lander. This simulator can generate random angular vibration in a frequency range from 0 to 2000Hz, the control precision is +/-1dB, and the linear translational speed can be set to the required descent speed. The operation and data processing methods of this developed simulator are the same as a normal shake table. The analysis and design methods are studied in the present paper, and test results are also provided.

Optical contacting for gravity probe star tracker

NASA Technical Reports Server (NTRS)

Wright, J. J.; Zissa, D. E.

1984-01-01

A star-tracker telescope, constructed entirely of fused silica elements optically contacted together, has been proposed to provide submilliarc-second pointing accuracy for Gravity Probe. A bibliography and discussion on optical contacting (the bonding of very flat, highly polished surfaces without the use of adhesives) are presented. Then results from preliminary experiments on the strength of optical contacts including a tensile strength test in liquid helium are discussed. Suggestions are made for further study to verify an optical contacting method for the Gravity Probe star-tracker telescope.

Multi-wavelength time-coincident optical communications system and methods thereof

NASA Technical Reports Server (NTRS)

Lekki, John (Inventor); Nguyen, Quang-Viet (Inventor)

2009-01-01

An optical communications transmitter includes a oscillator source, producing a clock signal, a data source, producing a data signal, a modulating circuit for modulating the clock signal using the data signal to produce modulating signals, optical drivers, receiving the modulating signals and producing optical driving signals based on the modulating signals and optical emitters, producing small numbers of photons based on the optical driving signals. The small numbers of photons are time-correlated between at least two separate optical transmission wavelengths and quantum states and the small number of photons can be detected by a receiver to reform the data signal.

An easy packaging hybrid optical element in grating based WDM application

NASA Astrophysics Data System (ADS)

Lan, Hsiao-Chin; Cheng, Chao-Chia; Wang, Chih-Ming; Chang, Jenq-Yang

2005-08-01

We developed a new optical element which integrates an off-axis diffractive grating and an on-axis refractive lens surface in a prism. With this optical element, the alignment tolerance can be improved by manufacturing technology of the grating based WDM device and is practicable for mass production. An 100-GHz 16-channel DWDM device which includes this optical element has been designed. Ray tracing and beam propagation method (BPM) simulations showed good performance on the insertion loss of 2.91+/-0.53dB and the adjacent cross talk of 58.02dB. The tolerance discussion for this DWDM device shows that this optical element could be practically achieved by either injection molding or the hot embossing method.

Three-Dimensional Displacement Measurement Using Diffractive Optic Interferometry

NASA Technical Reports Server (NTRS)

Gilbert, John A.; Cole, Helen J.; Shepherd, Robert L.; Ashley Paul R.

1999-01-01

This paper introduces a powerful new optical method which utilizes diffractive optic interferometry (DOI) to measure both in-plane and out-of-plane displacement with variable sensitivity using the same optical system. Sensitivity is varied by utilizing various combinations of the different wavefronts produced by a conjugate pair of binary Optical elements; a transmission grating is used to produce several illumination beams while a reflective grating replicated on the surface of a specimen, provides the reference for the undeformed state. A derivation of the equations which govern the method is included along with a discussion Of the experimental tests conducted to verify the theory. Overall, the results are excellent, with experimental data agreeing to within a few percent of the theoretical predictions.

Calibration of the optical torque wrench.

PubMed

Pedaci, Francesco; Huang, Zhuangxiong; van Oene, Maarten; Dekker, Nynke H

2012-02-13

The optical torque wrench is a laser trapping technique that expands the capability of standard optical tweezers to torque manipulation and measurement, using the laser linear polarization to orient tailored microscopic birefringent particles. The ability to measure torque of the order of kBT (∼4 pN nm) is especially important in the study of biophysical systems at the molecular and cellular level. Quantitative torque measurements rely on an accurate calibration of the instrument. Here we describe and implement a set of calibration approaches for the optical torque wrench, including methods that have direct analogs in linear optical tweezers as well as introducing others that are specifically developed for the angular variables. We compare the different methods, analyze their differences, and make recommendations regarding their implementations.

Recent Progress In Optical Oxygen Sensing

NASA Astrophysics Data System (ADS)

Wolfbeis, Otto S.; Leiner, Marc J. P.

1988-06-01

Following a brief review on the history of optical oxygen sensing (which shows that a variety of ideas exists in the literature that awaits the extension to fiber optic sensing schemes), the present state of probing oxygen by optical methods is discussed in terms of new methods and materials for sensor construction. Promising sensing schemes include simultaneous measurement of parameters such as oxygen and carbon dioxide with one fiber, measurement of fluorescence lifetimes and radiative energy transfer efficiency as well as phosphorescence quenching. New longwave-excitable fluorophores have been introduced recently, two-band emit-ting indicators can help to eliminate drift problems, and new methods have been found by which both indicators and enzymes may be entrapped in silicone rubber, which opens the way for the design of new biosensors. In a final chapter, the application of fiber optic oxygen sensors for blood gas measurement and as transducers in biosensors are presented.

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

Tauke-Pedretti, Anna; Skogen, Erik J; Vawter, Gregory A

An optical sampler includes a first and second 1.times.n optical beam splitters splitting an input optical sampling signal and an optical analog input signal into n parallel channels, respectively, a plurality of optical delay elements providing n parallel delayed input optical sampling signals, n photodiodes converting the n parallel optical analog input signals into n respective electrical output signals, and n optical modulators modulating the input optical sampling signal or the optical analog input signal by the respective electrical output signals, and providing n successive optical samples of the optical analog input signal. A plurality of output photodiodes and eADCsmore » convert the n successive optical samples to n successive digital samples. The optical modulator may be a photodiode interconnected Mach-Zehnder Modulator. A method of sampling the optical analog input signal is disclosed.« less

Clock recovery for high-speed optical communication

NASA Astrophysics Data System (ADS)

Pedrotti, Kenneth D.

1996-01-01

This paper reviews recent results for clock recovery circuits operating at speeds in excess of 1 Gbit/sec or realized as multichannel arrays. The emphasis is on synchronous optical network (SONET) type systems, their requirements, and the effect of the clock recovery circuits on system performance. Clock recovery approaches include filter based, phase-locked-loops, and all-optical methods.

Clock recovery for high-speed optical communication

NASA Astrophysics Data System (ADS)

Pedrotti, Ken

1996-01-01

This paper reviews recent results for clock recovery circuits operating at speeds in excess of 1 Gbit/sec or realized as multichannel arrays. The emphasis is on Synchronous Optical NETwork (SONET) type systems, their requirements, and the effect of the clock recovery circuits on system performance. Clock recovery approaches include filter based, phase-lockcd-loops, and all-optical methods.

75 FR 773 - TSCA Section 5 Premanufacture and Significant New Use Notification Electronic Reporting...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-06

... via CDX, optical disc (CD or DVD), and paper. Regardless of the method of submission, EPA will require... support documents (including NOCs), though optical discs may continue to be used. Two years after the effective date of this final rule, optical discs will no longer be accepted, and all submitters must submit...

Micro-optical elements produced using an photo-embossing technique in photopolymers

NASA Astrophysics Data System (ADS)

O'Neill, Feidhlim T.; Rowsome, Ita C.; Carr, Alun J.; Daniels, Stephen M.; Gleeson, Michael R.; Kelly, John V.; Close, Ciara; Lawrence, Justin R.; Sheridan, John T.

2005-09-01

Micro-optical devices are very important in current high-tech consumer items. The development of future products depends on both the evolution of fabrication techniques and on the development of new low cost mass production methods. Polymers offer ease of fabrication and low cost and are therefore excellent materials for the development of micro-optical devices. Polymer optical devices include passive optical elements, such as microlens arrays and waveguides, as well as active devices such as polymer based lasers. One of the most important areas of micro-optics is that of microlens design, manufacture and testing. The wide diversity of fabrication methods used for the production of these elements indicates their importance. One of these fabrication techniques is photo-embossing. The use of the photo-embossing technique and a photopolymer holographic recording material will be examined in this paper. A discussion of current attempts to model the fabrication process and a review of the experimental method will be given.

Narrowband resonant transmitter

DOEpatents

Hutchinson, Donald P.; Simpson, Marcus L.; Simpson, John T.

2004-06-29

A transverse-longitudinal integrated optical resonator (TLIR) is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide. The PBG is positioned between the first and second subwavelength resonant gratings. An electro-optic waveguide material may be used to permit tuning the TLIR and to permit the TLIR to perform signal modulation and switching. The TLIR may be positioned on a bulk substrate die with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a TLIR including fabricating a broadband reflective grating is disclosed. A method for tuning the TLIR's transmission resonance wavelength is also disclosed.

Transverse-longitudinal integrated resonator

DOEpatents

Hutchinson, Donald P [Knoxville, TN; Simpson, Marcus L [Knoxville, TN; Simpson, John T [Knoxville, TN

2003-03-11

A transverse-longitudinal integrated optical resonator (TLIR) is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide. The PBG is positioned between the first and second subwavelength resonant gratings. An electro-optic waveguide material may be used to permit tuning the TLIR and to permit the TLIR to perform signal modulation and switching. The TLIR may be positioned on a bulk substrate die with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a TLIR including fabricating a broadband reflective grating is disclosed. A method for tuning the TLIR's transmission resonance wavelength is also disclosed.

Transition operators in electromagnetic-wave diffraction theory. II - Applications to optics

NASA Technical Reports Server (NTRS)

Hahne, G. E.

1993-01-01

The theory developed by Hahne (1992) for the diffraction of time-harmonic electromagnetic waves from fixed obstacles is briefly summarized and extended. Applications of the theory are considered which comprise, first, a spherical harmonic expansion of the so-called radiation impedance operator in the theory, for a spherical surface, and second, a reconsideration of familiar short-wavelength approximation from the new standpoint, including a derivation of the so-called physical optics method on the basis of quasi-planar approximation to the radiation impedance operator, augmented by the method of stationary phase. The latter includes a rederivation of the geometrical optics approximation for the complete Green's function for the electromagnetic field in the presence of a smooth- and a convex-surfaced perfectly electrically conductive obstacle.

Optical soliton solutions of the cubic-quintic non-linear Schrödinger's equation including an anti-cubic term

NASA Astrophysics Data System (ADS)

Kaplan, Melike; Hosseini, Kamyar; Samadani, Farzan; Raza, Nauman

2018-07-01

A wide range of problems in different fields of the applied sciences especially non-linear optics is described by non-linear Schrödinger's equations (NLSEs). In the present paper, a specific type of NLSEs known as the cubic-quintic non-linear Schrödinger's equation including an anti-cubic term has been studied. The generalized Kudryashov method along with symbolic computation package has been exerted to carry out this objective. As a consequence, a series of optical soliton solutions have formally been retrieved. It is corroborated that the generalized form of Kudryashov method is a direct, effectual, and reliable technique to deal with various types of non-linear Schrödinger's equations.

Laser illumination of multiple capillaries that form a waveguide

DOEpatents

Dhadwal, Harbans S.; Quesada, Mark A.; Studier, F. William

1998-08-04

A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis.

Laser illumination of multiple capillaries that form a waveguide

DOEpatents

Dhadwal, H.S.; Quesada, M.A.; Studier, F.W.

1998-08-04

A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis. 35 figs.

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

Fired Cartridge Case Identification Using Optical Images and the Congruent Matching Cells (CMC) Method.

PubMed

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 - T CCF, T θ, T x and T y 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.

Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods

PubMed Central

Fantini, Sergio; Sassaroli, Angelo; Tgavalekos, Kristen T.; Kornbluth, Joshua

2016-01-01

Abstract. Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation. PMID:27403447

EDITORIAL: Recent developments in biomedical optics

NASA Astrophysics Data System (ADS)

Wang, Ruikang K.; Hebden, Jeremy C.; Tuchin, Valery V.

2004-04-01

The rapid growth in laser and photonic technology has resulted in new tools being proposed and developed for use in the medical and biological sciences. Specifically, a discipline known as biomedical optics has emerged which is providing a broad variety of optical techniques and instruments for diagnostic, therapeutic and basic science applications. New laser sources, detectors and measurement techniques are yielding powerful new methods for the study of diseases on all scales, from single molecules, to specific tissues and whole organs. For example, novel laser microscopes permit spectroscopic and force measurements to be performed on single protein molecules; new optical devices provide information on molecular dynamics and structure to perform `optical biopsy' non-invasively and almost instantaneously; and optical coherence tomography and diffuse optical tomography allow visualization of specific tissues and organs. Using genetic promoters to derive luciferase expression, bioluminescence methods can generate molecular light switches, which serve as functional indicator lights reporting cellular conditions and responses in living animals. This technique could allow rapid assessment of and response to the effects of anti-tumour drugs, antibiotics, or antiviral drugs. This issue of Physics in Medicine and Biology highlights recent research in biomedical optics, and is based on invited contributions to the International Conference on Advanced Laser Technology (Focused on Biomedical Optics) held at Cranfield University at Silsoe on 19--23 September 2003. This meeting included sessions devoted to: diffuse optical imaging and spectroscopy; optical coherence tomography and coherent domain techniques; optical sensing and applications in life science; microscopic, spectroscopic and opto-acoustic imaging; therapeutic and diagnostic applications; and laser interaction with organic and inorganic materials. Twenty-one papers are included in this special issue. The first paper gives an overview on the current status of scanning laser ophthalmoscopy and its role in bioscience and medicine, while the second paper describes the current problems in tissue engineering and the potential role for optical coherence tomography. The following seven papers present and discuss latest developments in infrared spectroscopy and diffuse optical tomography for medical diagnostics. Eight further papers report recent advances in optical coherence tomography, covering new and evolving methods and instrumentation, theoretical and numerical modelling, and its clinical applications. The remaining papers cover miscellaneous topics in biomedical optics, including new developments in opto-acoustic imaging techniques, laser speckle imaging of blood flow in microcirculations, and potential of hollow-core photonic-crystal fibres for laser dentistry. We thank all the authors for their valuable contributions and their prompt responses to reviewers' comments. We are also very grateful to the reviewers for their hard work and their considerable efforts to meet tight deadlines.

Material characterisation with methods of nonlinear optics

NASA Astrophysics Data System (ADS)

Prylepa, A.; Reitböck, C.; Cobet, M.; Jesacher, A.; Jin, X.; Adelung, R.; Schatzl-Linder, M.; Luckeneder, G.; Stellnberger, K.-H.; Steck, T.; Faderl, J.; Stehrer, T.; Stifter, D.

2018-01-01

In this review, we present nonlinear optical methods, based on the second and third order nonlinear polarization, especially in the context of material characterization tasks outside the area of life sciences—for which these techniques are mostly designed. An overview of application studies reported to date is given, together with a discussion on the advantages and limits of the individual methods. Furthermore, new ways of experimentally combining different optical concepts are introduced, and their potential for characterisation and inspection tasks is evaluated in the context of various case studies, including the investigation of semiconductor surfaces, metals and related corrosion products, as well as of organic materials.

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

Moisture sensor based on evanescent wave light scattering by porous sol-gel silica coating

DOEpatents

Tao, Shiquan; Singh, Jagdish P.; Winstead, Christopher B.

2006-05-02

An optical fiber moisture sensor that can be used to sense moisture present in gas phase in a wide range of concentrations is provided, as well techniques for making the same. The present invention includes a method that utilizes the light scattering phenomenon which occurs in a porous sol-gel silica by coating an optical fiber core with such silica. Thus, a porous sol-gel silica polymer coated on an optical fiber core forms the transducer of an optical fiber moisture sensor according to an embodiment. The resulting optical fiber sensor of the present invention can be used in various applications, including to sense moisture content in indoor/outdoor air, soil, concrete, and low/high temperature gas streams.

Fiber coupled optical spark delivery system

DOEpatents

Yalin, Azer; Willson, Bryan; Defoort, Morgan

2008-08-12

A spark delivery system for generating a spark using a laser beam is provided, the spark delivery system including a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. In addition, the laser delivery assembly includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. In accordance with embodiments of the present invention, the assembly may be used to create a spark in a combustion engine. In accordance with other embodiments of the present invention, a method of using the spark delivery system is provided. In addition, a method of choosing an appropriate fiber for creating a spark using a laser beam is also presented.

Methods for the additive manufacturing of semiconductor and crystal materials

DOEpatents

Stowe, Ashley C.; Speight, Douglas

2016-11-22

A method for the additive manufacturing of inorganic crystalline materials, including: physically combining a plurality of starting materials that are used to form an inorganic crystalline compound to be used as one or more of a semiconductor, scintillator, laser crystal, and optical filter; heating or melting successive regions of the combined starting materials using a directed heat source having a predetermined energy characteristic, thereby facilitating the reaction of the combined starting materials; and allowing each region of the combined starting materials to cool in a controlled manner, such that the desired inorganic crystalline compound results. The method also includes, prior to heating or melting the successive regions of the combined starting materials using the directed heat source, heating the combined starting materials to facilitate initial reaction of the combined starting materials. The method further includes translating the combined starting materials and/or the directed heat source between successive locations. The method still further includes controlling the mechanical, electrical, photonic, and/or optical properties of the inorganic crystalline compound.

CONFERENCE NOTE: European Optical Society, Topical Meeting Optical Metrology and Nanotechnology, Engelberg, Switzerland, 27 30 March 1994

NASA Astrophysics Data System (ADS)

1993-01-01

This meeting, organized by the Paul Scherrer Institute's Department of Applied Solid State Physics, will be held from 27 30 March 1994 at the Hotel Regina-Titlis, Engelberg, Switzerland. The aim is to bring together scientists from two important fields of current research and increasing industrial relevance. Optical metrology is a traditional discipline of applied optics which reached the nanometre scale a long time ago. Nanotechnology is setting new limits and represents a major challenge to metrology, as well as offering new opportunities to optics. The meeting is intended to help define a common future for optical metrology and nanotechnology. Topics to be covered include: nanometre position control and measuring techniques ultrahigh precision interferometry scanning probe microscopy (AFM, SNOM, etc.) surface modification by scanning probe methods precision surface fabrication and characterization nanolithography micro-optics, diffractive optics components, including systems and applications subwavelength optical structures synthetic optical materials structures and technologies for X-ray optics. For further information please contact: Jens Gobrecht (Secretary), Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland.Tel. (41)56992529; Fax (41) 5698 2635.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred J; Motala, Michael; Ahn, Jong-Hyun; Park, Sang-Il; Yu, Chang-Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2014-05-13

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John [Champaign, IL; Nuzzo, Ralph [Champaign, IL; Meitl, Matthew [Durham, NC; Menard, Etienne [Durham, NC; Baca, Alfred J [Urbana, IL; Motala, Michael [Champaign, IL; Ahn, Jong-Hyun [Suwon, KR; Park, Sang-II [Savoy, IL; Yu,; Chang-Jae, [Urbana, IL; Ko, Heung-Cho [Gwangju, KR; Stoykovich,; Mark, [Dover, NH; Yoon, Jongseung [Urbana, IL

2011-07-05

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred; Motala, Michael; Ahn, Jong -Hyun; Park, Sang -Il; Yu, Chang -Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2015-08-25

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Optical systems fabricated by printing-based assembly

DOEpatents

Rogers, John; Nuzzo, Ralph; Meitl, Matthew; Menard, Etienne; Baca, Alfred; Motala, Michael; Ahn, Jong-Hyun; Park, Sang-Il; Yu, Chang-Jae; Ko, Heung Cho; Stoykovich, Mark; Yoon, Jongseung

2017-03-21

Provided are optical devices and systems fabricated, at least in part, via printing-based assembly and integration of device components. In specific embodiments the present invention provides light emitting systems, light collecting systems, light sensing systems and photovoltaic systems comprising printable semiconductor elements, including large area, high performance macroelectronic devices. Optical systems of the present invention comprise semiconductor elements assembled, organized and/or integrated with other device components via printing techniques that exhibit performance characteristics and functionality comparable to single crystalline semiconductor based devices fabricated using conventional high temperature processing methods. Optical systems of the present invention have device geometries and configurations, such as form factors, component densities, and component positions, accessed by printing that provide a range of useful device functionalities. Optical systems of the present invention include devices and device arrays exhibiting a range of useful physical and mechanical properties including flexibility, shapeability, conformability and stretchablity.

Advanced Geometric Optics on a Programmable Pocket Calculator.

ERIC Educational Resources Information Center

Nussbaum, Allen

1979-01-01

Presents a ray-tracing procedure based on some ideas of Herzberger and the matrix approach to geometrical optics. This method, which can be implemented on a programmable pocket calculator, applies to any conic surface, including paraboloids, spheres, and planes. (Author/GA)

Control, Filtering and Prediction for Phased Arrays in Directed Energy Systems

DTIC Science & Technology

2016-04-30

adaptive optics. 15. SUBJECT TERMS control, filtering, prediction, system identification, adaptive optics, laser beam pointing, target tracking, phase... laser beam control; furthermore, wavefront sensors are plagued by the difficulty of maintaining the required alignment and focusing in dynamic mission...developed new methods for filtering, prediction and system identification in adaptive optics for high energy laser systems including phased arrays. The

Multiple-channel, total-reflection optic with controllable divergence

DOEpatents

Gibson, David M.; Downing, Robert G.

1997-01-01

An apparatus and method for providing focused x-ray, gamma-ray, charged particle and neutral particle, including neutron, radiation beams with a controllable amount of divergence are disclosed. The apparatus features a novel use of a radiation blocking structure, which, when combined with multiple-channel total reflection optics, increases the versatility of the optics by providing user-controlled output-beam divergence.

Multiple-channel, total-reflection optic with controllable divergence

DOEpatents

Gibson, D.M.; Downing, R.G.

1997-02-18

An apparatus and method for providing focused x-ray, gamma-ray, charged particle and neutral particle, including neutron, radiation beams with a controllable amount of divergence are disclosed. The apparatus features a novel use of a radiation blocking structure, which, when combined with multiple-channel total reflection optics, increases the versatility of the optics by providing user-controlled output-beam divergence. 11 figs.

An historical overview of cavity-enhanced methods

NASA Astrophysics Data System (ADS)

Paldus, B. A.; Kachanov, A. A.

2005-10-01

An historical overview of laser-based, spectroscopic methods that employ high-finesse optical resonators is presented. The overview begins with the early work in atomic absorption (1962) and optical cavities (1974) that led to the first mirror reflectivity measurements in 1980. This paper concludes with very recent extensions of cavity-enhanced methods for the study of condensed-phase media and biological systems. Methods described here include cavity ring-down spectroscopy, integrated cavity output spectroscopy, and noise-immune cavity-enhanced optical heterodyne molecular spectroscopy. Given the explosive growth of the field over the past decade, this review does not attempt to present a comprehensive bibliography of all work published in cavity-enhanced spectroscopy, but rather strives to illustrate the rich history, creative diversity, and broad applications potential of these methods.

Genetic algorithms and MCML program for recovery of optical properties of homogeneous turbid media

PubMed Central

Morales Cruzado, Beatriz; y Montiel, Sergio Vázquez; Atencio, José Alberto Delgado

2013-01-01

In this paper, we present and validate a new method for optical properties recovery of turbid media with slab geometry. This method is an iterative method that compares diffuse reflectance and transmittance, measured using integrating spheres, with those obtained using the known algorithm MCML. The search procedure is based in the evolution of a population due to selection of the best individual, i.e., using a genetic algorithm. This new method includes several corrections such as non-linear effects in integrating spheres measurements and loss of light due to the finite size of the sample. As a potential application and proof-of-principle experiment of this new method, we use this new algorithm in the recovery of optical properties of blood samples at different degrees of coagulation. PMID:23504404

Validation of an automated tractography method for the optic radiations as a biomarker of visual acuity in neurofibromatosis-associated optic pathway glioma.

PubMed

de Blank, Peter; Fisher, Michael J; Gittleman, Haley; Barnholtz-Sloan, Jill S; Badve, Chaitra; Berman, Jeffrey I

2018-01-01

Fractional anisotropy (FA) of the optic radiations has been associated with vision deficit in multiple intrinsic brain pathologies including NF1 associated optic pathway glioma, but hand-drawn regions of interest used in previous tractography methods limit consistency of this potential biomarker. We created an automated method to identify white matter tracts in the optic radiations and compared this method to previously reported hand-drawn tractography. Automated tractography of the optic radiation using probabilistic streamline fiber tracking between the lateral geniculate nucleus of the thalamus and the occipital cortex was compared to the hand-drawn method between regions of interest posterior to Meyer's loop and anterior to tract branching near the calcarine cortex. Reliability was assessed by two independent raters in a sample of 20 healthy child controls. Among 50 children with NF1-associated optic pathway glioma, the association of FA and visual acuity deficit was compared for both tractography methods. Hand-drawn tractography methods required 2.6±0.9min/participant; automated methods were performed in <1min of operator time for all participants. Cronbach's alpha was 0.83 between two independent raters for FA in hand-drawn tractography, but repeated automated tractography resulted in identical FA values (Cronbach's alpha=1). On univariate and multivariate analyses, FA was similarly associated with visual acuity loss using both methods. Receiver operator characteristic curves of both multivariate models demonstrated that both automated and hand-drawn tractography methods were equally able to distinguish normal from abnormal visual acuity. Automated tractography of the optic radiations offers a fast, reliable and consistent method of tract identification that is not reliant on operator time or expertise. This method of tract identification may be useful as DTI is developed as a potential biomarker for visual acuity. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

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.

A phase space approach to imaging from limited data

NASA Astrophysics Data System (ADS)

Testorf, Markus E.

2015-09-01

The optical instrument function is used as the basis to develop optical system theory for imaging applications. The detection of optical signals is conveniently described as the overlap integral of the Wigner distribution functions of instrument and optical signal. Based on this framework various optical imaging systems, including plenoptic cameras, phase-retrieval algorithms, and Shack-Hartman sensors are shown to acquire information about a domain in phase-space, with finite extension and finite resolution. It is demonstrated how phase space optics can be used both to analyze imaging systems, as well as for designing methods for image reconstruction.

Rotation of single live mammalian cells using dynamic holographic optical tweezers

NASA Astrophysics Data System (ADS)

Bin Cao; Kelbauskas, Laimonas; Chan, Samantha; Shetty, Rishabh M.; Smith, Dean; Meldrum, Deirdre R.

2017-05-01

We report on a method for rotating single mammalian cells about an axis perpendicular to the optical system axis through the imaging plane using dynamic holographic optical tweezers (HOTs). Two optical traps are created on the opposite edges of a mammalian cell and are continuously transitioned through the imaging plane along the circumference of the cell in opposite directions, thus providing the torque to rotate the cell in a controlled fashion. The method enables a complete 360° rotation of live single mammalian cells with spherical or near-to spherical shape in 3D space, and represents a useful tool suitable for the single cell analysis field, including tomographic imaging.

EXPRESS: Accurate Measurement of the Optical Constants n and k for a Series of 57 Inorganic and Organic Liquids for Optical Modeling and Detection

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

Myers, Tanya L.; Tonkyn, Russell G.; Danby, Tyler O.

For optical modeling and other purposes, we have created a library of 57 liquids for which we have measured the complex optical constants n and k. These liquids vary in their nature, ranging in properties including chemical structure, optical band strength, volatility and viscosity. By obtaining the optical constants one can in principle model most optical phenomena in media and at interfaces including reflection, refraction and dispersion. Based on the original methods of J.E. Bertie et al.1 [1Bert1], we have developed improved protocols using multiple path lengths to determine the optical constants n/k for dozens of liquids, including inorganic, organicmore » and organophosphorus compounds. Detailed descriptions of the measurement and data reduction protocols are discussed; agreement of the derived optical constant n and k values with literature values are presented. We also present results using the n/k values as applied to an optical modeling scenario whereby the derived data are presented and tested for models of 1 µm and 100 µm layers for DMMP (dimethyl methyl phosphonate) on both metal (aluminum) and dielectric (soda lime glass) substrates to show substantial differences between the reflected signal from highly reflective substrates and less-reflective substrates.« less

Comparison of corneal endothelial image analysis by Konan SP8000 noncontact and Bio-Optics Bambi systems.

PubMed

Benetz, B A; Diaconu, E; Bowlin, S J; Oak, S S; Laing, R A; Lass, J H

1999-01-01

Compare corneal endothelial image analysis by Konan SP8000 and Bio-Optics Bambi image-analysis systems. Corneal endothelial images from 98 individuals (191 eyes), ranging in age from 4 to 87 years, with a normal slit-lamp examination and no history of ocular trauma, intraocular surgery, or intraocular inflammation were obtained by the Konan SP8000 noncontact specular microscope. One observer analyzed these images by using the Konan system and a second observer by using the Bio-Optics Bambi system. Three methods of analyses were used: a fixed-frame method to obtain cell density (for both Konan and Bio-Optics Bambi) and a "dot" (Konan) or "corners" (Bio-Optics Bambi) method to determine morphometric parameters. The cell density determined by the Konan fixed-frame method was significantly higher (157 cells/mm2) than the Bio-Optics Bambi fixed-frame method determination (p<0.0001). However, the difference in cell density, although still statistically significant, was smaller and reversed comparing the Konan fixed-frame method with both Konan dot and Bio-Optics Bambi comers method (-74 cells/mm2, p<0.0001; -55 cells/mm2, p<0.0001, respectively). Small but statistically significant morphometric analyses differences between Konan and Bio-Optics Bambi were seen: cell density, +19 cells/mm2 (p = 0.03); cell area, -3.0 microm2 (p = 0.008); and coefficient of variation, +1.0 (p = 0.003). There was no statistically significant difference between these two methods in the percentage of six-sided cells detected (p = 0.55). Cell densities measured by the Konan fixed-frame method were comparable with Konan and Bio-Optics Bambi's morphometric analysis, but not with the Bio-Optics Bambi fixed-frame method. The two morphometric analyses were comparable with minimal or no differences for the parameters that were studied. The Konan SP8000 endothelial image-analysis system may be useful for large-scale clinical trials determining cell loss; its noncontact system has many clinical benefits (including patient comfort, safety, ease of use, and short procedure time) and provides reliable cell-density calculations.

Matrix Treatment of Ray Optics.

ERIC Educational Resources Information Center

Quon, W. Steve

1996-01-01

Describes a method to combine two learning experiences--optical physics and matrix mathematics--in a straightforward laboratory experiment that allows engineering/physics students to integrate a variety of learning insights and technical skills, including using lasers, studying refraction through thin lenses, applying concepts of matrix…

Optical trapping apparatus, methods and applications using photonic crystal resonators

DOEpatents

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.

Repair of a Mirror Coating on a Large Optic for High Laser Damage Applications using Ion Milling and Over-Coating Methods.

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

Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairsmore » were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO 2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. Finally, the repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 – 61.0 J/cm 2.« less

Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

NASA Astrophysics Data System (ADS)

Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

2017-01-01

When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating's high laser-induced damage threshold (LIDT) of 64.0 J/cm2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm2.

Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

DOE PAGES

Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

2016-07-08

Here, when an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched.more » Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm 2.« less

Repair of a Mirror Coating on a Large Optic for High Laser Damage Applications using Ion Milling and Over-Coating Methods.

DOE PAGES

Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

2016-06-01

When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairsmore » were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO 2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. Finally, the repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 – 61.0 J/cm 2.« less

Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

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

Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

Here, when an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched.more » Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm 2.« less

Systems and methods for optically measuring properties of hydrocarbon fuel gases

DOEpatents

Adler-Golden, S.; Bernstein, L.S.; Bien, F.; Gersh, M.E.; Goldstein, N.

1998-10-13

A system and method for optical interrogation and measurement of a hydrocarbon fuel gas includes a light source generating light at near-visible wavelengths. A cell containing the gas is optically coupled to the light source which is in turn partially transmitted by the sample. A spectrometer disperses the transmitted light and captures an image thereof. The image is captured by a low-cost silicon-based two-dimensional CCD array. The captured spectral image is processed by electronics for determining energy or BTU content and composition of the gas. The innovative optical approach provides a relatively inexpensive, durable, maintenance-free sensor and method which is reliable in the field and relatively simple to calibrate. In view of the above, accurate monitoring is possible at a plurality of locations along the distribution chain leading to more efficient distribution. 14 figs.

Systems and methods for optically measuring properties of hydrocarbon fuel gases

DOEpatents

Adler-Golden, Steven; Bernstein, Lawrence S.; Bien, Fritz; Gersh, Michael E.; Goldstein, Neil

1998-10-13

A system and method for optical interrogation and measurement of a hydrocarbon fuel gas includes a light source generating light at near-visible wavelengths. A cell containing the gas is optically coupled to the light source which is in turn partially transmitted by the sample. A spectrometer disperses the transmitted light and captures an image thereof. The image is captured by a low-cost silicon-based two-dimensional CCD array. The captured spectral image is processed by electronics for determining energy or BTU content and composition of the gas. The innovative optical approach provides a relatively inexpensive, durable, maintenance-free sensor and method which is reliable in the field and relatively simple to calibrate. In view of the above, accurate monitoring is possible at a plurality of locations along the distribution chain leading to more efficient distribution.

Experimental AMO physics in undergraduate optics and lasers courses

NASA Astrophysics Data System (ADS)

Hoyt, Chad

2017-04-01

This talk will describe experimental AMO research projects in undergraduate Lasers and Optics courses at Bethel University. The courses, which include a comprehensive lecture portion, are built on open-ended projects that have a novel aspect. Classes begin with four weeks of small student groups rotating between several standard laser and optics laboratory exercises. These may include, for example, alignment and characterization of a helium neon laser and measurements with a Michelson interferometer or a scanning Fabry-Pérot optical cavity. During the following seven weeks of the course, student groups (2-4 people) choose and pursue research questions in the lab. Their work culminates in a group manuscript and a twenty-minute presentation to the class. Projects in the spring, 2016 Optics course included experiments with ultracold lithium atoms in a magneto-optical trap, a prototype, portable, mode-locked erbium fiber laser, a home-built fiber laser frequency comb, double-slit imaging with single photons, and digital holographic tweezers (led by Nathan Lindquist). Projects in the spring, 2015 Lasers course included ultrafast optics with a mode-locked erbium fiber laser, quantum optics, surface plasmon lasers (led by Nathan Lindquist) and a low-cost, near-infrared spectrometer. Several of these projects are related to larger scale, funded research in the physics department. The format and experience in Lasers and Optics is representative of other upper-level courses at Bethel, including Fluid Mechanics and Computer Methods. A physics education research group from the University of Colorado evaluated the spring, 2015 Lasers and 2016 Optics courses. They focused on student experimental attitudes and measurements of student project ownership.

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

Myers, Tanya L.; Tonkyn, Russell G.; Danby, Tyler O.

For optical modeling and other purposes, we have created a library of 57 liquids for which we have measured the complex optical constants n and k. These liquids vary in their nature, ranging in properties including chemical structure, optical band strength, volatility and viscosity. By obtaining the optical constants one can in principle model most optical phenomena in media and at interfaces including reflection, refraction and dispersion. Based on the original methods of J.E. Bertie et al.1 [1Bert1], we have developed improved protocols using multiple path lengths to determine the optical constants n/k for dozens of liquids, including inorganic, organicmore » and organophosphorus compounds. Detailed descriptions of the measurement and data reduction protocols are discussed; agreement of the derived optical constant n and k values with literature values are presented. We also present results using the n/k values as applied to an optical modeling scenario whereby the derived data are presented and tested for models of 1 µm and 100 µm layers for DMMP (dimethyl methyl phosphonate) on both metal (aluminum) and dielectric (soda lime glass) substrates to show substantial differences between the reflected signal from highly reflective substrates and less-reflective substrates.« less

3D printed optical phantoms and deep tissue imaging for in vivo applications including oral surgery

NASA Astrophysics Data System (ADS)

Bentz, Brian Z.; Costas, Alfonso; Gaind, Vaibhav; Garcia, Jose M.; Webb, Kevin J.

2017-03-01

Progress in developing optical imaging for biomedical applications requires customizable and often complex objects known as "phantoms" for testing, evaluation, and calibration. This work demonstrates that 3D printing is an ideal method for fabricating such objects, allowing intricate inhomogeneities to be placed at exact locations in complex or anatomically realistic geometries, a process that is difficult or impossible using molds. We show printed mouse phantoms we have fabricated for developing deep tissue fluorescence imaging methods, and measurements of both their optical and mechanical properties. Additionally, we present a printed phantom of the human mouth that we use to develop an artery localization method to assist in oral surgery.

Exact solitary wave solution for higher order nonlinear Schrodinger equation using He's variational iteration method

NASA Astrophysics Data System (ADS)

Rani, Monika; Bhatti, Harbax S.; Singh, Vikramjeet

2017-11-01

In optical communication, the behavior of the ultrashort pulses of optical solitons can be described through nonlinear Schrodinger equation. This partial differential equation is widely used to contemplate a number of physically important phenomena, including optical shock waves, laser and plasma physics, quantum mechanics, elastic media, etc. The exact analytical solution of (1+n)-dimensional higher order nonlinear Schrodinger equation by He's variational iteration method has been presented. Our proposed solutions are very helpful in studying the solitary wave phenomena and ensure rapid convergent series and avoid round off errors. Different examples with graphical representations have been given to justify the capability of the method.

