Sample records for acousto-optic programmable dispersive

  1. Ultraviolet acousto-optic programmable dispersive filter laser pulse shaping in KDP.

    PubMed

    Coudreau, Sebastien; Kaplan, Daniel; Tournois, Pierre

    2006-06-15

    An acousto-optic programmable dispersive filter pulse shaper has been designed using KDP material for operation in the 200-500 nm wavelength range. With an acousto-optic interaction length of 72 mm, a spectral resolution of 0.15 nm has been measured to be consistent with theoretical predictions. Theory and experiments indicate that diffraction efficiencies up to 50% are expected in practical experimental conditions.

  2. Closed-loop carrier-envelope phase stabilization with an acousto-optic programmable dispersive filter.

    PubMed

    Forget, N; Canova, L; Chen, X; Jullien, A; Lopez-Martens, R

    2009-12-01

    We demonstrate arbitrary carrier-envelope (CE) phase control of femtosecond laser pulses by an acousto-optic programmable dispersive filter (AOPDF), with an accuracy better than pi/100 at a repetition rate of 1 kHz. We also demonstrate, for the first time to the best of our knowledge, 15 Hz closed-loop CE phase stabilization using an AOPDF inside a 1 kHz chirped pulse amplifier to correct for slow CE phase drifts.

  3. Acousto-Optic Interactions.

    DTIC Science & Technology

    The document reports the results of the experimental and theoretical investigation of acousto - optic interactions in guided wave structure for optical...waves and acoustic surface waves and experimental results of isotropic and anisotropic diffraction in LiNbO3 and quartz. A simple acousto - optic plate...CVD ZnO films on sapphire, which may be needed for the acousto - optic devices in thin films are also included. (Author)

  4. Electro-optic and acousto-optic scanning and deflection

    NASA Astrophysics Data System (ADS)

    Gottlieb, M.; Ireland, C. L. M.; Ley, J. M.

    This book attempts to cover sufficient electro- and acousto-optic theory for the reader to understand and appreciate the design and application of solid state optical deflectors. It is also hoped that for the more experienced engineer the book will serve as a useful reference book covering the most important work in this field of engineering. The theory of the electro-optic effect is considered along with the properties and selection of electro-optic materials, the principles of electro-optic deflectors, electro-optic deflector designs, and applications for electro-optic deflectors. Attention is given to EM wave propagation in a crystal, the linear electro-optic effect, the quadratic electro-optic effect in crystals and in liquids, electro-optic ceramics in the (Pb,La)(Zr,Ti)O3 system, and digital and analog light deflectors. Aspects related to acousto-optic deflectors are discussed, taking into account acousto-optic interactions, materials for acousto-optic scanning, acoustic techniques, scanning systems, and acousto-optic light diffraction in thin films.

  5. Ultrasound sensing using the acousto-optic effect in polymer dispersed liquid crystals

    NASA Astrophysics Data System (ADS)

    Trushkevych, O.; Eriksson, T. J. R.; Ramadas, S. N.; Dixon, S.; Edwards, R. S.

    2015-08-01

    Acousto-optic effects are demonstrated in polymer dispersed liquid crystal (PDLC) films, showing promise for applications in ultrasound sensing. The PDLC films are used to image two displacement profiles of air-coupled flexural transducers' resonant modes at 295 kHz and 730 kHz. Results are confirmed using laser vibrometry. The regions on the transducers with the largest displacements are clearly imaged by the PDLC films, with the resolution agreeing well with laser vibrometry scanning. Imaging takes significantly less time than a scanning system (switching time of a few seconds, as compared to 8 h for laser vibrometry). Heating effects are carefully monitored using thermal imaging and are found not to be the main cause of PDLC clearing.

  6. Acousto-optic replication of ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Yushkov, Konstantin B.; Molchanov, Vladimir Ya.; Ovchinnikov, Andrey V.; Chefonov, Oleg V.

    2017-10-01

    Precisely controlled sequences of ultrashort laser pulses are required in various scientific and engineering applications. We developed a phase-only acousto-optic pulse shaping method for replication of ultrashort laser pulses in a TW laser system. A sequence of several Fourier-transform-limited pulses is generated from a single femtosecond laser pulse by means of applying a piecewise linear phase modulation over the whole emission spectrum. Analysis demonstrates that the main factor which limits maximum delay between the pulse replicas is spectral resolution of the acousto-optic dispersive delay line used for pulse shaping. In experiments with a Cr:forsterite laser system, we obtained delays from 0.3 to 3.5 ps between two replicas of 190 fs transform-limited pulses at the central wavelength of laser emission, 1230 nm.

  7. Rigorous coupled wave analysis of acousto-optics with relativistic considerations.

    PubMed

    Xia, Guoqiang; Zheng, Weijian; Lei, Zhenggang; Zhang, Ruolan

    2015-09-01

    A relativistic analysis of acousto-optics is presented, and a rigorous coupled wave analysis is generalized for the diffraction of the acousto-optical effect. An acoustic wave generates a grating with temporally and spatially modulated permittivity, hindering direct applications of the rigorous coupled wave analysis for the acousto-optical effect. In a reference frame which moves with the acoustic wave, the grating is static, the medium moves, and the coupled wave equations for the static grating may be derived. Floquet's theorem is then applied to cast these equations into an eigenproblem. Using a Lorentz transformation, the electromagnetic fields in the grating region are transformed to the lab frame where the medium is at rest, and relativistic Doppler frequency shifts are introduced into various diffraction orders. In the lab frame, the boundary conditions are considered and the diffraction efficiencies of various orders are determined. This method is rigorous and general, and the plane waves in the resulting expansion satisfy the dispersion relation of the medium and are propagation modes. Properties of various Bragg diffractions are results, rather than preconditions, of this method. Simulations of an acousto-optical tunable filter made by paratellurite, TeO(2), are given as examples.

  8. Construction and characterization of ultraviolet acousto-optic based femtosecond pulse shapers

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

    Mcgrane, Shawn D; Moore, David S; Greenfield, Margo T

    2008-01-01

    We present all the information necessary for construction and characterization of acousto optic pulse shapers, with a focus on ultraviolet wavelengths, Various radio-frequency drive configurations are presented to allow optimization via knowledgeable trade-off of design features. Detailed performance characteristics of a 267 nm acousto-optic modulator (AOM) based pulse shaper are presented, Practical considerations for AOM based pulse shaping of ultra-broad bandwidth (sub-10 fs) amplified femtosecond pulse shaping are described, with particular attention paid to the effects of the RF frequency bandwidth and optical frequency bandwidth on the spatial dispersion of the output laser pulses.

  9. Laser-Based Acousto-Optic Uplink Communications Technique

    DTIC Science & Technology

    2003-08-18

    An apparatus for enabling acousto - optic communication comprising an in-water platform comprising means for emitting an acoustic signal to an acousto ...portion of the first interrogation beam and a second laser beam formed from the reflection of the first interrogation beam off of the acousto - optic interaction... optic interaction zone, an in-air platform comprising the ability for transmitting a first optical interrogation beam, the ability for receiving a

  10. Development of New Electro-Optic and Acousto-Optic Materials.

    DTIC Science & Technology

    1983-11-01

    Improved materials are required for active optical devices, including electro - optic and acousto-optic modulators, switches and tunable filters, as...many microwave applications. In addition, electro - optic and acousto-optic devices are materials limited because the materials currently available are...these materials for applications involving the electro - optic effect, degenerate four-wave mixing and surface acoustic wave technology.

  11. Acousto-Optic Beam Sampler, Part 2. Green’s Function Solution to Acousto-Optic Interaction Problem.

    DTIC Science & Technology

    This part of the ’ Acousto - Optic Beam Sampler,’ series lays down the formalism behind the Green’s function integral approach to solving the acousto ... optic scattering problem. The advantage of this formulation which is applicable to gases is shown through developing the solution to the scattering

  12. Experimental Investigation of Acousto-Optic Communications

    DTIC Science & Technology

    2003-09-01

    acousto - optic sensor shows promise as a means for detecting acoustic data projected towards the water surface from a submerged platform. The laser...simulation studies were conducted to demonstrate acousto - optic sensor feasibility for obtaining robust recordings of acoustic communication signals across

  13. Acousto-Optic and Linear Electro-Optic Properties of Organic Polymeric Materials

    DTIC Science & Technology

    1989-04-27

    Naval Research Laboratory Washington, DC 20375-5000 NRL Memorandum Report 6454 od I3 Acousto - Optic and Linear Electro-Optic Properties of Organic...PROGRAM P1RC;EC7 ASK Arlington, VA 22217-5000 ELEMENT NO NO1 I1I TITLE (Include Security Classification) Acousto - Optic and Linear Electro-Optic...briefly discussing the important molecular properties for enhanced acousto ~ optic and electro-Ooptic ef fects and then relating these to "current

  14. Eliminating Bias In Acousto-Optical Spectrum Analysis

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Lesh, James R.

    1992-01-01

    Scheme for digital processing of video signals in acousto-optical spectrum analyzer provides real-time correction for signal-dependent spectral bias. Spectrum analyzer described in "Two-Dimensional Acousto-Optical Spectrum Analyzer" (NPO-18092), related apparatus described in "Three-Dimensional Acousto-Optical Spectrum Analyzer" (NPO-18122). Essence of correction is to average over digitized outputs of pixels in each CCD row and to subtract this from the digitized output of each pixel in row. Signal processed electro-optically with reference-function signals to form two-dimensional spectral image in CCD camera.

  15. Wideband Waveguide Acousto-Optic Bragg Cell.

    DTIC Science & Technology

    The results of an effort to improve the performance specifications of acousto - optic Bragg cells are reported. Various configurations of multiple...would provide a 700 MHz acousto - optic bandwidth. Investigated were Bragg cells fabricated on Ti diffused LiNb03 waveguides as well as Ti diffused LiNb03

  16. Ferroic Crystals for Electro-Optic and Acousto-Optic Applications.

    DTIC Science & Technology

    properties for potential application in acousto - optic devices; and, (2) A systematic examination of the role of domain structures in modifying the...macroscopic properties of all types of ferroic crystals and the manner in which these property modifications could be exploited in acousto - optic , electro

  17. Guided-Wave TeO2 Acousto-Optic Devices

    DTIC Science & Technology

    1991-01-12

    In this research program, Guided-wave TeO2 Acousto - Optic Devices, the properties of surface acoustic waves on tellurium dioxide single crystal...surfaces has been studied for its potential applications as acousto - optic signal processing devices. Personal computer based numerical method has been...interaction with laser beams. Use of the acousto - optic probe, the surface acoustic wave velocity and field distribution have been obtained and compared

  18. Compensation of temporal and spatial dispersion for multiphoton acousto-optic laser-scanning microscopy

    NASA Astrophysics Data System (ADS)

    Iyer, Vijay; Saggau, Peter

    2003-10-01

    In laser-scanning microscopy, acousto-optic (AO) deflection provides a means to quickly position a laser beam to random locations throughout the field-of-view. Compared to conventional laser-scanning using galvanometer-driven mirrors, this approach increases the frame rate and signal-to-noise ratio, and reduces time spent illuminating sites of no interest. However, random-access AO scanning has not yet been combined with multi-photon microscopy, primarily because the femtosecond laser pulses employed are subject to significant amounts of both spatial and temporal dispersion upon propagation through common AO materials. Left uncompensated, spatial dispersion reduces the microscope"s spatial resolution while temporal dispersion reduces the multi-photon excitation efficacy. In previous work, we have demonstrated, 1) the efficacy of a single diffraction grating scheme which reduces the spatial dispersion at least 3-fold throughout the field-of-view, and 2) the use of a novel stacked-prism pre-chirper for compensating the temporal dispersion of a pair of AODs using a shorter mechanical path length (2-4X) than standard prism-pair arrangements. In this work, we demonstrate for the first time the use of these compensation approaches with a custom-made large-area slow-shear TeO2 AOD specifically suited for the development of a high-resolution 2-D random-access AO scanning multi-photon laser-scanning microscope (AO-MPLSM).

  19. Fast spatial beam shaping by acousto-optic diffraction for 3D non-linear microscopy.

    PubMed

    Akemann, Walther; Léger, Jean-François; Ventalon, Cathie; Mathieu, Benjamin; Dieudonné, Stéphane; Bourdieu, Laurent

    2015-11-02

    Acousto-optic deflection (AOD) devices offer unprecedented fast control of the entire spatial structure of light beams, most notably their phase. AOD light modulation of ultra-short laser pulses, however, is not straightforward to implement because of intrinsic chromatic dispersion and non-stationarity of acousto-optic diffraction. While schemes exist to compensate chromatic dispersion, non-stationarity remains an obstacle. In this work we demonstrate an efficient AOD light modulator for stable phase modulation using time-locked generation of frequency-modulated acoustic waves at the full repetition rate of a high power laser pulse amplifier of 80 kHz. We establish the non-local relationship between the optical phase and the generating acoustic frequency function and verify the system for temporal stability, phase accuracy and generation of non-linear two-dimensional phase functions.

  20. Accurate mode characterization of two-mode optical fibers by in-fiber acousto-optics.

    PubMed

    Alcusa-Sáez, E; Díez, A; Andrés, M V

    2016-03-07

    Acousto-optic interaction in optical fibers is exploited for the accurate and broadband characterization of two-mode optical fibers. Coupling between LP 01 and LP 1m modes is produced in a broadband wavelength range. Difference in effective indices, group indices, and chromatic dispersions between the guided modes, are obtained from experimental measurements. Additionally, we show that the technique is suitable to investigate the fine modes structure of LP modes, and some other intriguing features related with modes' cut-off.

  1. Exploring Novel Crystals and Designs for Acousto-Optic Devices

    NASA Astrophysics Data System (ADS)

    Pfeiffer, Jonathan B.