Integrating the Advanced Human Eye Model (AHEM) and optical instrument models to model complete visual optical systems inclusive of the typical or atypical eye

NASA Astrophysics Data System (ADS)

Donnelly, William J., III

2012-06-01

PURPOSE: To present a commercially available optical modeling software tool to assist the development of optical instrumentation and systems that utilize and/or integrate with the human eye. METHODS: A commercially available flexible eye modeling system is presented, the Advanced Human Eye Model (AHEM). AHEM is a module that the engineer can use to perform rapid development and test scenarios on systems that integrate with the eye. Methods include merging modeled systems initially developed outside of AHEM and performing a series of wizard-type operations that relieve the user from requiring an optometric or ophthalmic background to produce a complete eye inclusive system. Scenarios consist of retinal imaging of targets and sources through integrated systems. Uses include, but are not limited to, optimization, telescopes, microscopes, spectacles, contact and intraocular lenses, ocular aberrations, cataract simulation and scattering, and twin eye model (binocular) systems. RESULTS: Metrics, graphical data, and exportable CAD geometry are generated from the various modeling scenarios.

Method And Apparatus For Evaluatin Of High Temperature Superconductors

DOEpatents

Fishman, Ilya M.; Kino, Gordon S.

1996-11-12

A technique for evaluation of high-T.sub.c superconducting films and single crystals is based on measurement of temperature dependence of differential optical reflectivity of high-T.sub.c materials. In the claimed method, specific parameters of the superconducting transition such as the critical temperature, anisotropy of the differential optical reflectivity response, and the part of the optical losses related to sample quality are measured. The apparatus for performing this technique includes pump and probe sources, cooling means for sweeping sample temperature across the critical temperature and polarization controller for controlling a state of polarization of a probe light beam.

Review and analysis of avionic helmet-mounted displays

NASA Astrophysics Data System (ADS)

Li, Hua; Zhang, Xin; Shi, Guangwei; Qu, Hemeng; Wu, Yanxiong; Zhang, Jianping

2013-11-01

With the development of new concepts and principles over the past century, helmet-mounted displays (HMDs) have been widely applied. This paper presents a review of avionic HMDs and shows some areas of active and intensive research. This review is focused on the optical design aspects and is divided into three sections to explore new optical design methods, which include an off-axis design, design with freeform optical surface, and design with holographic optical waveguide technology. Building on the fundamentals of optical design and engineering, the principles section primarily expounds on the five optical system parameters, which include weight, field of view, modulation transfer function, exit pupil size, and eye relief. We summarized the previous design works using new components to achieve compact and lightweight HMDs. Moreover, the paper presents a partial summary of the more notable experimental, prototype, fielded, and future HMD fixed-wing and rotary-wing programs.

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.

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.

A novel optical gating method for laser gated imaging

NASA Astrophysics Data System (ADS)

Ginat, Ran; Schneider, Ron; Zohar, Eyal; Nesher, Ofer

2013-06-01

For the past 15 years, Elbit Systems is developing time-resolved active laser-gated imaging (LGI) systems for various applications. Traditional LGI systems are based on high sensitive gated sensors, synchronized to pulsed laser sources. Elbit propriety multi-pulse per frame method, which is being implemented in LGI systems, improves significantly the imaging quality. A significant characteristic of the LGI is its ability to penetrate a disturbing media, such as rain, haze and some fog types. Current LGI systems are based on image intensifier (II) sensors, limiting the system in spectral response, image quality, reliability and cost. A novel propriety optical gating module was developed in Elbit, untying the dependency of LGI system on II. The optical gating module is not bounded to the radiance wavelength and positioned between the system optics and the sensor. This optical gating method supports the use of conventional solid state sensors. By selecting the appropriate solid state sensor, the new LGI systems can operate at any desired wavelength. In this paper we present the new gating method characteristics, performance and its advantages over the II gating method. The use of the gated imaging systems is described in a variety of applications, including results from latest field experiments.

Attenuator And Conditioner

DOEpatents

Anderson, Gene R.; Armendariz, Marcelino G.; Carson, Richard F.; Bryan, Robert P.; Duckett, III, Edwin B.; Kemme, Shanalyn Adair; McCormick, Frederick B.; Peterson, David W.

2006-04-04

An apparatus and method of attenuating and/or conditioning optical energy for an optical transmitter, receiver or transceiver module is disclosed. An apparatus for attenuating the optical output of an optoelectronic connector including: a mounting surface; an array of optoelectronic devices having at least a first end; an array of optical elements having at least a first end; the first end of the array of optical elements optically aligned with the first end of the array of optoelectronic devices; an optical path extending from the first end of the array of optoelectronic devices and ending at a second end of the array of optical elements; and an attenuator in the optical path for attenuating the optical energy emitted from the array of optoelectronic devices. Alternatively, a conditioner may be adapted in the optical path for conditioning the optical energy emitted from the array of optoelectronic devices.

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.

Hybrid shearing and phase-shifting point diffraction interferometer

DOEpatents

Goldberg, Kenneth Alan; Naulleau, Patrick P.

2003-06-03

A new interferometry configuration combines the strengths of two existing interferometry methods, improving the quality and extending the dynamic range of both. On the same patterned mask, placed near the image-plane of an optical system under test, patterns for phase-shifting point diffraction interferometry and lateral shearing interferometry coexist. The former giving verifiable high accuracy for the measurement of nearly diffraction-limited optical systems. The latter enabling the measurement of optical systems with more than one wave of aberration in the system wavefront. The interferometry configuration is a hybrid shearing and point diffraction interferometer system for testing an optical element that is positioned along an optical path including: a source of electromagnetic energy in the optical path; a first beam splitter that is secured to a device that includes means for maneuvering the first beam splitter in a first position wherein the first beam splitter is in the optical path dividing light from the source into a reference beam and a test beam and in a second position wherein the first beam splitter is outside the optical path: a hybrid mask which includes a first section that defines a test window and at least one reference pinhole and a second section that defines a second beam splitter wherein the hybrid mask is secured to a device that includes means for maneuvering either the first section or the second section into the optical path positioned in an image plane that is created by the optical element, with the proviso that the first section of the hybrid mask is positioned in the optical path when first beam splitter is positioned in the optical path; and a detector positioned after the hybrid mask along the optical path.

CAE "FOCUS" for modelling and simulating electron optics systems: development and application

NASA Astrophysics Data System (ADS)

Trubitsyn, Andrey; Grachev, Evgeny; Gurov, Victor; Bochkov, Ilya; Bochkov, Victor

2017-02-01

Electron optics is a theoretical base of scientific instrument engineering. Mathematical simulation of occurring processes is a base for contemporary design of complicated devices of the electron optics. Problems of the numerical mathematical simulation are effectively solved by CAE system means. CAE "FOCUS" developed by the authors includes fast and accurate methods: boundary element method (BEM) for the electric field calculation, Runge-Kutta- Fieghlberg method for the charged particle trajectory computation controlling an accuracy of calculations, original methods for search of terms for the angular and time-of-flight focusing. CAE "FOCUS" is organized as a collection of modules each of which solves an independent (sub) task. A range of physical and analytical devices, in particular a microfocus X-ray tube of high power, has been developed using this soft.

The Recovery of Optical Quality after Laser Vision Correction

PubMed Central

Jung, Hyeong-Gi

2013-01-01

Purpose To evaluate the optical quality after laser in situ keratomileusis (LASIK) or serial photorefractive keratectomy (PRK) using a double-pass system and to follow the recovery of optical quality after laser vision correction. Methods This study measured the visual acuity, manifest refraction and optical quality before and one day, one week, one month, and three months after laser vision correction. Optical quality parameters including the modulation transfer function, Strehl ratio and intraocular scattering were evaluated with a double-pass system. Results This study included 51 eyes that underwent LASIK and 57 that underwent PRK. The optical quality three months post-surgery did not differ significantly between these laser vision correction techniques. Furthermore, the preoperative and postoperative optical quality did not differ significantly in either group. Optical quality recovered within one week after LASIK but took between one and three months to recover after PRK. The optical quality of patients in the PRK group seemed to recover slightly more slowly than their uncorrected distance visual acuity. Conclusions Optical quality recovers to the preoperative level after laser vision correction, so laser vision correction is efficacious for correcting myopia. The double-pass system is a useful tool for clinical assessment of optical quality. PMID:23908570

High-Sensitivity Spectrophotometry.

ERIC Educational Resources Information Center

Harris, T. D.

1982-01-01

Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

Using spectral methods to obtain particle size information from optical data: applications to measurements from CARES 2010

NASA Astrophysics Data System (ADS)

Atkinson, Dean B.; Pekour, Mikhail; Chand, Duli; Radney, James G.; Kolesar, Katheryn R.; Zhang, Qi; Setyan, Ari; O'Neill, Norman T.; Cappa, Christopher D.

2018-04-01

Multi-wavelength in situ aerosol extinction, absorption and scattering measurements made at two ground sites during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are analyzed using a spectral deconvolution method that allows extraction of particle-size-related information, including the fraction of extinction produced by the fine-mode particles and the effective radius of the fine mode. The spectral deconvolution method is typically applied to analysis of remote sensing measurements. Here, its application to in situ measurements allows for comparison with more direct measurement methods and validation of the retrieval approach. Overall, the retrieved fine-mode fraction and effective radius compare well with other in situ measurements, including size distribution measurements and scattering and absorption measurements made separately for PM1 and PM10, although there were some periods during which the different methods yielded different results. One key contributor to differences between the results obtained is the alternative, spectrally based definitions of fine and coarse modes from the optical methods, relative to instruments that use a physically defined cut point. These results indicate that for campaigns where size, composition and multi-wavelength optical property measurements are made, comparison of the results can result in closure or can identify unusual circumstances. The comparison here also demonstrates that in situ multi-wavelength optical property measurements can be used to determine information about particle size distributions in situations where direct size distribution measurements are not available.

Using spectral methods to obtain particle size information from optical data: applications to measurements from CARES 2010

DOE PAGES

Atkinson, Dean B.; Pekour, Mikhail; Chand, Duli; ...

2018-04-23

Here, multi-wavelength in situ aerosol extinction, absorption and scattering measurements made at two ground sites during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are analyzed using a spectral deconvolution method that allows extraction of particle-size-related information, including the fraction of extinction produced by the fine-mode particles and the effective radius of the fine mode. The spectral deconvolution method is typically applied to analysis of remote sensing measurements. Here, its application to in situ measurements allows for comparison with more direct measurement methods and validation of the retrieval approach. Overall, the retrieved fine-mode fraction and effective radius compare wellmore » with other in situ measurements, including size distribution measurements and scattering and absorption measurements made separately for PM 1 and PM 10, although there were some periods during which the different methods yielded different results. One key contributor to differences between the results obtained is the alternative, spectrally based definitions of fine and coarse modes from the optical methods, relative to instruments that use a physically defined cut point. These results indicate that for campaigns where size, composition and multi-wavelength optical property measurements are made, comparison of the results can result in closure or can identify unusual circumstances. The comparison here also demonstrates that in situ multi-wavelength optical property measurements can be used to determine information about particle size distributions in situations where direct size distribution measurements are not available.« less

Using spectral methods to obtain particle size information from optical data: applications to measurements from CARES 2010

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

Atkinson, Dean B.; Pekour, Mikhail; Chand, Duli

Here, multi-wavelength in situ aerosol extinction, absorption and scattering measurements made at two ground sites during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are analyzed using a spectral deconvolution method that allows extraction of particle-size-related information, including the fraction of extinction produced by the fine-mode particles and the effective radius of the fine mode. The spectral deconvolution method is typically applied to analysis of remote sensing measurements. Here, its application to in situ measurements allows for comparison with more direct measurement methods and validation of the retrieval approach. Overall, the retrieved fine-mode fraction and effective radius compare wellmore » with other in situ measurements, including size distribution measurements and scattering and absorption measurements made separately for PM 1 and PM 10, although there were some periods during which the different methods yielded different results. One key contributor to differences between the results obtained is the alternative, spectrally based definitions of fine and coarse modes from the optical methods, relative to instruments that use a physically defined cut point. These results indicate that for campaigns where size, composition and multi-wavelength optical property measurements are made, comparison of the results can result in closure or can identify unusual circumstances. The comparison here also demonstrates that in situ multi-wavelength optical property measurements can be used to determine information about particle size distributions in situations where direct size distribution measurements are not available.« less

Using spectral methods to obtain particle size information from optical data: applications to measurements from CARES 2010

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

Atkinson, Dean B.; Pekour, Mikhail; Chand, Duli

Multi-wavelength in situ aerosol extinction, absorption and scattering measurements made at two ground sites during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are analyzed using a spectral deconvolution method that allows extraction of particle-size-related information, including the fraction of extinction produced by the fine-mode particles and the effective radius of the fine mode. The spectral deconvolution method is typically applied to analysis of remote sensing measurements. Here, its application to in situ measurements allows for comparison with more direct measurement methods and validation of the retrieval approach. Overall, the retrieved fine-mode fraction and effective radius compare well withmore » other in situ measurements, including size distribution measurements and scattering and absorption measurements made separately for PM 1 and PM 10, although there were some periods during which the different methods yielded different results. One key contributor to differences between the results obtained is the alternative, spectrally based definitions of fine and coarse modes from the optical methods, relative to instruments that use a physically defined cut point. These results indicate that for campaigns where size, composition and multi-wavelength optical property measurements are made, comparison of the results can result in closure or can identify unusual circumstances. The comparison here also demonstrates that in situ multi-wavelength optical property measurements can be used to determine information about particle size distributions in situations where direct size distribution measurements are not available.« less

Reference-free, high-resolution measurement method of timing jitter spectra of optical frequency combs

PubMed Central

Kwon, Dohyeon; Jeon, Chan-Gi; Shin, Junho; Heo, Myoung-Sun; Park, Sang Eon; Song, Youjian; Kim, Jungwon

2017-01-01

Timing jitter is one of the most important properties of femtosecond mode-locked lasers and optical frequency combs. Accurate measurement of timing jitter power spectral density (PSD) is a critical prerequisite for optimizing overall noise performance and further advancing comb applications both in the time and frequency domains. Commonly used jitter measurement methods require a reference mode-locked laser with timing jitter similar to or lower than that of the laser-under-test, which is a demanding requirement for many laser laboratories, and/or have limited measurement resolution. Here we show a high-resolution and reference-source-free measurement method of timing jitter spectra of optical frequency combs using an optical fibre delay line and optical carrier interference. The demonstrated method works well for both mode-locked oscillators and supercontinua, with 2 × 10−9 fs2/Hz (equivalent to −174 dBc/Hz at 10-GHz carrier frequency) measurement noise floor. The demonstrated method can serve as a simple and powerful characterization tool for timing jitter PSDs of various comb sources including mode-locked oscillators, supercontinua and recently emerging Kerr-frequency combs; the jitter measurement results enabled by our method will provide new insights for understanding and optimizing timing noise in such comb sources. PMID:28102352

An efficient mosaic algorithm considering seasonal variation: application to KOMPSAT-2 satellite images.

PubMed

Choi, Jaewon; Jung, Hyung-Sup; Yun, Sang-Ho

2015-03-09

As the aerospace industry grows, images obtained from Earth observation satellites have been successfully used in various fields. Specifically, the demand for a high-resolution (HR) optical images is gradually increasing, and hence the generation of a high-quality mosaic image is being magnified as an interesting issue. In this paper, we have proposed an efficient mosaic algorithm for HR optical images that are significantly different due to seasonal change. The algorithm includes main steps such as: (1) seamline extraction from gradient magnitude and seam images; (2) histogram matching; and (3) image feathering. Eleven Kompsat-2 images characterized by seasonal variations are used for the performance validation of the proposed method. The results of the performance test show that the proposed method effectively mosaics Kompsat-2 adjacent images including severe seasonal changes. Moreover, the results reveal that the proposed method is applicable to HR optic images such as GeoEye, IKONOS, QuickBird, RapidEye, SPOT, WorldView, etc.

Method and system for evaluating integrity of adherence of a conductor bond to a mating surface of a substrate

DOEpatents

Telschow, K.L.; Siu, B.K.

1996-07-09

A method of evaluating integrity of adherence of a conductor bond to a substrate includes: (a) impinging a plurality of light sources onto a substrate; (b) detecting optical reflective signatures emanating from the substrate from the impinged light; (c) determining location of a selected conductor bond on the substrate from the detected reflective signatures; (d) determining a target site on the selected conductor bond from the detected reflective signatures; (e) optically imparting an elastic wave at the target site through the selected conductor bond and into the substrate; (f) optically detecting an elastic wave signature emanating from the substrate resulting from the optically imparting step; and (g) determining integrity of adherence of the selected conductor bond to the substrate from the detected elastic wave signature emanating from the substrate. A system is disclosed which is capable of conducting the method. 13 figs.

Method and system for evaluating integrity of adherence of a conductor bond to a mating surface of a substrate

DOEpatents

Telschow, Kenneth L.; Siu, Bernard K.

1996-01-01

A method of evaluating integrity of adherence of a conductor bond to a substrate includes: a) impinging a plurality of light sources onto a substrate; b) detecting optical reflective signatures emanating from the substrate from the impinged light; c) determining location of a selected conductor bond on the substrate from the detected reflective signatures; d) determining a target site on the selected conductor bond from the detected reflective signatures; e) optically imparting an elastic wave at the target site through the selected conductor bond and into the substrate; f) optically detecting an elastic wave signature emanating from the substrate resulting from the optically imparting step; and g) determining integrity of adherence of the selected conductor bond to the substrate from the detected elastic wave signature emanating from the substrate. A system is disclosed which is capable of conducting the method.

Energy reduction using multi-channels optical wireless communication based OFDM

NASA Astrophysics Data System (ADS)

Darwesh, Laialy; Arnon, Shlomi

2017-10-01

In recent years, an increasing number of data center networks (DCNs) have been built to provide various cloud applications. Major challenges in the design of next generation DC networks include reduction of the energy consumption, high flexibility and scalability, high data rates, minimum latency and high cyber security. Use of optical wireless communication (OWC) to augment the DC network could help to confront some of these challenges. In this paper we present an OWC multi channels communication method that could lead to significant energy reduction of the communication equipment. The method is to convert a high speed serial data stream to many slower and parallel streams and vies versa at the receiver. We implement this concept of multi channels using optical orthogonal frequency division multiplexing (O-OFDM) method. In our scheme, we use asymmetrically clipped optical OFDM (ACO-OFDM). Our results show that the realization of multi channels OFDM (ACO-OFDM) methods reduces the total energy consumption exponentially, as the number of channels transmitted through them rises.

Retinal projections in the electric catfish (Malapterurus electricus).

PubMed

Ebbesson, S O; O'Donnel, D

1980-01-01

The poorly developed visual system of the electric catfish was studied with silver-degeneration methods. Retinal projections were entirely contralateral to the hypothalamic optic nucleus, the lateral geniculate nucleus, the dorsomedial optic nucleus, the pretectal nuclei including the cortical nucleus, and the optic tectum. The small size and lack of differentiation of the visual system in the electric catfish suggest a relatively small role for this sensory system in this species.

Graded-Index "Whispering-Gallery" Optical Microresonators

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Maleki, Lute; Iltchenko, Vladimir; Matsko, Andrey

2006-01-01

Graded-index-of-refraction dielectric optical microresonators have been proposed as a superior alternative to prior dielectric optical microresonators, which include microspheres and microtori wherein electromagnetic waves propagate along circumferential paths in "whispering-gallery" modes. The design and method of fabrication of the proposed microresonators would afford improved performance by exploiting a combination of the propagation characteristics of the whisperinggallery modes and the effect of a graded index of refraction on the modes.

Optically triggered high voltage switch network and method for switching a high voltage

DOEpatents

El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Fiber optic spectroscopic digital imaging sensor and method for flame properties monitoring

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

Zelepouga, Serguei A; Rue, David M; Saveliev, Alexei V

2011-03-15

A system for real-time monitoring of flame properties in combustors and gasifiers which includes an imaging fiber optic bundle having a light receiving end and a light output end and a spectroscopic imaging system operably connected with the light output end of the imaging fiber optic bundle. Focusing of the light received by the light receiving end of the imaging fiber optic bundle by a wall disposed between the light receiving end of the fiber optic bundle and a light source, which wall forms a pinhole opening aligned with the light receiving end.

Recent progress in invariant pattern recognition

NASA Astrophysics Data System (ADS)

Arsenault, Henri H.; Chang, S.; Gagne, Philippe; Gualdron Gonzalez, Oscar

1996-12-01

We present some recent results in invariant pattern recognition, including methods that are invariant under two or more distortions of position, orientation and scale. There are now a few methods that yield good results under changes of both rotation and scale. Some new methods are introduced. These include locally adaptive nonlinear matched filters, scale-adapted wavelet transforms and invariant filters for disjoint noise. Methods using neural networks will also be discussed, including an optical method that allows simultaneous classification of multiple targets.

Optical Imaging of Ionizing Radiation from Clinical Sources

PubMed Central

Shaffer, Travis M.; Drain, Charles Michael

2016-01-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. PMID:27688469

Applications of Optical Microcavity Resonators in Analytical Chemistry

PubMed Central

Wade, James H.; Bailey, Ryan C.

2018-01-01

Optical resonator sensors are an emerging class of analytical technologies that use recirculating light confined within a microcavity to sensitively measure the surrounding environment. Bolstered by advances in microfabrication, these devices can be configured for a wide variety of chemical or biomolecular sensing applications. The review begins with a brief description of optical resonator sensor operation followed by discussions regarding sensor design, including different geometries, choices of material systems, methods of sensor interrogation, and new approaches to sensor operation. Throughout, key recent developments are highlighted, including advancements in biosensing and other applications of optical sensors. Alternative sensing mechanisms and hybrid sensing devices are then discussed in terms of their potential for more sensitive and rapid analyses. Brief concluding statements offer our perspective on the future of optical microcavity sensors and their promise as versatile detection elements within analytical chemistry. PMID:27049629

Optimization of x-ray capillary optics for mammography

NASA Astrophysics Data System (ADS)

Ross, Richard E.; Bradford, Carla D.; Peppler, Walter W.

2002-05-01

The purpose of this study is to develop a full-field digital mammography system utilizing capillary optics. Specific aims are to identify optic properties that affect image quality and to optimize those properties in the design of a multi-element capillary array. It has been shown that polycapillary optics significantly improve mammographic image quality through increased resolution and reduced x-ray scatter. For practical clinical application much larger multi-element optics will be required. This study quantified the contributing factors to the multi-element optic MTF and investigated methods to determine optimal parameters for a practical design. Individual and a prototype multi-element array of linearly tapered optics with a common focal point were investigated. A conventional (MO/MO) mammography tube and computed radiography system were used. The system and optic MTF were measured using the angled slit method with a slit camera (10 micron slit). MTF measurements were performed with both stationary and scanned optics. Contributions to MTF included: distortion within individual optics, misalignment between optics, capillary channel size, and vibration. Measurement techniques used to identify and quantify the contributions to optic MTF included a phantom chosen specifically for polycapillary optics. This phantom provided a method for assessing the coherence among capillaries within an optic as well as the relative alignment of the optics within the array. In addition, modifications to the scanning procedure allowed for the isolation and quantification of several contributors to the system MTF. Specifically, measurements were made using a stationary optic, a scanning optic, and an optic placed at multiple locations within the imaged field of view. These techniques yielded the optic MTF, the degradation of MTF due to loss of coherence within the optic, and the degradation of MTF due to vibration of the scanning mechanism. Distortion within individual optics was, typically, quite small. However, MTF degradation resulting from twist was significant in some optics. MTF degradation due to misalignment was relatively large in the prototype triad. Modeling found that misalignment up to 50 microns reduced MTF by less than 10 percent up to 3 cycles/mm. Channel diameters of 52 microns and 85 microns reduced MTF by 9 percent to 20 percent at 5 cycles/mm and provided an optimal tradeoff between transmission and MTF. Vibration was identified as a significant degradation to MTF but can easily reduced with simple modifications. In spite of some reduced optic MTF values, system MTF has always been significantly improved - in some cases almost by the magnification ratio. These results allow for accurate modeling of optic performance and optimization of design parameters. This study demonstrates that a multi-element array can be produced with nearly optimal properties. A large area array suitable for clinical trial is feasible and is the next step in this program.

Optical coherence tomography for the quantitative study of cerebrovascular physiology

PubMed Central

Srinivasan, Vivek J; Atochin, Dmitriy N; Radhakrishnan, Harsha; Jiang, James Y; Ruvinskaya, Svetlana; Wu, Weicheng; Barry, Scott; Cable, Alex E; Ayata, Cenk; Huang, Paul L; Boas, David A

2011-01-01

Doppler optical coherence tomography (DOCT) and OCT angiography are novel methods to investigate cerebrovascular physiology. In the rodent cortex, DOCT flow displays features characteristic of cerebral blood flow, including conservation along nonbranching vascular segments and at branch points. Moreover, DOCT flow values correlate with hydrogen clearance flow values when both are measured simultaneously. These data validate DOCT as a noninvasive quantitative method to measure tissue perfusion over a physiologic range. PMID:21364599

Method for in situ characterization of a medium of dispersed matter in a continuous phase

DOEpatents

Kaufman, Eric N.

1995-01-01

A method for in situ characterization of a medium of a dispersed phase in a continuous phase, including the steps of adding a fluorescent dye to one phase capable of producing fluorescence therein when the fluorescent dye is optically excited, optically exciting the fluorescent dye at a wavelength to produce fluorescence in the one phase, and monitoring the fluorescence to distinguish the continuous phase from the dispersed phase.

Analysis methods for polarization state and energy transmission of rays propagating in optical systems

NASA Astrophysics Data System (ADS)

Liu, Chao; Liu, Qiangsheng; Cen, Zhaofeng; Li, Xiaotong

2010-11-01

Polarization state of only completely polarized light can be analyzed by some software, ZEMAX for example. Based on principles of geometrical optics, novel descriptions of the light with different polarization state are provided in this paper. Differential calculus is well used for saving the polarization state and amplitudes of sampling rays when ray tracing. The polarization state changes are analyzed in terms of several typical circumstances, such as Brewster incidence, total reflection. Natural light and partially polarized light are discussed as an important aspect. Further more, a computing method including composition and decomposition of sampling rays at each surface is also set up to analyze the energy transmission of the rays for optical systems. Adopting these analysis methods mentioned, not only the polarization state changes of the incident rays can be obtained, but also the energy distributions can be calculated. Since the energy distributions are obtained, the surface with the most energy loss will be found in the optical system. The energy value and polarization state of light reaching the image surface will also be available. These analysis methods are very helpful for designing or analyzing optical systems, such as analyzing the energy of stray light in high power optical systems, researching the influences of optical surfaces to rays' polarization state in polarization imaging systems and so on.

Semiconductor optoelectronic devices for free-space optical communications

NASA Technical Reports Server (NTRS)

Katz, J.

1983-01-01

The properties of individual injection lasers are reviewed, and devices of greater complexity are described. These either include or are relevant to monolithic integration configurations of the lasers with their electronic driving circuitry, power combining methods of semiconductor lasers, and electronic methods of steering the radiation patterns of semiconductor lasers and laser arrays. The potential of AlGaAs laser technology for free-space optical communications systems is demonstrated. These solid-state components, which can generate and modulate light, combine the power of a number of sources and perform at least part of the beam pointing functions. Methods are proposed for overcoming the main drawback of semiconductor lasers, that is, their inability to emit the needed amount of optical power in a single-mode operation.

New biodiagnostics based on optical tweezers: typing red blood cells, and identification of drug resistant bacteria

NASA Astrophysics Data System (ADS)

Chen, Jia-Wen; Lin, Chuen-Fu; Wang, Shyang-Guang; Lee, Yi-Chieh; Chiang, Chung-Han; Huang, Min-Hui; Lee, Yi-Hsiung; Vitrant, Guy; Pan, Ming-Jeng; Lee, Horng-Mo; Liu, Yi-Jui; Baldeck, Patrice L.; Lin, Chih-Lang

2013-09-01

Measurements of optical tweezers forces on biological micro-objects can be used to develop innovative biodiagnostics methods. In the first part of this report, we present a new sensitive method to determine A, B, D types of red blood cells. Target antibodies are coated on glass surfaces. Optical forces needed to pull away RBC from the glass surface increase when RBC antigens interact with their corresponding antibodies. In this work, measurements of stripping optical forces are used to distinguish the major RBC types: group O Rh(+), group A Rh(+) and group B Rh(+). The sensitivity of the method is found to be at least 16-folds higher than the conventional agglutination method. In the second part of this report, we present an original way to measure in real time the wall thickness of bacteria that is one of the most important diagnostic parameters of bacteria drug resistance in hospital diagnostics. The optical tweezers force on a shell bacterium is proportional to its wall thickness. Experimentally, we determine the optical tweezers force applied on each bacteria family by measuring their escape velocity. Then, the wall thickness of shell bacteria can be obtained after calibrating with known bacteria parameters. The method has been successfully applied to indentify, from blind tests, Methicillinresistant Staphylococcus aureus (MRSA), including VSSA (NCTC 10442), VISA (Mu 50), and heto-VISA (Mu 3)

Dental Optical Coherence Tomography

PubMed Central

Hsieh, Yao-Sheng; Ho, Yi-Ching; Lee, Shyh-Yuan; Chuang, Ching-Cheng; Tsai, Jui-che; Lin, Kun-Feng; Sun, Chia-Wei

2013-01-01

This review paper describes the applications of dental optical coherence tomography (OCT) in oral tissue images, caries, periodontal disease and oral cancer. The background of OCT, including basic theory, system setup, light sources, spatial resolution and system limitations, is provided. The comparisons between OCT and other clinical oral diagnostic methods are also discussed. PMID:23857261

Using a Simple Optical Rangefinder To Teach Similar Triangles.

ERIC Educational Resources Information Center

Cuicchi, Paul M.; Hutchison, Paul S.

2003-01-01

Describes how the concept of similar triangles was taught using an optical method of estimating large distances as a corresponding activity. Includes the derivation of a formula to calculate one source of measurement error and is a nice exercise in the use of the properties of similar triangles. (Author/NB)

Metrological characterization methods for confocal chromatic line sensors and optical topography sensors

NASA Astrophysics Data System (ADS)

Seppä, Jeremias; Niemelä, Karri; Lassila, Antti

2018-05-01

The increasing use of chromatic confocal technology for, e.g. fast, in-line optical topography, and measuring thickness, roughness and profiles implies a need for the characterization of various aspects of the sensors. Single-point, line and matrix versions of chromatic confocal technology, encoding depth information into wavelength, have been developed. Of these, line sensors are particularly suitable for in-line process measurement. Metrological characterization and development of practical methods for calibration and checking is needed for new optical methods and devices. Compared to, e.g. tactile methods, optical topography measurement techniques have limitations related to light wavelength and coherence, optical properties of the sample including reflectivity, specularity, roughness and colour, and definition of optical versus mechanical surfaces. In this work, metrological characterization methods for optical line sensors were developed for scale magnification and linearity, sensitivity to sample properties, and dynamic characteristics. An accurate depth scale calibration method using a single prototype groove depth sample was developed for a line sensor and validated with laser-interferometric sample tracking, attaining (sub)micrometre level or better than 0.1% scale accuracy. Furthermore, the effect of different surfaces and materials on the measurement and depth scale was studied, in particular slope angle, specularity and colour. In addition, dynamic performance, noise, lateral scale and resolution were measured using the developed methods. In the case of the LCI1200 sensor used in this study, which has a 11.3 mm  ×  2.8 mm measurement range, the instrument depth scale was found to depend only minimally on sample colour, whereas measuring steeply sloped specular surfaces in the peripheral measurement area, in the worst case, caused a somewhat larger relative sample-dependent change (1%) in scale.

Optical microscope using an interferometric source of two-color, two-beam entangled photons

DOEpatents

Dress, William B.; Kisner, Roger A.; Richards, Roger K.

2004-07-13

Systems and methods are described for an optical microscope using an interferometric source of multi-color, multi-beam entangled photons. A method includes: downconverting a beam of coherent energy to provide a beam of multi-color entangled photons; converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; transforming at least a portion of the converged multi-color entangled photon beam by interaction with a sample to generate an entangled photon specimen beam; and combining the entangled photon specimen beam with an entangled photon reference beam within a single beamsplitter. An apparatus includes: a multi-refringent device providing a beam of multi-color entangled photons; a condenser device optically coupled to the multi-refringent device, the condenser device converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; a beam probe director and specimen assembly optically coupled to the condenser device; and a beam splitter optically coupled to the beam probe director and specimen assembly, the beam splitter combining an entangled photon specimen beam from the beam probe director and specimen assembly with an entangled photon reference beam.

Oxazine-based sensor for contaminant detection, fabrication method therefor, and uses thereof

DOEpatents

Nnanna, Agbai Agwu; Jalal, Ahmed Hasnian

2014-05-27

A sensor, a method for its fabrication, and a method for its use to detect contaminants, for example, ammonia, in stagnant and dynamic fluid media, especially liquid media. The sensor is an opto-chemical sensor that includes a polymer optical fiber, a sensing layer comprising oxazine 170 perchlorate on the polymer optical fiber, and a membrane layer on the sensing layer. The membrane layer is gas permeable and not permeable to the fluid in the fluid system, and moisture is entrapped by and between the sensing and membrane layers.

Concurrent application of TMS and near-infrared optical imaging: methodological considerations and potential artifacts

PubMed Central

Parks, Nathan A.

2013-01-01

The simultaneous application of transcranial magnetic stimulation (TMS) with non-invasive neuroimaging provides a powerful method for investigating functional connectivity in the human brain and the causal relationships between areas in distributed brain networks. TMS has been combined with numerous neuroimaging techniques including, electroencephalography (EEG), functional magnetic resonance imaging (fMRI), and positron emission tomography (PET). Recent work has also demonstrated the feasibility and utility of combining TMS with non-invasive near-infrared optical imaging techniques, functional near-infrared spectroscopy (fNIRS) and the event-related optical signal (EROS). Simultaneous TMS and optical imaging affords a number of advantages over other neuroimaging methods but also involves a unique set of methodological challenges and considerations. This paper describes the methodology of concurrently performing optical imaging during the administration of TMS, focusing on experimental design, potential artifacts, and approaches to controlling for these artifacts. PMID:24065911

Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material

PubMed Central

Meemon, Panomsak; Yao, Jianing; Lee, Kye-Sung; Thompson, Kevin P.; Ponting, Michael; Baer, Eric; Rolland, Jannick P.

2013-01-01

Gradient Refractive INdex (GRIN) optical components have historically fallen short of theoretical expectations. A recent breakthrough is the manufacturing of nanolayered spherical GRIN (S-GRIN) polymer optical elements, where the construction method yields refractive index gradients that exceed 0.08. Here we report on the application of optical coherence tomography (OCT), including micron-class axial and lateral resolution advances, as effective, innovative methods for performing nondestructive diagnostic metrology on S-GRIN. We show that OCT can be used to visualize and quantify characteristics of the material throughout the manufacturing process. Specifically, internal film structure may be revealed and data are processed to extract sub-surface profiles of each internal film of the material to quantify 3D film thickness and homogeneity. The technique provides direct feedback into the fabrication process directed at optimizing the quality of the nanolayered S-GRIN polymer optical components.

System and Method for Null-Lens Wavefront Sensing

NASA Technical Reports Server (NTRS)

Hill, Peter C. (Inventor); Thompson, Patrick L. (Inventor); Aronstein, David L. (Inventor); Bolcar, Matthew R. (Inventor); Smith, Jeffrey S. (Inventor)

2015-01-01

A method of measuring aberrations in a null-lens including assembly and alignment aberrations. The null-lens may be used for measuring aberrations in an aspheric optic with the null-lens. Light propagates from the aspheric optic location through the null-lens, while sweeping a detector through the null-lens focal plane. Image data being is collected at locations about said focal plane. Light is simulated propagating to the collection locations for each collected image. Null-lens aberrations may extracted, e.g., applying image-based wavefront-sensing to collected images and simulation results. The null-lens aberrations improve accuracy in measuring aspheric optic aberrations.

Service-oriented Software Defined Optical Networks for Cloud Computing

NASA Astrophysics Data System (ADS)

Liu, Yuze; Li, Hui; Ji, Yuefeng

2017-10-01

With the development of big data and cloud computing technology, the traditional software-defined network is facing new challenges (e.g., ubiquitous accessibility, higher bandwidth, more flexible management and greater security). This paper proposes a new service-oriented software defined optical network architecture, including a resource layer, a service abstract layer, a control layer and an application layer. We then dwell on the corresponding service providing method. Different service ID is used to identify the service a device can offer. Finally, we experimentally evaluate that proposed service providing method can be applied to transmit different services based on the service ID in the service-oriented software defined optical network.