    Acousto-optic devices are a versatile technology that are driven electronically to precisely and rapidly control the intensity, frequency, and propagation direction of a laser beam. Applications include acousto-optic scanners, filters, mode lockers, and modulators. Despite the popularity of acousto-optic devices, there currently is no UV transparent device that can satisfy the requirements of the atomic clock and quantum computing communities. In this thesis, I describe my experimental efforts for discovering a new UV transparent, acousto-optic crystal that can meet the experimental requirements. I also present my graphical representations for locating practical and efficient acousto-optic designs in a given medium. The first part of this thesis describes how to measure the elastic-stiffness and photoelastic coefficients of a given crystal. The elastic-stiffness coefficients are essential for designing acousto-optic devices because they determine the velocity, diffraction, and polarization of acoustic waves in a given medium. I used both resonant ultrasound spectroscopy and a modified version of Schaefer-Bergman diffraction to measure elastic coefficients. I discuss in detail the strengths, differences, and similarities of the two experiments. The photoelastic coefficients are necessary for determining the diffraction efficiency of a given acousto-optic geometry. Similar to the elastic coefficients, I employ a modified version of the Schaefer-Bergmann experiment to measure the photoelastic coefficients. I corroborate the measured results with the well established Dixon experiment. The second part of this thesis describes four different graphical representations that help locate practical and efficient acousto-optic designs. I describe in detail each algorithm and how to interpret the calculated results. Several examples are provided for commonly used acosuto-optic materials. The thesis concludes by describing the design and performance of an acousto-optic frequency

  2. Feedback and Acousto Optic Isolation Effects on Laser Stability.

    DTIC Science & Technology

    1977-03-01

    This paper analyzes the effect of optical feedback on laser frequency stability and the acousto optic isolator concept, which was demonstrated...nonlinearity such as saturation in the laser medium. The analysis mathematically corroborates the initial acousto optic isolator concept and the...limited experimental data available. In the study of the acousto optic isolator, it was determined that an acceptable analytic expression for the

  3. A spatio-temporally compensated acousto-optic scanner for two-photon microscopy providing large field of view.

    PubMed

    Kremer, Y; Léger, J-F; Lapole, R; Honnorat, N; Candela, Y; Dieudonné, S; Bourdieu, L

    2008-07-07

    Acousto-optic deflectors (AOD) are promising ultrafast scanners for non-linear microscopy. Their use has been limited until now by their small scanning range and by the spatial and temporal dispersions of the laser beam going through the deflectors. We show that the use of AOD of large aperture (13mm) compared to standard deflectors allows accessing much larger field of view while minimizing spatio-temporal distortions. An acousto-optic modulator (AOM) placed at distance of the AOD is used to compensate spatial and temporal dispersions. Fine tuning of the AOM-AOD setup using a frequency-resolved optical gating (GRENOUILLE) allows elimination of pulse front tilt whereas spatial chirp is minimized thanks to the large aperture AOD.

  4. A Compact Bulk Acousto-Optic Time Integrating Correlator.

    DTIC Science & Technology

    1984-11-01

    AD-A156 668 A COMPACT BULK ACOUSTO - OPTIC TIME INTEGRATING 1/1 CORRELATOR(U) ELECTRONICS RESEARCH LAB ADELAIDE (AUSTRALIA) D A FOGG NOV 84 ERL-9323-TR...DEFENCE RESEARCH CENTRE SALISBURY SOUTH AUSTRALIA TECHNICAL REPORT ER L-0323-TR A COMPACT BULK ACOUSTO - OPTIC TIME INTEGRATING CORRELATOR D.A.B. FOGG...LABORATORY TECHNICAL REPORT ERL-0323-TR A COMPACT BULK ACOUSTO - OPTIC TIME INTEGRATING CORRELATOR D.A.B. Fogg SUMMARY This report describes the design and

  5. Ultrafast acousto-optic mode conversion in optically birefringent ferroelectrics

    PubMed Central

    Lejman, Mariusz; Vaudel, Gwenaelle; Infante, Ingrid C.; Chaban, Ievgeniia; Pezeril, Thomas; Edely, Mathieu; Nataf, Guillaume F.; Guennou, Mael; Kreisel, Jens; Gusev, Vitalyi E.; Dkhil, Brahim; Ruello, Pascal

    2016-01-01

    The ability to generate efficient giga–terahertz coherent acoustic phonons with femtosecond laser makes acousto-optics a promising candidate for ultrafast light processing, which faces electronic device limits intrinsic to complementary metal oxide semiconductor technology. Modern acousto-optic devices, including optical mode conversion process between ordinary and extraordinary light waves (and vice versa), remain limited to the megahertz range. Here, using coherent acoustic waves generated at tens of gigahertz frequency by a femtosecond laser pulse, we reveal the mode conversion process and show its efficiency in ferroelectric materials such as BiFeO3 and LiNbO3. Further to the experimental evidence, we provide a complete theoretical support to this all-optical ultrafast mechanism mediated by acousto-optic interaction. By allowing the manipulation of light polarization with gigahertz coherent acoustic phonons, our results provide a novel route for the development of next-generation photonic-based devices and highlight new capabilities in using ferroelectrics in modern photonics. PMID:27492493

  6. Ultrafast acousto-optic mode conversion in optically birefringent ferroelectrics

    NASA Astrophysics Data System (ADS)

    Lejman, Mariusz; Vaudel, Gwenaelle; Infante, Ingrid C.; Chaban, Ievgeniia; Pezeril, Thomas; Edely, Mathieu; Nataf, Guillaume F.; Guennou, Mael; Kreisel, Jens; Gusev, Vitalyi E.; Dkhil, Brahim; Ruello, Pascal

    2016-08-01

    The ability to generate efficient giga-terahertz coherent acoustic phonons with femtosecond laser makes acousto-optics a promising candidate for ultrafast light processing, which faces electronic device limits intrinsic to complementary metal oxide semiconductor technology. Modern acousto-optic devices, including optical mode conversion process between ordinary and extraordinary light waves (and vice versa), remain limited to the megahertz range. Here, using coherent acoustic waves generated at tens of gigahertz frequency by a femtosecond laser pulse, we reveal the mode conversion process and show its efficiency in ferroelectric materials such as BiFeO3 and LiNbO3. Further to the experimental evidence, we provide a complete theoretical support to this all-optical ultrafast mechanism mediated by acousto-optic interaction. By allowing the manipulation of light polarization with gigahertz coherent acoustic phonons, our results provide a novel route for the development of next-generation photonic-based devices and highlight new capabilities in using ferroelectrics in modern photonics.

  7. Theory and Experiment Analysis of Two-Dimensional Acousto-Optic Interaction.

    DTIC Science & Technology

    1995-01-03

    The universal coupled wave equation of two dimensional acousto optic effect has been deduced and the solution of normal Raman-Hath acousto optic diffraction...was derived from it. The theory was compared with the experimental results of a two dimensional acousto optic device consisting of two one dimensional modulators. The experiment results agree with the theory. (AN)

  8. Scheme for Terminal Guidance Utilizing Acousto-Optic Correlator.

    DTIC Science & Technology

    longitudinally extending acousto - optic device as index of refraction variation pattern signals. Real time signals corresponding to the scene actually being viewed...by the vehicle are propagated across the stored signals, and the results of an acousto - optic correlation are utilized to determine X and Y error

  9. Experimental examination of frequency locking effect in acousto-optic system

    NASA Astrophysics Data System (ADS)

    Mantsevich, S. N.; Balakshy, V. I.

    2018-04-01

    The optoelectronic system containing collinear acousto-optic cell fabricated on the base of calcium molybdate crystal and positive electronic feedback circuit was examined. The feedback signal is formed due to the optical heterodyning effect that occurs on the cell output and takes place in the special regime of collinear acousto-optic diffraction. It was discovered that three operation modes that may exist in this system. The boundaries between the modes were determined. The positions of the boundaries depend on the main parameters of the system—the incident light intensity and the feedback gain value. The new for acousto-optics phenomenon of acousto-optic system self-oscillations frequency locking by the RF generator signal was discovered and examined experimentally. Such an effect has never been observed before in the acousto-optic systems. It was experimentally shown that frequency locking effect may be used to select one of the multimode semiconductor laser longitudinal modes to improve laser radiation spectral composition.

  10. Bulk and integrated acousto-optic spectrometers for molecular astronomy with heterodyne spectrometers

    NASA Technical Reports Server (NTRS)

    Chin, G.; Buhl, D.; Florez, J. M.

    1981-01-01

    A survey of acousto-optic spectrometers for molecular astronomy is presented, noting a technique of combining the acoustic bending of a collimated coherent light beam with a Bragg cell followed by an array of sensitive photodetectors. This acousto-optic spectrometer has a large bandwidth, a large number of channels, high resolution, and is energy efficient. Receiver development has concentrated on high-frequency heterodyne systems for the study of the chemical composition of the interstellar medium. RF spectrometers employing acousto-optic diffraction cells are described. Acousto-optic techniques have been suggested for applications to electronic warfare, electronic countermeasures and electronic support systems. Plans to use integrated optics for the further miniaturization of acousto-optic spectrometers are described. Bulk acousto-optic spectrometers with 300 MHz and 1 GHz bandwidths are being developed for use in the back-end of high-frequency heterodyne receivers for astronomical research.

  11. Real-Time and Memory Correlation via Acousto-Optic Processing,

    DTIC Science & Technology

    1978-06-01

    acousto - optic technology as an answer to these requirements appears very attractive. Three fundamental signal-processing schemes using the acousto ... optic interaction have been investigated: (i) real-time correlation and convolution, (ii) Fourier and discrete Fourier transformation, and (iii

  12. Low-frequency acousto-optic backscattering of Bessel light beams

    NASA Astrophysics Data System (ADS)

    Khilo, Nikolai A.; Belyi, Vladimir N.; Khilo, Petr A.; Kazak, Nikolai S.

    2018-05-01

    The use of Bessel light beams, as well as Bessel acoustic beams, substantially enhances the capabilities of acousto-optic methods for control of optical field. We present a theoretical study of the process of optical Bessel beams conversion by means of backward acousto-optic scattering on a Bessel acoustic field in a transversely isotropic crystal. It is shown that, with an appropriate choice of Bessel beams parameters, the backscattering in visible spectral range can be realized at relatively low acoustic frequencies less than one gigahertz. Under conditions of phase matching and transverse spatial synchronism, the efficiency of backscattering is sufficiently high, which is interesting, for example, for construction of acousto-optic spectral analyzers.

  13. Signal Coherence Recovery Using Acousto-Optic Fourier Transform Architectures

    DTIC Science & Technology

    1990-06-14

    processing of data in ground- and space-based applications. We have implemented a prototype one-dimensional time-integrating acousto - optic (AO) Fourier...theory of optimum coherence recovery (CR) applicable in computation-limited environments. We have demonstrated direct acousto - optic implementation of CR

  14. Space Qualification Issues in Acousto-optic and Electro-optic Devices

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.; Taylor, Edward W.; Trivedi, Sudhir; Kutcher, Sue; Soos, Jolanta

    2007-01-01

    Satellite and space-based applications of photonic devices and systems require operational reliability in the harsh environment of space for extended periods of time. This in turn requires every component of the systems and their packaging to meet space qualifications. Acousto- and electro-optical devices form the major components of many current space based optical systems, which is the focus of this paper. The major space qualification issues are related to: mechanical stability, thermal effects and operation of the devices in the naturally occurring space radiation environment. This paper will discuss acousto- and electro-optic materials and devices with respect to their stability against mechanical vibrations, thermal cycling in operating and non-operating conditions and device responses to space ionizing and displacement radiation effects. Selection of suitable materials and packaging to meet space qualification criteria will also be discussed. Finally, a general roadmap for production and testing of acousto- and electro-optic devices will be discussed.

  15. Three & Four Product Surface-Wave Acousto-Optic Time Integrating Correlators.

    DTIC Science & Technology

    four product correlated signals. A laser beam is split and shaped into first and second sheet beams. The first beam is directed to a first acousto - optic medium...where it is doubly diffracted by first and second signals. The second beam is directed to a second acousto - optic medium which is spatially...rotated 90 degs relative to the first acousto - optic medium where the second sheet beam is either singly diffracted by a third signal or doubly diffracted

  16. Acousto-Optic Spectrum Analyzer: Temporal Response and Detection of Pulsed Signals.

    DTIC Science & Technology

    1986-12-01

    ACOUSTO - OPTIC SPECTRUM ANALYZER: TEMPORAL RESPONSE AND I/i DETECTION OF PULSED SIGUALS(U) DEFENCE RESEARCH ESTABLISHMENT OTTANA (ONTARIO) J...8217:. -.....:.-...............--.. - ---:-..--.-..,. ,: i’,.. IJT~c FILE C P National Defe’ se + Deence nationale 0 0 ACOUSTO - OPTIC SPECTRUM ANALYZER: TEMPORAL RESPONSE AND DETECTION 0 OF PULSED...Ottawa |S, .±~ |-----------------------..,---.-- -- - - - rNatiorna! Defen~se Deterice r dornale ACOUSTO - OPTIC SPECTRUM ANALYZER: TEMPORAL RESPONSE

  17. Acousto-Optic Tunable Filter for Time-Domain Processing of Ultra-Short Optical Pulses,

    DTIC Science & Technology

    The application of acousto - optic tunable filters for shaping of ultra-fast pulses in the time domain is analyzed and demonstrated. With the rapid...advance of acousto - optic tunable filter (AOTF) technology, the opportunity for sophisticated signal processing capabilities arises. AOTFs offer unique

  18. Coherent multi-heterodyne spectroscopy using acousto-optic frequency combs.

    PubMed

    Durán, Vicente; Schnébelin, Cȏme; Guillet de Chatellus, Hugues

    2018-05-28

    We propose and characterize experimentally a new source of optical frequency combs for performing multi-heterodyne spectrometry. This comb modality is based on a frequency-shifting loop seeded with a continuous-wave (CW) monochromatic laser. The comb lines are generated by successive passes of the CW laser through an acousto-optic frequency shifter. We report the generation of frequency combs with more than 1500 mutually coherent lines, without resorting to non-linear broadening phenomena or external electronic modulation. The comb line spacing is easily reconfigurable from tens of MHz down to the kHz region. We first use a single acousto-optic frequency comb to conduct self-heterodyne interferometry with a high frequency resolution (500 kHz). By increasing the line spacing to 80 MHz, we demonstrate molecular spectroscopy on the sub-millisecond time scale. In order to reduce the detection bandwidth, we subsequently implement an acousto-optic dual-comb spectrometer with the aid of two mutually coherent frequency shifting loops. In each architecture, the potentiality of acousto-optic frequency combs for spectroscopy is validated by spectral measurements of hydrogen cyanide in the near-infrared region.

  19. Coherent multi-heterodyne spectroscopy using acousto-optic frequency combs

    NASA Astrophysics Data System (ADS)

    Durán, Vicente; Schnébelin, Cȏme; Guillet de Chatellus, Hugues

    2018-05-01

    We propose and characterize experimentally a new source of optical frequency combs for performing multi-heterodyne spectrometry. This comb modality is based on a frequency shifting loop seeded with a CW monochromatic laser. The comb lines are generated by successive passes of the CW laser through an acousto-optic frequency shifter. We report the generation of frequency combs with more than 1500 mutually coherent lines, without resorting to non-linear broadening phenomena or external electronic modulation. The comb line spacing is easily reconfigurable from tens of MHz down to the kHz region. We first use a single acousto-optic frequency comb to conduct self-heterodyne interferometry with a high frequency resolution (500 kHz). By increasing the line spacing to 80 MHz, we demonstrate molecular spectroscopy on the sub-millisecond time scale. In order to reduce the detection bandwidth, we subsequently implement an acousto-optic dual-comb spectrometer with the aid of two mutually coherent frequency shifting loops. In each architecture, the potentiality of acousto-optic frequency combs for spectroscopy is validated by spectral measurements of hydrogen cyanide in the near-infrared region.

  20. Acousto-Optic Technology for Topographic Feature Extraction and Image Analysis.

    DTIC Science & Technology

    1981-03-01

    This report contains all findings of the acousto - optic technology study for feature extraction conducted by Deft Laboratories Inc. for the U.S. Army...topographic feature extraction and image analysis using acousto - optic (A-O) technology. A conclusion of this study was that A-O devices are potentially

  1. The Acousto-Optic Interaction in an Infinite Slab of Isotropic Material,

    DTIC Science & Technology

    1980-04-01

    AD-A097 202 HARRY DIAMOND LABS ADELPHI MD F/S 17/1 THE ACOUSTO - OPTIC INTERACTION IN AN INFINITE SLAB OF ISOTROPIC -- ETC(U) APR 80 S D SCHARF...611101.91A0011 .A1.A1 HOL Project: A10935 1S. KEY WONS (Cf ft "W reweee eld. It neceseeM md Io.t.Itl by block nm er) Acousto - optics Diffraction Mathieu... Acousto - Optic Interaction for Bragg Angles ...................... 13 FIGURES 1. Incident wave is split by acoustic wave into discrete diffracted orders

  2. Advanced spectral processing of broadband light using acousto-optic devices with arbitrary transmission functions.

    PubMed

    Molchanov, Vladimir Ya; Yushkov, Konstantin B

    2014-06-30

    In the paper, we developed a dispersive method for transmission function synthesis of collinear and quasi-collinear acousto-optic tunable filters. General theoretical consideration was performed, and modelling was made for broadband and narrowband signals. Experimental results on spectral shaping of femtosecond laser emission were obtained. Binary spectral encoding of broadband emission was demonstrated.

  3. Piezo-optic, photoelastic, and acousto-optic properties of SrB4O7 crystals.

    PubMed

    Mytsyk, Bohdan; Demyanyshyn, Natalia; Martynyuk-Lototska, Irina; Vlokh, Rostyslav

    2011-07-20

    On the basis of studies of the piezo-optic effect, it has been shown that SrB(4)O(7) crystals can be used as efficient acousto-optic materials in the vacuum ultraviolet spectral range. The full matrices of piezo-optic and photoelastic coefficients have been experimentally obtained for these crystals. The acousto-optic figure of merit and the diffraction efficiency have been estimated for both the visible and deep ultraviolet spectral ranges. © 2011 Optical Society of America

  4. Growth of Acousto-Optic Crystals for Applications in Infrared Region of Spectrum

    DTIC Science & Technology

    2005-04-30

    Acousto - optic (AO) modulators, deflectors, filters offer convenience, reliability, compact size and fast speed in regulation of optical beams. So far...extremely low acousto - optic figure of merit, which automatically results in high requirements on driving electric power and poor diffraction efficiency. It

  5. Fiber-Coupled Acousto-Optical-Filter Spectrometer

    NASA Technical Reports Server (NTRS)

    Levin, Kenneth H.; Li, Frank Yanan

    1993-01-01

    Fiber-coupled acousto-optical-filter spectrometer steps rapidly through commanded sequence of wavelengths. Sample cell located remotely from monochromator and associated electronic circuitry, connected to them with optical fibers. Optical-fiber coupling makes possible to monitor samples in remote, hazardous, or confined locations. Advantages include compactness, speed, and no moving parts. Potential applications include control of chemical processes, medical diagnoses, spectral imaging, and sampling of atmospheres.

  6. 2-D Acousto-Optic Signal Processors for Simultaneous Spectrum Analysis and Direction Finding

    DTIC Science & Technology

    1990-11-01

    National Dfense Defence nationale 2-D ACOUSTO - OPTIC SIGNAL PROCESSORS FOR SIMULTANEOUS SPECTRUM ANALYSIS 00 AND DIRECTION FINDING (U) by NM Jim P.Y...Wr pdft .1w I0~1111191 3 05089 National DIfense Defence nationale 2-D ACOUSTO - OPTIC SIGNAL PROCESSORS FOR SIMULTANEOUS SPECTRUM ANALYSIS AND DIRECTION...Processing, J.T. Tippet et al., Eds., Chapter 38, pp. 715-748, MIT Press, Cambridge 1965. [6] A.E. Spezio," Acousto - optics for Electronic Warfare

  7. Sidelobe suppression in all-fiber acousto-optic tunable filter using torsional acoustic wave.

    PubMed

    Lee, Kwang Jo; Hwang, In-Kag; Park, Hyun Chul; Kim, Byoung Yoon

    2010-06-07

    We propose two techniques to suppress intrinsic sidelobe spectra in all-fiber acousto-optic tunable filter using torsional acoustic wave. The techniques are based on either double-pass filter configuration or axial tailoring of mode coupling strength along an acousto-optic interaction region in a highly birefringent optical fiber. The sidelobe peak in the filter spectrum is experimentally suppressed from -8.3 dB to -16.4 dB by employing double-pass configuration. Axial modulation of acousto-optic coupling strength is proposed using axial variation of the fiber diameter, and the simulation results show that the maximum side peak of -9.3 dB can be reduced to -22.2dB. We also discuss the possibility of further spectral shaping of the filter based on the axial tailoring of acousto-optic coupling strength.

  8. Acousto-optic RF signal acquisition system

    NASA Astrophysics Data System (ADS)

    Bloxham, Laurence H.

    1990-09-01

    This paper describes the architecture and performance of a prototype Acousto-Optic RF Signal Acquisition System designed to intercept, automatically identify, and track communication signals in the VHF band. The system covers 28.0 to 92.0 MHz with five manually selectable, dual conversion; 12.8 MHZ bandwidth front ends. An acousto-optic spectrum analyzer (AOSA) implemented using a tellurium dioxide (Te02) Bragg cell is used to channelize the 12.8 MHz pass band into 512 25 KHz channels. Polarization switching is used to suppress optical noise. Excellent isolation and dynamic range are achieved by using a linear array of 512 custom 40/50 micron fiber optic cables to collect the light at the focal plane of the AOSA and route the light to individual photodetectors. The photodetectors are operated in the photovoltaic mode to compress the greater than 60 dB input optical dynamic range into an easily processed electrical signal. The 512 signals are multiplexed and processed as a line in a video image by a customized digital image processing system. The image processor simultaneously analyzes the channelized signal data and produces a classical waterfall display.

  9. Spin-to-orbit conversion at acousto-optic diffraction of light: conservation of optical angular momentum.

    PubMed

    Skab, Ihor; Vlokh, Rostyslav

    2012-04-01

    Acousto-optic diffraction of light in optically active cubic crystals is analyzed from the viewpoint of conservation of optical angular momentum. It is shown that the availability of angular momentum in the diffracted optical beam can be necessarily inferred from the requirements of angular momentum conservation law. As follows from our analysis, a circularly polarized diffracted wave should bear an orbital angular momentum. The efficiency of the spin-to-orbit momentum conversion is governed by the efficiency of acousto-optic diffraction.

  10. Some recollections on acousto-optics research at the University of Gdańsk in the light of international cooperation and of the history of Spring Schools on Acousto-Optics and Applications.

    PubMed

    Kwiek, Piotr; Sliwiński, Antoni

    2009-03-01

    Some historical features of international cooperation that have been a background for originating the idea to organize since 1980 special international meetings named Spring Schools on Acousto-Optics and Applications and for continuing the events until now are presented. Thanks to the establishment of the Spring Schools, the group of acousto-opticians at the Gdańsk University have had the opportunity to exchange scientific experience and continue mutual cooperation in research with several acousto-optic centers and to publish a number of common papers. A few examples from these achievements and some historical facts illustrating research activity in the field of acousto-optics during past 30 years are recollected.

  11. Acousto-optical tunable filter for combined wideband, spectral, and optical coherence microscopy.

    PubMed

    Machikhin, Alexander S; Pozhar, Vitold E; Viskovatykh, Alexander V; Burmak, Ludmila I

    2015-09-01

    A multimodal technique for inspection of microscopic objects by means of wideband optical microscopy, spectral microscopy, and optical coherence microscopy is described, implemented, and tested. The key feature is the spectral selection of light in the output arm of an interferometer with use of the specialized imaging acousto-optical tunable filter. In this filter, two interfering optical beams are diffracted via the same ultrasound wave without destruction of interference image structure. The basic requirements for the acousto-optical tunable filter are defined, and mathematical formulas for calculation of its parameters are derived. Theoretical estimation of the achievable accuracy of the 3D image reconstruction is presented and experimental proofs are given. It is demonstrated that spectral imaging can also be accompanied by measurement of the quantitative reflectance spectra. Examples of inspection of optically transparent and nontransparent samples demonstrate the applicability of the technique.

  12. Discussion on the Modelling and Processing of Signals fom an Acousto-Optic Spectrum Analyzer.

    DTIC Science & Technology

    1987-06-01

    AD-AIBS 639 DISCUSSION ON THE MODELLING AND PROCESSIN OF SIGNALS 1/1 FOR RN ACOUSTO - OPTIC SPECTRUM ANALYZER(U)G DFENCE RESERCH ESTABGLISHMENT OTTANA...8217’~ AV - I National DefenseI Defence nationale DISCUSSION ON THE MODELLING AND PROCESSING OF SIGNALS FROM AN ACOUSTO - OPTIC SPECTRUM ANALYZER by Guy...signals generated by an Acousto - Optic Spectrum Analyzer (AOSA). It also shows how this calculation can be related to pulse modu- lated signals. In its

  13. A Comparative Study of Acousto-Optic Time-Integrating Correlators for Adaptive Jamming Cancellation

    DTIC Science & Technology

    1997-10-01

    This final report presents a comparative study of the space-integrating and time-integrating configurations of an acousto - optic correlator...systematically evaluate all existing acousto - optic correlator architectures and to determine which would be most suitable for adaptive jamming

  14. Acousto-Optic Beam Sampler, Part III: Diffraction Experiments at 10.6 micrometers.

    DTIC Science & Technology

    This report deals with the results of acousto - optic diffraction experiments in air at 10.6 micron. The laser used for the experiments was operated...fields. Detailed experiments were performed to investigate the dependence of the acousto - optic diffraction on incident laser power, acoustic drive voltage and angle of incidence.

  15. Wavelet transform: fundamentals, applications, and implementation using acousto-optic correlators

    NASA Astrophysics Data System (ADS)

    DeCusatis, Casimer M.; Koay, J.; Litynski, Daniel M.; Das, Pankaj K.

    1995-10-01

    In recent years there has been a great deal of interest in the use of wavelets to supplement or replace conventional Fourier transform signal processing. This paper provides a review of wavelet transforms for signal processing applications, and discusses several emerging applications which benefit from the advantages of wavelets. The wavelet transform can be implemented as an acousto-optic correlator; perfect reconstruction of digital signals may also be achieved using acousto-optic finite impulse response filter banks. Acousto-optic image correlators are discussed as a potential implementation of the wavelet transform, since a 1D wavelet filter bank may be encoded as a 2D image. We discuss applications of the wavelet transform including nondestructive testing of materials, biomedical applications in the analysis of EEG signals, and interference excision in spread spectrum communication systems. Computer simulations and experimental results for these applications are also provided.