Design and manufacturing methods for the integral field unit of the nirspec instrument on JWST

NASA Astrophysics Data System (ADS)

Lobb, Dan; Robertson, David

2017-11-01

An integral field unit, to be used with the near-IR spectrometer instrument of the James Webb Space Telescope (JWST), is currently under development by SSTL and CfAI. Special problems in design and manufacture of the optical system are outlined, and manufacturing methods for critical optical elements are discussed. The optical system is complex, requiring a total of 95 mirrors to produce 30 output channels. Emphasis is placed on the advantages of free-form machining in aluminium. These include: resistance to launch stress, insensitivity to temperature variations from ambient to cryogenic, and the possibility of relatively complex mirror surface shapes.

Optical Analog to Electromagnetically Induced Transparency in Cascaded Ring-Resonator Systems.

PubMed

Wang, Yonghua; Zheng, Hua; Xue, Chenyang; Zhang, Wendong

2016-07-25

The analogue of electromagnetically induced transparency in optical methods has shown great potential in slow light and sensing applications. Here, we experimentally demonstrated a coupled resonator induced transparency system with three cascaded ring coupled resonators in a silicon chip. The structure was modeled by using the transfer matrix method. Influences of various parameters including coupling ratio of couplers, waveguide loss and additional loss of couplers on transmission characteristic and group index have been investigated theoretically and numerically in detail. The transmission character of the system was measured by the vertical grating coupling method. The enhanced quality factor reached 1.22 × 10⁵. In addition, we further test the temperature performance of the device. The results provide a new method for the manipulation of light in highly integrated optical circuits and sensing applications.

Nanocrystal waveguide (NOW) laser

DOEpatents

Simpson, John T.; Simpson, Marcus L.; Withrow, Stephen P.; White, Clark W.; Jaiswal, Supriya L.

2005-02-08

A solid state laser includes an optical waveguide and a laser cavity including at least one subwavelength mirror disposed in or on the optical waveguide. A plurality of photoluminescent nanocrystals are disposed in the laser cavity. The reflective subwavelength mirror can be a pair of subwavelength resonant gratings (SWG), a pair of photonic crystal structures (PC), or a distributed feedback structure. In the case of a pair of mirrors, a PC which is substantially transmissive at an operating wavelength of the laser can be disposed in the laser cavity between the subwavelength mirrors to improve the mode structure, coherence and overall efficiency of the laser. A method for forming a solid state laser includes the steps of providing an optical waveguide, creating a laser cavity in the optical waveguide by disposing at least one subwavelength mirror on or in the waveguide, and positioning a plurality of photoluminescent nanocrystals in the laser cavity.

Localization microscopy of DNA in situ using Vybrant{sup ®} DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single molecule resolution

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

Żurek-Biesiada, Dominika; Szczurek, Aleksander T.; Prakash, Kirti

Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant{sup ®} DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of DNA in nuclei ofmore » fixed mammalian cells. This SMLM method enabled optical isolation and localization of large numbers of DNA-bound molecules, usually in excess of 10{sup 6} signals in one cell nucleus. The technique yielded high-quality images of nuclear DNA density, revealing subdiffraction chromatin structures of the size in the order of 100 nm; the interchromatin compartment was visualized at unprecedented optical resolution. The approach offers several advantages over previously described high resolution DNA imaging methods, including high specificity, an ability to record images using a single wavelength excitation, and a higher density of single molecule signals than reported in previous SMLM studies. The method is compatible with DNA/multicolor SMLM imaging which employs simple staining methods suited also for conventional optical microscopy. - Highlights: • Super-resolution imaging of nuclear DNA with Vybrant Violet and blue excitation. • 90nm resolution images of DNA structures in optically thick eukaryotic nuclei. • Enhanced resolution confirms the existence of DNA-free regions inside the nucleus. • Optimized imaging conditions enable multicolor super-resolution imaging.« less

Diagnostic apparatus and method for use in the alignment of one or more laser means onto a fiber optics interface

DOEpatents

Johnson, Steve A.; Shannon, Robert R.

1987-01-01

Diagnostic apparatus for use in determining the proper alignment of a plurality of laser beams onto a fiber optics interface is disclosed. The apparatus includes a lens assembly which serves two functions, first to focus a plurality of laser beams onto the fiber optics interface, and secondly to reflect and image the interface using scattered light to a monitor means. The monitor means permits indirect observation of the alignment or focusing of the laser beams onto the fiber optics interface.

High-temperature fiber optic pressure sensor

NASA Technical Reports Server (NTRS)

Berthold, J. W.

1984-01-01

Attention is given to a program to develop fiber optic methods to measure diaphragm deflection. The end application is intended for pressure transducers capable of operating to 540 C. In this paper are reported the results of a laboratory study to characterize the performance of the fiber-optic microbend sensor. The data presented include sensitivity and spring constant. The advantages and limitations of the microbend sensor for static pressure measurement applications are described. A proposed design is presented for a 540 C pressure transducer using the fiber optic microbend sensor.

Diagnostic apparatus and method for use in the alignment of one or more laser means onto a fiber optics interface

DOEpatents

Johnson, S.A.; Shannon, R.R.

1985-01-18

Diagnostic apparatus for use in determining the proper alignment of a plurality of laser beams onto a fiber optics interface is disclosed. The apparatus includes a lens assembly which serves two functions, first to focus a plurality of laser beams onto the fiber optics interface, and secondly to reflect and image the interface using scattered light to a monitor means. The monitor means permits indirect observation of the alignment or focusing of the laser beams onto the fiber optics interface.

Optical forces, torques, and force densities calculated at a microscopic level using a self-consistent hydrodynamics method

NASA Astrophysics Data System (ADS)

Ding, Kun; Chan, C. T.

2018-04-01

The calculation of optical force density distribution inside a material is challenging at the nanoscale, where quantum and nonlocal effects emerge and macroscopic parameters such as permittivity become ill-defined. We demonstrate that the microscopic optical force density of nanoplasmonic systems can be defined and calculated using the microscopic fields generated using a self-consistent hydrodynamics model that includes quantum, nonlocal, and retardation effects. We demonstrate this technique by calculating the microscopic optical force density distributions and the optical binding force induced by external light on nanoplasmonic dimers. This approach works even in the limit when the nanoparticles are close enough to each other so that electron tunneling occurs, a regime in which classical electromagnetic approach fails completely. We discover that an uneven distribution of optical force density can lead to a light-induced spinning torque acting on individual particles. The hydrodynamics method offers us an accurate and efficient approach to study optomechanical behavior for plasmonic systems at the nanoscale.

An Optical Actuation System and Curvature Sensor for a MR-compatible Active Needle

PubMed Central

Ryu, Seok Chang; Quek, Zhan Fan; Renaud, Pierre; Black, Richard J.; Daniel, Bruce L.; Cutkosky, Mark R.

2015-01-01

A side optical actuation method is presented for a slender MR-compatible active needle. The needle includes an active region with a shape memory alloy (SMA) wire actuator, where the wire generates a contraction force when optically heated by a laser delivered though optical fibers, producing needle tip bending. A prototype, with multiple side heating spots, demonstrates twice as fast an initial response compared to fiber tip heating when 0.8 W of optical power is applied. A single-ended optical sensor with a gold reflector is also presented to measure the curvature as a function of optical transmission loss. Preliminary tests with the sensor prototype demonstrate approximately linear response and a repeatable signal, independent of the bending history. PMID:26509099

WaferOptics® mass volume production and reliability

NASA Astrophysics Data System (ADS)

Wolterink, E.; Demeyer, K.

2010-05-01

The Anteryon WaferOptics® Technology platform contains imaging optics designs, materials, metrologies and combined with wafer level based Semicon & MEMS production methods. WaferOptics® first required complete new system engineering. This system closes the loop between application requirement specifications, Anteryon product specification, Monte Carlo Analysis, process windows, process controls and supply reject criteria. Regarding the Anteryon product Integrated Lens Stack (ILS), new design rules, test methods and control systems were assessed, implemented, validated and customer released for mass production. This includes novel reflowable materials, mastering process, replication, bonding, dicing, assembly, metrology, reliability programs and quality assurance systems. Many of Design of Experiments were performed to assess correlations between optical performance parameters and machine settings of all process steps. Lens metrologies such as FFL, BFL, and MTF were adapted for wafer level production and wafer mapping was introduced for yield management. Test methods for screening and validating suitable optical materials were designed. Critical failure modes such as delamination and popcorning were assessed and modeled with FEM. Anteryon successfully managed to integrate the different technologies starting from single prototypes to high yield mass volume production These parallel efforts resulted in a steep yield increase from 30% to over 90% in a 8 months period.

Human brain activity with functional NIR optical imager

NASA Astrophysics Data System (ADS)

Luo, Qingming

2001-08-01

In this paper we reviewed the applications of functional near infrared optical imager in human brain activity. Optical imaging results of brain activity, including memory for new association, emotional thinking, mental arithmetic, pattern recognition ' where's Waldo?, occipital cortex in visual stimulation, and motor cortex in finger tapping, are demonstrated. It is shown that the NIR optical method opens up new fields of study of the human population, in adults under conditions of simulated or real stress that may have important effects upon functional performance. It makes practical and affordable for large populations the complex technology of measuring brain function. It is portable and low cost. In cognitive tasks subjects could report orally. The temporal resolution could be millisecond or less in theory. NIR method will have good prospects in exploring human brain secret.

Comparisons between real and complex Gauss wavelet transform methods of three-dimensional shape reconstruction

NASA Astrophysics Data System (ADS)

Xu, Luopeng; Dan, Youquan; Wang, Qingyuan

2015-10-01

The continuous wavelet transform (CWT) introduces an expandable spatial and frequency window which can overcome the inferiority of localization characteristic in Fourier transform and windowed Fourier transform. The CWT method is widely applied in the non-stationary signal analysis field including optical 3D shape reconstruction with remarkable performance. In optical 3D surface measurement, the performance of CWT for optical fringe pattern phase reconstruction usually depends on the choice of wavelet function. A large kind of wavelet functions of CWT, such as Mexican Hat wavelet, Morlet wavelet, DOG wavelet, Gabor wavelet and so on, can be generated from Gauss wavelet function. However, so far, application of the Gauss wavelet transform (GWT) method (i.e. CWT with Gauss wavelet function) in optical profilometry is few reported. In this paper, the method using GWT for optical fringe pattern phase reconstruction is presented first and the comparisons between real and complex GWT methods are discussed in detail. The examples of numerical simulations are also given and analyzed. The results show that both the real GWT method along with a Hilbert transform and the complex GWT method can realize three-dimensional surface reconstruction; and the performance of reconstruction generally depends on the frequency domain appearance of Gauss wavelet functions. For the case of optical fringe pattern of large phase variation with position, the performance of real GWT is better than that of complex one due to complex Gauss series wavelets existing frequency sidelobes. Finally, the experiments are carried out and the experimental results agree well with our theoretical analysis.

Panoramic Augmented Reality for Persistence of Information in Counterinsurgency Environments (PARPICE)

DTIC Science & Technology

2010-12-01

including thermal optics  Much more precise target engagement and stabilization method Drawbacks  Mechanical malfunctions more common  Gunner has...complete panorama view that extends from 0–180 degrees off-center, from our camera system. Figure 20 360° view dome projection Figure 21 shows the...method can incorporate various types of synthetic vision aids, such as thermal or electro-optical sensors, to give the user the capability to see in

Localization microscopy of DNA in situ using Vybrant(®) DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single molecule resolution.

PubMed

Żurek-Biesiada, Dominika; Szczurek, Aleksander T; Prakash, Kirti; Mohana, Giriram K; Lee, Hyun-Keun; Roignant, Jean-Yves; Birk, Udo J; Dobrucki, Jurek W; Cremer, Christoph

2016-05-01

Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant(®) DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of DNA in nuclei of fixed mammalian cells. This SMLM method enabled optical isolation and localization of large numbers of DNA-bound molecules, usually in excess of 10(6) signals in one cell nucleus. The technique yielded high-quality images of nuclear DNA density, revealing subdiffraction chromatin structures of the size in the order of 100nm; the interchromatin compartment was visualized at unprecedented optical resolution. The approach offers several advantages over previously described high resolution DNA imaging methods, including high specificity, an ability to record images using a single wavelength excitation, and a higher density of single molecule signals than reported in previous SMLM studies. The method is compatible with DNA/multicolor SMLM imaging which employs simple staining methods suited also for conventional optical microscopy. Copyright © 2016. Published by Elsevier Inc.

Optical stress generator and detector

DOEpatents

Maris, Humphrey J.; Stoner, Robert J

2001-01-01

Disclosed is a system for the characterization of thin films and interfaces between thin films through measurements of their mechanical and thermal properties. In the system light is absorbed in a thin film or in a structure made up of several thin films, and the change in optical transmission or reflection is measured and analyzed. The change in reflection or transmission is used to give information about the ultrasonic waves that are produced in the structure. The information that is obtained from the use of the measurement methods and apparatus of this invention can include: (a) a determination of the thickness of thin films with a speed and accuracy that is improved compared to earlier methods; (b) a determination of the thermal, elastic, and optical properties of thin films; (c) a determination of the stress in thin films; and (d) a characterization of the properties of interfaces, including the presence of roughness and defects.

Optical stress generator and detector

DOEpatents

Maris, Humphrey J.; Stoner, Robert J.

1998-01-01

Disclosed is a system for the characterization of thin films and interfaces between thin films through measurements of their mechanical and thermal properties. In the system light is absorbed in a thin film or in a structure made up of several thin films, and the change in optical transmission or reflection is measured and analyzed. The change in reflection or transmission is used to give information about the ultrasonic waves that are produced in the structure. The information that is obtained from the use of the measurement methods and apparatus of this invention can include: (a) a determination of the thickness of thin films with a speed and accuracy that is improved compared to earlier methods; (b) a determination of the thermal, elastic, and optical properties of thin films; (c) a determination of the stress in thin films; and (d) a characterization of the properties of interfaces, including the presence of roughness and defects.

Optical stress generator and detector

DOEpatents

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

1998-05-05

Disclosed is a system for the characterization of thin films and interfaces between thin films through measurements of their mechanical and thermal properties. In the system light is absorbed in a thin film or in a structure made up of several thin films, and the change in optical transmission or reflection is measured and analyzed. The change in reflection or transmission is used to give information about the ultrasonic waves that are produced in the structure. The information that is obtained from the use of the measurement methods and apparatus of this invention can include: (a) a determination of the thickness of thin films with a speed and accuracy that is improved compared to earlier methods; (b) a determination of the thermal, elastic, and optical properties of thin films; (c) a determination of the stress in thin films; and (d) a characterization of the properties of interfaces, including the presence of roughness and defects. 32 figs.

Optical stress generator and detector

DOEpatents

Maris, Humphrey J.; Stoner, Robert J

2002-01-01

Disclosed is a system for the characterization of thin films and interfaces between thin films through measurements of their mechanical and thermal properties. In the system light is absorbed in a thin film or in a structure made up of several thin films, and the change in optical transmission or reflection is measured and analyzed. The change in reflection or transmission is used to give information about the ultrasonic waves that are produced in the structure. The information that is obtained from the use of the measurement methods and apparatus of this invention can include: (a) a determination of the thickness of thin films with a speed and accuracy that is improved compared to earlier methods; (b) a determination of the thermal, elastic, and optical properties of thin films; (c) a determination of the stress in thin films; and (d) a characterization of the properties of interfaces, including the presence of roughness and defects.

Optical stress generator and detector

DOEpatents

Maris, Humphrey J.; Stoner, Robert J

1999-01-01

Disclosed is a system for the characterization of thin films and interfaces between thin films through measurements of their mechanical and thermal properties. In the system light is absorbed in a thin film or in a structure made up of several thin films, and the change in optical transmission or reflection is measured and analyzed. The change in reflection or transmission is used to give information about the ultrasonic waves that are produced in the structure. The information that is obtained from the use of the measurement methods and apparatus of this invention can include: (a) a determination of the thickness of thin films with a speed and accuracy that is improved compared to earlier methods; (b) a determination of the thermal, elastic, and optical properties of thin films; (c) a determination of the stress in thin films; and (d) a characterization of the properties of interfaces, including the presence of roughness and defects.

Methods and systems for detecting gas flow by photoacoustic signal generation

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

Choudhury, Niloy; Challener, William Albert

A method for the detection of a gas flowing from a location in a structure is described. A hollow-core optical fiber is placed in a position adjacent the structure. The fiber includes a sound-conductive cladding layer; and further includes at least one aperture extending into its cross-sectional diameter. A beam of pulsed, optical is transmitted into the fiber with a tunable laser. The optical energy is characterized by a wavelength that can be absorbed by the gas that flows into the fiber through the aperture. This causes a temperature fluctuation in the region of gas absorption, which in turn generatesmore » an acoustic wave in the absorption region. The acoustic wave travels through the cladding layer, and can be detected with a microphone, so as to provide the location of gas flow, based on the recorded position and movement of the acoustic wave. A related system is also described.« less

Method and apparatus for shape and end position determination using an optical fiber

NASA Technical Reports Server (NTRS)

Moore, Jason P. (Inventor)

2010-01-01

A method of determining the shape of an unbound optical fiber includes collecting strain data along a length of the fiber, calculating curvature and bending direction data of the fiber using the strain data, curve-fitting the curvature and bending direction data to derive curvature and bending direction functions, calculating a torsion function using the bending direction function, and determining the 3D shape from the curvature, bending direction, and torsion functions. An apparatus for determining the 3D shape of the fiber includes a fiber optic cable unbound with respect to a protective sleeve, strain sensors positioned along the cable, and a controller in communication with the sensors. The controller has an algorithm for determining a 3D shape and end position of the fiber by calculating a set of curvature and bending direction data, deriving curvature, bending, and torsion functions, and solving Frenet-Serret equations using these functions.

Optical proximity correction for anamorphic extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

Clifford, Chris; Lam, Michael; Raghunathan, Ananthan; Jiang, Fan; Fenger, Germain; Adam, Kostas

2017-10-01

The change from isomorphic to anamorphic optics in high numerical aperture extreme ultraviolet scanners necessitates changes to the mask data preparation flow. The required changes for each step in the mask tape out process are discussed, with a focus on optical proximity correction (OPC). When necessary, solutions to new problems are demonstrated and verified by rigorous simulation. Additions to the OPC model include accounting for anamorphic effects in the optics, mask electromagnetics, and mask manufacturing. The correction algorithm is updated to include awareness of anamorphic mask geometry for mask rule checking. OPC verification through process window conditions is enhanced to test different wafer scale mask error ranges in the horizontal and vertical directions. This work will show that existing models and methods can be updated to support anamorphic optics without major changes. Also, the larger mask size in the Y direction can result in better model accuracy, easier OPC convergence, and designs that are more tolerant to mask errors.

Optical Imaging of Ionizing Radiation from Clinical Sources.

PubMed

Shaffer, Travis M; Drain, Charles Michael; Grimm, Jan

2016-11-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Design and evaluation of a freeform lens by using a method of luminous intensity mapping and a differential equation

NASA Astrophysics Data System (ADS)

Essameldin, Mahmoud; Fleischmann, Friedrich; Henning, Thomas; Lang, Walter

2017-02-01

Freeform optical systems are playing an important role in the field of illumination engineering for redistributing the light intensity, because of its capability of achieving accurate and efficient results. The authors have presented the basic idea of the freeform lens design method at the 117th annual meeting of the German Society of Applied Optics (DGAOProceedings). Now, we demonstrate the feasibility of the design method by designing and evaluating a freeform lens. The concepts of luminous intensity mapping, energy conservation and differential equation are combined in designing a lens for non-imaging applications. The required procedures to design a lens including the simulations are explained in detail. The optical performance is investigated by using a numerical simulation of optical ray tracing. For evaluation, the results are compared with another recently published design method, showing the accurate performance of the proposed method using a reduced number of mapping angles. As a part of the tolerance analyses of the fabrication processes, the influence of the light source misalignments (translation and orientation) on the beam-shaping performance is presented. Finally, the importance of considering the extended light source while designing a freeform lens using the proposed method is discussed.

Optical Metrology for the Segmented Optics on the Constellation-X Spectroscopy X-Ray Telescope

NASA Technical Reports Server (NTRS)

Content, David; Colella, David; Fleetwood, Charles; Hadjimichael, Theo; Lehan, John; McMann, Joseph; Reid, Paul; Saha, Timo; Wright, Geraldine; Zhang, William

2004-01-01

We present the metrology requirements and metrology implementation necessary to prove out the reflector technology for the Constellation X(C-X) spectroscopy X-ray telescope (SXT). This segmented, 1.6m diameter highly nested Wolter-1 telescope presents many metrology and alignment challenges. In particular, these mirrors have a stringent imaging error budget as compared to their intrinsic stiffness; This is required for Constellation-X to have sufficient effective area with the weight requirement. This has implications for the metrology that can be used. A variety of contract and noncontact optical profiling and interferometric methods are combined to test the formed glass substrates before replication and the replicated reflector segments.The reflectors are tested both stand-alone and in-situ in an alignment tower.Some of these methods have not been used on prior X-ray telescopes and some are feasible only because of the segmented approach used on the SXT. Methods discussed include high precision coordinate measurement machines using very low force or optical probe axial interferometric profiling azimuthal circularity profiling and use of advanced null optics such as conical computer generated hologram (CGHs).

Study of optical techniques for the Ames unitary wind tunnel, part 7

NASA Technical Reports Server (NTRS)

Lee, George

1993-01-01

A summary of optical techniques for the Ames Unitary Plan wind tunnels are discussed. Six optical techniques were studied: Schlieren, light sheet and laser vapor screen, angle of attack, model deformation, infrared imagery, and digital image processing. The study includes surveys and reviews of wind tunnel optical techniques, some conceptual designs, and recommendations for use of optical methods in the Ames Unitary Plan wind tunnels. Particular emphasis was placed on searching for systems developed for wind tunnel use and on commercial systems which could be readily adapted for wind tunnels. This final report is to summarize the major results and recommendations.

Calculation of the force acting on a micro-sized particle with optical vortex array laser beam tweezers

NASA Astrophysics Data System (ADS)

Kuo, Chun-Fu; Chu, Shu-Chun

2013-03-01

Optical vortices possess several special properties, including carrying optical angular momentum (OAM) and exhibiting zero intensity. Vortex array laser beams have attracts many interests due to its special mesh field distributions, which show great potential in the application of multiple optical traps and dark optical traps. Previously study developed an Ince-Gaussian Mode (IGM)-based vortex array laser beam1. This study develops a simulation model based on the discrete dipole approximation (DDA) method for calculating the resultant force acting on a micro-sized spherical dielectric particle that situated at the beam waist of the IGM-based vortex array laser beams1.

Optically stimulated differential impedance spectroscopy

DOEpatents

Maxey, Lonnie C; Parks, II, James E; Lewis, Sr., Samuel A; Partridge, Jr., William P

2014-02-18

Methods and apparatuses for evaluating a material are described. Embodiments typically involve use of an impedance measurement sensor to measure the impedance of a sample of the material under at least two different states of illumination. The states of illumination may include (a) substantially no optical stimulation, (b) substantial optical stimulation, (c) optical stimulation at a first wavelength of light, (d) optical stimulation at a second wavelength of light, (e) a first level of light intensity, and (f) a second level of light intensity. Typically a difference in impedance between the impedance of the sample at the two states of illumination is measured to determine a characteristic of the material.

Quantitative Image Recovery From Measured Blind Backscattered Data Using a Globally Convergent Inverse Method

DTIC Science & Technology

2012-01-01

research interests include in- 794 verse problems related to superresolution imaging and metamaterial design. 795 Dr. Fiddy is a Fellow of the Optical...verse problems related to superresolution imaging and metamaterial design. 795 Dr. Fiddy is a Fellow of the Optical Society of America, the IOP, and The

Review of optical breast imaging and spectroscopy

NASA Astrophysics Data System (ADS)

Grosenick, Dirk; Rinneberg, Herbert; Cubeddu, Rinaldo; Taroni, Paola

2016-09-01

Diffuse optical imaging and spectroscopy of the female breast is an area of active research. We review the present status of this field and discuss the broad range of methodologies and applications. Starting with a brief overview on breast physiology, the remodeling of vasculature and extracellular matrix caused by solid tumors is highlighted that is relevant for contrast in optical imaging. Then, the various instrumental techniques and the related methods of data analysis and image generation are described and compared including multimodality instrumentation, fluorescence mammography, broadband spectroscopy, and diffuse correlation spectroscopy. We review the clinical results on functional properties of malignant and benign breast lesions compared to host tissue and discuss the various methods to improve contrast between healthy and diseased tissue, such as enhanced spectroscopic information, dynamic variations of functional properties, pharmacokinetics of extrinsic contrast agents, including the enhanced permeability and retention effect. We discuss research on monitoring neoadjuvant chemotherapy and on breast cancer risk assessment as potential clinical applications of optical breast imaging and spectroscopy. Moreover, we consider new experimental approaches, such as photoacoustic imaging and long-wavelength tissue spectroscopy.

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.

Current developments in optical engineering and diffraction phenomena; Proceedings of the Meeting, San Diego, CA, Aug. 21, 22, 1986

NASA Astrophysics Data System (ADS)

Fischer, Robert E.; Smith, Warren J.; Harvey, James

1986-01-01

Papers dealing with current materials for gradient-index optics, an intelligent data-base system for optical designers; tilted mirror systems; a null-lens design approach for centrally obscured components; the use of the vector aberration theory to optimize an unobscured optical system; multizone bifocal contact lens design; and the concentric meniscus element are presented. Topics discussed include optical manufacturing in the Far East; the optical performance of molded-glass lenses for optical memory applications; through-wafer optical interconnects for multiwafer wafer-scale integrated architecture; optical thin-flim monitoring using optical fibers; aerooptical testing; optical inspection; and a system analysis program for a 32K microcomputer. Consideration is given to various theories, algorithms, and applications of diffraction, a vector formulation of a ray-equivalent method for Gaussian beam propagation; Fourier optical analysis of aberrations in focused laser beams; holography and moire interferometry; and phase-conjugate optical correctors for diffraction-limited applications.

Method and system for edge cladding of laser gain media

DOEpatents

Bayramian, Andrew James; Caird, John Allyn; Schaffers, Kathleen Irene

2014-03-25

A gain medium operable to amplify light at a gain wavelength and having reduced transverse ASE includes an input surface and an output surface opposing the input surface. The gain medium also includes a central region including gain material and extending between the input surface and the output surface along a longitudinal optical axis of the gain medium. The gain medium further includes an edge cladding region surrounding the central region and extending between the input surface and the output surface along the longitudinal optical axis of the gain medium. The edge cladding region includes the gain material and a dopant operable to absorb light at the gain wavelength.

Optical diagnostics integrated with laser spark delivery system

DOEpatents

Yalin, Azer [Fort Collins, CO; Willson, Bryan [Fort Collins, CO; Defoort, Morgan [Fort Collins, CO; Joshi, Sachin [Fort Collins, CO; Reynolds, Adam [Fort Collins, CO

2008-09-02

A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

Fiber laser coupled optical spark delivery system

DOEpatents

Yalin, Azer [Fort Collins, CO; Willson, Bryan [Fort Collins, CO; Defoort, Morgan [Fort Collins, CO; Joshi, Sachin [Fort Collins, CO; Reynolds, Adam [Fort Collins, CO

2008-03-04

A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

Crack Propagation Calculations for Optical Fibers under Static Bending and Tensile Loads Using Continuum Damage Mechanics

PubMed Central

Chen, Yunxia; Cui, Yuxuan; Gong, Wenjun

2017-01-01

Static fatigue behavior is the main failure mode of optical fibers applied in sensors. In this paper, a computational framework based on continuum damage mechanics (CDM) is presented to calculate the crack propagation process and failure time of optical fibers subjected to static bending and tensile loads. For this purpose, the static fatigue crack propagation in the glass core of the optical fiber is studied. Combining a finite element method (FEM), we use the continuum damage mechanics for the glass core to calculate the crack propagation path and corresponding failure time. In addition, three factors including bending radius, tensile force and optical fiber diameter are investigated to find their impacts on the crack propagation process and failure time of the optical fiber under concerned situations. Finally, experiments are conducted and the results verify the correctness of the simulation calculation. It is believed that the proposed method could give a straightforward description of the crack propagation path in the inner glass core. Additionally, the predicted crack propagation time of the optical fiber with different factors can provide effective suggestions for improving the long-term usage of optical fibers. PMID:29140284

Covert laser remote sensing and vibrometry

NASA Technical Reports Server (NTRS)

Maleki, Lutfollah (Inventor); Yu, Nan (Inventor); Matsko, Andrey B. (Inventor); Savchenkov, Anatoliy (Inventor)

2012-01-01

Designs of single-beam laser vibrometry systems and methods. For example, a method for detecting vibrations of a target based on optical sensing is provided to include operating a laser to produce a laser probe beam at a laser frequency and modulated at a modulation frequency onto a target; collecting light at or near the laser to collect light from the target while the target is being illuminated by the laser probe beam through an optical receiver aperture; using a narrow-band optical filter centered at the laser frequency to filter light collected from the optical receiver aperture to transmit light at the laser frequency while blocking light at other frequencies; using an optical detector to convert filtered light from the narrow-band optical filter to produce a receiver electrical signal; using a lock-in amplifier to detect and amplify the receiver electrical signal at the modulation frequency while rejecting signal components at other frequencies to produce an amplified receiver electrical signal; processing the amplified receiver electrical signal to extract information on vibrations of the target carried by reflected laser probe beam in the collected light; and controlling optical power of the laser probe beam at the target to follow optical power of background illumination at the target.

Optimal Filter Estimation for Lucas-Kanade Optical Flow

PubMed Central

Sharmin, Nusrat; Brad, Remus

2012-01-01

Optical flow algorithms offer a way to estimate motion from a sequence of images. The computation of optical flow plays a key-role in several computer vision applications, including motion detection and segmentation, frame interpolation, three-dimensional scene reconstruction, robot navigation and video compression. In the case of gradient based optical flow implementation, the pre-filtering step plays a vital role, not only for accurate computation of optical flow, but also for the improvement of performance. Generally, in optical flow computation, filtering is used at the initial level on original input images and afterwards, the images are resized. In this paper, we propose an image filtering approach as a pre-processing step for the Lucas-Kanade pyramidal optical flow algorithm. Based on a study of different types of filtering methods and applied on the Iterative Refined Lucas-Kanade, we have concluded on the best filtering practice. As the Gaussian smoothing filter was selected, an empirical approach for the Gaussian variance estimation was introduced. Tested on the Middlebury image sequences, a correlation between the image intensity value and the standard deviation value of the Gaussian function was established. Finally, we have found that our selection method offers a better performance for the Lucas-Kanade optical flow algorithm.

Crack Propagation Calculations for Optical Fibers under Static Bending and Tensile Loads Using Continuum Damage Mechanics.

PubMed

Chen, Yunxia; Cui, Yuxuan; Gong, Wenjun

2017-11-15

Static fatigue behavior is the main failure mode of optical fibers applied in sensors. In this paper, a computational framework based on continuum damage mechanics (CDM) is presented to calculate the crack propagation process and failure time of optical fibers subjected to static bending and tensile loads. For this purpose, the static fatigue crack propagation in the glass core of the optical fiber is studied. Combining a finite element method (FEM), we use the continuum damage mechanics for the glass core to calculate the crack propagation path and corresponding failure time. In addition, three factors including bending radius, tensile force and optical fiber diameter are investigated to find their impacts on the crack propagation process and failure time of the optical fiber under concerned situations. Finally, experiments are conducted and the results verify the correctness of the simulation calculation. It is believed that the proposed method could give a straightforward description of the crack propagation path in the inner glass core. Additionally, the predicted crack propagation time of the optical fiber with different factors can provide effective suggestions for improving the long-term usage of optical fibers.

Micro-optical fabrication by ultraprecision diamond machining and precision molding

NASA Astrophysics Data System (ADS)

Li, Hui; Li, Likai; Naples, Neil J.; Roblee, Jeffrey W.; Yi, Allen Y.

2017-06-01

Ultraprecision diamond machining and high volume molding for affordable high precision high performance optical elements are becoming a viable process in optical industry for low cost high quality microoptical component manufacturing. In this process, first high precision microoptical molds are fabricated using ultraprecision single point diamond machining followed by high volume production methods such as compression or injection molding. In the last two decades, there have been steady improvements in ultraprecision machine design and performance, particularly with the introduction of both slow tool and fast tool servo. Today optical molds, including freeform surfaces and microlens arrays, are routinely diamond machined to final finish without post machining polishing. For consumers, compression molding or injection molding provide efficient and high quality optics at extremely low cost. In this paper, first ultraprecision machine design and machining processes such as slow tool and fast too servo are described then both compression molding and injection molding of polymer optics are discussed. To implement precision optical manufacturing by molding, numerical modeling can be included in the future as a critical part of the manufacturing process to ensure high product quality.

On Applications of Disruption Tolerant Networking to Optical Networking in Space

NASA Technical Reports Server (NTRS)

Hylton, Alan Guy; Raible, Daniel E.; Juergens, Jeffrey; Iannicca, Dennis

2012-01-01

The integration of optical communication links into space networks via Disruption Tolerant Networking (DTN) is a largely unexplored area of research. Building on successful foundational work accomplished at JPL, we discuss a multi-hop multi-path network featuring optical links. The experimental test bed is constructed at the NASA Glenn Research Center featuring multiple Ethernet-to-fiber converters coupled with free space optical (FSO) communication channels. The test bed architecture models communication paths from deployed Mars assets to the deep space network (DSN) and finally to the mission operations center (MOC). Reliable versus unreliable communication methods are investigated and discussed; including reliable transport protocols, custody transfer, and fragmentation. Potential commercial applications may include an optical communications infrastructure deployment to support developing nations and remote areas, which are unburdened with supporting an existing heritage means of telecommunications. Narrow laser beam widths and control of polarization states offer inherent physical layer security benefits with optical communications over RF solutions. This paper explores whether or not DTN is appropriate for space-based optical networks, optimal payload sizes, reliability, and a discussion on security.

Remote atmospheric probing by ground to ground line of sight optical methods

NASA Technical Reports Server (NTRS)

Lawrence, R. S.

1969-01-01

The optical effects arising from refractive-index variations in the clear air are qualitatively described, and the possibilities are discussed of using those effects for remotely sensing the physical properties of the atmosphere. The effects include scintillations, path length fluctuations, spreading of a laser beam, deflection of the beam, and depolarization. The physical properties that may be measured include the average temperature along the path, the vertical temperature gradient, and the distribution along the path of the strength of turbulence and the transverse wind velocity. Line-of-sight laser beam methods are clearly effective in measuring the average properties, but less effective in measuring distributions along the path. Fundamental limitations to the resolution are pointed out and experiments are recommended to investigate the practicality of the methods.

Experimental and first principle study of the structure, electronic, optical and luminescence properties of M-type GdNbO4 phosphor

NASA Astrophysics Data System (ADS)

Ding, Shoujun; Zhang, Haotian; Zhang, Qingli; Chen, Yuanzhi; Dou, Renqin; Peng, Fang; Liu, Wenpeng; Sun, Dunlu

2018-06-01

In this work, GdNbO4 polycrystalline with monoclinic phase was prepared by traditional high-temperature solid-state reaction. Its structure was determined by X-ray diffraction and its unit cell parameters were obtained with Rietveld refinement method. Its luminescence properties (including absorbance, emission and luminescence lifetime) were investigated with experiment method and the CIE chromaticity coordinate was presented. Furthermore, a systematic theoretical calculation (including band gap, density of states and optical properties) based on the density function theory methods was performed on GdNbO4. Lastly, a comparison between experiment and calculated results was conducted. The calculated and experiment results obtained in this work can provide an essential understanding of GdNbO4 material.

Methods and apparatus for measurement of a dimensional characteristic and methods of predictive modeling related thereto

DOEpatents

Robertson, Eric P [Idaho Falls, ID; Christiansen, Richard L [Littleton, CO

2007-05-29

A method of optically determining a change in magnitude of at least one dimensional characteristic of a sample in response to a selected chamber environment. A magnitude of at least one dimension of the at least one sample may be optically determined subsequent to altering the at least one environmental condition within the chamber. A maximum change in dimension of the at least one sample may be predicted. A dimensional measurement apparatus for indicating a change in at least one dimension of at least one sample. The dimensional measurement apparatus may include a housing with a chamber configured for accommodating pressure changes and an optical perception device for measuring a dimension of at least one sample disposed in the chamber. Methods of simulating injection of a gas into a subterranean formation, injecting gas into a subterranean formation, and producing methane from a coal bed are also disclosed.

Methods for measurement of a dimensional characteristic and methods of predictive modeling related thereto

DOEpatents

Robertson, Eric P; Christiansen, Richard L.