  16. Classification of Acousto-Optic Correlation Signatures of Spread Spectrum Signals Using Artificial Neural Networks

    DTIC Science & Technology

    1989-12-01

    Ohio ’aPw iorlipuab muo i 0I2, AFIT/GE/ENG/89D-10 CLASSIFICATION OF ACOUSTO - OPTIC CORRELATION SIGNATURES OF SPREAD SPECTRUM SIGNALS USING ARTIFICIAL...ENG/89D- 10 CLASSIFICATION OF ACOUSTO - OPTIC CORRELATION SIGNATURES OF SPREAD SPECTRUM SIGNALS USING ARTIFICIAL NEURAL NETWORKS THESIS John W. DeBerry...Captain, USAF AFIT/GE/ENG/89D- 10 Approved for public release; distribution unlimited. AFIT/GE/ENG/89D-10 CLASSIFICATION OF ACOUSTO - OPTIC CORRELATION

  17. Acousto-Optic Interaction in Surface Acoustic Waves and Its Application to Real Time Signal Processing.

    DTIC Science & Technology

    1977-12-30

    ACOUSTO - OPTIC INTERACTION IN SURFACE ACOUSTIC WAVES AND ITS APP--ETC(U) DEC 77 0 SCHUMER, P DAS NOOOIJ -75-C-0772 NCLASSIFIED MA-ONR-30 Nt.EE E’h...CHART NAT*NAL BUREAU OF STANDARDS 1-63- ACOUSTO - OPTIC INTERACTION IN SURFACE ACOUSTIC WAVES AND ITS APPLICATION TO REAL TIME SIGNAL PROCESSING By 00 D... Acousto - optics , Integrated optics, Optical Signal Processing. 20. AbSKTRACT (Continue an reverse side it neceary and idewnt& by block mum ber) The

  18. Electro-Optic Effect in the PESO Acousto-Optic Modulator

    DTIC Science & Technology

    1994-11-09

    AD-A286 355 NAIC-ID(RS)T-0395-94 NATIONAL AIR INTELLIGENCE CENTER ELECTRO - OPTIC EFFECT IN THE PESO ACOUSTO-OPTIC MODULATOR by Tai Renzhong, Lu Futun...owing to coupling.betw;ee.elecuc grazing" and "acou- tic grating". Linear electro - optic effect in PESO modulator is helpful to the diffraction and...crystaO A-l/Am,ARjAb, anl / ar:.. thtta=30 and theta=900 . Along these two orientations. th;- electro - optic effect is restricted tcŽ the rn :-t m:,n e

  19. Acousto-optic modulation of a photonic crystal nanocavity with Lamb waves in microwave K band

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

    Tadesse, Semere A.; School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455; Li, Huan

    2015-11-16

    Integrating nanoscale electromechanical transducers and nanophotonic devices potentially can enable acousto-optic devices to reach unprecedented high frequencies and modulation efficiency. Here, we demonstrate acousto-optic modulation of a photonic crystal nanocavity using Lamb waves with frequency up to 19 GHz, reaching the microwave K band. The devices are fabricated in suspended aluminum nitride membrane. Excitation of acoustic waves is achieved with interdigital transducers with period as small as 300 nm. Confining both acoustic wave and optical wave within the thickness of the membrane leads to improved acousto-optic modulation efficiency in these devices than that obtained in previous surface acoustic wave devices. Ourmore » system demonstrates a scalable optomechanical platform where strong acousto-optic coupling between cavity-confined photons and high frequency traveling phonons can be explored.« less

  20. A Very Compact, High Speed and Rugged Acousto-Optic Tunable Filter for Wavelength Division Demultiplexing in Fiber Optic Communication Networks. Phase 1

    DTIC Science & Technology

    1995-06-30

    Novel concepts of near-collinear/collinear acousto - optic interactions have been investigated during this SBIR Phase I program. As a result, several...new acousto - optic tunable filters have been built and tested. The program is highlighted by: (1) Design, fabrication and experimental demonstration of...a novel TeO2 near-collinear acousto - optic tunable filter has been designed, fabricated and tested. The device exhibits a 1.29 nm spectral resolution

  1. Modelling Time-of-Arrival Ambiguities in a Combined Acousto-Optic and Crystal Video Receiver

    DTIC Science & Technology

    1995-11-01

    The probability of pulses overlapping in time being received by a combined acousto - optic /crystal video receiver is investigated. Theoretical analysis...number of pulses in that bandwidth. The number of frequency subbands with crystal detectors required to cover the acousto - optic receiver bandwidth is therefore a compromise between cost and complexity of implementation.

  2. Passive long range acousto-optic sensor

    NASA Astrophysics Data System (ADS)

    Slater, Dan

    2006-08-01

    Alexander Graham Bell's photophone of 1880 was a simple free space optical communication device that used the sun to illuminate a reflective acoustic diaphragm. A selenium photocell located 213 m (700 ft) away converted the acoustically modulated light beam back into sound. A variation of the photophone is presented here that uses naturally formed free space acousto-optic communications links to provide passive multichannel long range acoustic sensing. This system, called RAS (remote acoustic sensor), functions as a long range microphone with a demonstrated range in excess of 40 km (25 miles).

  3. Acousto-optic laser projection systems for displaying TV information

    NASA Astrophysics Data System (ADS)

    Gulyaev, Yu V.; Kazaryan, M. A.; Mokrushin, Yu M.; Shakin, O. V.

    2015-04-01

    This review addresses various approaches to television projection imaging on large screens using lasers. Results are presented of theoretical and experimental studies of an acousto-optic projection system operating on the principle of projecting an image of an entire amplitude-modulated television line in a single laser pulse. We consider characteristic features of image formation in such a system and the requirements for its individual components. Particular attention is paid to nonlinear distortions of the image signal, which show up most severely at low modulation signal frequencies. We discuss the feasibility of improving the process efficiency and image quality using acousto-optic modulators and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation.

  4. Design of far-infrared acousto-optic tunable filter based on backward collinear interaction.

    PubMed

    Voloshinov, Vitaly B; Porokhovnichenko, Dmitriy L; Dyakonov, Evgeniy A

    2018-04-10

    The paper proposes a design of acousto-optic cell applying backward collinear interaction and acoustic mode transformation in a KRS-5 crystal. This cell may serve as an acousto-optic tunable filter for far-infrared spectral range and is able to operate both with collimated optical beams and with divergent beams forming images. The problem of acoustic mode transformation by wave reflection from the crystal facet away from symmetry planes has been solved. Polarization properties of the backward collinear interaction in optically isotropic media are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals.

    PubMed

    Martynyuk-Lototska, Irina; Mys, Oksana; Dudok, Taras; Adamiv, Volodymyr; Smirnov, Yevgen; Vlokh, Rostyslav

    2008-07-01

    Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.

  6. Signal processing in an acousto-optical spectral colorimeter

    NASA Astrophysics Data System (ADS)

    Emeljanov, Sergey P.; Kludzin, Victor V.; Kochin, Leonid B.; Medvedev, Sergey V.; Polosin, Lev L.; Sokolov, Vladimir K.

    2002-02-01

    The algorithms of spectrometer signals processing in the acousto-optical spectral colorimeter, proposed earlier are discussed. This processing is directional on distortion elimination of an optical system spectral characteristics and photoelectric transformations, and also for calculation of tristimulus coefficients X,Y,Z in an international colorimetric system of a CIE - 31 and transformation them in coordinates of recommended CIE uniform contrast systems LUV and LAB.

  7. Acousto-optic infrared spectral imager for Pluto fast flyby

    NASA Technical Reports Server (NTRS)

    Glenar, D. A.; Hillman, J. J.

    1993-01-01

    Acousto-optic tunable filters (AOTF's) enable the design of compact, two-dimensional imaging spectrometers with high spectral and spatial resolution and with no moving parts. Tellurium dioxide AOTF's operate from about 400 nm to nearly 5 microns, and a single device will tune continuously over one octave by changing the RF acoustic frequency applied to the device. An infrared (1.2-2.5 micron) Acousto-Optic Imaging Spectrometer (AImS) was designed that closely conforms to the surface composition mapping objectives of the Pluto Fast Flyby. It features a 75-cm focal length telescope, infrared AOTF, and 256 x 256 NICMOS-3 focal plane array for acquiring narrowband images with a spectral resolving power (lambda/delta(lambda)) exceeding 250. We summarize the instrument design features and its expected performance at the Pluto-Charon encounter.

  8. Acousto-optic laser projection systems for displaying TV information

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

    Gulyaev, Yu V; Kazaryan, M A; Mokrushin, Yu M

    2015-04-30

    This review addresses various approaches to television projection imaging on large screens using lasers. Results are presented of theoretical and experimental studies of an acousto-optic projection system operating on the principle of projecting an image of an entire amplitude-modulated television line in a single laser pulse. We consider characteristic features of image formation in such a system and the requirements for its individual components. Particular attention is paid to nonlinear distortions of the image signal, which show up most severely at low modulation signal frequencies. We discuss the feasibility of improving the process efficiency and image quality using acousto-optic modulatorsmore » and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation. (review)« less

  9. Ultrasonic power measurement system based on acousto-optic interaction.

    PubMed

    He, Liping; Zhu, Fulong; Chen, Yanming; Duan, Ke; Lin, Xinxin; Pan, Yongjun; Tao, Jiaquan

    2016-05-01

    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 optical 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.

  10. Ultrasonic power measurement system based on acousto-optic interaction

    NASA Astrophysics Data System (ADS)

    He, Liping; Zhu, Fulong; Chen, Yanming; Duan, Ke; Lin, Xinxin; Pan, Yongjun; Tao, Jiaquan

    2016-05-01

    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 optical 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.

  11. SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Multistability in an acousto-optical system with a frequency feedback

    NASA Astrophysics Data System (ADS)

    Balakshiĭ, V. I.; Kazar'yan, A. Y.; Lee, A. A.

    1995-10-01

    An investigation was made of an acousto-optical system with hybrid feedback used to control the frequency of ultrasonic waves excited in an acousto-optical cell. An amplitude transparency, placed in front of a photodetector, ensured a nonlinear dependence of the intensity of the diffracted radiation reaching the detector on the ultrasound frequency. Conditions were found under which this nonlinearity gave rise to multistable states differing in respect of the amplitude, frequency, and direction of propagation of the diffracted beam. An analysis was made of various uses of such a system as an optical channel switch and in stabilisation of the direction of propagation of a light beam.

  12. Laser identification system based on acousto-optical barcode scanner principles

    NASA Astrophysics Data System (ADS)

    Khansuvarov, Ruslan A.; Korol, Georgy I.; Preslenev, Leonid N.; Bestugin, Aleksandr R.; Paraskun, Arthur S.

    2016-09-01

    The main purpose of the bar code in the modern world is the unique identification of the product, service, or any of their features, so personal and stationary barcode scanners so widely used. One of the important parameters of bar code scanners is their reliability, accuracy of the barcode recognition, response time and performance. Nowadays, the most popular personal barcode scanners contain a mechanical part, which extremely impairs the reliability indices. Group of SUAI engineers has proposed bar code scanner based on laser beam acoustic deflection effect in crystals [RU patent No 156009 issued 4/16/2015] Through the use of an acousto-optic deflector element in barcode scanner described by a group of engineers SUAI, it can be implemented in the manual form factor, and the stationary form factor of a barcode scanner. Being a wave electronic device, an acousto-optic element in the composition of the acousto-optic barcode scanner allows you to clearly establish a mathematical link between the encoded function of the bar code with the accepted input photodetector intensities function that allows you to speak about the great probability of a bar code clear definition. This paper provides a description of the issued patent, the description of the principles of operation based on the mathematical analysis, a description of the layout of the implemented scanner.

  13. Conjugation of fiber-coupled wide-band light sources and acousto-optical spectral elements

    NASA Astrophysics Data System (ADS)

    Machikhin, Alexander; Batshev, Vladislav; Polschikova, Olga; Khokhlov, Demid; Pozhar, Vitold; Gorevoy, Alexey

    2017-12-01

    Endoscopic instrumentation is widely used for diagnostics and surgery. The imaging systems, which provide the hyperspectral information of the tissues accessible by endoscopes, are particularly interesting and promising for in vivo photoluminescence diagnostics and therapy of tumour and inflammatory diseases. To add the spectral imaging feature to standard video endoscopes, we propose to implement acousto-optical (AO) filtration of wide-band illumination of incandescent-lamp-based light sources. To collect maximum light and direct it to the fiber-optic light guide inside the endoscopic probe, we have developed and tested the optical system for coupling the light source, the acousto-optical tunable filter (AOTF) and the light guide. The system is compact and compatible with the standard endoscopic components.

  14. Wide-band acousto-optic deflectors for large field of view two-photon microscope.

    PubMed

    Jiang, Runhua; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun

    2012-04-01

    Acousto-optic deflector (AOD) is an attractive scanner for two-photon microscopy because it can provide fast and versatile laser scanning and does not involve any mechanical movements. However, due to the small scan range of available AOD, the field of view (FOV) of the AOD-based microscope is typically smaller than that of the conventional galvanometer-based microscope. Here, we developed a novel wide-band AOD to enlarge the scan angle. Considering the maximum acceptable acoustic attenuation in the acousto-optic crystal, relatively lower operating frequencies and moderate aperture were adopted. The custom AOD was able to provide 60 MHz 3-dB bandwidth and 80% peak diffraction efficiency at 840 nm wavelength. Based on a pair of such AOD, a large FOV two-photon microscope was built with a FOV up to 418.5 μm (40× objective). The spatiotemporal dispersion was compensated simultaneously with a single custom-made prism. By means of dynamic power modulation, the variation of laser intensity within the FOV was reduced below 5%. The lateral and axial resolution of the system were 0.58-2.12 μm and 2.17-3.07 μm, respectively. Pollen grain images acquired by this system were presented to demonstrate the imaging capability at different positions across the entire FOV. © 2012 American Institute of Physics

  15. Acoustic and Acousto-Optic Characteristics of Silicon Nanofoam

    NASA Astrophysics Data System (ADS)

    Iino, Takeshi; Nakamura, Kentaro

    2009-07-01

    Silicon nanofoam is a porous material with a nanometer structure produced through a sol-gel process, and is used as a heat insulator. It is expected that the nanofoam may work as a good acoustic matching layer of an airborne ultrasonic transducer for highly sensitive and wideband ultrasound transmission/detection since the nanofoam has an extremely low acoustic impedance. The nanofoam may also have a possibility as an acousto-optic device because of its very low sound speed and optical transparency. In this study, we have estimated the fundamental acoustic characteristics of the nanofoam through acousto-optic measurements. Sound speed and acoustic attenuation were measured in the frequency range from 130 to 444 kHz using rectangular samples attached to a piezoelectric transducer. The sound speed and acoustic attenuation constant were approximately in the 140-150 m/s range and 4.3 ×10-11f1.9 dB/(mm·Hz1.9), respectively. It was observed that the change rate in the optical refractive index of the nanofoam owing to sound pressure was approximately in the range of (1.2-1.6) ×10-8 1/Pa. Raman-Nath diffraction occurred at a relatively low frequency since the sound speed is low. We also observed modulation in the polarization of the transmitted light owing to ultrasonic waves.

  16. Spectral resolution control of acousto-optical cells operating with collimated and divergent beams

    NASA Astrophysics Data System (ADS)

    Voloshinov, Vitaly B.; Mishin, Dimitry D.