2007-10-23

A method of optically determining a change in magnitude of at least one dimensional characteristic of a sample in response to a selected chamber environment. A magnitude of at least one dimension of the at least one sample may be optically determined subsequent to altering the at least one environmental condition within the chamber. A maximum change in dimension of the at least one sample may be predicted. A dimensional measurement apparatus for indicating a change in at least one dimension of at least one sample. The dimensional measurement apparatus may include a housing with a chamber configured for accommodating pressure changes and an optical perception device for measuring a dimension of at least one sample disposed in the chamber. Methods of simulating injection of a gas into a subterranean formation, injecting gas into a subterranean formation, and producing methane from a coal bed are also disclosed.

Study of the technics of coating stripping and FBG writing on polyimide fiber

NASA Astrophysics Data System (ADS)

Song, ZhiQiang; Qi, HaiFeng; Ni, JiaSheng; Wang, Chang

2017-10-01

Compared with ordinary optical fiber, polyimide fiber has the characteristics of high temperature resistance and high strength, which has important application in the field of optical fiber sensing. The common methods of polyimide coating stripping were introduced in this paper, including high temperature stripping, chemical stripping and arc ablation. In order to meet the requirements of FBG writing technology, a method using argon ion laser ablation coating was proposed. The method can precisely control the stripping length of the coating and completely does not affect the tensile strength of the optical fiber. According to the experiment, the fabrication process of polyimide FBG is stripping-hydrogen loadingwriting. Under the same conditions, 10 FBG samples were fabricated with good uniformity of wavelength bandwidth and reflectivity. UV laser ablation of polyimide coating has been proved to be a safe, reliable and efficient method.

Method for in situ characterization of a medium of dispersed matter in a continuous phase

DOEpatents

Kaufman, E.N.

1995-03-07

A method is described for the in situ characterization of a medium of a dispersed phase in a continuous phase, including the steps of adding a fluorescent dye to one phase capable of producing fluorescence therein when the fluorescent dye is optically excited, optically exciting the fluorescent dye at a wavelength to produce fluorescence in the one phase, and monitoring the fluorescence to distinguish the continuous phase from the dispersed phase. 2 figs.

Vision inspection system and method

NASA Technical Reports Server (NTRS)

Huber, Edward D. (Inventor); Williams, Rick A. (Inventor)

1997-01-01

An optical vision inspection system (4) and method for multiplexed illuminating, viewing, analyzing and recording a range of characteristically different kinds of defects, depressions, and ridges in a selected material surface (7) with first and second alternating optical subsystems (20, 21) illuminating and sensing successive frames of the same material surface patch. To detect the different kinds of surface features including abrupt as well as gradual surface variations, correspondingly different kinds of lighting are applied in time-multiplexed fashion to the common surface area patches under observation.

Analysis of tuning methods in semiconductor frequency-selective surfaces

NASA Astrophysics Data System (ADS)

Shemelya, Corey; Palm, Dominic; Fip, Tassilo; Rahm, Marco

2017-02-01

Advanced technology, such as sensing and communication equipment, has recently begun to combine optically sensitive nano-scale structures with customizable semiconductor material systems. Included within this broad field of study is the aptly named frequency-selective surface; which is unique in that it can be artificially designed to produce a specific electromagnetic or optical response. With the inherent utility of a frequency-selective surface, there has been an increased interest in the area of dynamic frequency-selective surfaces, which can be altered through optical or electrical tuning. This area has had exciting break throughs as tuning methods have evolved; however, these methods are typically energy intensive (optical tuning) or have met with limited success (electrical tuning). As such, this work investigates multiple structures and processes which implement semiconductor electrical biasing and/or optical tuning. Within this study are surfaces ranging from transmission meta-structures to metamaterial surface-waves and the associated coupling schemes. This work shows the utility of each design, while highlighting potential methods for optimizing dynamic meta-surfaces. As an added constraint, the structures were also designed to operate in unison with a state-of-the-art Ti:Sapphire Spitfire Ace and Spitfire Ace PA dual system (12 Watt) with pulse front matching THz generation and an EOS detection system. Additionally, the Ti:Sapphire laser system would provide the means for optical tunablity, while electrical tuning can be obtained through external power supplies.

Reverse process of usual optical analysis of boson-exchange superconductors: impurity effects on s- and d-wave superconductors.

PubMed

Hwang, Jungseek

2015-03-04

We performed a reverse process of the usual optical data analysis of boson-exchange superconductors. We calculated the optical self-energy from two (MMP and MMP+peak) input model electron-boson spectral density functions using Allen's formula for one normal and two (s- and d-wave) superconducting cases. We obtained the optical constants including the optical conductivity and the dynamic dielectric function from the optical self-energy using an extended Drude model, and finally calculated the reflectance spectrum. Furthermore, to investigate impurity effects on optical quantities we added various levels of impurities (from the clean to the dirty limit) in the optical self-energy and performed the same reverse process to obtain the optical conductivity, the dielectric function, and reflectance. From these optical constants obtained from the reverse process we extracted the impurity-dependent superfluid densities for two superconducting cases using two independent methods (the Ferrel-Glover-Tinkham sum rule and the extrapolation to zero frequency of -ϵ1(ω)ω(2)); we found that a certain level of impurities is necessary to get a good agreement on results obtained by the two methods. We observed that impurities give similar effects on various optical constants of s- and d-wave superconductors; the greater the impurities the more distinct the gap feature and the lower the superfluid density. However, the s-wave superconductor gives the superconducting gap feature more clearly than the d-wave superconductor because in the d-wave superconductors the optical quantities are averaged over the anisotropic Fermi surface. Our results supply helpful information to see how characteristic features of the electron-boson spectral function and the s- and d-wave superconducting gaps appear in various optical constants including raw reflectance spectrum. Our study may help with a thorough understanding of the usual optical analysis process. Further systematic study of experimental data collected at various conditions using the optical analysis process will help to reveal the origin of the mediated boson in the boson-exchange superconductors.

Passive thermo-optic feedback for robust athermal photonic systems

DOEpatents

Rakich, Peter T.; Watts, Michael R.; Nielson, Gregory N.

2015-06-23

Thermal control devices, photonic systems and methods of stabilizing a temperature of a photonic system are provided. A thermal control device thermally coupled to a substrate includes a waveguide for receiving light, an absorption element optically coupled to the waveguide for converting the received light to heat and an optical filter. The optical filter is optically coupled to the waveguide and thermally coupled to the absorption element. An operating point of the optical filter is tuned responsive to the heat from the absorption element. When the operating point is less than a predetermined temperature, the received light is passed to the absorption element via the optical filter. When the operating point is greater than or equal to the predetermined temperature, the received light is transmitted out of the thermal control device via the optical filter, without being passed to the absorption element.

Automated retinofugal visual pathway reconstruction with multi-shell HARDI and FOD-based analysis.

PubMed

Kammen, Alexandra; Law, Meng; Tjan, Bosco S; Toga, Arthur W; Shi, Yonggang

2016-01-15

Diffusion MRI tractography provides a non-invasive modality to examine the human retinofugal projection, which consists of the optic nerves, optic chiasm, optic tracts, the lateral geniculate nuclei (LGN) and the optic radiations. However, the pathway has several anatomic features that make it particularly challenging to study with tractography, including its location near blood vessels and bone-air interface at the base of the cerebrum, crossing fibers at the chiasm, somewhat-tortuous course around the temporal horn via Meyer's Loop, and multiple closely neighboring fiber bundles. To date, these unique complexities of the visual pathway have impeded the development of a robust and automated reconstruction method using tractography. To overcome these challenges, we develop a novel, fully automated system to reconstruct the retinofugal visual pathway from high-resolution diffusion imaging data. Using multi-shell, high angular resolution diffusion imaging (HARDI) data, we reconstruct precise fiber orientation distributions (FODs) with high order spherical harmonics (SPHARM) to resolve fiber crossings, which allows the tractography algorithm to successfully navigate the complicated anatomy surrounding the retinofugal pathway. We also develop automated algorithms for the identification of ROIs used for fiber bundle reconstruction. In particular, we develop a novel approach to extract the LGN region of interest (ROI) based on intrinsic shape analysis of a fiber bundle computed from a seed region at the optic chiasm to a target at the primary visual cortex. By combining automatically identified ROIs and FOD-based tractography, we obtain a fully automated system to compute the main components of the retinofugal pathway, including the optic tract and the optic radiation. We apply our method to the multi-shell HARDI data of 215 subjects from the Human Connectome Project (HCP). Through comparisons with post-mortem dissection measurements, we demonstrate the retinotopic organization of the optic radiation including a successful reconstruction of Meyer's loop. Then, using the reconstructed optic radiation bundle from the HCP cohort, we construct a probabilistic atlas and demonstrate its consistency with a post-mortem atlas. Finally, we generate a shape-based representation of the optic radiation for morphometry analysis. Copyright © 2015 Elsevier Inc. All rights reserved.

Flexible packaging for microelectronic devices

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

Anderson, Benjamin John; Nielson, Gregory N.; Cruz-Campa, Jose Luis

An apparatus, method, and system, the apparatus and system including a flexible microsystems enabled microelectronic device package including a microelectronic device positioned on a substrate; an encapsulation layer encapsulating the microelectronic device and the substrate; a protective layer positioned around the encapsulating layer; and a reinforcing layer coupled to the protective layer, wherein the substrate, encapsulation layer, protective layer and reinforcing layer form a flexible and optically transparent package around the microelectronic device. The method including encapsulating a microelectronic device positioned on a substrate within an encapsulation layer; sealing the encapsulated microelectronic device within a protective layer; and coupling themore » protective layer to a reinforcing layer, wherein the substrate, encapsulation layer, protective layer and reinforcing layer form a flexible and optically transparent package around the microelectronic device.« less

Optical Circuit Switched Protocol

NASA Technical Reports Server (NTRS)

Monacos, Steve P. (Inventor)

2000-01-01

The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

Shape sensing using multi-core fiber optic cable and parametric curve solutions.

PubMed

Moore, Jason P; Rogge, Matthew D

2012-01-30

The shape of a multi-core optical fiber is calculated by numerically solving a set of Frenet-Serret equations describing the path of the fiber in three dimensions. Included in the Frenet-Serret equations are curvature and bending direction functions derived from distributed fiber Bragg grating strain measurements in each core. The method offers advantages over prior art in that it determines complex three-dimensional fiber shape as a continuous parametric solution rather than an integrated series of discrete planar bends. Results and error analysis of the method using a tri-core optical fiber is presented. Maximum error expressed as a percentage of fiber length was found to be 7.2%.

Controlling ionotropic and metabotropic glutamate receptors with light: principles and potential

PubMed Central

Reiner, Andreas; Levitz, Joshua; Isacoff, Ehud Y.

2014-01-01

Light offers unique advantages for studying and manipulating biomolecules and the cellular processes that they control. Optical control of ionotropic and metabotropic glutamate receptors has garnered significant interest, since these receptors are central to signaling at neuronal synapses and only optical approaches provide the spatial and temporal resolution required to directly probe receptor function in cells and tissue. Following the classical method of glutamate photo-uncaging, recently developed methods have added other forms of remote control, including those with high molecular specificity and genetic targeting. These tools open the door to the direct optical control of synaptic transmission and plasticity, as well as the probing of native receptor function in intact neural circuits. PMID:25573450

A novel boundary layer sensor utilizing domain switching in ferroelectric liquid crystals

NASA Technical Reports Server (NTRS)

Parmar, D. S.

1991-01-01

This paper describes the design and the principles of operation of a novel sensor for the optical detection of a shear stress field induced by air or gas flow on a rigid surface. The detection relies on the effects of shear-induced optical switching in ferroelectric liquid crystals. It is shown that the method overcomes many of the limitations of similar measuring techniques including those using cholesteric liquid crystals. The present method offers a preferred alternative for flow visualization and skin friction measurements in wind-tunnel experiments on laminar boundary layer transition investigations. A theoretical model for the optical response to shear stress is presented together with a schematic diagram of the experimental setup.

Neurophotonics: non-invasive optical techniques for monitoring brain functions

PubMed Central

Torricelli, Alessandro; Contini, Davide; Mora, Alberto Dalla; Pifferi, Antonio; Re, Rebecca; Zucchelli, Lucia; Caffini, Matteo; Farina, Andrea; Spinelli, Lorenzo

2014-01-01

Summary The aim of this review is to present the state of the art of neurophotonics, a recently founded discipline lying at the interface between optics and neuroscience. While neurophotonics also includes invasive techniques for animal studies, in this review we focus only on the non-invasive methods that use near infrared light to probe functional activity in the brain, namely the fast optical signal, diffuse correlation spectroscopy, and functional near infrared spectroscopy methods. We also present an overview of the physical principles of light propagation in biological tissues, and of the main physiological sources of signal. Finally, we discuss the open issues in models, instrumentation, data analysis and clinical approaches. PMID:25764252

Diffraction-limited imaging with very large telescopes; Proceedings of the NATO Advanced Study Institute, Cargese, France, Sept. 13-23, 1988

NASA Astrophysics Data System (ADS)

Alloin, D. M.; Mariotti, J.-M.

Recent advances in optics and observation techniques for very large astronomical telescopes are discussed in reviews and reports. Topics addressed include Fourier optics and coherence, optical propagation and image formation through a turbulent atmosphere, radio telescopes, continuously deformable telescopes for optical interferometry (I), amplitude estimation from speckle I, noise calibration of speckle imagery, and amplitude estimation from diluted-array I. Consideration is given to first-order imaging methods, speckle imaging with the PAPA detector and the Knox-Thompson algorithm, phase-closure imaging, real-time wavefront sensing and adaptive optics, differential I, astrophysical programs for high-angular-resolution optical I, cophasing telescope arrays, aperture synthesis for space observatories, and lunar occultations for marcsec resolution.

NOAO testing procedures for large optics

NASA Astrophysics Data System (ADS)

Stepp, Larry M.; Poczulp, Gary A.; Pearson, Earl T.; Roddier, Nicolas A.

1992-03-01

This paper describes optical testing procedures used at the National Optical Astronomy Observatories (NOAO) for testing large optics. It begins with a discussion of the philosophy behind the testing approach and then describes a number of different testing methods used at NOAO, including the wire test, full-aperture and sub-aperture Hartmann testing, and scatterplate interferometry. Specific innovations that enhance the testing capabilities are mentioned. NOAO data reduction software is described. Examples are given of specific output formats that are useful to the optician, using illustrations taken from recent testing of a 3.5- meter, f/1.75 borosilicate honeycomb mirror. Finally, we discuss some of the optical testing challenges posed by the large optics for the Gemini 8-meter Telescopes Project.

Optimal model-based sensorless adaptive optics for epifluorescence microscopy.

PubMed

Pozzi, Paolo; Soloviev, Oleg; Wilding, Dean; Vdovin, Gleb; Verhaegen, Michel

2018-01-01

We report on a universal sample-independent sensorless adaptive optics method, based on modal optimization of the second moment of the fluorescence emission from a point-like excitation. Our method employs a sample-independent precalibration, performed only once for the particular system, to establish the direct relation between the image quality and the aberration. The method is potentially applicable to any form of microscopy with epifluorescence detection, including the practically important case of incoherent fluorescence emission from a three dimensional object, through minor hardware modifications. We have applied the technique successfully to a widefield epifluorescence microscope and to a multiaperture confocal microscope.

An Improved Optical Tweezers Assay for Measuring the Force Generation of Single Kinesin Molecules

PubMed Central

Nicholas, Matthew P.; Rao, Lu; Gennerich, Arne

2014-01-01

Numerous microtubule-associated molecular motors, including several kinesins and cytoplasmic dynein, produce opposing forces that regulate spindle and chromosome positioning during mitosis. The motility and force generation of these motors are therefore critical to normal cell division, and dysfunction of these processes may contribute to human disease. Optical tweezers provide a powerful method for studying the nanometer motility and piconewton force generation of single motor proteins in vitro. Using kinesin-1 as a prototype, we present a set of step-by-step, optimized protocols for expressing a kinesin construct (K560-GFP) in Escherichia coli, purifying it, and studying its force generation in an optical tweezers microscope. We also provide detailed instructions on proper alignment and calibration of an optical trapping microscope. These methods provide a foundation for a variety of similar experiments. PMID:24633799

Light-leaking region segmentation of FOG fiber based on quality evaluation of infrared image

NASA Astrophysics Data System (ADS)

Liu, Haoting; Wang, Wei; Gao, Feng; Shan, Lianjie; Ma, Yuzhou; Ge, Wenqian

2014-07-01

To improve the assembly reliability of Fiber Optic Gyroscope (FOG), a light leakage detection system and method is developed. First, an agile movement control platform is designed to implement the pose control of FOG optical path component in 6 Degrees of Freedom (DOF). Second, an infrared camera is employed to capture the working state images of corresponding fibers in optical path component after the manual assembly of FOG; therefore the entire light transmission process of key sections in light-path can be recorded. Third, an image quality evaluation based region segmentation method is developed for the light leakage images. In contrast to the traditional methods, the image quality metrics, including the region contrast, the edge blur, and the image noise level, are firstly considered to distinguish the image characters of infrared image; then the robust segmentation algorithms, including graph cut and flood fill, are all developed for region segmentation according to the specific image quality. Finally, after the image segmentation of light leakage region, the typical light-leaking type, such as the point defect, the wedge defect, and the surface defect can be identified. By using the image quality based method, the applicability of our proposed system can be improved dramatically. Many experiment results have proved the validity and effectiveness of this method.

Microfluidic microarray systems and methods thereof

DOEpatents

West, Jay A. A. [Castro Valley, CA; Hukari, Kyle W [San Ramon, CA; Hux, Gary A [Tracy, CA

2009-04-28

Disclosed are systems that include a manifold in fluid communication with a microfluidic chip having a microarray, an illuminator, and a detector in optical communication with the microarray. Methods for using these systems for biological detection are also disclosed.

Report on twisted nematic and supertwisted nematic device characterization program

NASA Technical Reports Server (NTRS)

1995-01-01

In this study we measured the optical characteristics of normally white twisted nematic (NWTN) and super twisted nematic (STN ) cells. Though no dynamic computer model was available, the static observations were compared with computer simulated behavior. The measurements were taken as a function of both viewing angle and applied voltage and included in the static case not only luminance but also contrast ratio and chromaticity . We employed the computer model Twist Cell Optics, developed at Kent State in conjunction with this study, and whose optical modeling foundation, Iike the ViDEOS program, is the 4 x 4 matrix method of Berreman. In order to resolve discrepancies between the experimental and modeled data the optical parameters of the individual cell components, where not known, were determined using refractometry, profilometry, and various forms of ellipsometry. The resulting agreement between experiment and model is quite good due primarily to a better understanding of the structure and optics of dichroic sheet polarizers. A description of the model and test cells employed are given in section 2. Section 3 contains the experimental data gathered and section 4 gives examples of the fit between model and experiment. Also included with this report are a pair of papers which resulted from the research and which detail the polarizer properties and some of the cell characterization methods.

Underwater optical communications using orbital angular momentum-based spatial division multiplexing

NASA Astrophysics Data System (ADS)

Willner, Alan E.; Zhao, Zhe; Ren, Yongxiong; Li, Long; Xie, Guodong; Song, Haoqian; Liu, Cong; Zhang, Runzhou; Bao, Changjing; Pang, Kai

2018-02-01

In this paper, we review high-capacity underwater optical communications using orbital angular momentum (OAM)-based spatial division multiplexing. We discuss methods to generate and detect blue-green optical data-carrying OAM beams as well as various underwater effects, including attenuation, scattering, current, and thermal gradients on OAM beams. Attention is also given to the system performance of high-capacity underwater optical communication links using OAM-based space division multiplexing. The paper closes with a discussion of a digital signal processing (DSP) algorithm to mitigate the inter-mode crosstalk caused by thermal gradients.

Modeling of Adaptive Optics-Based Free-Space Communications Systems

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

Wilks, S C; Morris, J R; Brase, J M

2002-08-06

We introduce a wave-optics based simulation code written for air-optic laser communications links, that includes a detailed model of an adaptive optics compensation system. We present the results obtained by this model, where the phase of a communications laser beam is corrected, after it propagates through a turbulent atmosphere. The phase of the received laser beam is measured using a Shack-Hartmann wavefront sensor, and the correction method utilizes a MEMS mirror. Strehl improvement and amount of power coupled to the receiving fiber for both 1 km horizontal and 28 km slant paths are presented.

Optical versus tactile geometry measurement: alternatives or counterparts

NASA Astrophysics Data System (ADS)

Lehmann, Peter

2003-05-01

This contribution deals with measuring strategies and methods for the determination of several geometrical features, covering the surface micro-topography and the form of mechanical objects. The measuring principles used in optical surface metrology include optical focusing profilers, confocal point measuring and areal measuring sensors as well as interferometrical principles such as white light interferometry and speckle techniques. In comparison with stylus instruments optical techniques provide certain advantages such as a fast data acquisition, in-process applicability or contactless measurement. However, the frequency response characteristics of optical and tactile measurement differ significantly. In addition, optical sensors are commonly more influenced by critical geometrical conditions and optical properties of an object. For precise form measurement mechanical instruments dominate till now. One reason for this may be, that commonly the complete 360 degrees geometry of the measuring object has to be analyzed. Another point is that optical principles such as form measuring interferometry fail in cases of complex object geometry or rougher object surfaces. Other methods, e.g. fringe projection or digital holography, till now do not meet the accuracy demands of precision engineered workpieces. Hence, a combination of mechanical concepts and optical sensors represents an interesting potential for current and future measuring tasks, which require high accuracy and maximum flexibility.

Novel Fiber-Optic Ring Acoustic Emission Sensor

PubMed Central

Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-01

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments. PMID:29342858

Novel Fiber-Optic Ring Acoustic Emission Sensor.

PubMed

Wei, Peng; Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-13

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

Waveguide device and method for making same

DOEpatents

Forman, Michael A [San Francisco, CA

2007-08-14

A monolithic micromachined waveguide device or devices with low-loss, high-power handling, and near-optical frequency ranges is set forth. The waveguide and integrated devices are capable of transmitting near-optical frequencies due to optical-quality sidewall roughness. The device or devices are fabricated in parallel, may be mass produced using a LIGA manufacturing process, and may include a passive component such as a diplexer and/or an active capping layer capable of particularized signal processing of the waveforms propagated by the waveguide.

Optical Security System Based on the Biometrics Using Holographic Storage Technique with a Simple Data Format

NASA Astrophysics Data System (ADS)

Jun, An Won

2006-01-01

We implement a first practical holographic security system using electrical biometrics that combines optical encryption and digital holographic memory technologies. Optical information for identification includes a picture of face, a name, and a fingerprint, which has been spatially multiplexed by random phase mask used for a decryption key. For decryption in our biometric security system, a bit-error-detection method that compares the digital bit of live fingerprint with of fingerprint information extracted from hologram is used.

Natural photonics for industrial inspiration.

PubMed

Parker, Andrew R

2009-05-13

There are two considerations for optical biomimetics: the diversity of submicrometre architectures found in the natural world, and the industrial manufacture of these. A review exists on the latter subject, where current engineering methods are considered along with those of the natural cells. Here, on the other hand, I will provide a modern review of the different categories of reflectors and antireflectors found in animals, including their optical characterization. The purpose of this is to inspire designers within the $2 billion annual optics industry.

Characterization of ion-assisted induced absorption in A-Si thin-films used for multivariate optical computing

NASA Astrophysics Data System (ADS)

Nayak, Aditya B.; Price, James M.; Dai, Bin; Perkins, David; Chen, Ding Ding; Jones, Christopher M.

2015-06-01

Multivariate optical computing (MOC), an optical sensing technique for analog calculation, allows direct and robust measurement of chemical and physical properties of complex fluid samples in high-pressure/high-temperature (HP/HT) downhole environments. The core of this MOC technology is the integrated computational element (ICE), an optical element with a wavelength-dependent transmission spectrum designed to allow the detector to respond sensitively and specifically to the analytes of interest. A key differentiator of this technology is it uses all of the information present in the broadband optical spectrum to determine the proportion of the analyte present in a complex fluid mixture. The detection methodology is photometric in nature; therefore, this technology does not require a spectrometer to measure and record a spectrum or a computer to perform calculations on the recorded optical spectrum. The integrated computational element is a thin-film optical element with a specific optical response function designed for each analyte. The optical response function is achieved by fabricating alternating layers of high-index (a-Si) and low-index (SiO2) thin films onto a transparent substrate (BK7 glass) using traditional thin-film manufacturing processes (e.g., ion-assisted e-beam vacuum deposition). A proprietary software and process are used to control the thickness and material properties, including the optical constants of the materials during deposition to achieve the desired optical response function. The ion-assisted deposition is useful for controlling the densification of the film, stoichiometry, and material optical constants as well as to achieve high deposition growth rates and moisture-stable films. However, the ion-source can induce undesirable absorption in the film; and subsequently, modify the optical constants of the material during the ramp-up and stabilization period of the e-gun and ion-source, respectively. This paper characterizes the unwanted absorption in the a-Si thin-film using advanced thin-film metrology methods, including spectroscopic ellipsometry and Fourier transform infrared (FTIR) spectroscopy. The resulting analysis identifies a fundamental mechanism contributing to this absorption and a method for minimizing and accounting for the unwanted absorption in the thin-film such that the exact optical response function can be achieved.

Integrated narrowband optical filter based on embedded subwavelength resonant grating structures

DOEpatents

Grann, Eric B.; Sitter, Jr., David N.

2000-01-01

A resonant grating structure in a waveguide and methods of tuning the performance of the grating structure are described. An apparatus includes a waveguide; and a subwavelength resonant grating structure embedded in the waveguide. The systems and methods provide advantages including narrowband filtering capabilities, minimal sideband reflections, spatial control, high packing density, and tunability.

Partially coherent X-ray wavefront propagation simulations including grazing-incidence focusing optics.

PubMed

Canestrari, Niccolo; Chubar, Oleg; Reininger, Ruben

2014-09-01

X-ray beamlines in modern synchrotron radiation sources make extensive use of grazing-incidence reflective optics, in particular Kirkpatrick-Baez elliptical mirror systems. These systems can focus the incoming X-rays down to nanometer-scale spot sizes while maintaining relatively large acceptance apertures and high flux in the focused radiation spots. In low-emittance storage rings and in free-electron lasers such systems are used with partially or even nearly fully coherent X-ray beams and often target diffraction-limited resolution. Therefore, their accurate simulation and modeling has to be performed within the framework of wave optics. Here the implementation and benchmarking of a wave-optics method for the simulation of grazing-incidence mirrors based on the local stationary-phase approximation or, in other words, the local propagation of the radiation electric field along geometrical rays, is described. The proposed method is CPU-efficient and fully compatible with the numerical methods of Fourier optics. It has been implemented in the Synchrotron Radiation Workshop (SRW) computer code and extensively tested against the geometrical ray-tracing code SHADOW. The test simulations have been performed for cases without and with diffraction at mirror apertures, including cases where the grazing-incidence mirrors can be hardly approximated by ideal lenses. Good agreement between the SRW and SHADOW simulation results is observed in the cases without diffraction. The differences between the simulation results obtained by the two codes in diffraction-dominated cases for illumination with fully or partially coherent radiation are analyzed and interpreted. The application of the new method for the simulation of wavefront propagation through a high-resolution X-ray microspectroscopy beamline at the National Synchrotron Light Source II (Brookhaven National Laboratory, USA) is demonstrated.

Application of Shack-Hartmann wavefront sensing technology to transmissive optic metrology

NASA Astrophysics Data System (ADS)

Rammage, Ron R.; Neal, Daniel R.; Copland, Richard J.

2002-11-01

Human vision correction optics must be produced in quantity to be economical. At the same time every human eye is unique and requires a custom corrective solution. For this reason the vision industries need fast, versatile and accurate methodologies for characterizing optics for production and research. Current methods for measuring these optics generally yield a cubic spline taken from less than 10 points across the surface of the lens. As corrective optics have grown in complexity this has become inadequate. The Shack-Hartmann wavefront sensor is a device that measures phase and irradiance of light in a single snapshot using geometric properties of light. Advantages of the Shack-Hartmann sensor include small size, ruggedness, accuracy, and vibration insensitivity. This paper discusses a methodology for designing instruments based on Shack-Hartmann sensors. The method is then applied to the development of an instrument for accurate measurement of transmissive optics such as gradient bifocal spectacle lenses, progressive addition bifocal lenses, intrarocular devices, contact lenses, and human corneal tissue. In addition, this instrument may be configured to provide hundreds of points across the surface of the lens giving improved spatial resolution. Methods are explored for extending the dynamic range and accuracy to meet the expanding needs of the ophthalmic and optometric industries. Data is presented demonstrating the accuracy and repeatability of this technique for the target optics.

Improving the quantitative accuracy of optical-emission computed tomography by incorporating an attenuation correction: application to HIF1 imaging

NASA Astrophysics Data System (ADS)

Kim, E.; Bowsher, J.; Thomas, A. S.; Sakhalkar, H.; Dewhirst, M.; Oldham, M.

2008-10-01

Optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT) are new techniques for imaging the 3D structure and function (including gene expression) of whole unsectioned tissue samples. This work presents a method of improving the quantitative accuracy of optical-ECT by correcting for the 'self'-attenuation of photons emitted within the sample. The correction is analogous to a method commonly applied in single-photon-emission computed tomography reconstruction. The performance of the correction method was investigated by application to a transparent cylindrical gelatin phantom, containing a known distribution of attenuation (a central ink-doped gelatine core) and a known distribution of fluorescing fibres. Attenuation corrected and uncorrected optical-ECT images were reconstructed on the phantom to enable an evaluation of the effectiveness of the correction. Significant attenuation artefacts were observed in the uncorrected images where the central fibre appeared ~24% less intense due to greater attenuation from the surrounding ink-doped gelatin. This artefact was almost completely removed in the attenuation-corrected image, where the central fibre was within ~4% of the others. The successful phantom test enabled application of attenuation correction to optical-ECT images of an unsectioned human breast xenograft tumour grown subcutaneously on the hind leg of a nude mouse. This tumour cell line had been genetically labelled (pre-implantation) with fluorescent reporter genes such that all viable tumour cells expressed constitutive red fluorescent protein and hypoxia-inducible factor 1 transcription-produced green fluorescent protein. In addition to the fluorescent reporter labelling of gene expression, the tumour microvasculature was labelled by a light-absorbing vasculature contrast agent delivered in vivo by tail-vein injection. Optical-CT transmission images yielded high-resolution 3D images of the absorbing contrast agent, and revealed highly inhomogeneous vasculature perfusion within the tumour. Optical-ECT emission images yielded high-resolution 3D images of the fluorescent protein distribution in the tumour. Attenuation-uncorrected optical-ECT images showed clear loss of signal in regions of high attenuation, including regions of high perfusion, where attenuation is increased by increased vascular ink stain. Application of attenuation correction showed significant changes in an apparent expression of fluorescent proteins, confirming the importance of the attenuation correction. In conclusion, this work presents the first development and application of an attenuation correction for optical-ECT imaging. The results suggest that successful attenuation correction for optical-ECT is feasible and is essential for quantitatively accurate optical-ECT imaging.

Low Frequency Error Analysis and Calibration for High-Resolution Optical Satellite's Uncontrolled Geometric Positioning

NASA Astrophysics Data System (ADS)

Wang, Mi; Fang, Chengcheng; Yang, Bo; Cheng, Yufeng

2016-06-01

The low frequency error is a key factor which has affected uncontrolled geometry processing accuracy of the high-resolution optical image. To guarantee the geometric quality of imagery, this paper presents an on-orbit calibration method for the low frequency error based on geometric calibration field. Firstly, we introduce the overall flow of low frequency error on-orbit analysis and calibration, which includes optical axis angle variation detection of star sensor, relative calibration among star sensors, multi-star sensor information fusion, low frequency error model construction and verification. Secondly, we use optical axis angle change detection method to analyze the law of low frequency error variation. Thirdly, we respectively use the method of relative calibration and information fusion among star sensors to realize the datum unity and high precision attitude output. Finally, we realize the low frequency error model construction and optimal estimation of model parameters based on DEM/DOM of geometric calibration field. To evaluate the performance of the proposed calibration method, a certain type satellite's real data is used. Test results demonstrate that the calibration model in this paper can well describe the law of the low frequency error variation. The uncontrolled geometric positioning accuracy of the high-resolution optical image in the WGS-84 Coordinate Systems is obviously improved after the step-wise calibration.

Lightweight high-performance 1-4 meter class spaceborne mirrors: emerging technology for demanding spaceborne requirements

NASA Astrophysics Data System (ADS)

Hull, Tony; Hartmann, Peter; Clarkson, Andrew R.; Barentine, John M.; Jedamzik, Ralf; Westerhoff, Thomas

2010-07-01

Pending critical spaceborne requirements, including coronagraphic detection of exoplanets, require exceptionally smooth mirror surfaces, aggressive lightweighting, and low-risk cost-effective optical manufacturing methods. Simultaneous development at Schott for production of aggressively lightweighted (>90%) Zerodur® mirror blanks, and at L-3 Brashear for producing ultra-smooth surfaces on Zerodur®, will be described. New L-3 techniques for large-mirror optical fabrication include Computer Controlled Optical Surfacing (CCOS) pioneered at L-3 Tinsley, and the world's largest MRF machine in place at L-3 Brashear. We propose that exceptional mirrors for the most critical spaceborne applications can now be produced with the technologies described.

Analysis technique for controlling system wavefront error with active/adaptive optics

NASA Astrophysics Data System (ADS)

Genberg, Victor L.; Michels, Gregory J.

2017-08-01

The ultimate goal of an active mirror system is to control system level wavefront error (WFE). In the past, the use of this technique was limited by the difficulty of obtaining a linear optics model. In this paper, an automated method for controlling system level WFE using a linear optics model is presented. An error estimate is included in the analysis output for both surface error disturbance fitting and actuator influence function fitting. To control adaptive optics, the technique has been extended to write system WFE in state space matrix form. The technique is demonstrated by example with SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

Approximate Solution Methods for Spectral Radiative Transfer in High Refractive Index Layers

NASA Technical Reports Server (NTRS)

Siegel, R.; Spuckler, C. M.

1994-01-01

Some ceramic materials for high temperature applications are partially transparent for radiative transfer. The refractive indices of these materials can be substantially greater than one which influences internal radiative emission and reflections. Heat transfer behavior of single and laminated layers has been obtained in the literature by numerical solutions of the radiative transfer equations coupled with heat conduction and heating at the boundaries by convection and radiation. Two-flux and diffusion methods are investigated here to obtain approximate solutions using a simpler formulation than required for exact numerical solutions. Isotropic scattering is included. The two-flux method for a single layer yields excellent results for gray and two band spectral calculations. The diffusion method yields a good approximation for spectral behavior in laminated multiple layers if the overall optical thickness is larger than about ten. A hybrid spectral model is developed using the two-flux method in the optically thin bands, and radiative diffusion in bands that are optically thick.

Physical-geometric optics method for large size faceted particles.

PubMed

Sun, Bingqiang; Yang, Ping; Kattawar, George W; Zhang, Xiaodong

2017-10-02

A new physical-geometric optics method is developed to compute the single-scattering properties of faceted particles. It incorporates a general absorption vector to accurately account for inhomogeneous wave effects, and subsequently yields the relevant analytical formulas effective and computationally efficient for absorptive scattering particles. A bundle of rays incident on a certain facet can be traced as a single beam. For a beam incident on multiple facets, a systematic beam-splitting technique based on computer graphics is used to split the original beam into several sub-beams so that each sub-beam is incident only on an individual facet. The new beam-splitting technique significantly reduces the computational burden. The present physical-geometric optics method can be generalized to arbitrary faceted particles with either convex or concave shapes and with a homogeneous or an inhomogeneous (e.g., a particle with a core) composition. The single-scattering properties of irregular convex homogeneous and inhomogeneous hexahedra are simulated and compared to their counterparts from two other methods including a numerically rigorous method.

OPTiM: Optical projection tomography integrated microscope using open-source hardware and software

PubMed Central

Andrews, Natalie; Davis, Samuel; Bugeon, Laurence; Dallman, Margaret D.; McGinty, James

2017-01-01

We describe the implementation of an OPT plate to perform optical projection tomography (OPT) on a commercial wide-field inverted microscope, using our open-source hardware and software. The OPT plate includes a tilt adjustment for alignment and a stepper motor for sample rotation as required by standard projection tomography. Depending on magnification requirements, three methods of performing OPT are detailed using this adaptor plate: a conventional direct OPT method requiring only the addition of a limiting aperture behind the objective lens; an external optical-relay method allowing conventional OPT to be performed at magnifications >4x; a remote focal scanning and region-of-interest method for improved spatial resolution OPT (up to ~1.6 μm). All three methods use the microscope’s existing incoherent light source (i.e. arc-lamp) and all of its inherent functionality is maintained for day-to-day use. OPT acquisitions are performed on in vivo zebrafish embryos to demonstrate the implementations’ viability. PMID:28700724

Emissive sensors and devices incorporating these sensors

DOEpatents

Swager, Timothy M; Zhang, Shi-Wei

2013-02-05

The present invention generally relates to luminescent and/or optically absorbing compositions and/or precursors to those compositions, including solid films incorporating these compositions/precursors, exhibiting increased luminescent lifetimes, quantum yields, enhanced stabilities and/or amplified emissions. The present invention also relates to sensors and methods for sensing analytes through luminescent and/or optically absorbing properties of these compositions and/or precursors. Examples of analytes detectable by the invention include electrophiles, alkylating agents, thionyl halides, and phosphate ester groups including phosphoryl halides, cyanides and thioates such as those found in certain chemical warfare agents. The present invention additionally relates to devices and methods for amplifying emissions, such as those produced using the above-described compositions and/or precursors, by incorporating the composition and/or precursor within a polymer having an energy migration pathway. In some cases, the compositions and/or precursors thereof include a compound capable of undergoing a cyclization reaction.

Visual perception system and method for a humanoid robot

NASA Technical Reports Server (NTRS)

Chelian, Suhas E. (Inventor); Linn, Douglas Martin (Inventor); Wampler, II, Charles W. (Inventor); Bridgwater, Lyndon (Inventor); Wells, James W. (Inventor); Mc Kay, Neil David (Inventor)

2012-01-01

A robotic system includes a humanoid robot with robotic joints each moveable using an actuator(s), and a distributed controller for controlling the movement of each of the robotic joints. The controller includes a visual perception module (VPM) for visually identifying and tracking an object in the field of view of the robot under threshold lighting conditions. The VPM includes optical devices for collecting an image of the object, a positional extraction device, and a host machine having an algorithm for processing the image and positional information. The algorithm visually identifies and tracks the object, and automatically adapts an exposure time of the optical devices to prevent feature data loss of the image under the threshold lighting conditions. A method of identifying and tracking the object includes collecting the image, extracting positional information of the object, and automatically adapting the exposure time to thereby prevent feature data loss of the image.

The multisensor payload 'Structura' for the observation of atmospheric night glows from the ISS board

NASA Astrophysics Data System (ADS)

Krot, Yury; Beliaev, Boris; Katkovsky, Leonid

2016-10-01

Aerospace Research Department of the Institute of Applied Physical Problems at Belarusian State University has developed a prototype of the optical payload intended for a space experiment on the ISS board. The prototype includes four optical modules for the night glows observation, in particular spatial-brightness and spectral characteristics in the altitude range of 80-320 km. Objects of the interest are emitting top layers of the atmosphere including exited OH radicals, atomic and molecular oxygen and sodium layers. The goal of the space experiment is a research of night glows over different regions of the Earth and a connection with natural disasters like earthquakes, cyclones, etc. Two optical modules for spatial distribution of atomic oxygen layers along the altitude consist of input lenses, spectral interferential filters and line CCD detectors. The optical module for registration of exited OH radical emissions is formed from CCD array spectrometer. The payload includes also a panchromatic (400-900 nm) high sensitive imaging camera for observing of the glows general picture. The optical modules of the prototype have been tested and general optical characteristics were determined in laboratory conditions. A solution of an astigmatism reducing of a concave diffraction grating and a method of the second diffraction order correction were applied and improved spectrometer's optical characteristics. Laboratory equipment and software were developed to imitate a dynamic scene of the night glows in laboratory conditions including an imitation of linear spectra and the spatial distribution of emissions.

Propagation of coherent light pulses with PHASE

NASA Astrophysics Data System (ADS)

Bahrdt, J.; Flechsig, U.; Grizzoli, W.; Siewert, F.

2014-09-01

The current status of the software package PHASE for the propagation of coherent light pulses along a synchrotron radiation beamline is presented. PHASE is based on an asymptotic expansion of the Fresnel-Kirchhoff integral (stationary phase approximation) which is usually truncated at the 2nd order. The limits of this approximation as well as possible extensions to higher orders are discussed. The accuracy is benchmarked against a direct integration of the Fresnel-Kirchhoff integral. Long range slope errors of optical elements can be included by means of 8th order polynomials in the optical element coordinates w and l. Only recently, a method for the description of short range slope errors has been implemented. The accuracy of this method is evaluated and examples for realistic slope errors are given. PHASE can be run either from a built-in graphical user interface or from any script language. The latter method provides substantial flexibility. Optical elements including apertures can be combined. Complete wave packages can be propagated, as well. Fourier propagators are included in the package, thus, the user may choose between a variety of propagators. Several means to speed up the computation time were tested - among them are the parallelization in a multi core environment and the parallelization on a cluster.

Estimating respiratory rate from FBG optical sensors by using signal quality measurement.

PubMed

Yongwei Zhu; Maniyeri, Jayachandran; Fook, Victor Foo Siang; Haihong Zhang

2015-08-01

Non-intrusiveness is one of the advantages of in-bed optical sensor device for monitoring vital signs, including heart rate and respiratory rate. Estimating respiratory rate reliably using such sensors, however, is challenging, due to body movement, signal variation according to different subjects or body positions, etc. This paper presents a method for reliable respiratory rate estimation for FBG optical sensors by introducing signal quality estimation. The method estimates the quality of the signal waveform by detecting regularly repetitive patterns using proposed spectrum and cepstrum analysis. Multiple window sizes are used to cater for a wide range of target respiratory rates. Furthermore, the readings of multiple sensors are fused to derive a final respiratory rate. Experiments with 12 subjects and 2 body positions were conducted using polysomnography belt signal as groundtruth. The results demonstrated the effectiveness of the method.

Passive Fully Polarimetric W-Band Millimeter-Wave Imaging

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

Bernacki, Bruce E.; Kelly, James F.; Sheen, David M.

2012-04-01

We present the theory, design, and experimental results obtained from a scanning passive W-band fully polarimetric imager. Passive millimeter-wave imaging offers persistent day/nighttime imaging and the ability to penetrate dust, clouds and other obscurants, including clothing and dry soil. The single-pixel scanning imager includes both far-field and near-field fore-optics for investigation of polarization phenomena. Using both fore-optics, a variety of scenes including natural and man-made objects was imaged and these results are presented showing the utility of polarimetric imaging for anomaly detection. Analysis includes conventional Stokes-parameter based approaches as well as multivariate image analysis methods.

Feasibility of interstitial diffuse optical tomography using cylindrical diffusing fiber for prostate PDT

PubMed Central

Liang, Xing; Wang, Ken Kang-Hsin; Zhu, Timothy C.

2013-01-01

Interstitial diffuse optical tomography (DOT) has been used to characterize spatial distribution of optical properties for prostate photodynamic therapy (PDT) dosimetry. We have developed an interstitial DOT method using cylindrical diffuse fibers (CDFs) as light sources, so that the same light sources can be used for both DOT measurement and PDT treatment. In this novel interstitial CDF-DOT method, absolute light fluence per source strength (in unit of 1/cm2) is used to separate absorption and scattering coefficients. A mathematical phantom and a solid prostate phantom including anomalies with known optical properties were used, respectively, to test the feasibility of reconstructing optical properties using interstitial CDF-DOT. Three dimension spatial distributions of the optical properties were reconstructed for both scenarios. Our studies show that absorption coefficient can be reliably extrapolated while there are some cross talks between absorption and scattering properties. Even with the suboptimal reduced scattering coefficients, the reconstructed light fluence rate agreed with the measured values to within ±10%, thus the proposed CDF-DOT allows greatly improved light dosimetry calculation for interstitial PDT. PMID:23629149

Explicit formulation of second and third order optical nonlinearity in the FDTD framework

NASA Astrophysics Data System (ADS)

Varin, Charles; Emms, Rhys; Bart, Graeme; Fennel, Thomas; Brabec, Thomas

2018-01-01

The finite-difference time-domain (FDTD) method is a flexible and powerful technique for rigorously solving Maxwell's equations. However, three-dimensional optical nonlinearity in current commercial and research FDTD softwares requires solving iteratively an implicit form of Maxwell's equations over the entire numerical space and at each time step. Reaching numerical convergence demands significant computational resources and practical implementation often requires major modifications to the core FDTD engine. In this paper, we present an explicit method to include second and third order optical nonlinearity in the FDTD framework based on a nonlinear generalization of the Lorentz dispersion model. A formal derivation of the nonlinear Lorentz dispersion equation is equally provided, starting from the quantum mechanical equations describing nonlinear optics in the two-level approximation. With the proposed approach, numerical integration of optical nonlinearity and dispersion in FDTD is intuitive, transparent, and fully explicit. A strong-field formulation is also proposed, which opens an interesting avenue for FDTD-based modelling of the extreme nonlinear optics phenomena involved in laser filamentation and femtosecond micromachining of dielectrics.

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.

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.

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.

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.

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.

Design and fabrication of N x N optical couplers based on organic polymer optical waveguides

NASA Astrophysics Data System (ADS)

Krchnavek, Robert R.; Rode, Daniel L.

1994-08-01

In this report, we examine the design and fabrication of a planar, 10x10 optical coupler utilizing photopolymerizable organic polymers. Background information on the theory of operation of the coupler culminating in a set of design equations is presented. The details of the material processing are described, including the preparation of monomer mixtures that result in single-mode polymer waveguides (lambda = 1300 nm) that have core dimensions approximately equal to those of single-mode fiber. This is necessary to insure high coupling efficiency between the planar device and optical fiber. A unique method of aligning and attaching optical fibers to the coupler is demonstrated. This method relies on patterned alignment ways, a transcision cut, and single-mode D-fiber. A theoretical analysis of the in situ monitoring technique used to fabricate the single-mode D-fiber is presented and compared favorably with the experimental results. Finally, the 10x10 coupler is characterized. We have measured an excess loss of approximately 8 dB.

Self-consistent projection operator theory in nonlinear quantum optical systems: A case study on degenerate optical parametric oscillators

NASA Astrophysics Data System (ADS)

Degenfeld-Schonburg, Peter; Navarrete-Benlloch, Carlos; Hartmann, Michael J.

2015-05-01

Nonlinear quantum optical systems are of paramount relevance for modern quantum technologies, as well as for the study of dissipative phase transitions. Their nonlinear nature makes their theoretical study very challenging and hence they have always served as great motivation to develop new techniques for the analysis of open quantum systems. We apply the recently developed self-consistent projection operator theory to the degenerate optical parametric oscillator to exemplify its general applicability to quantum optical systems. We show that this theory provides an efficient method to calculate the full quantum state of each mode with a high degree of accuracy, even at the critical point. It is equally successful in describing both the stationary limit and the dynamics, including regions of the parameter space where the numerical integration of the full problem is significantly less efficient. We further develop a Gaussian approach consistent with our theory, which yields sensibly better results than the previous Gaussian methods developed for this system, most notably standard linearization techniques.

Optical alignment of the VLTI

NASA Astrophysics Data System (ADS)

Guisard, Stephane

2003-02-01

When completed the VLTI project will be composed by four 8.2 m Unit Telescopes (UT) and four 1.8 m Auxiliay Telescopes (AT) with their respective Coude trains and relay optics, two test siderostats, 6 (up to 8) Delay lines and 8 Beam compressors with their corresponding feeding mirrors. There will be more than 200 optical components, mirrors and lenses, with diameters ranging from 5 mm to 8200 mm. Their surface shapes range from flat to off-axis ellipsoid, including also spherical, on and off-axis hyperbolae and parabolas as well as cylindrical surfaces. Depending on the interferometer configuration, the different possible optical path lengths are of the order of 100 to 300 meters. We describe briefly the principles chosen as well as the types of criteria and method used for the alignment. The method can certainly be applied to other optical systems. The explanations given are understandable to the non-optician, this text is not intended to be an alignment procedure.

Multi-color pyrometry imaging system and method of operating the same

DOEpatents

Estevadeordal, Jordi; Nirmalan, Nirm Velumylum; Tralshawala, Nilesh; Bailey, Jeremy Clyde

2017-03-21

A multi-color pyrometry imaging system for a high-temperature asset includes at least one viewing port in optical communication with at least one high-temperature component of the high-temperature asset. The system also includes at least one camera device in optical communication with the at least one viewing port. The at least one camera device includes a camera enclosure and at least one camera aperture defined in the camera enclosure, The at least one camera aperture is in optical communication with the at least one viewing port. The at least one camera device also includes a multi-color filtering mechanism coupled to the enclosure. The multi-color filtering mechanism is configured to sequentially transmit photons within a first predetermined wavelength band and transmit photons within a second predetermined wavelength band that is different than the first predetermined wavelength band.

Beam shaping for laser initiated optical primers

NASA Astrophysics Data System (ADS)

Lizotte, Todd E.

2008-08-01

Remington was one of the first firearm manufacturing companies to file a patent for laser initiated firearms, in 1969. Nearly 40 years later, the development of laser initiated firearms has not become a mainstream technology in the civilian market. Requiring a battery is definitely a short coming, so it is easy to see how such a concept would be problematic. Having a firearm operate reliably and the delivery of laser energy in an efficient manner to ignite the shock-sensitive explosive primer mixtures is a tall task indeed. There has been considerable research on optical element based methods of transferring or compressing laser energy to ignite primer charges, including windows, laser chip primers and various lens shaped windows to focus the laser energy. The focusing of laser light needs to achieve igniting temperatures upwards of >400°C. Many of the patent filings covering this type of technology discuss simple approaches where a single point of light might be sufficient to perform this task. Alternatively a multi-point method might provide better performance, especially for mission critical applications, such as precision military firearms. This paper covers initial design and performance test of the laser beam shaping optics to create simultaneous multiple point ignition locations and a circumferential intense ring for igniting primer charge compounds. A simple initial test of the ring beam shaping technique was evaluated on a standard large caliber primer to determine its effectiveness on igniting the primer material. Several tests were conducted to gauge the feasibility of laser beam shaping, including optic fabrication and mounting on a cartridge, optic durability and functional ignition performance. Initial data will be presented, including testing of optically elements and empirical primer ignition / burn analysis.

Online damage inspection of optics for ATP system

NASA Astrophysics Data System (ADS)

Chen, Jing; Jiang, Yu; Mao, Yao; Gan, Xun; Liu, Qiong

2016-09-01

In the Electro-Optical acquisition-tracking-pointing system (ATP), the optical components will be damaged with the several influencing factors. In this situation, the rate will increase sharply when the arrival of damage to some extent. As the complex processing techniques and long processing cycle of optical components, the damage will cause the great increase of the system development cost and cycle. Therefore, it is significant to detect the laser-induced damage in the ATP system. At present, the major research on the on-line damage detection technology of optical components is for the large optical system in the international. The relevant detection systems have complicated structures and many of components, and require enough installation space reserved, which do not apply for ATP system. To solve the problem mentioned before, This paper use a method based on machine vision to detect the damage on-line for the present ATP system. To start with, CCD and PC are used for image acquisition. Secondly, smoothing filters are used to restrain false damage points produced by noise. Then, with the shape feature included in the damage image, the OTSU Method which can define the best segmentation threshold automatically is used to achieve the goal to locate the damage regions. At last, we can supply some opinions for the lifetime of the optical components by analyzing the damage data, such as damage area, damage position. The method has the characteristics of few-detectors and simple-structures which can be installed without any changes of the original light path. With the method, experimental results show that it is stable and effective to achieve the goal of detecting the damage of optical components on-line in the ATP system.

System and method for ultrafast optical signal detecting via a synchronously coupled anamorphic light pulse encoded laterally

DOEpatents

Heebner, John E [Livermore, CA

2010-08-03

In one general embodiment, a method for ultrafast optical signal detecting is provided. In operation, a first optical input signal is propagated through a first wave guiding layer of a waveguide. Additionally, a second optical input signal is propagated through a second wave guiding layer of the waveguide. Furthermore, an optical control signal is applied to a top of the waveguide, the optical control signal being oriented diagonally relative to the top of the waveguide such that the application is used to influence at least a portion of the first optical input signal propagating through the first wave guiding layer of the waveguide. In addition, the first and the second optical input signals output from the waveguide are combined. Further, the combined optical signals output from the waveguide are detected. In another general embodiment, a system for ultrafast optical signal recording is provided comprising a waveguide including a plurality of wave guiding layers, an optical control source positioned to propagate an optical control signal towards the waveguide in a diagonal orientation relative to a top of the waveguide, at least one optical input source positioned to input an optical input signal into at least a first and a second wave guiding layer of the waveguide, and a detector for detecting at least one interference pattern output from the waveguide, where at least one of the interference patterns results from a combination of the optical input signals input into the first and the second wave guiding layer. Furthermore, propagation of the optical control signal is used to influence at least a portion of the optical input signal propagating through the first wave guiding layer of the waveguide.

Deterministic magnetorheological finishing of optical aspheric mirrors

NASA Astrophysics Data System (ADS)

Song, Ci; Dai, Yifan; Peng, Xiaoqiang; Li, Shengyi; Shi, Feng

2009-05-01

A new method magnetorheological finishing (MRF) used for deterministical finishing of optical aspheric mirrors is applied to overcome some disadvantages including low finishing efficiency, long iterative time and unstable convergence in the process of conventional polishing. Based on the introduction of the basic principle of MRF, the key techniques to implement deterministical MRF are also discussed. To demonstrate it, a 200 mm diameter K9 class concave asphere with a vertex radius of 640mm was figured on MRF polish tool developed by ourselves. Through one process about two hours, the surface accuracy peak-to-valley (PV) is improved from initial 0.216λ to final 0.179λ and root-mean-square (RMS) is improved from 0.027λ to 0.017λ (λ = 0.6328um ). High-precision and high-efficiency convergence of optical aspheric surface error shows that MRF is an advanced optical manufacturing method that owns high convergence ratio of surface figure, high precision of optical surfacing, stabile and controllable finishing process. Therefore, utilizing MRF to finish optical aspheric mirrors determinately is credible and stabile; its advantages can be also used for finishing optical elements on varieties of types such as plane mirrors and spherical mirrors.

Comparison of seven optical clearing methods for mouse brain

NASA Astrophysics Data System (ADS)

Wan, Peng; Zhu, Jingtan; Yu, Tingting; Zhu, Dan

2018-02-01

Recently, a variety of tissue optical clearing techniques have been developed to reduce light scattering for imaging deeper and three-dimensional reconstruction of tissue structures. Combined with optical imaging techniques and diverse labeling methods, these clearing methods have significantly promoted the development of neuroscience. However, most of the protocols were proposed aiming for specific tissue type. Though there are some comparison results, the clearing methods covered are limited and the evaluation indices are lack of uniformity, which made it difficult to select a best-fit protocol for clearing in practical applications. Hence, it is necessary to systematically assess and compare these clearing methods. In this work, we evaluated the performance of seven typical clearing methods, including 3DISCO, uDISCO, SeeDB, ScaleS, ClearT2, CUBIC and PACT, on mouse brain samples. First, we compared the clearing capability on both brain slices and whole-brains by observing brain transparency. Further, we evaluated the fluorescence preservation and the increase of imaging depth. The results showed that 3DISCO, uDISCO and PACT posed excellent clearing capability on mouse brains, ScaleS and SeeDB rendered moderate transparency, while ClearT2 was the worst. Among those methods, ScaleS was the best on fluorescence preservation, and PACT achieved the highest increase of imaging depth. This study is expected to provide important reference for users in choosing most suitable brain optical clearing method.

Optical fabrication and testing; Proceedings of the Meeting, Singapore, Oct. 22-27, 1990

NASA Astrophysics Data System (ADS)

Lorenzen, Manfred; Campbell, Duncan R.; Johnson, Craig W.

1991-03-01

Various papers on optical fabrication and testing are presented. Individual topics addressed include: interferometry with laser diodes, new methods for economic production of prisms and lenses, interferometer accuracy and precision, optical testing with wavelength scanning interferometer, digital Talbot interferometer, high-sensitivity interferometric technique for strain measurements, absolute interferometric testing of spherical surfaces, contouring using gratings created on an LCD panel, three-dimensional inspection using laser-based dynamic fringe projection, noncontact optical microtopography, laser scan microscope and infrared laser scan microscope, photon scanning tunneling microscopy. Also discussed are: combination-matching problems in the layout design of minilaser rangefinder, design and testing of a cube-corner array for laser ranging, mode and far-field pattern of diode laser-phased arrays, new glasses for optics and optoelectronics, optical properties of Li-doped ZnO films, application and machining of Zerodur for optical purposes, finish machining of optical components in mass production.

Optical fabrication and testing; Proceedings of the Meeting, Singapore, Oct. 22-27, 1990

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

Lorenzen, M.; Campbell, D.R.; Johnson, C.W.

1991-01-01

Various papers on optical fabrication and testing are presented. Individual topics addressed include: interferometry with laser diodes, new methods for economic production of prisms and lenses, interferometer accuracy and precision, optical testing with wavelength scanning interferometer, digital Talbot interferometer, high-sensitivity interferometric technique for strain measurements, absolute interferometric testing of spherical surfaces, contouring using gratings created on an LCD panel, three-dimensional inspection using laser-based dynamic fringe projection, noncontact optical microtopography, laser scan microscope and infrared laser scan microscope, photon scanning tunneling microscopy. Also discussed are: combination-matching problems in the layout design of minilaser rangefinder, design and testing of a cube-corner arraymore » for laser ranging, mode and far-field pattern of diode laser-phased arrays, new glasses for optics and optoelectronics, optical properties of Li-doped ZnO films, application and machining of Zerodur for optical purposes, finish machining of optical components in mass production.« less

High Availability in Optical Networks

NASA Astrophysics Data System (ADS)

Grover, Wayne D.; Wosinska, Lena; Fumagalli, Andrea

2005-09-01

Call for Papers: High Availability in Optical Networks Submission Deadline: 1 January 2006 The Journal of Optical Networking (JON) is soliciting papers for a feature Issue pertaining to all aspects of reliable components and systems for optical networks and concepts, techniques, and experience leading to high availability of services provided by optical networks. Most nations now recognize that telecommunications in all its forms -- including voice, Internet, video, and so on -- are "critical infrastructure" for the society, commerce, government, and education. Yet all these services and applications are almost completely dependent on optical networks for their realization. "Always on" or apparently unbreakable communications connectivity is the expectation from most users and for some services is the actual requirement as well. Achieving the desired level of availability of services, and doing so with some elegance and efficiency, is a meritorious goal for current researchers. This requires development and use of high-reliability components and subsystems, but also concepts for active reconfiguration and capacity planning leading to high availability of service through unseen fast-acting survivability mechanisms. The feature issue is also intended to reflect some of the most important current directions and objectives in optical networking research, which include the aspects of integrated design and operation of multilevel survivability and realization of multiple Quality-of-Protection service classes. Dynamic survivable service provisioning, or batch re-provisioning is an important current theme, as well as methods that achieve high availability at far less investment in spare capacity than required by brute force service path duplication or 100% redundant rings, which is still the surprisingly prevalent practice. Papers of several types are envisioned in the feature issue, including outlook and forecasting types of treatments, optimization and analysis, new concepts for survivability, or papers on availability analysis methods or results. Customer, vendor, and researcher viewpoints and priorities will all be given consideration. Especially valuable to the community would be papers that include or provide measured data on actual reliability and availability performance of optical networking components or systems. The scope of the papers includes, but is not limited to, the following topics: Reliability and availability measurement techniques specific to optical network devices or services. Data on SRLG statistics and frequency of different actual failure causes. Real-life accounts or data on failure and repair rates or projected values for use in availability analysis. Availability analysis methods, especially for survivable networks with reconfigurable or adaptive failure-specific responses. Availability analysis and comparisons of basic schemes for survivability. Differentiated availability schemes. Design for Multiple Quality of Protection. Different schemes for on-demand survivable service provisioning. Basic comparisons or proposals of new survivability mechanisms and architectures. Concepts yielding higher than 1+1 protection switching availability at less than 100% redundancy. Survivable service provisioning in domains of optical transparency: dealing with signal impairments. To submit to this special issue, follow the normal procedure for submission to JON, indicating "Feature Issue: Optical Network Availability" in the "Comments" field of the online submission form. For all other questions relating to this feature issue, please send an e-mail to jon@osa.org, subject line "Feature Issue: Optical Network Availability." Additional information can be found on the JON website: http://www.osa-jon.org/submission/

International Lens Design Conference, Monterey, CA, June 11-14, 1990, Proceedings

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

Lawrence, G.N.

1990-01-01

The present conference on lens design encompasses physical and geometrical optics, diffractive optics, the optimization of optical design, software packages, ray tracing, the use of artificial intelligence, the achromatization of materials, zoom optics, microoptics and GRIN lenses, and IR lens design. Specific issues addressed include diffraction-performance calculations in lens design, the optimization of the optical transfer function, a rank-down method for automatic lens design, applications of quadric surfaces, the correction of aberrations by using HOEs in UV and visible imaging systems, and an all-refractive telescope for intersatellite communications. Also addressed are automation techniques for optics manufacturing, all-reflective phased-array imaging telescopes,more » the thermal aberration analysis of a Nd:YAG laser, the analysis of illumination systems, athermalized FLIR optics, and the design of array systems using shared symmetry.« less

A Comparison of High Spectral Resolution Infrared Cloud-Top Pressure Altitude Algorithms Using S-HIS Measurements

NASA Technical Reports Server (NTRS)

Holz, Robert E.; Ackerman, Steve; Antonelli, Paolo; Nagle, Fred; McGill, Matthew; Hlavka, Dennis L.; Hart, William D.

2005-01-01

This paper presents a comparison of cloud-top altitude retrieval methods applied to S-HIS (Scanning High Resolution Interferometer Sounder) measurements. Included in this comparison is an improvement to the traditional CO2 Slicing method. The new method, CO2 Sorting, determines optimal channel pairs to apply the CO2 Slicing. Measurements from collocated samples of the Cloud Physics Lidar (CPL) and Modis Airborne Simulator (MAS) instruments assist in the comparison. For optically thick clouds good correlation between the S-HIS and lidar cloud-top retrievals are found. For tenuous ice clouds there can be large differences between lidar (CPL) and S-HIS retrieved cloud-tops. It is found that CO2 Sorting significantly reduces the cloud height biases for the optically thin cloud (total optical depths less then 1.0). For geometrically thick but optically thin cirrus clouds large differences between the S-HIS infrared cloud top retrievals and the CPL detected cloud top where found. For these cases the cloud height retrieved by the S-HIS cloud retrievals correlated closely with the level the CPL integrated cloud optical depth was approximately 1.0.

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

Wang, K; Zhang, B; Eslami, S

Purpose: We present a newly developed on-board optical tomography system for SARRP. Innovative features include the compact design and fast acquisition optical method to perform 3D soft tissue radiation guidance. Because of the on-board feature and the combination of the CBCT, diffusive optical tomography (DOT), bioluminescence and fluorescence tomography (BLT and FT), this integrated system is expected to provide more accurate soft tissue guidance than an off-line system as well as highly sensitive functional imaging in preclinical research. Methods: Images are acquired in the order of CBCT, DOT and then BLT/FT, where the SARRP CBCT and DOT are used tomore » provide the anatomical and optical properties information to enhance the subsequent BLT/FT optical reconstruction. The SARRP stage is redesigned to include 9 imbedded optical fibers in contact with the animal's skin. These fibers, connected to a white light lamp or laser, serve as the light sources for the DOT or FT, respectively. A CCD camera with f/1.4 lens and multi-spectral filter set is used as the optical detector and is mounted on a portable cart ready to dock into the SARRP. No radiation is delivered during optical image acquisition. A 3-way mirror system capable of 180 degree rotation around the animal reflects the optical signal to the camera at multiple projection angles. A special black-painted dome covers the stage and provides the light shielding. Results: Spontaneous metastatic bioluminescent liver and lung tumor models will be used to validate the 3D BLT reconstruction. To demonstrate the capability of our FT system, GastroSense750 fluorescence agent will be used to imaging the mouse stomach and intestinal region in 3D. Conclusion: We expect that this integrated CBCT and optical tomography on-board a SARRP will present new research opportunities for pre-clinical radiation research. Supported by NCI RO1-CA 158100.« less

Portable sample preparation and analysis system for micron and sub-micron particle characterization using light scattering and absorption spectroscopy

DOEpatents

Stark, Peter C [Los Alamos, NM; Zurek, Eduardo [Barranquilla, CO; Wheat, Jeffrey V [Fort Walton Beach, FL; Dunbar, John M [Santa Fe, NM; Olivares, Jose A [Los Alamos, NM; Garcia-Rubio, Luis H [Temple Terrace, FL; Ward, Michael D [Los Alamos, NM

2011-07-26

There is provided a method and device for remote sampling, preparation and optical interrogation of a sample using light scattering and light absorption methods. The portable device is a filtration-based device that removes interfering background particle material from the sample matrix by segregating or filtering the chosen analyte from the sample solution or matrix while allowing the interfering background particles to be pumped out of the device. The segregated analyte is then suspended in a diluent for analysis. The device is capable of calculating an initial concentration of the analyte, as well as diluting the analyte such that reliable optical measurements can be made. Suitable analytes include cells, microorganisms, bioparticles, pathogens and diseases. Sample matrixes include biological fluids such as blood and urine, as well as environmental samples including waste water.

Multiparallel Three-Dimensional Optical Microscopy

NASA Technical Reports Server (NTRS)

Nguyen, Lam K.; Price, Jeffrey H.; Kellner, Albert L.; Bravo-Zanoquera, Miguel

2010-01-01

Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.

Fast, externally triggered, digital phase controller for an optical lattice

NASA Astrophysics Data System (ADS)

Sadgrove, Mark; Nakagawa, Ken'ichi

2011-11-01

We present a method to control the phase of an optical lattice according to an external trigger signal. The method has a latency of less than 30 μs. Two phase locked digital synthesizers provide the driving signal for two acousto-optic modulators which control the frequency and phase of the counter-propagating beams which form a standing wave (optical lattice). A micro-controller with an external interrupt function is connected to the desired external signal, and updates the phase register of one of the synthesizers when the external signal changes. The standing wave (period λ/2 = 390 nm) can be moved by units of 49 nm with a mean jitter of 28 nm. The phase change is well known due to the digital nature of the synthesizer, and does not need calibration. The uses of the scheme include coherent control of atomic matter-wave dynamics.

Electrical and optical performance of transparent conducting oxide films deposited by electrostatic spray assisted vapour deposition.

PubMed

Hou, Xianghui; Choy, Kwang-Leong; Liu, Jun-Peng

2011-09-01

Transparent conducting oxide (TCO) films have the remarkable combination of high electrical conductivity and optical transparency. There is always a strong motivation to produce TCO films with good performance at low cost. Electrostatic Spray Assisted Vapor Deposition (ESAVD), as a variant of chemical vapour deposition (CVD), is a non-vacuum and low-cost deposition method. Several types of TCO films have been deposited using ESAVD process, including indium tin oxide (ITO), antimony-doped tin oxide (ATO), and fluorine doped tin oxide (FTO). This paper reports the electrical and optical properties of TCO films produced by ESAVD methods, as well as the effects of post treatment by plasma hydrogenation on these TCO films. The possible mechanisms involved during plasma hydrogenation of TCO films are also discussed. Reduction and etching effect during plasma hydrogenation are the most important factors which determine the optical and electrical performance of TCO films.

Multimedia: Beyond the Desktop.

ERIC Educational Resources Information Center

Galbreath, Jeremy

1993-01-01

Describes the Central Media Resource System (CMRS), a method that allows multimedia instruction to large groups of students. Highlights include the information infrastructure, including fiber optics and coaxial cable; use of the CMRS in the classroom and in the media resource center; and future possibilities, including local and wide area…

Optical proximity correction for anamorphic extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

Clifford, Chris; Lam, Michael; Raghunathan, Ananthan; Jiang, Fan; Fenger, Germain; Adam, Kostas

2017-10-01

The change from isomorphic to anamorphic optics in high numerical aperture (NA) extreme ultraviolet (EUV) scanners necessitates changes to the mask data preparation flow. The required changes for each step in the mask tape out process are discussed, with a focus on optical proximity correction (OPC). When necessary, solutions to new problems are demonstrated, and verified by rigorous simulation. Additions to the OPC model include accounting for anamorphic effects in the optics, mask electromagnetics, and mask manufacturing. The correction algorithm is updated to include awareness of anamorphic mask geometry for mask rule checking (MRC). OPC verification through process window conditions is enhanced to test different wafer scale mask error ranges in the horizontal and vertical directions. This work will show that existing models and methods can be updated to support anamorphic optics without major changes. Also, the larger mask size in the Y direction can result in better model accuracy, easier OPC convergence, and designs which are more tolerant to mask errors.

Probing and monitoring aerosol and atmospheric clouds with an electro-optic oscillator.

PubMed

Arnon, S; Kopeika, N S

1996-09-20

Monitoring, probing, and sensing characteristics of aerosol clouds is difficult and complicated. Probing the characteristics of aerosols is most useful in the chemical and microelectronic industry for processing control of aerosols and emulsion, decreasing bit error rate in adaptive optical communication systems, and in acquiring data for atmospheric science and environment quality. We present a new mathematical and optical engineering model for monitoring characteristics of aerosol clouds. The model includes the temporal transfer function of aerosol clouds as a variable parameter in an electro-optic oscillator. The frequency of the oscillator changes according to changes in the characteristics of the clouds (density, size distribution, physical thickness, the medium and the particulate refractive indices, and spatial distribution). It is possible to measure only one free characteristic at a given time. An example of a practical system for monitoring the density of aerosol clouds is given. The frequency of the oscillator changes from 1.25 to 0.43 MHz for changes in aerosol density from 2000 to 3000 particulates cm(-3). The advantages of this new method compared with the transmissometer methods are (a) no necessity for line-of-sight measurement geometry, (b) accurate measurement of high optical thickness media is possible, (c) under certain conditions measurements can include characteristics of aerosol clouds related to light scatter that cannot be or are difficult to measure with a transmissometer, and (d) the cloud bandwidth for free space optical communication is directly measurable.

Optical flows method for lightweight agile remote sensor design and instrumentation

NASA Astrophysics Data System (ADS)

Wang, Chong; Xing, Fei; Wang, Hongjian; You, Zheng

2013-08-01

Lightweight agile remote sensors have become one type of the most important payloads and were widely utilized in space reconnaissance and resource survey. These imaging sensors are designed to obtain the high spatial, temporary and spectral resolution imageries. Key techniques in instrumentation include flexible maneuvering, advanced imaging control algorithms and integrative measuring techniques, which are closely correlative or even acting as the bottle-necks for each other. Therefore, mutual restrictive problems must be solved and optimized. Optical flow is the critical model which to be fully represented in the information transferring as well as radiation energy flowing in dynamic imaging. For agile sensors, especially with wide-field-of view, imaging optical flows may distort and deviate seriously when they perform large angle attitude maneuvering imaging. The phenomena are mainly attributed to the geometrical characteristics of the three-dimensional earth surface as well as the coupled effects due to the complicated relative motion between the sensor and scene. Under this circumstance, velocity fields distribute nonlinearly, the imageries may badly be smeared or probably the geometrical structures are changed since the image velocity matching errors are not having been eliminated perfectly. In this paper, precise imaging optical flow model is established for agile remote sensors, for which optical flows evolving is factorized by two forms, which respectively due to translational movement and image shape changing. Moreover, base on that, agile remote sensors instrumentation was investigated. The main techniques which concern optical flow modeling include integrative design with lightweight star sensors along with micro inertial measurement units and corresponding data fusion, the assemblies of focal plane layout and control, imageries post processing for agile remote sensors etc. Some experiments show that the optical analyzing method is effective to eliminate the limitations for the performance indexes, and succeeded to be applied for integrative system design. Finally, a principle prototype of agile remote sensor designed by the method is discussed.

Methods for determination of optic nerve blood flow.

PubMed Central

Glazer, L. C.

1988-01-01

A variety of studies have been conducted over the past two decades to determine if decreased optic nerve blood flow has a role in the etiology of glaucomatous nerve damage. Five basic methods have been employed in examining blood flow. Invasive studies, utilizing electrodes placed in the optic nerve head, represent one of the first attempts to measure blood flow. More recently, the methodologies have included axoplasmic flow analysis, microspheres, radioactive tracers such as iodoantipyrine, and laser doppler measurements. The results of these studies are inconclusive and frequently contradictory. When the studies are grouped by methodology, only the iodoantipyrine data are consistent. While each of the experimental techniques has limitations, iodoantipyrine appears to have better resolution than either invasive studies or microspheres. PMID:3284212

Laser-ultrasound spectroscopy apparatus and method with detection of shear resonances for measuring anisotropy, thickness, and other properties

DOEpatents

Levesque, Daniel; Moreau, Andre; Dubois, Marc; Monchalin, Jean-Pierre; Bussiere, Jean; Lord, Martin; Padioleau, Christian

2000-01-01

Apparatus and method for detecting shear resonances includes structure and steps for applying a radiation pulse from a pulsed source of radiation to an object to generate elastic waves therein, optically detecting the elastic waves generated in the object, and analyzing the elastic waves optically detected in the object. These shear resonances, alone or in combination with other information, may be used in the present invention to improve thickness measurement accuracy and to determine geometrical, microstructural, and physical properties of the object. At least one shear resonance in the object is detected with the elastic waves optically detected in the object. Preferably, laser-ultrasound spectroscopy is utilized to detect the shear resonances.