    1994-01-01

    The paper is devoted to theoretical and experimental investigations of acousto-optical interactions in crystals which may be used for spectral filtration of light in tunable acousto- optical filters. Attention is paid to spectral resolution control during operation with divergent or collimated noncoherent optical beams. In all examined cases spectral bands of anisotropic Bragg diffraction were regulated by means of novel electronical methods. Resolution control was achieved in paratellurite cells with non-collinear and quasi-collinear regimes of the diffraction. Filtration spectral bandwidths for visible light were electronically changed by a factor of 10 divided by 20 by drive electrical signals switching and drive electrical power regulations.

  17. A Statistical Analysis of the Output Signals of an Acousto-Optic Spectrum Analyzer for CW (Continuous-Wave) Signals

    DTIC Science & Technology

    1988-10-01

    A statistical analysis on the output signals of an acousto - optic spectrum analyzer (AOSA) is performed for the case when the input signal is a...processing, Electronic warfare, Radar countermeasures, Acousto - optic , Spectrum analyzer, Statistical analysis, Detection, Estimation, Canada, Modelling.

  18. Experimental demonstration of remote, passive acousto-optic sensing.

    PubMed

    Antonelli, Lynn; Blackmon, Fletcher

    2004-12-01

    Passively detecting underwater sound from the air can allow aircraft and surface vessels to monitor the underwater acoustic environment. Experimental research into an optical hydrophone is being conducted for remote, aerial detection of underwater sound. A laser beam is directed onto the water surface to measure the velocity of the vibrations occurring as the underwater acoustic signal reaches the water surface. The acoustically generated surface vibrations modulate the phase of the laser beam. Sound detection occurs when the laser is reflected back towards the sensor. Therefore, laser alignment on the specularly reflecting water surface is critical. As the water surface moves, the laser beam is reflected away from the photodetector and no signal is obtained. One option to mitigate this problem is to continually steer the laser onto a spot on the water surface that provides a direct back-reflection. Results are presented from a laboratory test that investigates the feasibility of the acousto-optic sensor detection on hydrostatic and hydrodynamic surfaces using a laser Doppler vibrometer in combination with a laser-based, surface normal glint tracker for remotely detecting underwater sound. This paper outlines the acousto-optic sensor and tracker concepts and presents experimental results comparing sensor operation under various sea surface conditions.

  19. Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection

    PubMed Central

    Zhang, Qinduan; Chang, Jun; Wang, Zongliang; Wang, Fupeng; Qin, Zengguang

    2017-01-01

    We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f0 = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C2H2) to select the laser wavelength. The system achieved a linear response (R2 = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times. PMID:29295599

  20. Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection.

    PubMed

    Zhang, Qinduan; Chang, Jun; Wang, Qiang; Wang, Zongliang; Wang, Fupeng; Qin, Zengguang

    2017-12-25

    We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f ₀ = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C₂H₂) to select the laser wavelength. The system achieved a linear response (R² = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.

  1. Acousto-optical Transducer with Surface Plasmons

    NASA Astrophysics Data System (ADS)

    Kolomenskii, A. A.; Surovic, E.; Schuessler, H. A.

    2018-04-01

    The surface plasmon resonance (SPR) is a sensitive technique for the detection of changes in dielectric parameters in close proximity to a metal film supporting surface plasmon waves. Here we study the application of the SPR effect to an efficient conversion of an acoustic signal into an optical one. Such a transducer potentially has a large bandwidth and good sensitivity. When an acoustic wave is incident onto a receiving plate positioned within the penetration depth of the surface plasmons, it creates displacements of the surface of the plate and, thus, modulates the dielectric properties in the proximity of the gold film. This modulation, in turn, modifies the light reflection under surface plasmon resonance conditions. We simulate characteristics of this acousto-optical transducer with surface plasmons and provide sets of parameters at the optical wavelength of 800 nm and 633 nm for its realization.

  2. High-speed optical coherence tomography using fiberoptic acousto-optic phase modulation

    NASA Astrophysics Data System (ADS)

    Xie, Tuqiang; Wang, Zhenguo; Pan, Yingtian

    2003-12-01

    We report a new rapid-scanning optical delay device suitable for high-speed optical coherence tomography (OCT) in which an acousto-optic modulator (AOM) is used to independently modulate the Doppler frequency shift of the reference light beam for optical heterodyne detection. Experimental results show that the fluctuation of the measured Doppler frequency shift is less than +/-0.2% over 95% duty cycle of OCT imaging, thus allowing for enhanced signal-to-noise ratio of optical heterodyne detection. The increased Doppler frequency shift by AOM also permits complete envelop demodulation without the compromise of reducing axial resolution; if used with a resonant rapid-scanning optical delay, it will permit high-performance real-time OCT imaging. Potentially, this new rapid-scanning optical delay device will improve the performance of high-speed Doppler OCT techniques.

  3. Wave packet interferometry and quantum state reconstruction by acousto-optic phase modulation

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

    Tekavec, Patrick F.; Dyke, Thomas R.; Marcus, Andrew H.

    2006-11-21

    Studies of wave packet dynamics often involve phase-selective measurements of coherent optical signals generated from sequences of ultrashort laser pulses. In wave packet interferometry (WPI), the separation between the temporal envelopes of the pulses must be precisely monitored or maintained. Here we introduce a new (and easy to implement) experimental scheme for phase-selective measurements that combines acousto-optic phase modulation with ultrashort laser excitation to produce an intensity-modulated fluorescence signal. Synchronous detection, with respect to an appropriately constructed reference, allows the signal to be simultaneously measured at two phases differing by 90 deg. Our method effectively decouples the relative temporal phasemore » from the pulse envelopes of a collinear train of optical pulse pairs. We thus achieve a robust and high signal-to-noise scheme for WPI applications, such as quantum state reconstruction and electronic spectroscopy. The validity of the method is demonstrated, and state reconstruction is performed, on a model quantum system - atomic Rb vapor. Moreover, we show that our measurements recover the correct separation between the absorptive and dispersive contributions to the system susceptibility.« less

  4. Piezo-, elasto- and acousto-optic properties of Tl3AsS4 crystals.

    PubMed

    Mytsyk, Bohdan; Kryvyy, Taras; Demyanyshyn, Natalya; Mys, Oksana; Martynyuk-Lototska, Iryna; Kokhan, Oleksandr; Vlokh, Rostyslav

    2018-05-10

    Complete matrices of piezo-optic and elasto-optic tensors are experimentally determined for Tl 3 AsS 4 crystals. It is revealed that the piezo-optic coefficients are very high, ∼10 -11   N/m 2 in the order of magnitude. This implies that Tl 3 AsS 4 can be referred to the best piezo-optic materials. The same concerns the elasto-optic coefficients, of which absolute values are in the interval 0.28-0.54. It is also found that, at the anisotropic and isotropic interactions with the slowest transverse and longitudinal acoustic waves, the acousto-optic figure of merit reaches extremely high values (1.99×10 -12   s 3 /kg and 9.45×10 -13   s 3 /kg, respectively). In other words, the Tl 3 AsS 4 crystals can be referred to as one of the best acousto-optic materials for the visible and infrared spectral ranges.

  5. Amplitude and phase measurements based on low-coherence interferometry with acousto-optic spectral image filtration

    NASA Astrophysics Data System (ADS)

    Machikhin, Alexander; Burmak, Ludmila; Pozhar, Vitold

    2018-04-01

    The manuscript addresses the advantages and possible applications of acousto-optic image spectral filtration in lowcoherence interferometry. In particular, an effective operation of acousto-optical tunable filters in combination with Michelson-type interferometers is shown. The results of original experiments are presented. It is demonstrated that amplitude and phase spatial distributions of light waves reflected from or transmitted through the object can be fast determined in contactless manner for any spectral intervals with use of the presented techniques.

  6. Acousto-Optic Measurements in CFRP Laminates Using Fiber Bragg Grating Sensors

    DTIC Science & Technology

    2011-09-01

    level. The main objective of this paper is to describe the results of an acousto - optic experiment using FBG sensors and present FR as a potential way of determining accumulated damage in a carbon composite structure.

  7. Acousto-Optic Processing of 2-D Signals Using Temporal and Spatial Integration.

    DTIC Science & Technology

    1983-05-31

    Documents includes data on: Architectures; Coherence Properties of Pulsed Laser Diodes; Acousto - optic device data; Dynamic Range Issues; Image correlation; Synthetic aperture radar; 2-D Fourier transform; and Moments.

  8. Potentials of the acousto-optical spectral data processing on a basis of a novel algorithm of the collinear wave heterodyning in a large-aperture KRS-5 crystalline cell

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Maximov, Jewgemij; Sanchez Lucero, Daniel

    2010-02-01

    Recently proposed modern technique of a precise spectrum analysis within an algorithm of the collinear wave heterodyning implies a two-stage integrated processing, namely, the wave heterodyning of a signal in a square-law nonlinear medium and then the optical processing in the same cell. Technical advantage of this approach is in providing a direct processing of ultra-high-frequency radio-wave signals with essentially improved frequency resolution. This algorithm can be realized on a basis of various physical principles, and we consider an opportunity of involving the potentials of modern acousto-optics for these purposes. From this viewpoint, one needs a large-aperture effective acousto-optical cell, which operates in the Bragg regime and performs the ultra-high-frequency co-directional collinear acoustic wave heterodyning. The technique under consideration imposes specific requirements on the cell's material, namely, a high optical quality of large-size crystalline boules, high-efficient acousto-optical and acoustic interactions, and low group velocity of acoustic waves together with square-low dispersive acoustic losses. We focus our attention on the solid solutions of thallium chalcogenides and take the TlBr-TlI (thallium bromine - thallium iodine) solution, which forms KRS-5 cubic-symmetry crystals with the mass-ratio 58% of TlBr to 42% of TlI. Analysis shows that the acousto-optical cell made of a KRS-5 crystal oriented along the [111] -axis and the corresponding longitudinal elastic mode for producing the dynamic diffractive grating in that crystal can be exploited. With the acoustic velocity of about 1.92 mm/μs and attenuation of approximately 10 dB/(cm GHz2), similar cell is capable to provide an optical aperture of 50 mm and one of the highest figures of acousto-optical merit in solid states in the visible range. Such a cell is rather desirable for applications to direct parallel multi-channel optical spectrum analysis with substantially improved

  9. Acousto-optical modulation of light at a doubled sound frequency

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

    Kotov, V M; Averin, S V; Shkerdin, G N

    2016-02-28

    A method of acousto-optical (AO) Bragg diffraction is proposed that provides the amplitude modulation of optical radiation at a doubled acoustic frequency. The method is based on the double transmission of the light through the AO modulator made of a gyrotropic crystal and is experimentally tested by the example of the modulation of light with a wavelength of 0.63 μm, controlled by the paratellurite AO cell. (acoustooptics)

  10. Acousto-optical assessment of skin viscoelasticity

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, Sean J.; Duncan, Donald D.

    2003-07-01

    A multiphysics approach, combining acoustics, optics, and mechanics can be used to detect regions of skin with distinct mechanical behavior that may indicate a pathology, such as a cancerous skin lesion. Herein, an acousto-optical approach to evaluating the viscoelastic behavior of superficial skin layers will be presented. The method relies upon inducing low frequency guided surface waves in the skin and detecting these waves by monitoring the shift in the backscattered laser speckle pattern created by illuminating a small region of the skin with coherent light. Artificial lesions in the form of chemical cross-linking and chemical softening were induced in superficial porcine skin layers and detected based upon variations in local mechanical behavior. The lesions affect not only the time-of-flight of the guided surface waves, but also change the relative phase of the acoustic waves as determined optically. The method may be applicable in the study and diagnosis of superficial skin lesions.

  11. Acousto-optic resonant coupling of three spatial modes in an optical fiber.

    PubMed

    Park, Hee Su; Song, Kwang Yong

    2014-01-27

    A fiber-optic analogue to an externally driven three-level quantum state is demonstrated by acousto-optic coupling of the spatial modes in a few-mode fiber. Under the condition analogous to electromagnetically induced transparency, a narrow-bandwidth transmission within an absorption band for the fundamental mode is demonstrated. The presented structure is an efficient converter between the fundamental mode and the higher-order modes that cannot be easily addressed by previous techniques, therefore can play a significant role in the next-generation space-division multiplexing communications as an arbitrarily mode-selectable router.

  12. An Experimental Study of Ultra-Wide-Band and Ultra-Wide-Aperture Non-Collinear Acousto-Optic Diffraction in an Optically Biaxial Potassium Arsenate Titanyl Crystal

    NASA Astrophysics Data System (ADS)

    Milkov, M. G.; Voloshinov, V. B.; Isaenko, L. I.; Vedenyapin, V. N.

    2018-01-01

    Acousto-optic interaction in an optically biaxial crystalline medium under propagation of light close to one of the optical axes of a potassium arsenate titanyl KTiOAsO4 crystal has been studied. The experimental dependences of the intensity of a diffracted optical beam on the angle of light incidence on an ultrasonic wave have been obtained. It has been shown that a flat cut of a wave-vector surface provides development of an ultra-wide-aperture and ultra-wide-band acousto-optic deflector to control radiation in the visible and infrared electromagnetic spectral ranges.

  13. SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Realisation of video-frequency filters on the basis of a new mode of operation of an acousto-optical correlator with spatial integration

    NASA Astrophysics Data System (ADS)

    Ushakov, V. N.

    1995-10-01

    A video-frequency acousto-optical correlator with spatial integration, which widens the functional capabilities of correlation-type acousto-optical processors, is described. The correlator is based on a two-dimensional reference transparency and it can filter arbitrary video signals of spectral width limited by the pass band of an acousto-optical modulator. The calculated pulse characteristic is governed by the structure of the reference transparency. A procedure for the synthesis of this transparency is considered and experimental results are reported.