Controlling ionotropic and metabotropic glutamate receptors with light: principles and potential.

PubMed

Reiner, Andreas; Levitz, Joshua; Isacoff, Ehud Y

2015-02-01

Light offers unique advantages for studying and manipulating biomolecules and the cellular processes that they control. Optical control of ionotropic and metabotropic glutamate receptors has garnered significant interest, since these receptors are central to signaling at neuronal synapses and only optical approaches provide the spatial and temporal resolution required to directly probe receptor function in cells and tissue. Following the classical method of glutamate photo-uncaging, recently developed methods have added other forms of remote control, including those with high molecular specificity and genetic targeting. These tools open the door to the direct optical control of synaptic transmission and plasticity, as well as the probing of native receptor function in intact neural circuits. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optical and magnetic properties of porous anodic alumina/Ni nanocomposite films

NASA Astrophysics Data System (ADS)

Zhang, Jing-Jing; Li, Zi-Yue; Zhang, Zhi-Jun; Wu, Tian-Shan; Sun, Hui-Yuan

2013-06-01

A simple method to tune the optical properties of porous anodic alumina (PAA) films embedded with Ni is reported. The films display highly saturated colors after being synthesized by an ac electrodeposition method. The optical properties of the samples can be effectively tuned by varying the oxidation time of aluminum. The ultrashort Ni nanowires (100 nm long and 50 nm in diameter) present only fcc phase and show no apparent averaged effective magnetic anisotropy. The coercivity mechanism of the Ni nanowires in our case is consistent with fanning mechanism based on a chain-of-spheres model. PAA/Ni films with structural color and magnetic properties have friability-resistant feature and can be used in many areas, including decoration, display, and multifunctional anti-counterfeiting technology.

Optical and Photothermal Behaviors of Colloidal and Self-Assembled Magnetic-Plasmonic Nanostructures

NASA Astrophysics Data System (ADS)

Liu, Kai

This dissertation is based on numerous efforts in exploring the capabilties of numerical simulation for investigating novel optical phenomena in different colloidal plasmonic systems. The dissertation includes five chapters. Chapter 1 contains a general introduction to the fundamentals of plasmonic behaviors in colloidal clusters and bottom-up self-assembly methods for manufacturing colloidal clusters which include magnetic based and DNA-assisted pathways. Chapter 2 presents a systematic comparison of optical and thermodynamic properties of near-infrared colloidal nanoparticles, including SiO2 Au core-shell, Au nanocage and Au nanorod, and an example of the nanobubble-based photothermal therapy application. In Chapter 3, a optical phenomenon named Fano resonance is demonstrated in a colloidal heptamer design which consists of seven Fe 3O4 Au core-shell nanoparticles. The incorporation of the magnetic core enables a magnetic-assisted self-assembly process which will be discussed after the photonic analysis. In Chapter 4, the optical behaviors in a 1D magnetic-plasmonic chain are explored. A demonstration of the magnetic-based self-assembly of this 1D chain is given. Chapter 5 is focused on the study of the chiral optical responses in a helical nanoscale system which follows a 3D helical arrangement of Fe3O4 Au core-shell nanoparticles.

Optical Testing and Verification Methods for the James Webb Space Telescope Integrated Science Instrument Module Element

NASA Technical Reports Server (NTRS)

Antonille, Scott R.; Miskey, Cherie L.; Ohl, Raymond G.; Rohrbach, Scott O.; Aronstein, David L.; Bartoszyk, Andrew E.; Bowers, Charles W.; Cofie, Emmanuel; Collins, Nicholas R.; Comber, Brian J.;

Optical testing and verification methods for the James Webb Space Telescope Integrated Science Instrument Module element

NASA Astrophysics Data System (ADS)

Antonille, Scott R.; Miskey, Cherie L.; Ohl, Raymond G.; Rohrbach, Scott O.; Aronstein, David L.; Bartoszyk, Andrew E.; Bowers, Charles W.; Cofie, Emmanuel; Collins, Nicholas R.; Comber, Brian J.; Eichhorn, William L.; Glasse, Alistair C.; Gracey, Renee; Hartig, George F.; Howard, Joseph M.; Kelly, Douglas M.; Kimble, Randy A.; Kirk, Jeffrey R.; Kubalak, David A.; Landsman, Wayne B.; Lindler, Don J.; Malumuth, Eliot M.; Maszkiewicz, Michael; Rieke, Marcia J.; Rowlands, Neil; Sabatke, Derek S.; Smith, Corbett T.; Smith, J. Scott; Sullivan, Joseph F.; Telfer, Randal C.; Te Plate, Maurice; Vila, M. Begoña.; Warner, Gerry D.; Wright, David; Wright, Raymond H.; Zhou, Julia; Zielinski, Thomas P.

2016-09-01

NASA's James Webb Space Telescope (JWST) is a 6.5m diameter, segmented, deployable telescope for cryogenic IR space astronomy. The JWST Observatory includes the Optical Telescope Element (OTE) and the Integrated Science Instrument Module (ISIM), that contains four science instruments (SI) and the Fine Guidance Sensor (FGS). The SIs are mounted to a composite metering structure. The SIs and FGS were integrated to the ISIM structure and optically tested at NASA's Goddard Space Flight Center using the Optical Telescope Element SIMulator (OSIM). OSIM is a full-field, cryogenic JWST telescope simulator. SI performance, including alignment and wavefront error, was evaluated using OSIM. We describe test and analysis methods for optical performance verification of the ISIM Element, with an emphasis on the processes used to plan and execute the test. The complexity of ISIM and OSIM drove us to develop a software tool for test planning that allows for configuration control of observations, implementation of associated scripts, and management of hardware and software limits and constraints, as well as tools for rapid data evaluation, and flexible re-planning in response to the unexpected. As examples of our test and analysis approach, we discuss how factors such as the ground test thermal environment are compensated in alignment. We describe how these innovative methods for test planning and execution and post-test analysis were instrumental in the verification program for the ISIM element, with enough information to allow the reader to consider these innovations and lessons learned in this successful effort in their future testing for other programs.

Optical add/drop filter for wavelength division multiplexed systems

DOEpatents

Deri, Robert J.; Strand, Oliver T.; Garrett, Henry E.

2002-01-01

An optical add/drop filter for wavelength division multiplexed systems and construction methods are disclosed. The add/drop filter includes a first ferrule having a first pre-formed opening for receiving a first optical fiber; an interference filter oriented to pass a first set of wavelengths along the first optical fiber and reflect a second set of wavelengths; and, a second ferrule having a second pre-formed opening for receiving the second optical fiber, and the reflected second set of wavelengths. A method for constructing the optical add/drop filter consists of the steps of forming a first set of openings in a first ferrule; inserting a first set of optical fibers into the first set of openings; forming a first set of guide pin openings in the first ferrule; dividing the first ferrule into a first ferrule portion and a second ferrule portion; forming an interference filter on the first ferrule portion; inserting guide pins through the first set of guide pin openings in the first ferrule portion and second ferrule portion to passively align the first set of optical fibers; removing material such that light reflected from the interference filter from the first set of optical fibers is accessible; forming a second set of openings in a second ferrule; inserting a second set of optical fibers into the second set of openings; and positioning the second ferrule with respect to the first ferrule such that the second set of optical fibers receive the light reflected from the interference filter.

Simulation of the optical coating deposition

NASA Astrophysics Data System (ADS)

Grigoriev, Fedor; Sulimov, Vladimir; Tikhonravov, Alexander

2018-04-01

A brief review of the mathematical methods of thin-film growth simulation and results of their applications is presented. Both full-atomistic and multi-scale approaches that were used in the studies of thin-film deposition are considered. The results of the structural parameter simulation including density profiles, roughness, porosity, point defect concentration, and others are discussed. The application of the quantum level methods to the simulation of the thin-film electronic and optical properties is considered. Special attention is paid to the simulation of the silicon dioxide thin films.

Diffraction mode terahertz tomography

DOEpatents

Ferguson, Bradley; Wang, Shaohong; Zhang, Xi-Cheng

2006-10-31

A method of obtaining a series of images of a three-dimensional object. The method includes the steps of transmitting pulsed terahertz (THz) radiation through the entire object from a plurality of angles, optically detecting changes in the transmitted THz radiation using pulsed laser radiation, and constructing a plurality of imaged slices of the three-dimensional object using the detected changes in the transmitted THz radiation. The THz radiation is transmitted through the object as a two-dimensional array of parallel rays. The optical detection is an array of detectors such as a CCD sensor.

Gaussian-Beam/Physical-Optics Design Of Beam Waveguide

NASA Technical Reports Server (NTRS)

Veruttipong, Watt; Chen, Jacqueline C.; Bathker, Dan A.

1993-01-01

In iterative method of designing wideband beam-waveguide feed for paraboloidal-reflector antenna, Gaussian-beam approximation alternated with more nearly exact physical-optics analysis of diffraction. Includes curved and straight reflectors guiding radiation from feed horn to subreflector. For iterative design calculations, curved mirrors mathematically modeled as thin lenses. Each distance Li is combined length of two straight-line segments intersecting at one of flat mirrors. Method useful for designing beam-waveguide reflectors or mirrors required to have diameters approximately less than 30 wavelengths at one or more intended operating frequencies.

Determination of water pH using absorption-based optical sensors: evaluation of different calculation methods

NASA Astrophysics Data System (ADS)

Wang, Hongliang; Liu, Baohua; Ding, Zhongjun; Wang, Xiangxin

2017-02-01

Absorption-based optical sensors have been developed for the determination of water pH. In this paper, based on the preparation of a transparent sol-gel thin film with a phenol red (PR) indicator, several calculation methods, including simple linear regression analysis, quadratic regression analysis and dual-wavelength absorbance ratio analysis, were used to calculate water pH. Results of MSSRR show that dual-wavelength absorbance ratio analysis can improve the calculation accuracy of water pH in long-term measurement.

Development, history, and future of automated cell counters.

PubMed

Green, Ralph; Wachsmann-Hogiu, Sebastian

2015-03-01

Modern automated hematology instruments use either optical methods (light scatter), impedance-based methods based on the Coulter principle (changes in electrical current induced by blood cells flowing through an electrically charged opening), or a combination of both optical and impedance-based methods. Progressive improvement in these instruments has allowed the enumeration and evaluation of blood cells with great accuracy, precision, and speed at very low cost. Future directions of hematology instrumentation include the addition of new parameters and the development of point-of-care instrumentation. In the future, in-vivo analysis of blood cells may allow noninvasive and near-continuous measurements. Copyright © 2015 Elsevier Inc. All rights reserved.

New exact solutions of the Tzitzéica-type equations in non-linear optics using the expa function method

NASA Astrophysics Data System (ADS)

Hosseini, K.; Ayati, Z.; Ansari, R.

2018-04-01

One specific class of non-linear evolution equations, known as the Tzitzéica-type equations, has received great attention from a group of researchers involved in non-linear science. In this article, new exact solutions of the Tzitzéica-type equations arising in non-linear optics, including the Tzitzéica, Dodd-Bullough-Mikhailov and Tzitzéica-Dodd-Bullough equations, are obtained using the expa function method. The integration technique actually suggests a useful and reliable method to extract new exact solutions of a wide range of non-linear evolution equations.

On-ground Simulation of the Proton Spectrum in Space

NASA Astrophysics Data System (ADS)

Liu, Hai; Guan, Minchao; He, Shiyu; Yang, Dezhuang; Wang, Huaiyi; Abraimov, V. V.

2009-01-01

The distribution of proton energy losses in optical parts including optical lenses and mirrors was calculated using SRIM program, based on Mont Carlo method. The effect of proton energy on the optical spectrum of lenses and mirrors was also investigated through irradiation experiments, with the proton energy varying from 0.03 to 1 MeV. An approach of on-ground simulation of the proton spectrum in space was proposed taking into account the different characteristics of proton spectra in the radiation belt, solar cosmic ray, and galactic cosmic rays in GEO as well as the corresponding distribution of energy loss in optical parts.

Resonant inelastic scattering by use of geometrical optics.

PubMed

Schulte, Jörg; Schweiger, Gustav

2003-02-01

We investigate the inelastic scattering on spherical particles that contain one concentric inclusion in the case of input and output resonances, using a geometrical optics method. The excitation of resonances is included in geometrical optics by use of the concept of tunneled rays. To get a quantitative description of optical tunneling on spherical surfaces, we derive appropriate Fresnel-type reflection and transmission coefficients for the tunneled rays. We calculate the inelastic scattering cross section in the case of input and output resonances and investigate the influence of the distribution of the active material in the particle as well as the influence of the inclusion on inelastic scattering.

Optical microtopographic inspection of asphalt pavement surfaces

NASA Astrophysics Data System (ADS)

Costa, Manuel F. M.; Freitas, E. F.; Torres, H.; Cerezo, V.

2017-08-01

Microtopographic and rugometric characterization of surfaces is routinely and effectively performed non-invasively by a number of different optical methods. Rough surfaces are also inspected using optical profilometers and microtopographer. The characterization of road asphalt pavement surfaces produced in different ways and compositions is fundamental for economical and safety reasons. Having complex structures, including topographically with different ranges of form error and roughness, the inspection of asphalt pavement surfaces is difficult to perform non-invasively. In this communication we will report on the optical non-contact rugometric characterization of the surface of different types of road pavements performed at the Microtopography Laboratory of the Physics Department of the University of Minho.

System and Method for Generating a Frequency Modulated Linear Laser Waveform

NASA Technical Reports Server (NTRS)

Pierrottet, Diego F. (Inventor); Petway, Larry B. (Inventor); Amzajerdian, Farzin (Inventor); Barnes, Bruce W. (Inventor); Lockard, George E. (Inventor); Hines, Glenn D. (Inventor)

2017-01-01

A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

System and Method for Generating a Frequency Modulated Linear Laser Waveform

NASA Technical Reports Server (NTRS)

Pierrottet, Diego F. (Inventor); Petway, Larry B. (Inventor); Amzajerdian, Farzin (Inventor); Barnes, Bruce W. (Inventor); Lockard, George E. (Inventor); Hines, Glenn D. (Inventor)

2014-01-01

A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

T-matrix method in plasmonics: An overview

NASA Astrophysics Data System (ADS)

Khlebtsov, Nikolai G.

2013-07-01

Optical properties of isolated and coupled plasmonic nanoparticles (NPs) are of great interest for many applications in nanophotonics, nanobiotechnology, and nanomedicine owing to rapid progress in fabrication, characterization, and surface functionalization technologies. To simulate optical responses from plasmonic nanostructures, various electromagnetic analytical and numerical methods have been adapted, tested, and used during the past two decades. Currently, the most popular numerical techniques are those that do not suffer from geometrical and composition limitations, e.g., the discrete dipole approximation (DDA), the boundary (finite) element method (BEM, FEM), the finite difference time domain method (FDTDM), and others. However, the T-matrix method still has its own niche in plasmonic science because of its great numerical efficiency, especially for systems with randomly oriented particles and clusters. In this review, I consider the application of the T-matrix method to various plasmonic problems, including dipolar, multipolar, and anisotropic properties of metal NPs; sensing applications; surface enhanced Raman scattering; optics of 1D-3D nanoparticle assemblies; plasmonic particles and clusters near and on substrates; and manipulation of plasmonic NPs with laser tweezers.

Electronic Holography with a Broad Spectrum Laser for Time Gated Imaging Through Highly Scattering Media.

NASA Astrophysics Data System (ADS)

Shih, Marian Pei-Ling

The problem of optical imaging through a highly scattering volume diffuser, in particular, biological tissue, has received renewed interest in recent years because of a search for alternative imaging diagnostics in the optical wavelengths for the early detection of human breast cancer. This dissertation discusses the optical imaging of objects obscured by diffusers that contribute an otherwise overwhelming degree of multiple scatter. Many optical imaging techniques are based on the first-arriving light principle. These methods usually combine a transilluminating optical short pulse with a time windowing gate in order to form a flat shadowgraph image of absorbing objects either embedded within or hidden behind a scattering medium. The gate selectively records an image of the first-arriving light, while simultaneously rejecting the later-arriving scattered light. One set of the many implementations of the first -arriving light principle relies on the gating property of holography. This thesis presents several holographic optical gating experiments that demonstrate the role that the temporal coherence function of the illumination source plays in the imaging of all objects with short coherence length holography, with special emphasis on the application to image through diffusers and its resolution capabilities. Previous researchers have already successfully combined electronic holography, holography in which the recording medium is a two dimensional detector array instead of photographic film, with light-in-flight holography into a short coherence length holography method that images through various types of multiply scattering random media, including chicken breast tissue and wax. This thesis reports further experimental exploration of the short coherence holography method for imaging through severely scattering diffusers. There is a study on the effectiveness of spatial filtering of the first-arriving light, as well as a report of the imaging, by means of the short coherence holographic method, of an absorber through a living human hand. This thesis also includes both theoretical analyses and experimental results of a spectral dispersion holography system which, instead of optically synthesizing the broad spectrum illumination source that is used for the short coherence holography method, digitally synthesizes a broad spectrum hologram from a collection of single frequency component holograms. This system has the time gating properties of short coherence length holography, as well as experimentally demonstrated applications for imaging through multiply scattering media.

Bonding by Hydroxide-Catalyzed Hydration and Dehydration

NASA Technical Reports Server (NTRS)

Gwo, Dz-Hung

2008-01-01

A simple, inexpensive method for bonding solid objects exploits hydroxide-catalyzed hydration and dehydration to form silicate-like networks in thin surface and interfacial layers between the objects. The method can be practiced at room temperature or over a wide range of temperatures. The method was developed especially to enable the formation of precise, reliable bonds between precise optical components. The bonds thus formed exhibit the precision and transparency of bonds formed by the conventional optical-contact method and the strength and reliability of high-temperature frit bonds. The method also lends itself to numerous non-optical applications in which there are requirements for precise bonds and/or requirements for bonds, whether precise or imprecise, that can reliably withstand severe environmental conditions. Categories of such non-optical applications include forming composite materials, coating substrates, forming laminate structures, and preparing objects of defined geometry and composition. The method is applicable to materials that either (1) can form silicate-like networks in the sense that they have silicate-like molecular structures that are extensible into silicate-like networks or (2) can be chemically linked to silicate-like networks by means of hydroxide-catalyzed hydration and dehydration. When hydrated, a material of either type features surface hydroxyl (-OH) groups. In this method, a silicate-like network that bonds two substrates can be formed either by a bonding material alone or by the bonding material together with material from either or both of the substrates. Typically, an aqueous hydroxide bonding solution is dispensed and allowed to flow between the mating surfaces by capillary action. If the surface figures of the substrates do not match precisely, bonding could be improved by including a filling material in the bonding solution. Preferably, the filling material should include at least one ingredient that can be hydrated to have exposed hydroxyl groups and that can be chemically linked, by hydroxide catalysis, to a silicate-like network. The silicate-like network could be generated in situ from the filling material and/or substrate material, or could be originally present in the bonding material.

Multiscale solutions of radiative heat transfer by the discrete unified gas kinetic scheme

NASA Astrophysics Data System (ADS)

Luo, Xiao-Ping; Wang, Cun-Hai; Zhang, Yong; Yi, Hong-Liang; Tan, He-Ping

2018-06-01

The radiative transfer equation (RTE) has two asymptotic regimes characterized by the optical thickness, namely, optically thin and optically thick regimes. In the optically thin regime, a ballistic or kinetic transport is dominant. In the optically thick regime, energy transport is totally dominated by multiple collisions between photons; that is, the photons propagate by means of diffusion. To obtain convergent solutions to the RTE, conventional numerical schemes have a strong dependence on the number of spatial grids, which leads to a serious computational inefficiency in the regime where the diffusion is predominant. In this work, a discrete unified gas kinetic scheme (DUGKS) is developed to predict radiative heat transfer in participating media. Numerical performances of the DUGKS are compared in detail with conventional methods through three cases including one-dimensional transient radiative heat transfer, two-dimensional steady radiative heat transfer, and three-dimensional multiscale radiative heat transfer. Due to the asymptotic preserving property, the present method with relatively coarse grids gives accurate and reliable numerical solutions for large, small, and in-between values of optical thickness, and, especially in the optically thick regime, the DUGKS demonstrates a pronounced computational efficiency advantage over the conventional numerical models. In addition, the DUGKS has a promising potential in the study of multiscale radiative heat transfer inside the participating medium with a transition from optically thin to optically thick regimes.

Optical fiber head for providing lateral viewing

DOEpatents

Everett, Matthew J.; Colston, Billy W.; James, Dale L.; Brown, Steve; Da Silva, Luiz

2002-01-01

The head of an optical fiber comprising the sensing probe of an optical heterodyne sensing device includes a planar surface that intersects the perpendicular to axial centerline of the fiber at a polishing angle .theta.. The planar surface is coated with a reflective material so that light traveling axially through the fiber is reflected transverse to the fiber's axial centerline, and is emitted laterally through the side of the fiber. Alternatively, the planar surface can be left uncoated. The polishing angle .theta. must be no greater than 39.degree. or must be at least 51.degree.. The emitted light is reflected from adjacent biological tissue, collected by the head, and then processed to provide real-time images of the tissue. The method for forming the planar surface includes shearing the end of the optical fiber and applying the reflective material before removing the buffer that circumscribes the cladding and the core.

Demonstration of theoretical and experimental simulations in fiber optics course

NASA Astrophysics Data System (ADS)

Yao, Tianfu; Wang, Xiaolin; Shi, Jianhua; Lei, Bing; Liu, Wei; Wang, Wei; Hu, Haojun

2017-08-01

"Fiber optics" course plays a supporting effect in the curriculum frame of optics and photonics at both undergraduate and postgraduate levels. Moreover, the course can be treated as compulsory for students specialized in the fiber-related field, such as fiber communication, fiber sensing and fiber light source. The corresponding content in fiber optics requires the knowledge of geometrical and physical optics as background, including basic optical theory and fiber components in practice. Thus, to help the students comprehend the relatively abundant and complex content, it is necessary to investigate novel teaching method assistant the classic lectures. In this paper, we introduce the multidimensional pattern in fiber-optics teaching involving theoretical and laboratory simulations. First, the theoretical simulations is demonstrated based on the self-developed software named "FB tool" which can be installed in both smart phone with Android operating system and personal computer. FB tool covers the fundamental calculations relating to transverse modes, fiber lasers and nonlinearities and so on. By comparing the calculation results with other commercial software like COMSOL, SFTool shows high accuracy with high speed. Then the laboratory simulations are designed including fiber coupling, Erbium doped fiber amplifiers, fiber components and so on. The simulations not only supports students understand basic knowledge in the course, but also provides opportunities to develop creative projects in fiber optics.

International Seminar on Laser and Opto-Electronic Technology in Industry: State-of-the-Art Review, Xiamen, People's Republic of China, June 25-28, 1986, Proceedings

NASA Astrophysics Data System (ADS)

Ke, Jingtang; Pryputniewicz, Ryszard J.

Various papers on the state of the art in laser and optoelectronic technology in industry are presented. Individual topics addressed include: wavelength compensation for holographic optical element, optoelectronic techniques for measurement and inspection, new optical measurement methods in Western Europe, applications of coherent optics at ISL, imaging techniques for gas turbine development, the Rolls-Royce experience with industrial holography, panoramic holocamera for tube and borehole inspection, optical characterization of electronic materials, optical strain measurement of rotating components, quantitative interpretation of holograms and specklegrams, laser speckle technique for hydraulic structural model test, study of holospeckle interferometry, common path shearing fringe scanning interferometer, and laser interferometry applied to nondestructive testing of tires.

Ultrafast optical pulse delivery with fibers for nonlinear microscopy

PubMed Central

Kim, Daekeun; Choi, Heejin; Yazdanfar, Siavash; So, Peter T. C.

2008-01-01

Nonlinear microscopies including multiphoton excitation fluorescence microscopy and multiple-harmonic generation microscopy have recently gained popularity for cellular and tissue imaging. The optimization of these imaging methods for minimally invasive use will require optical fibers to conduct light into tight space where free space delivery is difficult. The delivery of high peak power laser pulses with optical fibers is limited by dispersion resulting from nonlinear refractive index responses. In this paper, we characterize a variety of commonly used optical fibers in terms of how they affect pulse profile and imaging performance of nonlinear microscopy; the following parameters are quantified: spectral bandwidth and temporal pulse width, two-photon excitation efficiency, and optical resolution. A theoretical explanation for the measured performance of these is also provided. PMID:18816597

Optical Design for Extremely Large Telescope Adaptive Optics Systems

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

Bauman, Brian J.

2003-01-01

Designing an adaptive optics (AO) system for extremely large telescopes (ELT's) will present new optical engineering challenges. Several of these challenges are addressed in this work, including first-order design of multi-conjugate adaptive optics (MCAO) systems, pyramid wavefront sensors (PWFS's), and laser guide star (LGS) spot elongation. MCAO systems need to be designed in consideration of various constraints, including deformable mirror size and correction height. The y,{bar y} method of first-order optical design is a graphical technique that uses a plot with marginal and chief ray heights as coordinates; the optical system is represented as a segmented line. This method ismore » shown to be a powerful tool in designing MCAO systems. From these analyses, important conclusions about configurations are derived. PWFS's, which offer an alternative to Shack-Hartmann (SH) wavefront sensors (WFS's), are envisioned as the workhorse of layer-oriented adaptive optics. Current approaches use a 4-faceted glass pyramid to create a WFS analogous to a quad-cell SH WFS. PWFS's and SH WFS's are compared and some newly-considered similarities and PWFS advantages are presented. Techniques to extend PWFS's are offered: First, PWFS's can be extended to more pixels in the image by tiling pyramids contiguously. Second, pyramids, which are difficult to manufacture, can be replaced by less expensive lenslet arrays. An approach is outlined to convert existing SH WFS's to PWFS's for easy evaluation of PWFS's. Also, a demonstration of PWFS's in sensing varying amounts of an aberration is presented. For ELT's, the finite altitude and finite thickness of LGS's means that the LGS will appear elongated from the viewpoint of subapertures not directly under the telescope. Two techniques for dealing with LGS spot elongation in SH WFS's are presented. One method assumes that the laser will be pulsed and uses a segmented micro-electromechanical system (MEMS) to track the LGS light subaperture by subaperture as the light is returned from the upward-propagating laser pulse. A second method can be used if the laser is not pulsed. A lenslet array is described which creates ''pixels'' which are aligned with the axes of the elongated spot of each subaperture, without requiring special charge-coupled devices (CCD's).« less

Total Internal Reflection Microscopy (TIRM) as a nondestructive surface damage assessment tool

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

Liao, Z.M.; Cohen, S.J.; Taylor, J.R.

1994-10-01

An easy to use, nondestructive, method for evaluating subsurface damage in polished substrates has been established at LLNL. Subsurface damage has been related to laser damage in coated optical components used in high power, high repetition rate laser systems. Total Internal Reflection Microscopy (TIRM) has been shown to be a viable nondestructive technique in analyzing subsurface damage in optical components. A successful TIRM system has been established for evaluating subsurface damage on fused silica components. Laser light scattering from subsurface damage sites is collected through a Nomarski microscope. These images are then captured by a CCD camera for analysis onmore » a computer. A variety of optics, including components with intentional subsurface damage due to grinding and polishing, have been analyzed and their TIRM images compared to an existing destructive etching method. Methods for quantitative measurement of subsurface damage are also discussed.« less

Specimen illumination apparatus with optical cavity for dark field illumination

DOEpatents

Pinkel, Daniel; Sudar, Damir; Albertson, Donna

1999-01-01

An illumination apparatus with a specimen slide holder, an illumination source, an optical cavity producing multiple reflection of illumination light to a specimen comprising a first and a second reflective surface arranged to achieve multiple reflections of light to a specimen is provided. The apparatus can further include additional reflective surfaces to achieve the optical cavity, a slide for mounting the specimen, a coverslip which is a reflective component of the optical cavity, one or more prisms for directing light within the optical cavity, antifading solutions for improving the viewing properties of the specimen, an array of materials for analysis, fluorescent components, curved reflective surfaces as components of the optical cavity, specimen detection apparatus, optical detection equipment, computers for analysis of optical images, a plane polarizer, fiberoptics, light transmission apertures, microscopic components, lenses for viewing the specimen, and upper and lower mirrors above and below the specimen slide as components of the optical cavity. Methods of using the apparatus are also provided.

Subsurface damage in some single crystalline optical materials.

PubMed

Randi, Joseph A; Lambropoulos, John C; Jacobs, Stephen D

2005-04-20

We present a nondestructive method for estimating the depth of subsurface damage (SSD) in some single crystalline optical materials (silicon, lithium niobate, calcium fluoride, magnesium fluoride, and sapphire); the method is established by correlating surface microroughness measurements, specifically, the peak-to-valley (p-v) microroughness, to the depth of SSD found by a novel destructive method. Previous methods for directly determining the depth of SSD may be insufficient when applied to single crystals that are very soft or very hard. Our novel destructive technique uses magnetorheological finishing to polish spots onto a ground surface. We find that p-v surface microroughness, appropriately scaled, gives an upper bound to SSD. Our data suggest that SSD in the single crystalline optical materials included in our study (deterministically microground, lapped, and sawed) is always less than 1.4 times the p-v surface microroughness found by white-light interferometry. We also discuss another way of estimating SSD based on the abrasive size used.

Uniform enhancement of optical micro-angiography images using Rayleigh contrast-limited adaptive histogram equalization.

PubMed

Yousefi, Siavash; Qin, Jia; Zhi, Zhongwei; Wang, Ruikang K

2013-02-01

Optical microangiography is an imaging technology that is capable of providing detailed functional blood flow maps within microcirculatory tissue beds in vivo. Some practical issues however exist when displaying and quantifying the microcirculation that perfuses the scanned tissue volume. These issues include: (I) Probing light is subject to specular reflection when it shines onto sample. The unevenness of the tissue surface makes the light energy entering the tissue not uniform over the entire scanned tissue volume. (II) The biological tissue is heterogeneous in nature, meaning the scattering and absorption properties of tissue would attenuate the probe beam. These physical limitations can result in local contrast degradation and non-uniform micro-angiogram images. In this paper, we propose a post-processing method that uses Rayleigh contrast-limited adaptive histogram equalization to increase the contrast and improve the overall appearance and uniformity of optical micro-angiograms without saturating the vessel intensity and changing the physical meaning of the micro-angiograms. The qualitative and quantitative performance of the proposed method is compared with those of common histogram equalization and contrast enhancement methods. We demonstrate that the proposed method outperforms other existing approaches. The proposed method is not limited to optical microangiography and can be used in other image modalities such as photo-acoustic tomography and scanning laser confocal microscopy.

Contrast enhanced spectroscopic optical coherence tomography

NASA Technical Reports Server (NTRS)

Xu, Chenyang (Inventor); Boppart, Stephen A. (Inventor)

2010-01-01

A method of forming an image of a sample includes performing SOCT on a sample. The sample may include a contrast agent, which may include an absorbing agent and/or a scattering agent. A method of forming an image of tissue may include selecting a contrast agent, delivering the contrast agent to the tissue, acquiring SOCT data from the tissue, and converting the SOCT data into an image. The contributions to the SOCT data of an absorbing agent and a scattering agent in a sample may be quantified separately.

Microoptical System And Fabrication Method Therefor

DOEpatents

Sweatt, William C.; Christenson, Todd R.

2005-03-15

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

Design of precise assembly equipment of large aperture optics

NASA Astrophysics Data System (ADS)

Pei, Guoqing; Xu, Xu; Xiong, Zhao; Yan, Han; Qin, Tinghai; Zhou, Hai; Yuan, Xiaodong

2017-05-01

High-energy solid-state laser is an important way to achieve laser fusion research. Laser fusion facility includes thousands of various types of large aperture optics. These large aperture optics should be assembled with high precision and high efficiency. Currently, however, the assembly of large aperture optics is by man's hand which is in low level of efficiency and labor-intensive. Here, according to the characteristics of the assembly of large aperture optics, we designed three kinds of grasping devices. Using Finite Element Method, we simulated the impact of the grasping device on the PV value and the RMS value of the large aperture optics. The structural strength of the grasping device's key part was analyzed. An experiment was performed to illustrate the reliability and precision of the grasping device. We anticipate that the grasping device would complete the assembly of large aperture optics precisely and efficiently.

Allocation of spectral and spatial modes in multidimensional metro-access optical networks

NASA Astrophysics Data System (ADS)

Gao, Wenbo; Cvijetic, Milorad

2018-04-01

Introduction of spatial division multiplexing (SDM) has added a new dimension in an effort to increase optical fiber channel capacity. At the same time, it can also be explored as an advanced optical networking tool. In this paper, we have investigated the resource allocation to end-users in multidimensional networking structure with plurality of spectral and spatial modes actively deployed in different networking segments. This presents a more comprehensive method as compared to the common practice where the segments of optical network are analyzed independently since the interaction between network hierarchies is included into consideration. We explored the possible transparency from the metro/core network to the optical access network, analyzed the potential bottlenecks from the network architecture perspective, and identified an optimized network structure. In our considerations, the viability of optical grooming through the entire hierarchical all-optical network is investigated by evaluating the effective utilization and spectral efficiency of the network architecture.

Mach-zehnder based optical marker/comb generator for streak camera calibration

DOEpatents

Miller, Edward Kirk

2015-03-03

This disclosure is directed to a method and apparatus for generating marker and comb indicia in an optical environment using a Mach-Zehnder (M-Z) modulator. High speed recording devices are configured to record image or other data defining a high speed event. To calibrate and establish time reference, the markers or combs are indicia which serve as timing pulses (markers) or a constant-frequency train of optical pulses (comb) to be imaged on a streak camera for accurate time based calibration and time reference. The system includes a camera, an optic signal generator which provides an optic signal to an M-Z modulator and biasing and modulation signal generators configured to provide input to the M-Z modulator. An optical reference signal is provided to the M-Z modulator. The M-Z modulator modulates the reference signal to a higher frequency optical signal which is output through a fiber coupled link to the streak camera.

Microoptical system and fabrication method therefor

DOEpatents

Sweatt, William C.; Christenson, Todd R.

2003-07-08

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

LASERS IN MEDICINE: Laser diagnostics of biofractals

NASA Astrophysics Data System (ADS)

Ushenko, A. G.

1999-12-01

An optical approach to the problem of modelling and diagnostics of the structures of biofractal formations was considered in relation to human bone tissue. A model was proposed for the optical properties of this tissue, including three levels of fractal organisation: microcrystalline, macrocrystalline, and architectural. The studies were based on laser coherent polarimetry ensuring the retrieval of the fullest information about the optical and polarisation properties of bone tissue. A method was developed for contactless noninvasive diagnostics of the orientational and mineralogical structure of bone tissue considered as a biofractal.

Quantum-optical coherence tomography with classical light.

PubMed

Lavoie, J; Kaltenbaek, R; Resch, K J

2009-03-02

Quantum-optical coherence tomography (Q-OCT) is an interferometric technique for axial imaging offering several advantages over conventional methods. Chirped-pulse interferometry (CPI) was recently demonstrated to exhibit all of the benefits of the quantum interferometer upon which Q-OCT is based. Here we use CPI to measure axial interferograms to profile a sample accruing the important benefits of Q-OCT, including automatic dispersion cancellation, but with 10 million times higher signal. Our technique solves the artifact problem in Q-OCT and highlights the power of classical correlation in optical imaging.

Optical power of VCSELs stabilized to 35 ppm/°C without a TEC

NASA Astrophysics Data System (ADS)

Downing, John

2015-03-01

This paper reports a method and system comprising a light source, an electronic method, and a calibration procedure for stabilizing the optical power of vertical-cavity surface-emitting lasers (VCSELs) and laser diodes (LDs) without the use thermoelectric coolers (TECs). The system eliminates the needs for custom interference coatings, polarization adjustments, and the exact alignment required by the optical method reported in 2013 [1]. It can precisely compensate for the effects of temperature and wavelength drift on photodiode responsivity as well as changes in VCSEL beam quality and polarization angle over a 50°C temperature range. Data obtained from light sources built with single-mode polarization-locked VCSELs demonstrate that 30 ppm/°C stability can be readily obtained. The system has advantages over TECstabilized laser modules that include: 1) 90% lower relative RMS optical power and temperature sensitivity, 2) a five-fold enhancement of wall-plug efficiency, 3) less component testing and sorting, 4) lower manufacturing costs, and 5) automated calibration in batches at time of manufacture is practical. The system is ideally suited for battery-powered environmental and in-home medical monitoring applications.

High-resolution matrix-assisted laser desorption ionization–imaging mass spectrometry of lipids in rodent optic nerve tissue

PubMed Central

Anderson, David M. G.; Mills, Daniel; Spraggins, Jeffrey; Lambert, Wendi S.; Calkins, David J.