  14. Investigation of magnesium fluoride crystals for imaging acousto-optic tunable filter applications.

    PubMed

    Voloshinov, Vitaly B; Gupta, Neelam

    2006-05-01

    Results of an investigation of acousto-optic (AO) cells using single crystals of magnesium fluoride (MgF2) are presented. Two acousto-optic tunable filter (AOTF) cells for imaging application have been designed and tested in the visible and ultraviolet (UV) regions of the spectrum from 190 to 490 nm. The two imaging filters were developed by using the wide-angle AO interaction geometry in the (010) and (11 0) planes of the crystal. These filters were used to obtain spectral images at the shortest wavelengths achieved so far. Advantages and drawbacks of this crystal are discussed and photoelastic, acoustic, and AO properties of MgF2 are examined. The investigation confirmed that MgF2-based AOTF cells can be used in the deep UV region up to 110 nm.

  15. Influence of wavelength-dependent-loss on dispersive wave in nonlinear optical fibers.

    PubMed

    Herrera, Rodrigo Acuna

    2012-11-01

    In this work, we study numerically the influence of wavelength-dependent loss on the generation of dispersive waves (DWs) in nonlinear fiber. This kind of loss can be obtained, for instance, by the acousto-optic effect in fiber optics. We show that this loss lowers DW frequency in an opposite way that the Raman effect does. Also, we see that the Raman effect does not change the DW frequency too much when wavelength-dependent loss is included. Finally, we show that the DW frequency is not practically affected by fiber length.

  16. Tandem-pulsed acousto-optics: an analytical framework of modulated high-contrast speckle patterns.

    PubMed

    Resink, S G; Steenbergen, W

    2015-06-07

    Recently we presented acousto-optic (AO) probing of scattering media using addition or subtraction of speckle patterns due to tandem nanosecond pulses. Here we present a theoretical framework for ideal (polarized, noise-free) speckle patterns with unity contrast that links ultrasound-induced optical phase modulation, the fraction of light that is tagged by ultrasound, speckle contrast, mean square difference of speckle patterns and the contrast of the summation of speckle patterns acquired at different ultrasound phases. We derive the important relations from basic assumptions and definitions, and then validate them with simulations. For ultrasound-generated phase modulation angles below 0.7 rad (assuming uniform modulation), we are now able to relate speckle pattern statistics to the acousto-optic phase modulation. Hence our theory allows quantifying speckle observations in terms of ultrasonically tagged fractions of light for near-unity-contrast speckle patterns.

  17. Rational calculation accuracy in acousto-optical matrix-vector processor

    NASA Astrophysics Data System (ADS)

    Oparin, V. V.; Tigin, Dmitry V.

    1994-01-01

    The high speed of parallel computations for a comparatively small-size processor and acceptable power consumption makes the usage of acousto-optic matrix-vector multiplier (AOMVM) attractive for processing of large amounts of information in real time. The limited accuracy of computations is an essential disadvantage of such a processor. The reduced accuracy requirements allow for considerable simplification of the AOMVM architecture and the reduction of the demands on its components.

  18. Development of a Flyable Acousto-Optic Laser Beam Deflection System for a Head Up Display of the Future.

    DTIC Science & Technology

    Rayleigh criteria). The system was designed for stroke writing but was demonstrated with lissajous writing. The acousto - optic deflectors employed...The report describes a laser display which is to be used in a Head-Up Display of the future. The uniqueness of the display is that it uses acousto ... optic components for the modulation and deflection of the laser beam. As a result, there are no moving parts, which increases the reliability and life

  19. Acousto-optic filtering of lidar signals

    NASA Technical Reports Server (NTRS)

    Kolarov, G.; Deleva, A.; Mitsev, TS.

    1992-01-01

    The predominant part of the noise in lidar receivers is created by the background radiation; therefore, one of the most important elements of the receiving optics is a spectrally selecting filter placed in front of the photodetector. Interference filters are usually used to transmit a given wavelength. Specific properties of the interference filters, such as simple design, reliability, small size, and large aperture, combined with high transmission coefficient and narrow spectral band, make them the preferred spectral device in many cases. However, problems arise in applications such as the Differential Absorption Lidar (DIAL) technique, where fast tuning within a wide spectral region is necessary. Tunable acousto-optical filters (TAOF), used recently in astrophysical observations to suppress the background radiation, can be employed with success in lidar sounding. They are attractive due to the possibility for fast spectral scanning with a narrow transmission band. The TAOF's advantages are fully evident in DIAL lidars where one must simultaneously receive signals at two laser frequencies.

  20. Spectroscopic imaging using acousto-optic tunable filters

    NASA Astrophysics Data System (ADS)

    Bouhifd, Mounir; Whelan, Maurice

    2007-07-01

    We report on novel hyper-spectral imaging filter-modules based on acousto-optic tuneable filters (AOTF). The AOTF functions as a full-field tuneable bandpass filter which offers fast continuous or random access tuning with high filtering efficiency. Due to the diffractive nature of the device, the unfiltered zero-order and the filtered first-order images are geometrically separated. The modules developed exploit this feature to simultaneously route both the transmitted white-light image and the filtered fluorescence image to two separate cameras. Incorporation of prisms in the optical paths and careful design of the relay optics in the filter module have overcome a number of aberrations inherent to imaging through AOTFs, leading to excellent spatial resolution. A number of practical uses of this technique, both for in vivo auto-fluorescence endoscopy and in vitro fluorescence microscopy were demonstrated. We describe the operational principle and design of recently improved prototype instruments for fluorescence-based diagnostics and demonstrate their performance by presenting challenging hyper-spectral fluorescence imaging applications.

  1. Optical assessment of tissue mechanics: acousto-optical elastography of skin

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, Sean J.

    2003-10-01

    A multiphysics approach, combining acoustics, optics, and mechanics can be used to detect regions of skin with distinct mechanical behavior that may indicate a pathology, such as a cancerous skin lesion. Herein, an acousto - optical approach to evaluating the viscoelastic behavior of superficial skin layers will be presented. The method relies upon inducing low frequency guided surface waves in the skin and detecting these waves by monitoring the shift in the backscattered laser speckle pattern created by illuminating a small region of the skin with coherent light. Artificial lesions in the form of chemical cross-linking and chemical softening were induced in superficial porcine skin layers and detected based upon variations in local mechanical behavior. The lesions affect not only the time-of-flight of the guided surface waves, but also change the relative phase of the acoustic waves as determined optically. The method may be applicable in the study and diagnosis of superficial skin lesions.

  2. Non-reciprocal optical mirrors based on spatio-temporal acousto-optic modulation

    NASA Astrophysics Data System (ADS)

    Fleury, R.; Sounas, D. L.; Alù, A.

    2018-03-01

    Here, we investigate a scheme to realize free-space isolators and highly non-reciprocal mirrors with weak modulation imparted by an acoustic wave. We propose a strategy to dramatically break time-reversal symmetry by exploiting resonant interactions between a travelling acoustic wave and highly resonant Fabry-Pérot modes, inducing total reflection of an optical beam at a given angle, and no reflection at the negative angle. Different from conventional acousto-optic isolators, which are based on non-resonant frequency conversion and filtering, our proposal operates at the frequency of the optical signal by tailoring the resonant properties of the structure as well as the acoustic wave frequency and intensity, enabling 50 dB isolation with modest modulation requirements. Operation in the reflection mode allows for close-to-zero insertion loss, enabling disruptive opportunities in our ability to control and manipulate photons.

  3. Electronic frequency tuning of the acousto-optic mode-locking device of a laser

    NASA Astrophysics Data System (ADS)

    Magdich, L. N.; Balakshy, V. I.; Mantsevich, S. N.

    2017-11-01

    The effect of the electronic tuning of the acoustic resonances in an acousto-optic mode-locking device of a laser is investigated theoretically and experimentally. The problem of the excitation of a Fabry-Perot acoustic resonator by a plate-like piezoelectric transducer (PET) is solved in the approximation of plane acoustic waves taking into consideration the actual parameters of an RF generator and the elements for matching the PET to the generator. Resonances are tuned by changing the matching inductance that was connected in parallel to the transducer of the acousto-optic cell. The cell used in the experiment was manufactured from fused silica and included a lithium niobate PET. Changes in the matching inductance in the range of 0.025 to 0.2 μH provided the acoustic-resonance frequency tuning by 0.19 MHz, which exceeds the acoustic- resonance half-width.

  4. 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.

  5. Laboratory tools and e-learning elements in training of acousto-optics

    NASA Astrophysics Data System (ADS)

    Barócsi, Attila; Lenk, Sándor; Ujhelyi, Ferenc; Majoros, Tamás.; Maák, Paál.

    2015-10-01

    Due to the acousto-optic (AO) effect, the refractive index of an optical interaction medium is perturbed by an acoustic wave induced in the medium that builds up a phase grating that will diffract the incident light beam if the condition of constructive interference is satisfied. All parameters, such as magnitude, period or phase of the grating can be controlled that allows the construction of useful devices (modulators, switches, one or multi-dimensional deflectors, spectrum analyzers, tunable filters, frequency shifters, etc.) The research and training of acousto-optics have a long-term tradition at our department. In this presentation, we introduce the related laboratory exercises fitted into an e-learning frame. The BSc level exercise utilizes a laser source and an AO cell to demonstrate the effect and principal AO functions explaining signal processing terms such as amplitude or frequency modulation, modulation depth and Fourier transformation ending up in building a free space sound transmitting and demodulation system. The setup for MSc level utilizes an AO filter with mono- and polychromatic light sources to learn about spectral analysis and synthesis. Smart phones can be used to generate signal inputs or outputs for both setups as well as to help students' preparation and reporting.

  6. Acousto-optic modulation in diode pumped solid state lasers

    NASA Astrophysics Data System (ADS)

    Jabczynski, Jan K.; Zendzian, Waldemar; Kwiatkowski, Jacek

    2007-02-01

    The main properties of acousto-optic modulators (AOM) applied in laser technology are presented and discussed in the paper. The critical review of application of AOMs in several types of diode pumped solid state lasers (DPSSL) is given. The short description of few DPSSLs developed in our group is presented in the following chapters of the paper. The parameters of a simple AO-Q-switched Nd:YVO 4 laser (peak power up to 60 kW, pulse duration of 5-15 ns, repetition rate in the range 10-100 kHz, with average power above 5 W) are satisfactory for different application as follows: higher harmonic generation, pumping of 'eye-safe' OPOs etc. The achieved brightness of 10 17 W/m2/srd is comparable to the strongest technological Q-switched lasers of kW class of average power. The main aim of paper is to present novel type of lasers with acousto-optic modulation namely: AO-q-switched and mode locked (AO-QML) lasers. We have designed the 3.69-m long Z-type resonator of the frequency matched to the RF frequency of AOM. As a gain medium the Nd:YVO 4 crystal end pumped by 20 W laser diode was applied. The energy of envelope of QML pulse train was up to 130 μJ with sub-nanosecond mode locked pulse of maximum 30-μJ energy.

  7. An acousto-optic sensor based on resonance grating waveguide structure

    PubMed Central

    Xie, Antonio Jou; Song, Fuchuan; Seo, Sang-Woo

    2014-01-01

    This paper presents an acousto-optic (AO) sensor based on resonance grating waveguide structure. The sensor is fabricated using elastic polymer materials to achieve a good sensitivity to ultrasound pressure waves. Ultrasound pressure waves modify the structural parameters of the sensor and result in the optical resonance shift of the sensor. This converts into a light intensity modulation. A commercial ultrasound transducer at 20 MHz is used to characterize a fabricated sensor and detection sensitivity at different optical source wavelength within a resonance spectrum is investigated. Practical use of the sensor at a fixed optical source wavelength is presented. Ultimately, the geometry of the planar sensor structure is suitable for two-dimensional, optical pressure imaging applications such as pressure wave detection and mapping, and ultrasound imaging. PMID:25045203

  8. Vacuum suppression of acousto-optic self-modulation in a broad-area Nd-doped yttrium-aluminum-garnet single-shot laser

    NASA Astrophysics Data System (ADS)

    Rus, M. Odín Soler; Cabrera-Granado, E.; Guerra Pérez, J. M.

    2013-07-01

    We report on the origin of an acousto-optic Raman-Nath self-modulation found in a broad-area Nd:YAG single-shot laser. Operating the laser device under vacuum conditions suppresses the spectral splitting associated with acousto-optic modulation by the shock waves produced by the discharge of the pumping flash lamps. This splitting is reproduced by a general class B laser model that takes into account the dynamical density grating generated by a stationary acoustic radial wave.

  9. Analysis and Characterization of an Acousto-Optic Beam Position Control System

    DTIC Science & Technology

    2002-07-01

    glass or plastic. This device can be viewed as a medium where light interacts with sound yielding a diffracted light beam. Bragg cells can operate in...by “optical activity” is considered to be very small for TeO2 [2]. The birefringence is due to the fact the index of refraction in for the incident...equations describes behavior of the acousto-optic device. The acoustic velocity can be expressed as follows. azat vvv Θ+Θ= 22222 sincos For TeO2 vt=616 m

  10. Highly efficient acousto-optic diffraction in Sn2P2S6 crystals.

    PubMed

    Martynyuk-Lototska, I Yu; Mys, O G; Grabar, A A; Stoika, I M; Vysochanskii, Yu M; Vlokh, R O

    2008-01-01

    We have studied the acousto-optic (AO) diffraction in Sn2P2S6 crystals and found that they manifest high values of an AO figure of merit. The above crystals may therefore be used as highly efficient materials in different AO applications.

  11. Acousto-optic pointing and tracking systems for free-space laser communications

    NASA Astrophysics Data System (ADS)

    Nikulin, V.; Khandekar, R.; Sofka, J.; Tartakovsky, G.

    2005-08-01

    Implementation of long-range laser communication systems holds great promise for high-bandwidth applications. They are viewed as a technology that in the nearest future will handle most of the "last mile" communication traffic for the individual subscribers, corporate offices, military, and possibly deep space probes. Indeed, lasers allow for concentration of energy within tightly focused beams and narrow spectral interval, thus offering high throughput, information security, weight and size of components and power requirements that could not be matched by RF systems. However, the advantages of optical communication systems come in the same package with several major challenges. In particular, high data rates should be complemented by high-precision wide-bandwidth position control of a laser beam. In many applications the ability to maintain a link is affected by the complex maneuvers performed by mobile communication platforms, resident vibrations, and atmospheric effects. The search for the most effective and reliable way to shape and steer the laser beam is an on-going effort. This paper is focused on the application of acousto-optic technology as an alternative to electro-mechanical devices. With realization that an acousto-optic Bragg cell is only a component of the entire communication system, which should perform complex tasks of acquisition, pointing, and tracking of the remote terminal, we present an attempt to consider this problem from the "systems" point of view.