2013-01-01

Purpose To develop a method for generating high spatial resolution (10 µm) matrix-assisted laser desorption ionization (MALDI) images of lipids in rodent optic nerve tissue. Methods Ice-embedded optic nerve tissue from rats and mice were cryosectioned across the coronal and sagittal axes of the nerve fiber. Sections were thaw mounted on gold-coated MALDI plates and were washed with ammonium acetate to remove biologic salts before being coated in 2,5-dihydroxybenzoic acid by sublimation. MALDI images were generated in positive and negative ion modes at 10 µm spatial resolution. Lipid identification was performed with a high mass resolution Fourier transform ion cyclotron resonance mass spectrometer. Results Several lipid species were observed with high signal intensity in MALDI images of optic nerve tissue. Several lipids were localized to specific structures including in the meninges surrounding the optic nerve and in the central neuronal tissue. Specifically, phosphatidylcholine species were observed throughout the nerve tissue in positive ion mode while sulfatide species were observed in high abundance in the meninges surrounding the optic nerve in negative ion mode. Accurate mass measurements and fragmentation using sustained off-resonance irradiation with a high mass resolution Fourier transform ion cyclotron resonance mass spectrometer instrument allowed for identification of lipid species present in the small structure of the optic nerve directly from tissue sections. Conclusions An optimized sample preparation method provides excellent sensitivity for lipid species present within optic nerve tissue. This allowed the laser spot size and fluence to be reduced to obtain a high spatial resolution of 10 µm. This new imaging modality can now be applied to determine spatial and molecular changes in optic nerve tissue with disease. PMID:23559852

Meeting the Cool Neighbors. XII. An Optically Anchored Analysis of the Near-infrared Spectra of L Dwarfs

NASA Astrophysics Data System (ADS)

Cruz, Kelle L.; Núñez, Alejandro; Burgasser, Adam J.; Abrahams, Ellianna; Rice, Emily L.; Reid, I. Neill; Looper, Dagny

2018-01-01

Discrepancies between competing optical and near-infrared (NIR) spectral typing systems for L dwarfs have motivated us to search for a classification scheme that ties the optical and NIR schemes together, and addresses complexities in the spectral morphology. We use new and extant optical and NIR spectra to compile a sample of 171 L dwarfs, including 27 low-gravity β and γ objects, with spectral coverage from 0.6–2.4 μm. We present 155 new low-resolution NIR spectra and 19 new optical spectra. We utilize a method for analyzing NIR spectra that partially removes the broad-band spectral slope and reveals similarities in the absorption features between objects of the same optical spectral type. Using the optical spectra as an anchor, we generate near-infrared spectral average templates for L0–L8, L0–L4γ, and L0–L1β type dwarfs. These templates reveal that NIR spectral morphologies are correlated with the optical types. They also show the range of spectral morphologies spanned by each spectral type. We compare low-gravity and field-gravity templates to provide recommendations on the minimum required observations for credibly classifying low-gravity spectra using low-resolution NIR data. We use the templates to evaluate the existing NIR spectral standards and propose new ones where appropriate. Finally, we build on the work of Kirkpatrick et al. to provide a spectral typing method that is tied to the optical and can be used when only H or K band data are available. The methods we present here provide resolutions to several long-standing issues with classifying L dwarf spectra and could also be the foundation for a spectral classification scheme for cloudy exoplanets.

Broadband Phase Retrieval for Image-Based Wavefront Sensing

NASA Technical Reports Server (NTRS)

Dean, Bruce H.

2007-01-01

A focus-diverse phase-retrieval algorithm has been shown to perform adequately for the purpose of image-based wavefront sensing when (1) broadband light (typically spanning the visible spectrum) is used in forming the images by use of an optical system under test and (2) the assumption of monochromaticity is applied to the broadband image data. Heretofore, it had been assumed that in order to obtain adequate performance, it is necessary to use narrowband or monochromatic light. Some background information, including definitions of terms and a brief description of pertinent aspects of image-based phase retrieval, is prerequisite to a meaningful summary of the present development. Phase retrieval is a general term used in optics to denote estimation of optical imperfections or aberrations of an optical system under test. The term image-based wavefront sensing refers to a general class of algorithms that recover optical phase information, and phase-retrieval algorithms constitute a subset of this class. In phase retrieval, one utilizes the measured response of the optical system under test to produce a phase estimate. The optical response of the system is defined as the image of a point-source object, which could be a star or a laboratory point source. The phase-retrieval problem is characterized as image-based in the sense that a charge-coupled-device camera, preferably of scientific imaging quality, is used to collect image data where the optical system would normally form an image. In a variant of phase retrieval, denoted phase-diverse phase retrieval [which can include focus-diverse phase retrieval (in which various defocus planes are used)], an additional known aberration (or an equivalent diversity function) is superimposed as an aid in estimating unknown aberrations by use of an image-based wavefront-sensing algorithm. Image-based phase-retrieval differs from such other wavefront-sensing methods, such as interferometry, shearing interferometry, curvature wavefront sensing, and Shack-Hartmann sensing, all of which entail disadvantages in comparison with image-based methods. The main disadvantages of these non-image based methods are complexity of test equipment and the need for a wavefront reference.

System and method for optically locating microchannel positions

DOEpatents

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.

Multiple Lens Experiment.

ERIC Educational Resources Information Center

Waring, Richard C.

1980-01-01

Describes an experiment which makes use of a number of concepts from geometrical optics. The apparatus and method which is intended for students in elementary college physics classes are included. (HM)

Method and apparatus for pulse stacking

DOEpatents

Harney, Robert C.

1977-01-01

An active pulse stacking system including an etalon and an electro-optical modulator apparatus combined with a pulse-forming network capable of forming and summing a sequence of time-delayed optical waveforms arising from, for example, a single laser pulse. The Pockels cell pulse stacker may attain an efficiency of about 2.6% while providing a controllable faster-than-exponential time rise in transmitted pulse intensity.

Precision mechanical structure of an ultra-high-resolution spectrometer for inelastic X-ray scattering instrument

DOEpatents

Shu, Deming; Shvydko, Yuri; Stoupin, Stanislav A.; Khachatryan, Ruben; Goetze, Kurt A.; Roberts, Timothy

2015-04-14

A method and an ultrahigh-resolution spectrometer including a precision mechanical structure for positioning inelastic X-ray scattering optics are provided. The spectrometer includes an X-ray monochromator and an X-ray analyzer, each including X-ray optics of a collimating (C) crystal, a pair of dispersing (D) element crystals, anomalous transmission filter (F) and a wavelength (W) selector crystal. A respective precision mechanical structure is provided with the X-ray monochromator and the X-ray analyzer. The precision mechanical structure includes a base plate, such as an aluminum base plate; positioning stages for D-crystal alignment; positioning stages with an incline sensor for C/F/W-crystal alignment, and the positioning stages including flexure-based high-stiffness structure.

Tailored vectorial light fields: flower, spider web and hybrid structures

NASA Astrophysics Data System (ADS)

Otte, Eileen; Alpmann, Christina; Denz, Cornelia

2017-04-01

We present the realization and analysis of tailored vector fields including polarization singularities. The fields are generated by a holographic method based on an advanced system including a spatial light modulator. We demonstrate our systems capabilities realizing specifically customized vector fields including stationary points of defined polarization in its transverse plane. Subsequently, vectorial flowers and spider webs as well as unique hybrid structures of these are introduced, and embedded singular points are characterized. These sophisticated light fields reveal attractive properties that pave the way to advanced application in e.g. optical micromanipulation. Beyond particle manipulation, they contribute essentially to actual questions in singular optics.

Enhanced linear photonic nanojet generated by core-shell optical microfibers

NASA Astrophysics Data System (ADS)

Liu, Cheng-Yang; Yen, Tzu-Ping; Chen, Chien-Wen

2017-05-01

The generation of linear photonic nanojet using core-shell optical microfiber is demonstrated numerically and experimentally in the visible light region. The power flow patterns for the core-shell optical microfiber are calculated by using the finite-difference time-domain method. The focusing properties of linear photonic nanojet are evaluated in terms of length and width along propagation and transversal directions. In experiment, the silica optical fiber is etched chemically down to 6 μm diameter and coated with metallic thin film by using glancing angle deposition. We show that the linear photonic nanojet is enhanced clearly by metallic shell due to surface plasmon polaritons. The large-area superresolution imaging can be performed by using a core-shell optical microfiber in the far-field system. The potential applications of this core-shell optical microfiber include micro-fluidics and nano-structure measurements.

Optical and sensing properties of sol-gel derived vanadium pentoxide thin films with porous and dense structures

NASA Astrophysics Data System (ADS)

Babeva, T.; Awala, H.; Grand, J.; Lazarova, K.; Vasileva, M.; Mintova, S.

2018-03-01

The sol-gel and spin-coating methods were used for deposition of thin transparent V2O5 films on optical glass substrates and silicon wafers. Different synthesis and deposition conditions, including synthesis temperatures and post-deposition annealing, were used aiming at obtaining transparent films with high refractive index and good optical quality. The surface morphology and structure of the films were studied by SEM and XRD. The optical properties (refractive index, extinction coefficient and optical band gap) and thickness of the V2O5 films were determined from their transmittance and reflectance spectra. The potential application of the films as building blocks of optical sensors was demonstrated by preparation of multilayered structures comprising both V2O5 and BEA-type zeolite films and testing their response towards acetone vapors.

An adaptive optics imaging system designed for clinical use.

PubMed

Zhang, Jie; Yang, Qiang; Saito, Kenichi; Nozato, Koji; Williams, David R; Rossi, Ethan A

2015-06-01

Here we demonstrate a new imaging system that addresses several major problems limiting the clinical utility of conventional adaptive optics scanning light ophthalmoscopy (AOSLO), including its small field of view (FOV), reliance on patient fixation for targeting imaging, and substantial post-processing time. We previously showed an efficient image based eye tracking method for real-time optical stabilization and image registration in AOSLO. However, in patients with poor fixation, eye motion causes the FOV to drift substantially, causing this approach to fail. We solve that problem here by tracking eye motion at multiple spatial scales simultaneously by optically and electronically integrating a wide FOV SLO (WFSLO) with an AOSLO. This multi-scale approach, implemented with fast tip/tilt mirrors, has a large stabilization range of ± 5.6°. Our method consists of three stages implemented in parallel: 1) coarse optical stabilization driven by a WFSLO image, 2) fine optical stabilization driven by an AOSLO image, and 3) sub-pixel digital registration of the AOSLO image. We evaluated system performance in normal eyes and diseased eyes with poor fixation. Residual image motion with incremental compensation after each stage was: 1) ~2-3 arc minutes, (arcmin) 2) ~0.5-0.8 arcmin and, 3) ~0.05-0.07 arcmin, for normal eyes. Performance in eyes with poor fixation was: 1) ~3-5 arcmin, 2) ~0.7-1.1 arcmin and 3) ~0.07-0.14 arcmin. We demonstrate that this system is capable of reducing image motion by a factor of ~400, on average. This new optical design provides additional benefits for clinical imaging, including a steering subsystem for AOSLO that can be guided by the WFSLO to target specific regions of interest such as retinal pathology and real-time averaging of registered images to eliminate image post-processing.

Simplified Generation of High-Angular-Momentum Light Beams

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Strekalov, Dmitry; Grudinin, Ivan

2007-01-01

A simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering- gallery-mode (WGM) resonator, and optical fibers. The method also can be used to generate a Bessel beam. ( Bessel beam denotes a member of a class of non-diffracting beams, so named because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have high values of angular momentum.) High-angular-momentum light beams are used in some applications in biology and nanotechnology, wherein they are known for their ability to apply torque to make microscopic objects rotate. High-angular-momentum light beams could also be used to increase bandwidths of fiber-optic communication systems. The present simplified method of generating a high-angular-momentum light beam was conceived as an alternative to prior such methods, which are complicated and require optical setups that include, variously, holograms, modulating Fabry-Perot cavities, or special microstructures. The present simplified method exploits a combination of the complex structure of the electromagnetic field inside a WGM resonator, total internal reflection in the WGM resonator, and the electromagnetic modes supported by an optical fiber. The optical fiber used to extract light from the WGM resonator is made of fused quartz. The output end of this fiber is polished flat and perpendicular to the fiber axis. The input end of this fiber is cut on a slant and placed very close to the WGM resonator at an appropriate position and orientation. To excite the resonant whispering- gallery modes, light is introduced into the WGM resonator via another optical fiber that is part of a pigtailed fiber-optic coupler. Light extracted from the WGM resonator is transformed into a high-angular- momentum beam inside the extraction optical fiber and this beam is emitted from the polished flat output end. By adjusting the geometry of this apparatus, it is possible to generate a variety of optical beams characterized by a wide range of parameters. These beams generally have high angular momenta and can be of either Bessel or Bessel-related types.

Apparatus for processing electromagnetic radiation and method

NASA Technical Reports Server (NTRS)

Gatewood, George D. (Inventor)

1983-01-01

Measuring apparatus including a ruled member having alternate transparent and opaque zones. An optical coupler connecting the ruled member with electromagnetic radiation-conversion apparatus. The conversion apparatus may include a photomultiplier and a discriminator. Radiation impinging on the ruled member will, in part, be converted to electrical pulses which correspond to the intensity of the radiation. A method of processing electromagnetic radiation includes providing a member having alternating dark and light zones, establishing movement of the member through the beam of electromagnetic radiation with the dark zones interrupting passage of radiation through the rule, providing an optical coupler to connect a portion of the radiation with a conversion station where the radiation portion is converted into an electrical pulse which is related to the intensity of the radiation received at the conversion station. The electrical pulses may be counted and the digitized signals stored or permanently recorded to produce positional information.

Attacking the information access problem with expert systems

NASA Technical Reports Server (NTRS)

Ragusa, James M.; Orwig, Gary W.

1991-01-01

The results of applications research directed at finding an improved method of storing and accessing information are presented. Twelve microcomputer-based expert systems shells and five laser-optical formats have been studied, and the general and specific methods of interfacing these technologies are being tested in prototype systems. Shell features and interfacing capabilities are discussed, and results from the study of five laser-optical formats are recounted including the video laser, compact, and WORM disks, and laser cards and film. Interfacing, including laser disk device driver interfacing, is discussed and it is pointed out that in order to control the laser device from within the expert systems application, the expert systems shell must be able to access the device driver software. Potential integrated applications are investigated and an initial list is provided including consumer services, travel, law enforcement, human resources, marketing, and education and training.

Barium iodide and strontium iodide crystals andd scintillators implementing the same

DOEpatents

Payne, Stephen A; Cherepy, Nerine J; Hull, Giulia E; Drobshoff, Alexander D; Burger, Arnold

2013-11-12

In one embodiment, a material comprises a crystal comprising strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector according to another embodiment includes a scintillator optic comprising europium-doped strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector in yet another embodiment includes a scintillator optic comprising SrI.sub.2 and BaI.sub.2, wherein a ratio of SrI.sub.2 to BaI.sub.2 is in a range of between 0:1 A method for manufacturing a crystal suitable for use in a scintillator includes mixing strontium iodide-containing crystals with a source of Eu.sup.2+, heating the mixture above a melting point of the strontium iodide-containing crystals, and cooling the heated mixture near the seed crystal for growing a crystal. Additional materials, systems, and methods are presented.

Combination of Thin Lenses--A Computer Oriented Method.

ERIC Educational Resources Information Center

Flerackers, E. L. M.; And Others

1984-01-01

Suggests a method treating geometric optics using a microcomputer to do the calculations of image formation. Calculations are based on the connection between the composition of lenses and the mathematics of fractional linear equations. Logic of the analysis and an example problem are included. (JM)

Light Scattering based detection of food pathogens

USDA-ARS?s Scientific Manuscript database

The current methods for detecting foodborne pathogens are mostly destructive (i.e., samples need to be pretreated), and require time, personnel, and laboratories for analyses. Optical methods including light scattering based techniques have gained a lot of attention recently due to its their rapid a...

Focal plane based wavefront sensing with random DM probes

NASA Astrophysics Data System (ADS)

Pluzhnik, Eugene; Sirbu, Dan; Belikov, Ruslan; Bendek, Eduardo; Dudinov, Vladimir N.

2017-09-01

An internal coronagraph with an adaptive optical system for wavefront control is being considered for direct imaging of exoplanets with upcoming space missions and concepts, including WFIRST, HabEx, LUVOIR, EXCEDE and ACESat. The main technical challenge associated with direct imaging of exoplanets is to control of both diffracted and scattered light from the star so that even a dim planetary companion can be imaged. For a deformable mirror (DM) to create a dark hole with 10-10 contrast in the image plane, wavefront errors must be accurately measured on the science focal plane detector to ensure a common optical path. We present here a method that uses a set of random phase probes applied to the DM to obtain a high accuracy wavefront estimate even for a dynamically changing optical system. The presented numerical simulations and experimental results show low noise sensitivity, high reliability, and robustness of the proposed approach. The method does not use any additional optics or complex calibration procedures and can be used during the calibration stage of any direct imaging mission. It can also be used in any optical experiment that uses a DM as an active optical element in the layout.

Implementation of a computationally efficient least-squares algorithm for highly under-determined three-dimensional diffuse optical tomography problems.

PubMed

Yalavarthy, Phaneendra K; Lynch, Daniel R; Pogue, Brian W; Dehghani, Hamid; Paulsen, Keith D

2008-05-01

Three-dimensional (3D) diffuse optical tomography is known to be a nonlinear, ill-posed and sometimes under-determined problem, where regularization is added to the minimization to allow convergence to a unique solution. In this work, a generalized least-squares (GLS) minimization method was implemented, which employs weight matrices for both data-model misfit and optical properties to include their variances and covariances, using a computationally efficient scheme. This allows inversion of a matrix that is of a dimension dictated by the number of measurements, instead of by the number of imaging parameters. This increases the computation speed up to four times per iteration in most of the under-determined 3D imaging problems. An analytic derivation, using the Sherman-Morrison-Woodbury identity, is shown for this efficient alternative form and it is proven to be equivalent, not only analytically, but also numerically. Equivalent alternative forms for other minimization methods, like Levenberg-Marquardt (LM) and Tikhonov, are also derived. Three-dimensional reconstruction results indicate that the poor recovery of quantitatively accurate values in 3D optical images can also be a characteristic of the reconstruction algorithm, along with the target size. Interestingly, usage of GLS reconstruction methods reduces error in the periphery of the image, as expected, and improves by 20% the ability to quantify local interior regions in terms of the recovered optical contrast, as compared to LM methods. Characterization of detector photo-multiplier tubes noise has enabled the use of the GLS method for reconstructing experimental data and showed a promise for better quantification of target in 3D optical imaging. Use of these new alternative forms becomes effective when the ratio of the number of imaging property parameters exceeds the number of measurements by a factor greater than 2.

Optimized optical clearing method for imaging central nervous system

NASA Astrophysics Data System (ADS)

Yu, Tingting; Qi, Yisong; Gong, Hui; Luo, Qingming; Zhu, Dan

2015-03-01

The development of various optical clearing methods provides a great potential for imaging entire central nervous system by combining with multiple-labelling and microscopic imaging techniques. These methods had made certain clearing contributions with respective weaknesses, including tissue deformation, fluorescence quenching, execution complexity and antibody penetration limitation that makes immunostaining of tissue blocks difficult. The passive clarity technique (PACT) bypasses those problems and clears the samples with simple implementation, excellent transparency with fine fluorescence retention, but the passive tissue clearing method needs too long time. In this study, we not only accelerate the clearing speed of brain blocks but also preserve GFP fluorescence well by screening an optimal clearing temperature. The selection of proper temperature will make PACT more applicable, which evidently broaden the application range of this method.

Method and apparatus for ultra-high-sensitivity, incremental and absolute optical encoding

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1999-01-01

An absolute optical linear or rotary encoder which encodes the motion of an object (3) with increased resolution and encoding range and decreased sensitivity to damage to the scale includes a scale (5), which moves with the object and is illuminated by a light source (11). The scale carries a pattern (9) which is imaged by a microscope optical system (13) on a CCD array (17) in a camera head (15). The pattern includes both fiducial markings (31) which are identical for each period of the pattern and code areas (33) which include binary codings of numbers identifying the individual periods of the pattern. The image of the pattern formed on the CCD array is analyzed by an image processor (23) to locate the fiducial marking, decode the information encoded in the code area, and thereby determine the position of the object.

Research on adaptive optics image restoration algorithm based on improved joint maximum a posteriori method

NASA Astrophysics Data System (ADS)

Zhang, Lijuan; Li, Yang; Wang, Junnan; Liu, Ying

2018-03-01

In this paper, we propose a point spread function (PSF) reconstruction method and joint maximum a posteriori (JMAP) estimation method for the adaptive optics image restoration. Using the JMAP method as the basic principle, we establish the joint log likelihood function of multi-frame adaptive optics (AO) images based on the image Gaussian noise models. To begin with, combining the observed conditions and AO system characteristics, a predicted PSF model for the wavefront phase effect is developed; then, we build up iterative solution formulas of the AO image based on our proposed algorithm, addressing the implementation process of multi-frame AO images joint deconvolution method. We conduct a series of experiments on simulated and real degraded AO images to evaluate our proposed algorithm. Compared with the Wiener iterative blind deconvolution (Wiener-IBD) algorithm and Richardson-Lucy IBD algorithm, our algorithm has better restoration effects including higher peak signal-to-noise ratio ( PSNR) and Laplacian sum ( LS) value than the others. The research results have a certain application values for actual AO image restoration.

Progress Report on Optimizing X-ray Optical Prescriptions for Wide-Field Applications

NASA Technical Reports Server (NTRS)

Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.; Weisskopf, M. C.

2011-01-01

We report on the present status of our continuing efforts to develop a method for optimizing wide-field nested x-ray telescope mirror prescriptions. Utilizing extensive Monte-Carlo ray trace simulations, we find an analytic form for the root-mean-square dispersion of rays from a Wolter I optic on the surface of a flat focal plane detector as a function of detector tilt away from the nominal focal plane and detector displacement along the optical axis. The configuration minimizing the ray dispersion from a nested array of Wolter I telescopes is found by solving a linear system of equations for tilt and individual mirror pair displacement. Finally we outline our initial efforts at expanding this method to include higher order polynomial terms in the mirror prescriptions.

A real-time optical tracking and measurement processing system for flying targets.

PubMed

Guo, Pengyu; Ding, Shaowen; Zhang, Hongliang; Zhang, Xiaohu

2014-01-01

Optical tracking and measurement for flying targets is unlike the close range photography under a controllable observation environment, which brings extreme conditions like diverse target changes as a result of high maneuver ability and long cruising range. This paper first designed and realized a distributed image interpretation and measurement processing system to achieve resource centralized management, multisite simultaneous interpretation and adaptive estimation algorithm selection; then proposed a real-time interpretation method which contains automatic foreground detection, online target tracking, multiple features location, and human guidance. An experiment is carried out at performance and efficiency evaluation of the method by semisynthetic video. The system can be used in the field of aerospace tests like target analysis including dynamic parameter, transient states, and optical physics characteristics, with security control.

In situ optical diagnostic for monitoring or control of sodium diffusion in photovoltaics manufacturing

DOEpatents

Li, Jian; Levi, Dean; Contreras, Miguel; Glynn, Stephen

2015-09-15

A method of fabricating a photovoltaic device 100, includes the steps of providing a glass substrate 102, depositing a molybdenum layer 104 on a surface of the glass substrate, directing light through the glass substrate to the near-substrate region of the molybdenum layer 206, detecting an optical property of the near-substrate region of the molybdenum layer after interaction with the incident light 208 and determining a density of the near-substrate region of the molybdenum layer from the detected optical property 210. A molybdenum deposition parameter may be controlled based upon the determined density of the near-substrate region of the molybdenum layer 218. A non-contact method measures a density of the near-substrate region of a molybdenum layer and a deposition chamber 300.

Micro-laser

DOEpatents

Hutchinson, Donald P.; Richards, Roger K.

2003-07-22

A micro-laser is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide and at least one amplifying medium in the waveguide. PBG features are positioned between the first and second subwavelength resonant gratings and allow introduction of amplifying mediums into the highly resonant guided micro-laser microcavity. The micro-laser may be positioned on a die of a bulk substrate material with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a micro-laser is disclosed. A method for tuning the micro-laser is also disclosed. The micro-laser may be used as an optical regenerator, or a light source for data transfer or for optical computing.

Organic crystalline films for optical applications and related methods of fabrication

NASA Technical Reports Server (NTRS)

Leyderman, Alexander (Inventor)

2001-01-01

A method for forming an optical device includes the steps of providing a first plate having a first face defining a recess, filling the recess with a material which can be crystallized, and covering the first face and the recess with a second plate having a second face, so that the second face is in contact with the first face and the material in the recess is completely enclosed by the first and second plates. The material in the recess is thereby protected from chemical and mechanical damage, as well as evaporation. In addition, the plates can be transparent, allowing the material in the recess to be visually monitored. A grown crystalline film packed in the cell can be used as a non-liner and/or electro-optical device.

A Real-Time Optical Tracking and Measurement Processing System for Flying Targets

PubMed Central

Guo, Pengyu; Ding, Shaowen; Zhang, Hongliang; Zhang, Xiaohu

2014-01-01

Optical tracking and measurement for flying targets is unlike the close range photography under a controllable observation environment, which brings extreme conditions like diverse target changes as a result of high maneuver ability and long cruising range. This paper first designed and realized a distributed image interpretation and measurement processing system to achieve resource centralized management, multisite simultaneous interpretation and adaptive estimation algorithm selection; then proposed a real-time interpretation method which contains automatic foreground detection, online target tracking, multiple features location, and human guidance. An experiment is carried out at performance and efficiency evaluation of the method by semisynthetic video. The system can be used in the field of aerospace tests like target analysis including dynamic parameter, transient states, and optical physics characteristics, with security control. PMID:24987748

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.

Novel image processing method study for a label-free optical biosensor

NASA Astrophysics Data System (ADS)

Yang, Chenhao; Wei, Li'an; Yang, Rusong; Feng, Ying

2015-10-01

Optical biosensor is generally divided into labeled type and label-free type, the former mainly contains fluorescence labeled method and radioactive-labeled method, while fluorescence-labeled method is more mature in the application. The mainly image processing methods of fluorescent-labeled biosensor includes smooth filtering, artificial gridding and constant thresholding. Since some fluorescent molecules may influence the biological reaction, label-free methods have been the main developing direction of optical biosensors nowadays. The using of wider field of view and larger angle of incidence light path which could effectively improve the sensitivity of the label-free biosensor also brought more difficulties in image processing, comparing with the fluorescent-labeled biosensor. Otsu's method is widely applied in machine vision, etc, which choose the threshold to minimize the intraclass variance of the thresholded black and white pixels. It's capacity-constrained with the asymmetrical distribution of images as a global threshold segmentation. In order to solve the irregularity of light intensity on the transducer, we improved the algorithm. In this paper, we present a new image processing algorithm based on a reflectance modulation biosensor platform, which mainly comprises the design of sliding normalization algorithm for image rectification and utilizing the improved otsu's method for image segmentation, in order to implement automatic recognition of target areas. Finally we used adaptive gridding method extracting the target parameters for analysis. Those methods could improve the efficiency of image processing, reduce human intervention, enhance the reliability of experiments and laid the foundation for the realization of high throughput of label-free optical biosensors.

Method and apparatus for ceramic analysis

DOEpatents

Jankowiak, Ryszard J.; Schilling, Chris; Small, Gerald J.; Tomasik, Piotr

2003-04-01

The present invention relates to a method and apparatus for ceramic analysis, in particular, a method for analyzing density, density gradients and/or microcracks, including an apparatus with optical instrumentation for analysis of density, density gradients and/or microcracks in ceramics. The method provides analyzing density of a ceramic comprising exciting a component on a surface/subsurface of the ceramic by exposing the material to excitation energy. The method may further include the step of obtaining a measurement of an emitted energy from the component. The method may additionally include comparing the measurement of the emitted energy from the component with a predetermined reference measurement so as to obtain a density for said ceramic.

Free-space laser communication technologies II; Proceedings of the Meeting, Los Angeles, CA, Jan. 15-17, 1990

NASA Technical Reports Server (NTRS)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1990-01-01

Various papers on free-space laser communication technologies are presented. Individual topics addressed include: optical intersatellite link experiment between the earth station and ETS-VI, the Goddard optical communications program, technologies and techniques for lasercom terminal size, weight, and cost reduction, laser beam acquisition and tracking system for ETS-VI laser communication equipment, analog dividers for acquisition and tracking signal normalization, fine pointing mechanism using multilayered piezoelectric actuator for optical ISL system, analysis of SILEX tracking sensor performance, new telescope concept for space communication, telescope considered as a very high gain antenna, design of compact transceiver optical systems for optical intersatellite links, ultralightweight optics for laser communications, highly sensitive measurement method for stray light and retroreflected light, depolarization effects on free space laser transceiver communication systems, in-orbit measurements of microaccelerations of ESA's communication satellite Olympus, high-performance laser diode transmitter for optical free space communication, diode-pumped Nd:host laser transmitter for intersatellite optical communications, single-frequency diode-pumped laser for free-space communication.

Transverse strain measurements using fiber optic grating based sensors

NASA Technical Reports Server (NTRS)

Udd, Eric (Inventor)

1998-01-01

A system and method to sense the application of transverse stress to an optical fiber which includes a light source that producing a relatively wide spectrum light beam. The light beam is reflected or transmitted off of an optical grating in the core of an optical fiber that is transversely stressed either directly or by the exposure to pressure when the fiber is bifringent so that the optical fiber responds to the pressure to transversely stress its core. When transversely stressed, the optical grating produces a reflection or transmission from the light beam that has two peaks or minimums in its frequency spectrum whose spacing and/or spread are indicative of the forces applied to the fiber. One or more detectors sense the reflection or transmissions from the optical grating to produce an output representative of the applied force. Multiple optical gratings and detectors may be employed to simultaneously measure temperature or the forces at different locations along the fiber.

Stokes solitons in optical microcavities

NASA Astrophysics Data System (ADS)

Yang, Qi-Fan; Yi, Xu; Yang, Ki Youl; Vahala, Kerry

2017-01-01

Solitons are wave packets that resist dispersion through a self-induced potential well. They are studied in many fields, but are especially well known in optics on account of the relative ease of their formation and control in optical fibre waveguides. Besides their many interesting properties, solitons are important to optical continuum generation, in mode-locked lasers, and have been considered as a natural way to convey data over great distances. Recently, solitons have been realized in microcavities, thereby bringing the power of microfabrication methods to future applications. This work reports a soliton not previously observed in optical systems, the Stokes soliton. The Stokes soliton forms and regenerates by optimizing its Raman interaction in space and time within an optical potential well shared with another soliton. The Stokes and the initial soliton belong to distinct transverse mode families and benefit from a form of soliton trapping that is new to microcavities and soliton lasers in general. The discovery of a new optical soliton can impact work in other areas of photonics, including nonlinear optics and spectroscopy.

In vivo light scattering for the detection of cancerous and precancerous lesions of the cervix

PubMed Central

Mourant, Judith R.; Powers, Tamara M.; Bocklage, Thérese J.; Greene, Heather M.; Dorin, Maxine H.; Waxman, Alan G.; Zsemlye, Meggan M.; Smith, Harriet O.

2009-01-01

A non-invasive optical diagnostic system for detection of cancerous and precancerous lesions of the cervix was evaluated, in vivo. The optical system included a fiber optic probe designed to measure polarized and unpolarized light transport properties of a small volume of tissue. An algorithm for diagnosing tissue based on the optical measurements was developed which used four optical properties, three of which were related to light scattering properties and the fourth of which was related to hemoglobin concentration. A sensitivity of ∼77% and specificities in the mid 60's were obtained for separating high grade squamous intraepithelial lesions and cancer from other pathologies and normal tissue. The use of different cross-validation methods in algorithm development is analyzed and the relative difficulties of diagnosing certain pathologies is assessed. Furthermore, the robustness of the optical system for use by different doctors and to changes in fiber optic probe were also assessed and potential improvements in the optical system are discussed. PMID:19340117

Scanning system, infrared noise equivalent temperature difference: Measurement procedure

NASA Technical Reports Server (NTRS)

Cannon, J. B., Jr.

1975-01-01

A procedure is described for determining the noise equivalent difference temperature for infrared electro-optical instruments. The instrumentation required, proper measurements, and methods of calculation are included.

Separation of presampling and postsampling modulation transfer functions in infrared sensor systems

NASA Astrophysics Data System (ADS)

Espinola, Richard L.; Olson, Jeffrey T.; O'Shea, Patrick D.; Hodgkin, Van A.; Jacobs, Eddie L.

2006-05-01

New methods of measuring the modulation transfer function (MTF) of electro-optical sensor systems are investigated. These methods are designed to allow the separation and extraction of presampling and postsampling components from the total system MTF. The presampling MTF includes all the effects prior to the sampling stage of the imaging process, such as optical blur and detector shape. The postsampling MTF includes all the effects after sampling, such as interpolation filters and display characteristics. Simulation and laboratory measurements are used to assess the utility of these techniques. Knowledge of these components and inclusion into sensor models, such as the U.S. Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate's NVThermIP, will allow more accurate modeling and complete characterization of sensor performance.

Optical Properties of the DIRC Fused Silica Radiator

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

Convery, Mark R

2003-04-15

The DIRC detector is successfully operating as the hadronic particle identification system for the BaBar experiment at SLAC. The production of its Cherenkov radiator required much effort in practice, both in manufacture and conception, which in turn required a large number of R&D measurements. One of the major outcomes of this R&D work was an understanding of methods to select radiation hard and optically uniform fused silica material. Others included measurement of the wavelength dependency of the internal reflection coefficient, and its sensitivity to the surface pollution, selection of the radiator support, selection of good optical glue, etc. This notemore » summarizes the optical R&D test results.« less

Resolving phase information of the optical local density of state with scattering near-field probes

NASA Astrophysics Data System (ADS)

Prasad, R.; Vincent, R.

2016-10-01

We theoretically discuss the link between the phase measured using a scattering optical scanning near-field microscopy (s-SNOM) and the local density of optical states (LDOS). A remarkable result is that the LDOS information is directly included in the phase of the probe. Therefore by monitoring the spatial variation of the trans-scattering phase, we locally measure the phase modulation associated with the probe and the optical paths. We demonstrate numerically that a technique involving two-phase imaging of a sample with two different sized tips should allow to obtain the image the pLDOS. For this imaging method, numerical comparison with extinction probe measurement shows crucial qualitative and quantitative improvement.

Optical encryption and QR codes: secure and noise-free information retrieval.

PubMed

Barrera, John Fredy; Mira, Alejandro; Torroba, Roberto

2013-03-11

We introduce for the first time the concept of an information "container" before a standard optical encrypting procedure. The "container" selected is a QR code which offers the main advantage of being tolerant to pollutant speckle noise. Besides, the QR code can be read by smartphones, a massively used device. Additionally, QR code includes another secure step to the encrypting benefits the optical methods provide. The QR is generated by means of worldwide free available software. The concept development probes that speckle noise polluting the outcomes of normal optical encrypting procedures can be avoided, then making more attractive the adoption of these techniques. Actual smartphone collected results are shown to validate our proposal.

High spatial resolution particle detectors

DOEpatents

Boatner, Lynn A.; Mihalczo, John T.

2012-09-04

Disclosed below are representative embodiments of methods, apparatus, and systems for detecting particles, such as radiation or charged particles. One exemplary embodiment disclosed herein is particle detector comprising an optical fiber with a first end and second end opposite the first end. The optical fiber of this embodiment further comprises a doped region at the first end and a non-doped region adjacent to the doped region. The doped region of the optical fiber is configured to scintillate upon interaction with a target particle, thereby generating one or more photons that propagate through the optical fiber and to the second end. Embodiments of the disclosed technology can be used in a variety of applications, including associated particle imaging and cold neutron scattering.

High spatial resolution particle detectors

DOEpatents

Boatner, Lynn A.; Mihalczo, John T.

2015-10-13

Disclosed below are representative embodiments of methods, apparatus, and systems for detecting particles, such as radiation or charged particles. One exemplary embodiment disclosed herein is particle detector comprising an optical fiber with a first end and second end opposite the first end. The optical fiber of this embodiment further comprises a doped region at the first end and a non-doped region adjacent to the doped region. The doped region of the optical fiber is configured to scintillate upon interaction with a target particle, thereby generating one or more photons that propagate through the optical fiber and to the second end. Embodiments of the disclosed technology can be used in a variety of applications, including associated particle imaging and cold neutron scattering.

Using integrated models to minimize environmentally induced wavefront error in optomechanical design and analysis

NASA Astrophysics Data System (ADS)

Genberg, Victor L.; Michels, Gregory J.

2017-08-01

The ultimate design goal of an optical system subjected to dynamic loads is to minimize system level wavefront error (WFE). In random response analysis, system WFE is difficult to predict from finite element results due to the loss of phase information. In the past, the use of ystem WFE was limited by the difficulty of obtaining a linear optics model. In this paper, an automated method for determining system level WFE using a linear optics model is presented. An error estimate is included in the analysis output based on fitting errors of mode shapes. The technique is demonstrated by example with SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

Target isolation system, high power laser and laser peening method and system using same

DOEpatents

Dane, C. Brent; Hackel, Lloyd A.; Harris, Fritz

2007-11-06

A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

Microscopic Imaging and Spectroscopy with Scattered Light

PubMed Central

Boustany, Nada N.; Boppart, Stephen A.; Backman, Vadim

2012-01-01

Optical contrast based on elastic scattering interactions between light and matter can be used to probe cellular structure and dynamics, and image tissue architecture. The quantitative nature and high sensitivity of light scattering signals to subtle alterations in tissue morphology, as well as the ability to visualize unstained tissue in vivo, has recently generated significant interest in optical scatter based biosensing and imaging. Here we review the fundamental methodologies used to acquire and interpret optical scatter data. We report on recent findings in this field and present current advances in optical scatter techniques and computational methods. Cellular and tissue data enabled by current advances in optical scatter spectroscopy and imaging stand to impact a variety of biomedical applications including clinical tissue diagnosis, in vivo imaging, drug discovery and basic cell biology. PMID:20617940

Potential of OFDM for next generation optical access

NASA Astrophysics Data System (ADS)

Fritzsche, Daniel; Weis, Erik; Breuer, Dirk

2011-01-01

This paper shows the requirements for next generation optical access (NGOA) networks and analyzes the potential of OFDM (orthogonal frequency division multiplexing) for the use in such network scenarios. First, we show the motivation for NGOA systems based on the future requirements on FTTH access systems and list the advantages of OFDM in such scenarios. In the next part, the basics of OFDM and different methods to generate and detect optical OFDM signals are explained and analyzed. At the transmitter side the options include intensity modulation and the more advanced field modulation of the optical OFDM signal. At the receiver there is the choice between direct detection and coherent detection. As the result of this discussion we show our vision of the future use of OFDM in optical access networks.

Embedded high-contrast distributed grating structures

DOEpatents

Zubrzycki, Walter J.; Vawter, Gregory A.; Allerman, Andrew A.

2002-01-01

A new class of fabrication methods for embedded distributed grating structures is claimed, together with optical devices which include such structures. These new methods are the only known approach to making defect-free high-dielectric contrast grating structures, which are smaller and more efficient than are conventional grating structures.

Comparative study of solar optics for paraboloidal concentrators

NASA Technical Reports Server (NTRS)

Wen, L.; Poon, P.; Carley, W.; Huang, L.

1979-01-01

Different analytical methods for computing the flux distribution on the focal plane of a paraboloidal solar concentrator are reviewed. An analytical solution in algebraic form is also derived for an idealized model. The effects resulting from using different assumptions in the definition of optical parameters used in these methodologies are compared and discussed in detail. These parameters include solar irradiance distribution (limb darkening and circumsolar), reflector surface specular spreading, surface slope error, and concentrator pointing inaccuracy. The type of computational method selected for use depends on the maturity of the design and the data available at the time the analysis is made.

Light emitting diode package element with internal meniscus for bubble free lens placement

DOEpatents

Tarsa, Eric; Yuan, Thomas C.; Becerra, Maryanne; Yadev, Praveen

2010-09-28

A method for fabricating a light emitting diode (LED) package comprising providing an LED chip and covering at least part of the LED chip with a liquid encapsulant having a radius of curvature. An optical element is provided having a bottom surface with at least a portion having a radius of curvature larger than the liquid encapsulant. The larger radius of curvature portion of the optical element is brought into contact with the liquid encapsulant. The optical element is then moved closer to the LED chip, growing the contact area between said optical element and said liquid encapsulant. The liquid encapsulant is then cured. A light emitting diode comprising a substrate with an LED chip mounted to it. A meniscus ring is on the substrate around the LED chip with the meniscus ring having a meniscus holding feature. An inner encapsulant is provided over the LED chip with the inner encapsulant having a contacting surface on the substrate, with the meniscus holding feature which defines the edge of the contacting surface. An optical element is included having a bottom surface with at least a portion that is concave. The optical element is arranged on the substrate with the concave portion over the LED chip. A contacting encapsulant is included between the inner encapsulant and optical element.

Alignment displacements of the solar optical telescope primary mirror

NASA Technical Reports Server (NTRS)

Medenica, W. V.

1978-01-01

Solar optical telescope is a space shuttle payload which is at the present time (1978) being planned. The selected alignment method for the telescope's primary mirror is such that the six inclined legs supporting the mirror are at the same time motorized alignment actuators, changing their own length according to the alignment requirement and command. The alignment displacements were described, including circumvention of some apparent NASTRAN limitations.

Nonlinear optical response in narrow graphene nanoribbons

NASA Astrophysics Data System (ADS)

Karimi, Farhad; Knezevic, Irena

We present an iterative method to calculate the nonlinear optical response of armchair graphene nanoribbons (aGNRs) and zigzag graphene nanoribbons (zGNRs) while including the effects of dissipation. In contrast to methods that calculate the nonlinear response in the ballistic (dissipation-free) regime, here we obtain the nonlinear response of an electronic system to an external electromagnetic field while interacting with a dissipative environment (to second order). We use a self-consistent-field approach within a Markovian master-equation formalism (SCF-MMEF) coupled with full-wave electromagnetic equations, and we solve the master equation iteratively to obtain the higher-order response functions. We employ the SCF-MMEF to calculate the nonlinear conductance and susceptibility, as well as to calculate the dependence of the plasmon dispersion and plasmon propagation length on the intensity of the electromagnetic field in GNRs. The electron scattering mechanisms included in this work are scattering with intrinsic phonons, ionized impurities, surface optical phonons, and line-edge roughness. Unlike in wide GNRs, where ionized-impurity scattering dominates dissipation, in ultra-narrow nanoribbons on polar substrates optical-phonon scattering and ionized-impurity scattering are equally prominent. Support by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0008712.

Dye lasing arrangement including an optical assembly for altering the cross-section of its pumping beam and method

DOEpatents

O'Neil, Richard W.; Sweatt, William C.

1992-01-01

An optical assembly is disclosed herein along with a method of operation for use in a dye lasing arrangement, for example a dye laser oscillator or a dye amplifier, in which a continuous stream of dye is caused to flow through a given zone in a cooperating dye chamber while the zone is being illuminated by light from a pumping beam which is directed into the given zone. This in turn causes the dye therein to lase and thereby produce a new dye beam in the case of a dye laser oscillator or amplify a dye beam in the case of a dye amplifier. The optical assembly so disclosed is designed to alter the pump beam such that the beam enters the dye chamber with a different cross-sectional configuration, preferably one having a more uniform intensity profile, than its initially produced cross-sectional configuration. To this end, the assembly includes a network of optical components which first act on the beam while the latter retains its initially produced cross-sectional configuration for separating it into a plurality of predetermined segments and then recombines the separated components in a predetermined way which causes the recombined beam to have the different cross-sectional configuration.

Phonon-assisted optical absorption in BaSnO 3 from first principles

NASA Astrophysics Data System (ADS)

Monserrat, Bartomeu; Dreyer, Cyrus E.; Rabe, Karin M.

2018-03-01

The perovskite BaSnO3 provides a promising platform for the realization of an earth-abundant n -type transparent conductor. Its optical properties are dominated by a dispersive conduction band of Sn 5 s states and by a flatter valence band of O 2 p states, with an overall indirect gap of about 2.9 eV . Using first-principles methods, we study the optical properties of BaSnO3 and show that both electron-phonon interactions and exact exchange, included using a hybrid functional, are necessary to obtain a qualitatively correct description of optical absorption in this material. In particular, the electron-phonon interaction drives phonon-assisted optical absorption across the minimum indirect gap and therefore determines the absorption onset, and it also leads to the temperature dependence of the absorption spectrum. Electronic correlations beyond semilocal density functional theory are key to determine the dynamical stability of the cubic perovskite structure, as well as the correct energies of the conduction bands that dominate absorption. Our work demonstrates that phonon-mediated absorption processes should be included in the design of novel transparent conductor materials.

Electronic band structures and optical properties of type-II superlattice photodetectors with interfacial effect.

PubMed

Qiao, Peng-Fei; Mou, Shin; Chuang, Shun Lien

2012-01-30

The electronic band structures and optical properties of type-II superlattice (T2SL) photodetectors in the mid-infrared (IR) range are investigated. We formulate a rigorous band structure model using the 8-band k · p method to include the conduction and valence band mixing. After solving the 8 × 8 Hamiltonian and deriving explicitly the new momentum matrix elements in terms of envelope functions, optical transition rates are obtained through the Fermi's golden rule under various doping and injection conditions. Optical measurements on T2SL photodetectors are compared with our model and show good agreement. Our modeling results of quantum structures connect directly to the device-level design and simulation. The predicted doping effect is readily applicable to the optimization of photodetectors. We further include interfacial (IF) layers to study the significance of their effect. Optical properties of T2SLs are expected to have a large tunable range by controlling the thickness and material composition of the IF layers. Our model provides an efficient tool for the designs of novel photodetectors.

Optical Histology: High-Resolution Visualization of Tissue Microvasculature

NASA Astrophysics Data System (ADS)

Moy, Austin Jing-Ming

Mammalian tissue requires the delivery of nutrients, growth factors, and the exchange of oxygen and carbon dioxide gases to maintain normal function. These elements are delivered by the blood, which travels through the connected network of blood vessels, known as the vascular system. The vascular system consists of large feeder blood vessels (arteries and veins) that are connected to the small blood vessels (arterioles and venules), which in turn are connected to the capillaries that are directly connected to the tissue and facilitate gas exchange and nutrient delivery. These small blood vessels and capillaries make up an intricate but organized network of blood vessels that exist in all mammalian tissues known as the microvasculature and are very important in maintaining the health and proper function of mammalian tissue. Due to the importance of the microvasculature in tissue survival, disruption of the microvasculature typically leads to tissue dysfunction and tissue death. The most prevalent method to study the microvasculature is visualization. Immunohistochemistry (IHC) is the gold-standard method to visualize tissue microvasculature. IHC is very well-suited for highly detailed interrogation of the tissue microvasculature at the cellular level but is unwieldy and impractical for wide-field visualization of the tissue microvasculature. The objective my dissertation research was to develop a method to enable wide-field visualization of the microvasculature, while still retaining the high-resolution afforded by optical microscopy. My efforts led to the development of a technique dubbed "optical histology" that combines chemical and optical methods to enable high-resolution visualization of the microvasculature. The development of the technique first involved preliminary studies to quantify optical property changes in optically cleared tissues, followed by development and demonstration of the methodology. Using optical histology, I successfully obtained high resolution, depth sectioned images of the microvasculature in mouse brain and the coronary microvasculature in mouse heart. Future directions of optical histology include the potential to facilitate visualization of the entire microvascular structure of an organ as well as visualization of other tissue molecular markers of interest.

Design, fabrication and analysis of integrated optical waveguide devices

NASA Astrophysics Data System (ADS)

Sikorski, Yuri

Throughout the present dissertation, the main effort has been to develop the set of design rules for optical integrated circuits (OIC). At the present time, when planar optical integrated circuits seem to be the leading technology, and industry is heading towards much higher levels of integration, such design rules become necessary. It is known that analysis of light propagation in rectangular waveguides can not be carried out exactly. Various approximations become necessary, and their validity is discussed in this text. Various methods are used in the text for calculating the same problems, and results are compared. A few new concepts have been suggested to avoid approximations used elsewhere. The second part of this dissertation is directed to the development of a new technique for the fabrication of optical integrated circuits inside optical glass. This technique is based on the use of ultrafast laser pulses to alter the properties of glasses. Using this method we demonstrated the possibility of changing the refractive index of various passive and active optical glasses as well as ablating the material on the surface in a controlled fashion. A number of optical waveguide devices (e.g. waveguides, directional couplers, diffraction gratings, fiber Bragg gratings, V-grooves in dual-clad optical fibers, optical waveguide amplifiers) were fabricated and tested. Testing included measurements of loss/throughput, near-field mode profiles, efficiency and thermal stability. All of the experimental setup and test results are reported in the dissertation. We also demonstrated the possibility of using this technique to fabricate future bio-optical devices that will incorporate an OIC and a microfluidic circuit on a single substrate. Our results are expected to serve as a guide for the design and fabrication of a new generation of integrated optical and bio-optical devices.

Microscopy imaging system and method employing stimulated raman spectroscopy as a contrast mechanism

DOEpatents

Xie, Xiaoliang Sunney [Lexington, MA; Freudiger, Christian [Boston, MA; Min, Wei [Cambridge, MA

2011-09-27

A microscopy imaging system includes a first light source for providing a first train of pulses at a first center optical frequency .omega..sub.1, a second light source for providing a second train of pulses at a second center optical frequency .omega..sub.2, a modulator system, an optical detector, and a processor. The modulator system is for modulating a beam property of the second train of pulses at a modulation frequency f of at least 100 kHz. The optical detector is for detecting an integrated intensity of substantially all optical frequency components of the first train of pulses from the common focal volume by blocking the second train of pulses being modulated. The processor is for detecting, a modulation at the modulation frequency f, of the integrated intensity of the optical frequency components of the first train of pulses to provide a pixel of an image for the microscopy imaging system.

Intravascular Optical Imaging Technology for Investigating the Coronary Artery

PubMed Central

Suter, Melissa J.; Nadkarni, Seemantini K.; Weisz, Giora; Tanaka, Atsushi; Jaffer, Farouc A.; Bouma, Brett E.; Tearney, Guillermo J.

2012-01-01

There is an ever-increasing demand for new imaging methods that can provide additional information about the coronary wall to better characterize and stratify high-risk plaques, and to guide interventional and pharmacologic management of patients with coronary artery disease. While there are a number of imaging modalities that facilitate the assessment of coronary artery pathology, this review paper focuses on intravascular optical imaging modalities that provide information on the microstructural, compositional, biochemical, biomechanical, and molecular features of coronary lesions and stents. The optical imaging modalities discussed include angioscopy, optical coherence tomography, polarization sensitive-optical coherence tomography, laser speckle imaging, near-infrared spectroscopy, time-resolved laser induced fluorescence spectroscopy, Raman spectroscopy, and near-infrared fluorescence molecular imaging. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in the evaluation of the coronary artery in the future. PMID:21920342

Coherent phonon optics in a chip with an electrically controlled active device.

PubMed

Poyser, Caroline L; Akimov, Andrey V; Campion, Richard P; Kent, Anthony J

2015-02-05

Phonon optics concerns operations with high-frequency acoustic waves in solid media in a similar way to how traditional optics operates with the light beams (i.e. photons). Phonon optics experiments with coherent terahertz and sub-terahertz phonons promise a revolution in various technical applications related to high-frequency acoustics, imaging, and heat transport. Previously, phonon optics used passive methods for manipulations with propagating phonon beams that did not enable their external control. Here we fabricate a phononic chip, which includes a generator of coherent monochromatic phonons with frequency 378 GHz, a sensitive coherent phonon detector, and an active layer: a doped semiconductor superlattice, with electrical contacts, inserted into the phonon propagation path. In the experiments, we demonstrate the modulation of the coherent phonon flux by an external electrical bias applied to the active layer. Phonon optics using external control broadens the spectrum of prospective applications of phononics on the nanometer scale.

Waveguide metatronics: Lumped circuitry based on structural dispersion.

PubMed

Li, Yue; Liberal, Iñigo; Della Giovampaola, Cristian; Engheta, Nader

2016-06-01

Engineering optical nanocircuits by exploiting modularization concepts and methods inherited from electronics may lead to multiple innovations in optical information processing at the nanoscale. We introduce the concept of "waveguide metatronics," an advanced form of optical metatronics that uses structural dispersion in waveguides to obtain the materials and structures required to construct this class of circuitry. Using numerical simulations, we demonstrate that the design of a metatronic circuit can be carried out by using a waveguide filled with materials with positive permittivity. This includes the implementation of all "lumped" circuit elements and their assembly in a single circuit board. In doing so, we extend the concepts of optical metatronics to frequency ranges where there are no natural plasmonic materials available. The proposed methodology could be exploited as a platform to experimentally validate optical metatronic circuits in other frequency regimes, such as microwave frequency setups, and/or to provide a new route to design optical nanocircuitry.

Methods and apparatus for broadband frequency comb stabilization

DOEpatents

Cox, Jonathan A; Kaertner, Franz X

2015-03-17

Feedback loops can be used to shift and stabilize the carrier-envelope phase of a frequency comb from a mode-locked fibers laser or other optical source. Compared to other frequency shifting and stabilization techniques, feedback-based techniques provide a wideband closed-loop servo bandwidth without optical filtering, beam pointing errors, or group velocity dispersion. It also enables phase locking to a stable reference, such as a Ti:Sapphire laser, continuous-wave microwave or optical source, or self-referencing interferometer, e.g., to within 200 mrad rms from DC to 5 MHz. In addition, stabilized frequency combs can be coherently combined with other stable signals, including other stabilized frequency combs, to synthesize optical pulse trains with pulse durations of as little as a single optical cycle. Such a coherent combination can be achieved via orthogonal control, using balanced optical cross-correlation for timing stabilization and balanced homodyne detection for phase stabilization.

Far-ultraviolet refractive index of optical materials for solar blind channel (SBC) filters for the HST advanced camera for surveys (ACS)

NASA Astrophysics Data System (ADS)

Leviton, Douglas B.; Madison, Timothy J.; Petrone, Peter

1998-10-01

Refractive index measurements using the minimum deviation method have been carried out for prisms of a variety of far ultraviolet optical materials used in the manufacture of Solar Blind Channel (SBC) filters for the HST Advanced Camera for Surveys (ACS). Some of the materials measured are gaining popularity in a variety of high technology applications including high power excimer lasers and advanced microlithography optics operating in a wavelength region where high quality knowledge of optical material properties is sparse yet critical. Our measurements are of unusually high accuracy and precision for this wavelength region owing to advanced instrumentation in the large vacuum chamber of the Diffraction Grating Evaluation Facility (DGEF) at Goddard Space Flight Center (GSFC) used to implement a minimum deviation method refractometer. Index values for CaF2, BaF2, LiF, and far ultraviolet grades of synthetic sapphire and synthetic fused silica are reported and compared with values from the literature.

Optical polarizer material

DOEpatents

Ebbers, C.A.

1999-08-31

Several crystals have been identified which can be grown using standard single crystals growth techniques and which have a high birefringence. The identified crystals include Li.sub.2 CO.sub.3, LiNaCO.sub.3, LiKCO.sub.3, LiRbCO.sub.3 and LiCsCO.sub.3. The condition of high birefringence leads to their application as optical polarizer materials. In one embodiment of the invention, the crystal has the chemical formula LiK.sub.(1-w-x-y) Na.sub.(1-w-x-z) Rb.sub.(1-w-y-z) Cs.sub.(1-x-y-z) CO.sub.3, where w+x+y+z=1. In another embodiment, the crystalline material may be selected from a an alkali metal carbonate and a double salt of alkali metal carbonates, where the polarizer has a Wollaston configuration, a Glan-Thompson configuration or a Glan-Taylor configuration. A method of making an LiNaCO.sub.3 optical polarizer is described. A similar method is shown for making an LiKCO.sub.3 optical polarizer.

Optical polarizer material

DOEpatents

Ebbers, Christopher A.

1999-01-01

Several crystals have been identified which can be grown using standard single crystals growth techniques and which have a high birefringence. The identified crystals include Li.sub.2 CO.sub.3, LiNaCO.sub.3, LiKCO.sub.3, LiRbCO.sub.3 and LiCsCO.sub.3. The condition of high birefringence leads to their application as optical polarizer materials. In one embodiment of the invention, the crystal has the chemical formula LiK.sub.(1-w-x-y) Na.sub.(1-w-x-z) Rb.sub.(1-w-y-z) Cs.sub.(1-x-y-z) CO.sub.3, where w+x+y+z=1. In another embodiment, the crystalline material may be selected from a an alkali metal carbonate and a double salt of alkali metal carbonates, where the polarizer has a Wollaston configuration, a Glan-Thompson configuration or a Glan-Taylor configuration. A method of making an LiNaCO.sub.3 optical polarizer is described. A similar method is shown for making an LiKCO.sub.3 optical polarizer.

Methods, systems, and apparatus for storage, transfer and/or control of information via matter wave dynamics

NASA Technical Reports Server (NTRS)

Vestergaard Hau, Lene (Inventor)

2012-01-01

Methods, systems and apparatus for generating atomic traps, and for storing, controlling and transferring information between first and second spatially separated phase-coherent objects, or using a single phase-coherent object. For plural objects, both phase-coherent objects have a macroscopic occupation of a particular quantum state by identical bosons or identical BCS-paired fermions. The information may be optical information, and the phase-coherent object(s) may be Bose-Einstein condensates, superfluids, or superconductors. The information is stored in the first phase-coherent object at a first storage time and recovered from the second phase-coherent object, or the same first phase-coherent object, at a second revival time. In one example, an integrated silicon wafer-based optical buffer includes an electrolytic atom source to provide the phase-coherent object(s), a nanoscale atomic trap for the phase-coherent object(s), and semiconductor-based optical sources to cool the phase-coherent object(s) and provide coupling fields for storage and transfer of optical information.

Full skin quantitative optical coherence elastography achieved by combining vibration and surface acoustic wave methods

NASA Astrophysics Data System (ADS)

Li, Chunhui; Guan, Guangying; Huang, Zhihong; Wang, Ruikang K.; Nabi, Ghulam

2015-03-01

By combining with the phase sensitive optical coherence tomography (PhS-OCT), vibration and surface acoustic wave (SAW) methods have been reported to provide elastography of skin tissue respectively. However, neither of these two methods can provide the elastography in full skin depth in current systems. This paper presents a feasibility study on an optical coherence elastography method which combines both vibration and SAW in order to give the quantitative mechanical properties of skin tissue with full depth range, including epidermis, dermis and subcutaneous fat. Experiments are carried out on layered tissue mimicking phantoms and in vivo human forearm and palm skin. A ring actuator generates vibration while a line actuator were used to excited SAWs. A PhS-OCT system is employed to provide the ultrahigh sensitive measurement of the generated waves. The experimental results demonstrate that by the combination of vibration and SAW method the full skin bulk mechanical properties can be quantitatively measured and further the elastography can be obtained with a sensing depth from ~0mm to ~4mm. This method is promising to apply in clinics where the quantitative elasticity of localized skin diseases is needed to aid the diagnosis and treatment.

Improvement of an algorithm for recognition of liveness using perspiration in fingerprint devices

NASA Astrophysics Data System (ADS)

Parthasaradhi, Sujan T.; Derakhshani, Reza; Hornak, Lawrence A.; Schuckers, Stephanie C.

2004-08-01

Previous work in our laboratory and others have demonstrated that spoof fingers made of a variety of materials including silicon, Play-Doh, clay, and gelatin (gummy finger) can be scanned and verified when compared to a live enrolled finger. Liveness, i.e. to determine whether the introduced biometric is coming from a live source, has been suggested as a means to circumvent attacks using spoof fingers. We developed a new liveness method based on perspiration changes in the fingerprint image. Recent results showed approximately 90% classification rate using different classification methods for various technologies including optical, electro-optical, and capacitive DC, a shorter time window and a diverse dataset. This paper focuses on improvement of the live classification rate by using a weight decay method during the training phase in order to improve the generalization and reduce the variance of the neural network based classifier. The dataset included fingerprint images from 33 live subjects, 33 spoofs created with dental impression material and Play-Doh, and fourteen cadaver fingers. 100% live classification was achieved with 81.8 to 100% spoof classification, depending on the device technology. The weight-decay method improves upon past reports by increasing the live and spoof classification rate.

Astronomical Optical Interferometry. I. Methods and Instrumentation

NASA Astrophysics Data System (ADS)

Jankov, S.

2010-12-01

Previous decade has seen an achievement of large interferometric projects including 8-10m telescopes and 100m class baselines. Modern computer and control technology has enabled the interferometric combination of light from separate telescopes also in the visible and infrared regimes. Imaging with milli-arcsecond (mas) resolution and astrometry with micro-arcsecond (muas) precision have thus become reality. Here, I review the methods and instrumentation corresponding to the current state in the field of astronomical optical interferometry. First, this review summarizes the development from the pioneering works of Fizeau and Michelson. Next, the fundamental observables are described, followed by the discussion of the basic design principles of modern interferometers. The basic interferometric techniques such as speckle and aperture masking interferometry, aperture synthesis and nulling interferometry are disscused as well. Using the experience of past and existing facilities to illustrate important points, I consider particularly the new generation of large interferometers that has been recently commissioned (most notably, the CHARA, Keck, VLT and LBT Interferometers). Finally, I discuss the longer-term future of optical interferometry, including the possibilities of new large-scale ground-based projects and prospects for space interferometry.

Double lens device for tunable harmonic generation of laser beams in KBBF/RBBF crystals or other non-linear optic materials

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

Kaminski, Adam

A method and apparatus to generate harmonically related laser wavelengths includes a pair of lenses at opposing faces of a non-linear optical material. The lenses are configured to promote incoming and outgoing beams to be normal to each outer lens surface over a range of acceptance angles of the incoming laser beam. This reduces reflection loss for higher efficiency operation. Additionally, the lenses allow a wider range of wavelengths for lasers for more universal application. Examples of the lenses include plano-cylindrical and plano-spherical form factors.

Photothermal imaging scanning microscopy

DOEpatents

Chinn, Diane [Pleasanton, CA; Stolz, Christopher J [Lathrop, CA; Wu, Zhouling [Pleasanton, CA; Huber, Robert [Discovery Bay, CA; Weinzapfel, Carolyn [Tracy, CA

2006-07-11

Photothermal Imaging Scanning Microscopy produces a rapid, thermal-based, non-destructive characterization apparatus. Also, a photothermal characterization method of surface and subsurface features includes micron and nanoscale spatial resolution of meter-sized optical materials.

Method of and device for detecting oil pollutions on water surfaces

DOEpatents

Belov, Michael Leonidovich [Moscow, RU; Gorodnichev, Victor Aleksandrovich [Moscow, RU; Kozintsev, Valentin Ivanovich [Moscow, RU; Smimova, Olga Alekseevna [Moscow, RU; Fedotov, Yurii Victorovich [Moscow, RU; Khroustaleva, Anastasiva Michailovnan [Moscow, RU

2008-08-26

Detection of oil pollution on water surfaces includes providing echo signals obtained from optical radiation of a clean water area at two wavelengths, optically radiating an investigated water area at two wavelengths and obtaining echo signals from the optical radiation of the investigated water area at the two wavelengths, comparing the echo signals obtained from the radiation of the investigated area at two wavelengths with the echo signals obtained from the radiation of the clean water area, and based on the comparison, determining presence or absence of oil pollution in the investigated water area.

Thermal coefficient of delay for various coaxial and fiber-optic cables

NASA Technical Reports Server (NTRS)

Lutes, G. F.; Diener, W.

1989-01-01

Data are presented on the thermal coefficient of delay for various coaxial and fiber optic cables, as measured by the Frequency and Timing Systems Engineering Group and the Time and Frequency Systems Research Group. The measured pressure coefficient of delay is also given for the air-dielectric coaxial cables. A description of the measurement method and a description of each of the cables and its use at JPL and in the DSN are included. An improvement in frequency and phase stability by a factor of ten is possible with the use of fiber optics.

Linear and angular retroreflecting interferometric alignment target

DOEpatents

Maxey, L. Curtis

2001-01-01

The present invention provides a method and apparatus for measuring both the linear displacement and angular displacement of an object using a linear interferometer system and an optical target comprising a lens, a reflective surface and a retroreflector. The lens, reflecting surface and retroreflector are specifically aligned and fixed in optical connection with one another, creating a single optical target which moves as a unit that provides multi-axis displacement information for the object with which it is associated. This displacement information is useful in many applications including machine tool control systems and laser tracker systems, among others.

Apparatus and Method for Packaging and Integrating Microphotonic Devices

NASA Technical Reports Server (NTRS)

Nguyen, Hung (Inventor)

2008-01-01

An apparatus is disclosed that includes a carrier structure and an optical coupling arrangement. The carrier structure is made of a silicon material and allows for the packaging and integrating of microphotonic devices onto a single chip. The optical coupling mechanism enables laser light to be coupled into and out of a microphotonic resonant disk integrated on the carrier. The carrier provides first, second and third cavities that are dimensioned so as to accommodate the insertion and snug fitting of the microphotonic resonant disk and first and second prisms that are implemented by the optical coupling arrangement to accommodate the laser coupling.

TweezPal - Optical tweezers analysis and calibration software

NASA Astrophysics Data System (ADS)

Osterman, Natan

2010-11-01

Optical tweezers, a powerful tool for optical trapping, micromanipulation and force transduction, have in recent years become a standard technique commonly used in many research laboratories and university courses. Knowledge about the optical force acting on a trapped object can be gained only after a calibration procedure which has to be performed (by an expert) for each type of trapped objects. In this paper we present TweezPal, a user-friendly, standalone Windows software tool for optical tweezers analysis and calibration. Using TweezPal, the procedure can be performed in a matter of minutes even by non-expert users. The calibration is based on the Brownian motion of a particle trapped in a stationary optical trap, which is being monitored using video or photodiode detection. The particle trajectory is imported into the software which instantly calculates position histogram, trapping potential, stiffness and anisotropy. Program summaryProgram title: TweezPal Catalogue identifier: AEGR_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGR_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 44 891 No. of bytes in distributed program, including test data, etc.: 792 653 Distribution format: tar.gz Programming language: Borland Delphi Computer: Any PC running Microsoft Windows Operating system: Windows 95, 98, 2000, XP, Vista, 7 RAM: 12 Mbytes Classification: 3, 4.14, 18, 23 Nature of problem: Quick, robust and user-friendly calibration and analysis of optical tweezers. The optical trap is calibrated from the trajectory of a trapped particle undergoing Brownian motion in a stationary optical trap (input data) using two methods. Solution method: Elimination of the experimental drift in position data. Direct calculation of the trap stiffness from the positional variance. Calculation of 1D optical trapping potential from the positional distribution of data points. Trap stiffness calculation by fitting a parabola to the trapping potential. Presentation of X-Y positional density for close inspection of the 2D trapping potential. Calculation of the trap anisotropy. Running time: Seconds

Plasma emission spectroscopy method of tumor therapy

DOEpatents

Fleming, Kevin J.

1997-01-01

Disclosed are a method and apparatus for performing photon diagnostics using a portable and durable apparatus which incorporates the use of a remote sensing probe in fiberoptic communication with an interferometer or spectrometer. Also disclosed are applications for the apparatus including optically measuring high velocities and analyzing plasma/emission spectral characteristics.

Glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals for frequency conversion of lasers

NASA Astrophysics Data System (ADS)

Fang, Zaijin; Xiao, Xusheng; Wang, Xin; Ma, Zhijun; Lewis, Elfed; Farrell, Gerald; Wang, Pengfei; Ren, Jing; Guo, Haitao; Qiu, Jianrong

2017-03-01

A glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba2TiSi2O8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic fibers. When irradiated using a 1030 nm femtosecond laser, an enhanced green emission at a wavelength of 515 nm is observed in the glass-ceramic fiber, which demonstrates second harmonic generation of a laser action in the fabricated glass-ceramic fibers. Therefore, this new glass-ceramic fiber not only provides a highly promising development for frequency conversion of lasers in all optical fiber based networks, but the melt-in-tube fabrication method also offers excellent opportunities for fabricating a wide range of novel glass-ceramic optical fibers for multiple future applications including fiber telecommunications and lasers.

Glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals for frequency conversion of lasers

PubMed Central

Fang, Zaijin; Xiao, Xusheng; Wang, Xin; Ma, Zhijun; Lewis, Elfed; Farrell, Gerald; Wang, Pengfei; Ren, Jing; Guo, Haitao; Qiu, Jianrong

2017-01-01

A glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba2TiSi2O8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic fibers. When irradiated using a 1030 nm femtosecond laser, an enhanced green emission at a wavelength of 515 nm is observed in the glass-ceramic fiber, which demonstrates second harmonic generation of a laser action in the fabricated glass-ceramic fibers. Therefore, this new glass-ceramic fiber not only provides a highly promising development for frequency conversion of lasers in all optical fiber based networks, but the melt-in-tube fabrication method also offers excellent opportunities for fabricating a wide range of novel glass-ceramic optical fibers for multiple future applications including fiber telecommunications and lasers. PMID:28358045

Uniform enhancement of optical micro-angiography images using Rayleigh contrast-limited adaptive histogram equalization

PubMed Central

Yousefi, Siavash; Qin, Jia; Zhi, Zhongwei

2013-01-01

Optical microangiography is an imaging technology that is capable of providing detailed functional blood flow maps within microcirculatory tissue beds in vivo. Some practical issues however exist when displaying and quantifying the microcirculation that perfuses the scanned tissue volume. These issues include: (I) Probing light is subject to specular reflection when it shines onto sample. The unevenness of the tissue surface makes the light energy entering the tissue not uniform over the entire scanned tissue volume. (II) The biological tissue is heterogeneous in nature, meaning the scattering and absorption properties of tissue would attenuate the probe beam. These physical limitations can result in local contrast degradation and non-uniform micro-angiogram images. In this paper, we propose a post-processing method that uses Rayleigh contrast-limited adaptive histogram equalization to increase the contrast and improve the overall appearance and uniformity of optical micro-angiograms without saturating the vessel intensity and changing the physical meaning of the micro-angiograms. The qualitative and quantitative performance of the proposed method is compared with those of common histogram equalization and contrast enhancement methods. We demonstrate that the proposed method outperforms other existing approaches. The proposed method is not limited to optical microangiography and can be used in other image modalities such as photo-acoustic tomography and scanning laser confocal microscopy. PMID:23482880

Glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals for frequency conversion of lasers.

PubMed

Fang, Zaijin; Xiao, Xusheng; Wang, Xin; Ma, Zhijun; Lewis, Elfed; Farrell, Gerald; Wang, Pengfei; Ren, Jing; Guo, Haitao; Qiu, Jianrong

2017-03-30

A glass-ceramic optical fiber containing Ba 2 TiSi 2 O 8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba 2 TiSi 2 O 8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic fibers. When irradiated using a 1030 nm femtosecond laser, an enhanced green emission at a wavelength of 515 nm is observed in the glass-ceramic fiber, which demonstrates second harmonic generation of a laser action in the fabricated glass-ceramic fibers. Therefore, this new glass-ceramic fiber not only provides a highly promising development for frequency conversion of lasers in all optical fiber based networks, but the melt-in-tube fabrication method also offers excellent opportunities for fabricating a wide range of novel glass-ceramic optical fibers for multiple future applications including fiber telecommunications and lasers.

Research on automatic Hartmann test of membrane mirror

NASA Astrophysics Data System (ADS)

Zhong, Xing; Jin, Guang; Liu, Chunyu; Zhang, Peng

2010-10-01

Electrostatic membrane mirror is ultra-lightweight and easy to acquire a large diameter comparing with traditional optical elements, so its development and usage is the trend of future large mirrors. In order to research the control method of the static stretching membrane mirror, the surface configuration must be tested. However, membrane mirror's shape is always changed by variable voltages on the electrodes, and the optical properties of membrane materials using in our experiment are poor, so it is difficult to test membrane mirror by interferometer and null compensator method. To solve this problem, an automatic optical test procedure for membrane mirror is designed based on Hartmann screen method. The optical path includes point light source, CCD camera, splitter and diffuse transmittance screen. The spots' positions on the diffuse transmittance screen are pictured by CCD camera connected with computer, and image segmentation and centroid solving is auto processed. The CCD camera's lens distortion is measured, and fixing coefficients are given to eliminate the spots' positions recording error caused by lens distortion. To process the low sampling Hartmann test results, Zernike polynomial fitting method is applied to smooth the wave front. So low frequency error of the membrane mirror can be measured then. Errors affecting the test accuracy are also analyzed in this paper. The method proposed in this paper provides a reference for surface shape detection in membrane mirror research.

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.

An interferometer having fused optical fibers, and apparatus and method using the interferometer

NASA Technical Reports Server (NTRS)

Hellbaum, Richard F. (Inventor); Claus, Richard O. (Inventor); Murphy, Kent A. (Inventor); Gunther, Michael F. (Inventor)

1992-01-01

An interferometer includes a first optical fiber coupled to a second optical fiber by fusing. At a fused portion, the first and second optical fibers are cut to expose respective cores. The cut or fused end of the first and second optical fibers is arranged to oppose a diaphragm or surface against which a physical phenomenon such as pressure or stress, is applied. In a first embodiment, a source light which is generally single-mode monochromatic, coherent light, is input to the first optical fiber and by evanescence, effectively crosses to the second optical fiber at the fused portion. Source light from the second optical fiber is reflected by the diaphragm or surface, and received at the second optical fiber to generate an output light which has an intensity which depends upon interference of reference light based on the source light, and the reflected light reflected from the diaphragm or surface. The intensity of the output light represents a positional relationship or displacement between the interferometer and the diaphragm or surface.