  12. A compact Acousto-Optic Lens for 2D and 3D femtosecond based 2-photon microscopy.

    PubMed

    Kirkby, Paul A; Srinivas Nadella, K M Naga; Silver, R Angus

    2010-06-21

    We describe a high speed 3D Acousto-Optic Lens Microscope (AOLM) for femtosecond 2-photon imaging. By optimizing the design of the 4 AO Deflectors (AODs) and by deriving new control algorithms, we have developed a compact spherical AOL with a low temporal dispersion that enables 2-photon imaging at 10-fold lower power than previously reported. We show that the AOLM can perform high speed 2D raster-scan imaging (>150 Hz) without scan rate dependent astigmatism. It can deflect and focus a laser beam in a 3D random access sequence at 30 kHz and has an extended focusing range (>137 mum; 40X 0.8NA objective). These features are likely to make the AOLM a useful tool for studying fast physiological processes distributed in 3D space.

  13. Acousto-Optic Tunable Filter Hyperspectral Microscope Imaging Method for Characterizing Spectra from Foodborne Pathogens.

    USDA-ARS?s Scientific Manuscript database

    Hyperspectral microscope imaging (HMI) method, which provides both spatial and spectral characteristics of samples, can be effective for foodborne pathogen detection. The acousto-optic tunable filter (AOTF)-based HMI method can be used to characterize spectral properties of biofilms formed by Salmon...

  14. Display system employing acousto-optic tunable filter

    NASA Technical Reports Server (NTRS)

    Lambert, James L. (Inventor)

    1995-01-01

    An acousto-optic tunable filter (AOTF) is employed to generate a display by driving the AOTF with a RF electrical signal comprising modulated red, green, and blue video scan line signals and scanning the AOTF with a linearly polarized, pulsed light beam, resulting in encoding of color video columns (scan lines) of an input video image into vertical columns of the AOTF output beam. The AOTF is illuminated periodically as each acoustically-encoded scan line fills the cell aperture of the AOTF. A polarizing beam splitter removes the unused first order beam component of the AOTF output and, if desired, overlays a real world scene on the output plane. Resolutions as high as 30,000 lines are possible, providing holographic display capability.

  15. Display system employing acousto-optic tunable filter

    NASA Technical Reports Server (NTRS)

    Lambert, James L. (Inventor)

    1993-01-01

    An acousto-optic tunable filter (AOTF) is employed to generate a display by driving the AOTF with a RF electrical signal comprising modulated red, green, and blue video scan line signals and scanning the AOTF with a linearly polarized, pulsed light beam, resulting in encoding of color video columns (scan lines) of an input video image into vertical columns of the AOTF output beam. The AOTF is illuminated periodically as each acoustically-encoded scan line fills the cell aperture of the AOTF. A polarizing beam splitter removes the unused first order beam component of the AOTF output and, if desired, overlays a real world scene on the output plane. Resolutions as high as 30,000 lines are possible, providing holographic display capability.

  16. Study of the spectral bandwidth of a double-pass acousto-optic system [Invited].

    PubMed

    Champagne, Justine; Kastelik, Jean-Claude; Dupont, Samuel; Gazalet, Joseph

    2018-04-01

    Acousto-optic tunable filters are known as efficient instruments for spectral and spatial filtering of light. In this paper, we analyze the bandwidth dependence of a double-pass filter. The interaction geometry chosen allows the simultaneous diffraction of the ordinary and the extraordinary optical modes by a single ultrasonic frequency. We present the main parameters of a custom device (design, optical range, driving frequency) and experimental results concerning the angular deviation of the beams including the effect of optical birefringence. The spectral resolution and the side lobes' significance are discussed. Spectral bandwidth of such a system is analyzed.

  17. Acousto-Optic Imaging Spectrometers for Mars Surface Science

    NASA Technical Reports Server (NTRS)

    Glenar, D. A.; Blaney, D. L.

    2000-01-01

    NASA's long term plan for Mars sample collection and return requires a highly streamlined approach for spectrally characterizing a landing site, documenting the mineralogical make-up of the site and guiding the collections of samples which represent the diversity of the site. Ideally, image data should be acquired at hundreds of VIS and IR wavelengths, in order to separately distinguish numerous anticipated species, using principal component analysis and linear unmixing. Cameras with bore-sighted point spectrometers can acquire spectra of isolated scene elements, but it requires 10(exp 2) to 10(exp 2) successive motions and precise relative pointing knowledge in order to create a single data cube which qualifies as a spectral map. These and other competing science objectives have to be accomplished within very short lander/rover operational lifetime (a few sols). True, 2-D imaging spectroscopy greatly speeds up the data acquisition process, since the spectra of all pixels in the scene are collected at once. This task can be accomplished with cameras that use electronically tunable acousto-optic tunable filters (AOTFs) as the optical tuning element. AOTFs made from TeO2 are now a mature technology, and operate at wavelengths from near-UV to about 5 microns. Because of incremental improvements in the last few years, present generation devices are rugged, radiation-hard and operate at temperatures down to at least 150K so they can be safely integrated into the ambient temperature optics of in-situ instruments such as planetary or small-body landers. They have been used for ground-based astronomy, and were also baselined for the ST-4 Champollion IR comet lander experiment (CIRCLE), prior to cancellation of the ST-4 mission last year. AIMS (for Acousto-optic Imaging spectrometer), is a prototype lander instrument which is being built at GSFC with support by the NASA OSS Advanced Technologies and Mission Studies, Mars Instrument Definition and Development Program (MIDP

  18. Development and application of a ray-based model of light propagation through a spherical acousto-optic lens

    PubMed Central

    Evans, Geoffrey J.; Kirkby, Paul A.; Nadella, K. M. Naga Srinivas; Marin, Bóris; Silver, R. Angus

    2016-01-01

    A spherical acousto-optic lens (AOL) consists of four acousto-optic deflectors (AODs) that can rapidly and precisely control the focal position of an optical beam in 3D space. Development and application of AOLs has increased the speed at which 3D random access point measurements can be performed with a two-photon microscope. This has been particularly useful for measuring brain activity with fluorescent reporter dyes because neuronal signalling is rapid and sparsely distributed in 3D space. However, a theoretical description of light propagation through AOLs has lagged behind their development, resulting in only a handful of simplified principles to guide AOL design and optimization. To address this we have developed a ray-based computer model of an AOL incorporating acousto-optic diffraction and refraction by anisotropic media. We extended an existing model of a single AOD with constant drive frequency to model a spherical AOL: four AODs in series driven with linear chirps. AOL model predictions of the relationship between optical transmission efficiency and acoustic drive frequency including second order diffraction effects closely matched experimental measurements from a 3D two-photon AOL microscope. Moreover, exploration of different AOL drive configurations identified a new simple rule for maximizing the field of view of our compact AOL design. By providing a theoretical basis for understanding optical transmission through spherical AOLs, our open source model is likely to be useful for comparing and improving different AOL designs, as well as identifying the acoustic drive configurations that provide the best transmission performance over the 3D focal region. PMID:26368449

  19. Development and application of a ray-based model of light propagation through a spherical acousto-optic lens.

    PubMed

    Evans, Geoffrey J; Kirkby, Paul A; Naga Srinivas Nadella, K M; Marin, Bóris; Angus Silver, R

    2015-09-07

    A spherical acousto-optic lens (AOL) consists of four acousto-optic deflectors (AODs) that can rapidly and precisely control the focal position of an optical beam in 3D space. Development and application of AOLs has increased the speed at which 3D random access point measurements can be performed with a two-photon microscope. This has been particularly useful for measuring brain activity with fluorescent reporter dyes because neuronal signalling is rapid and sparsely distributed in 3D space. However, a theoretical description of light propagation through AOLs has lagged behind their development, resulting in only a handful of simplified principles to guide AOL design and optimization. To address this we have developed a ray-based computer model of an AOL incorporating acousto-optic diffraction and refraction by anisotropic media. We extended an existing model of a single AOD with constant drive frequency to model a spherical AOL: four AODs in series driven with linear chirps. AOL model predictions of the relationship between optical transmission efficiency and acoustic drive frequency including second order diffraction effects closely matched experimental measurements from a 3D two-photon AOL microscope. Moreover, exploration of different AOL drive configurations identified a new simple rule for maximizing the field of view of our compact AOL design. By providing a theoretical basis for understanding optical transmission through spherical AOLs, our open source model is likely to be useful for comparing and improving different AOL designs, as well as identifying the acoustic drive configurations that provide the best transmission performance over the 3D focal region.

  20. Acousto-optic time- and space-integrating spotlight-mode SAR processor

    NASA Astrophysics Data System (ADS)

    Haney, Michael W.; Levy, James J.; Michael, Robert R., Jr.

    1993-09-01

    The technical approach and recent experimental results for the acousto-optic time- and space- integrating real-time SAR image formation processor program are reported. The concept overcomes the size and power consumption limitations of electronic approaches by using compact, rugged, and low-power analog optical signal processing techniques for the most computationally taxing portions of the SAR imaging problem. Flexibility and performance are maintained by the use of digital electronics for the critical low-complexity filter generation and output image processing functions. The results include a demonstration of the processor's ability to perform high-resolution spotlight-mode SAR imaging by simultaneously compensating for range migration and range/azimuth coupling in the analog optical domain, thereby avoiding a highly power-consuming digital interpolation or reformatting operation usually required in all-electronic approaches.

  1. Full-field acoustomammography using an acousto-optic sensor.

    PubMed

    Sandhu, J S; Schmidt, R A; La Rivière, P J

    2009-06-01

    In this Letter the authors introduce a wide-field transmission ultrasound approach to breast imaging based on the use of a large area acousto-optic (AO) sensor. Accompanied by a suitable acoustic source, such a detector could be mounted on a traditional mammography system and provide a mammographylike ultrasound projection image of the compressed breast in registration with the x-ray mammogram. The authors call the approach acoustography. The hope is that this additional information could improve the sensitivity and specificity of screening mammography. The AO sensor converts ultrasound directly into a visual image by virtue of the acousto-optic effect of the liquid crystal layer contained in the AO sensor. The image is captured with a digital video camera for processing, analysis, and storage. In this Letter, the authors perform a geometrical resolution analysis and also present images of a multimodality breast phantom imaged with both mammography and acoustography to demonstrate the feasibility of the approach. The geometric resolution analysis suggests that the technique could readily detect tumors of diameter of 3 mm using 8.5 MHz ultrasound, with smaller tumors detectable with higher frequency ultrasound, though depth penetration might then become a limiting factor. The preliminary phantom images show high contrast and compare favorably to digital mammograms of the same phantom. The authors have introduced and established, through phantom imaging, the feasibility of a full-field transmission ultrasound detector for breast imaging based on the use of a large area AO sensor. Of course variations in attenuation of connective, glandular, and fatty tissues will lead to images with more cluttered anatomical background than those of the phantom imaged here. Acoustic coupling to the mammographically compressed breast, particularly at the margins, will also have to be addressed.

  2. Full-field acoustomammography using an acousto-optic sensor

    PubMed Central

    Sandhu, J. S.; Schmidt, R. A.; La Rivière, P. J.

    2009-01-01

    In this Letter the authors introduce a wide-field transmission ultrasound approach to breast imaging based on the use of a large area acousto-optic (AO) sensor. Accompanied by a suitable acoustic source, such a detector could be mounted on a traditional mammography system and provide a mammographylike ultrasound projection image of the compressed breast in registration with the x-ray mammogram. The authors call the approach acoustography. The hope is that this additional information could improve the sensitivity and specificity of screening mammography. The AO sensor converts ultrasound directly into a visual image by virtue of the acousto-optic effect of the liquid crystal layer contained in the AO sensor. The image is captured with a digital video camera for processing, analysis, and storage. In this Letter, the authors perform a geometrical resolution analysis and also present images of a multimodality breast phantom imaged with both mammography and acoustography to demonstrate the feasibility of the approach. The geometric resolution analysis suggests that the technique could readily detect tumors of diameter of 3 mm using 8.5 MHz ultrasound, with smaller tumors detectable with higher frequency ultrasound, though depth penetration might then become a limiting factor. The preliminary phantom images show high contrast and compare favorably to digital mammograms of the same phantom. The authors have introduced and established, through phantom imaging, the feasibility of a full-field transmission ultrasound detector for breast imaging based on the use of a large area AO sensor. Of course variations in attenuation of connective, glandular, and fatty tissues will lead to images with more cluttered anatomical background than those of the phantom imaged here. Acoustic coupling to the mammographically compressed breast, particularly at the margins, will also have to be addressed. PMID:19610321

  3. A new multifunction acousto-optic signal processor

    NASA Technical Reports Server (NTRS)

    Berg, N. J.; Casseday, M. W.; Filipov, A. N.; Pellegrino, J. M.

    1984-01-01

    An acousto-optic architecture for simultaneously obtaining time integration correlation and high-speed power spectrum analysis was constructed using commercially available TeO2 modulators and photodiode detector-arrays. The correlator section of the processor uses coherent interferometry to attain maximum bandwidth and dynamic range while achieving a time-bandwidth product of 1 million. Two correllator outputs are achieved in this system configuration. One is optically filtered and magnified 2 : 1 to decrease the spatial frequency to a level where a 25-MHz bandwidth may be sampled by a 62-mm array with elements on 25-micro centers. The other output is magnified by a factor of 10 such that the center 4 microseconds of information is available for estimation of time-difference-of-arrival to within 10 ns. The Bragg cell spectrum-analyzer section, which also has two outputs, resolves a 25-MHz instantaneous bandwidth to 25 kHz and can determine discrete-frequency reception time to within 15 microseconds. A microprocessor combines spectrum analysis information with that obtained from the correlator.

  4. Combined laser heating and tandem acousto-optical filter for two-dimensional temperature distribution on the surface of the heated microobject

    NASA Astrophysics Data System (ADS)

    Bykov, A. A.; Kutuza, I. B.; Zinin, P. V.; Machikhin, A. S.; Troyan, I. A.; Bulatov, K. M.; Batshev, V. I.; Mantrova, Y. V.; Gaponov, M. I.; Prakapenka, V. B.; Sharma, S. K.

    2018-01-01

    Recently it has been shown that it is possible to measure the two-dimensional distribution of the surface temperature of microscopic specimens. The main component of the system is a tandem imaging acousto-optical tunable filter synchronized with a video camera. In this report, we demonstrate that combining the laser heating system with a tandem imaging acousto-optical tunable filter allows measurement of the temperature distribution under laser heating of the platinum plates as well as a visualization of the infrared laser beam, that is widely used for laser heating in diamond anvil cells.

  5. A compact acousto-optic lens for 2D and 3D femtosecond based 2-photon microscopy

    PubMed Central

    Kirkby, Paul A.; Naga Srinivas, N.K.M.; Silver, R. Angus

    2010-01-01

    We describe a high speed 3D Acousto-Optic Lens Microscope (AOLM) for femtosecond 2-photon imaging. By optimizing the design of the 4 AO Deflectors (AODs) and by deriving new control algorithms, we have developed a compact spherical AOL with a low temporal dispersion that enables 2-photon imaging at 10-fold lower power than previously reported. We show that the AOLM can perform high speed 2D raster-scan imaging (>150 Hz) without scan rate dependent astigmatism. It can deflect and focus a laser beam in a 3D random access sequence at 30 kHz and has an extended focusing range (>137 μm; 40X 0.8NA objective). These features are likely to make the AOLM a useful tool for studying fast physiological processes distributed in 3D space PMID:20588506

  6. Peculiarities of Forming a Multiband Transmission Function Based on Multifrequency Acousto-Optic Diffraction

    NASA Astrophysics Data System (ADS)

    Proklov, V. V.; Rezvov, Yu. G.

    2018-01-01

    An analytical solution for the transmission function of noncoherent wideband radiation is obtained under acousto-optic (AO) filtering using a discrete set of monochromatic AO waves with a small spectral overlap. We studied characteristics of the AO transformation of a continuous spectrum of noncoherent radiation into a given set of discrete narrow bands of spectral transmission by excitation of a discrete set of sound frequencies. We carried out the analysis of transmission functions of individual channels taking into account a partial overlap of their spectra and possible intermodulation distortions. It is shown that a stationary value of the root-mean-square light power is found at the electronic output due to the photoelectric transformation and detecting diffracted light. Based on this, a necessary stationary, multiband, and nearly equidistant transmission function of a device can be formed by using a relevant spectrum of acoustic excitation. Peculiarities of this way of forming the multiband transmission function are revealed: the limitation of diffraction efficiency for an individual channel, the possibility of decoupling side lobes of adjacent channels, etc. A multiband acousto-optic filter (MAOF) was simulated that was based on a paratellurite monocrystal (TeO2), which was previously used for experimental optical encoding. The theoretical and experimental results are in gratifying agreement.

  7. Acousto-optic modulation and opto-acoustic gating in piezo-optomechanical circuits

    PubMed Central

    Balram, Krishna C.; Davanço, Marcelo I.; Ilic, B. Robert; Kyhm, Ji-Hoon; Song, Jin Dong; Srinivasan, Kartik

    2017-01-01

    Acoustic wave devices provide a promising chip-scale platform for efficiently coupling radio frequency (RF) and optical fields. Here, we use an integrated piezo-optomechanical circuit platform that exploits both the piezoelectric and photoelastic coupling mechanisms to link 2.4 GHz RF waves to 194 THz (1550 nm) optical waves, through coupling to propagating and localized 2.4 GHz acoustic waves. We demonstrate acousto-optic modulation, resonant in both the optical and mechanical domains, in which waveforms encoded on the RF carrier are mapped to the optical field. We also show opto-acoustic gating, in which the application of modulated optical pulses interferometrically gates the transmission of propagating acoustic pulses. The time-domain characteristics of this system under both pulsed RF and pulsed optical excitation are considered in the context of the different physical pathways involved in driving the acoustic waves, and modelled through the coupled mode equations of cavity optomechanics. PMID:28580373

  8. Non-Magnetic On-Chip Resonant Acousto-Optic Isolator at 780 nm

    DTIC Science & Technology

    2017-08-04

    SPONSOR/MONITOR’S ACRONYM(S) Air Force Research Laboratory Space Vehicles Directorate 3550 Aberdeen Avenue SE Kirtland AFB, NM 87117-5776 AFRL /RVBYE 11...Belvoir, VA 22060-6218 AFRL /RVIL Kirtland AFB, NM 87117-5776 Official Record Copy AFRL /RVBYE/Dr. Brian Kasch 1 cy Approved for public release... AFRL -RV-PS- AFRL -RV-PS- TR-2017-0170 TR-2017-0170 NON-MAGNETIC ON-CHIP RESONANT ACOUSTO- OPTIC ISOLATOR AT 780 nm Gaurav Bahl University of

  9. Pre-Juno Optical Analysis of Jupiter's Atmosphere with the NMSU Acousto-optic Imaging Camera

    NASA Astrophysics Data System (ADS)

    Dahl, Emma; Chanover, Nancy J.; Voelz, David; Kuehn, David M.; Strycker, Paul D.

    2016-10-01

    Jupiter's upper atmosphere is a highly dynamic system in which clouds and storms change color, shape, and size on variable timescales. The exact mechanism by which the deep atmosphere affects these changes in the uppermost cloud deck is still unknown. With Juno's arrival at Jupiter in July 2016, the thermal radiation from the deep atmosphere will be measurable with the spacecraft's Microwave Radiometer. By taking detailed optical measurements of Jupiter's uppermost cloud deck in conjunction with Juno's microwave observations, we can provide a context in which to better understand these observations. This data will also provide a complement to the near-IR sensitivity of the Jovian InfraRed Auroral Mapper and will expand on the limited spectral coverage of JunoCam. Ultimately, we can utilize the two complementary datasets in order to thoroughly characterize Jupiter's atmosphere in terms of its vertical cloud structure, color distribution, and dynamical state throughout the Juno era. In order to obtain high spectral resolution images of Jupiter's atmosphere in the optical regime, we use the New Mexico State University Acousto-optic Imaging Camera (NAIC). NAIC contains an acousto-optic tunable filter, which allows us to take hyperspectral image cubes of Jupiter from 450-950 nm at an average spectral resolution (λ/dλ) of 242. We present an analysis of our pre-Juno dataset obtained with NAIC at the Apache Point Observatory 3.5-m telescope during the night of March 28, 2016. Under primarily photometric conditions, we obtained 6 hyperspectral image cubes of Jupiter over the course of the night, totaling approximately 2,960 images. From these data we derive low-resolution optical spectra of the Great Red Spot and a representative belt and zone to compare with previous work and laboratory measurements of candidate chromophore materials. Future work will focus on radiative transfer modeling to elucidate the Jovian cloud structure during the Juno era. This work was supported

  10. Acousto-optic control of internal acoustic reflection in tellurium dioxide crystal in case of strong elastic energy walkoff [Invited].

    PubMed

    Voloshinov, Vitaly; Polikarpova, Nataliya; Ivanova, Polina; Khorkin, Vladimir

    2018-04-01

    Peculiar cases of acoustic wave propagation and reflection may be observed in strongly anisotropic acousto-optical crystals. A tellurium dioxide crystal serves as a prime example of such media, since it possesses record indexes of acoustic anisotropy. We studied one of the unusual scenarios of acoustic incidence and reflection from a free crystal-vacuum boundary in paratellurite. The directions of the acoustic waves in the (001) plane of the crystal were determined, and their basic characteristics were calculated. The carried-out acousto-optic experiment at the wavelength of light 532 nm and the acoustic frequency 73 MHz confirmed the theoretical predictions. The effects examined in the paper include the acoustic wave propagation with the record walkoff angle 74°. We also observed the incidence of the wave on the boundary at the angle exceeding 90°. Finally, we registered the close-to-back reflection of acoustic energy following the incidence. One of the stunning aspects is the distribution of energy between the incident and the back-reflected wave. The unusual features of the acoustic wave reflections pointed out in the paper are valuable for their possible applications in acousto-optic devices.

  11. Near-to-eye electroholography via guided-wave acousto-optics for augmented reality

    NASA Astrophysics Data System (ADS)

    Jolly, Sundeep; Savidis, Nickolaos; Datta, Bianca; Smalley, Daniel; Bove, V. Michael

    2017-03-01

    Near-to-eye holographic displays act to directly project wavefronts into a viewer's eye in order to recreate 3-D scenes for augmented or virtual reality applications. Recently, several solutions for near-to-eye electroholography have been proposed based on digital spatial light modulators in conjunction with supporting optics, such as holographic waveguides for light delivery; however, such schemes are limited by the inherent low space-bandwidth product available with current digital SLMs. In this paper, we depict a fully monolithic, integrated optical platform for transparent near-to-eye holographic display requiring no supporting optics. Our solution employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram.

  12. Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors.

    PubMed

    Salomé, R; Kremer, Y; Dieudonné, S; Léger, J-F; Krichevsky, O; Wyart, C; Chatenay, D; Bourdieu, L

    2006-06-30

    Two-photon scanning microscopy (TPSM) is a powerful tool for imaging deep inside living tissues with sub-cellular resolution. The temporal resolution of TPSM is however strongly limited by the galvanometric mirrors used to steer the laser beam. Fast physiological events can therefore only be followed by scanning repeatedly a single line within the field of view. Because acousto-optic deflectors (AODs) are non-mechanical devices, they allow access at any point within the field of view on a microsecond time scale and are therefore excellent candidates to improve the temporal resolution of TPSM. However, the use of AOD-based scanners with femtosecond pulses raises several technical difficulties. In this paper, we describe an all-digital TPSM setup based on two crossed AODs. It includes in particular an acousto-optic modulator (AOM) placed at 45 degrees with respect to the AODs to pre-compensate for the large spatial distortions of femtosecond pulses occurring in the AODs, in order to optimize the spatial resolution and the fluorescence excitation. Our setup allows recording from freely selectable point-of-interest at high speed (1kHz). By maximizing the time spent on points of interest, random-access TPSM (RA-TPSM) constitutes a promising method for multiunit recordings with millisecond resolution in biological tissues.

  13. Research on FBG-based longitudinal-acousto-optic modulator with Fourier mode coupling method.

    PubMed

    Li, Zhuoxuan; Pei, Li; Liu, Chao; Ning, Tigang; Yu, Shaowei

    2012-10-20

    Fourier mode coupling model was first applied to achieve the spectra property of a fiber Bragg grating (FBG)-based longitudinal-acousto-optic modulator. Compared with traditional analysis algorithms, such as the transfer matrix method, the Fourier mode coupling model could improve the computing efficiency up to 100 times with a guarantee of accuracy. In this paper, based on the theoretical analysis of this model, the spectra characteristics of the modulator in different frequencies and acoustically induced strains were numerically simulated. In the experiment, a uniform FBG was modulated by acoustic wave (AW) at 12 different frequencies. In particular, the modulator responses at 563 and 885.5 KHz with three different lead zirconate titanate (PZT) loads applied were plotted for illustration, and the linear fitting of experimental data demonstrated a good match with the simulation result. The acoustic excitation of the longitudinal wave is obtained using a conic silica horn attached to the surface of a shear-mode PZT plate paralleled to the fiber axis. This way of generating longitudinal AW with a transversal PZT may shed light on the optimal structural design for the FBG-based longitudinal-acousto-optic modulator.

  14. Effect of metal coating in all-fiber acousto-optic tunable filter using torsional wave.

    PubMed

    Song, Du-Ri; Jun, Chang Su; Do Lim, Sun; Kim, Byoung Yoon

    2014-12-15

    Torsional mode acousto-optic tunable filter (AOTF) is demonstrated using a metal-coated birefringent optical fiber for an improved robustness. The changes in acoustic and optical properties of a metal-coated birefringent optical fiber induced by the thin metal coating were analyzed experimentally and theoretically. The filter wavelength shift is successfully explained as a result of combined effect of acoustic wavelength change and optical birefringence change. We also demonstrated a small form-factor configuration by coiling the fiber with 6 cm diameter without performance degradation. The center wavelength of the filter can be tuned >35 nm by changing the applied frequency, and the coupling efficiency is higher than 92% with <5 nm 3-dB bandwidth.

  15. Bulk and integrated acousto-optic spectrometers for radio astronomy

    NASA Technical Reports Server (NTRS)

    Chin, G.; Buhl, D.; Florez, J. M.

    1981-01-01

    The development of sensitive heterodyne receivers (front end) in the centimeter and millimeter range, and the construction of sensitive RF spectrometers (back end) enable the spectral lines of interstellar molecules to be detected and identified. A technique was developed which combines acoustic bending of a collimated coherent light beam by a Bragg cell followed by detection by a sensitive array of photodetectors (thus forming an RF acousto-optic spectrometer (AOS). An AOS has wide bandwidth, large number of channels, and high resolution, and is compact, lightweight, and energy efficient. The thrust of receiver development is towards high frequency heterodyne systems, particularly in the millimeter, submillimeter, far infrared, and 10 micron spectral ranges.

  16. Investigation of a mercurous chloride acousto-optic cell based on longitudinal acoustic mode.

    PubMed

    Gupta, Neelam

    2009-03-01

    A number of spectral imagers using acousto-optic tunable filters (AOTFs) operating from the UV to the longwave infrared (LWIR) using KDP, MgF(2), TeO(2), and Tl(3)AsSe(3) crystals to cover different spectral regions have been developed. In the LWIR there is a lack of high quality acousto-optic (AO) materials. Mercurous halide (Hg(2)Cl(2) and Hg(2)Br(2)) crystals are highly anisotropic with a high AO figure of merit due to slow acoustic velocities and high photoelastic constants and are transparent over a wide spectral region from 0.35 to 20 mum for Hg(2)Cl(2) and from 0.4 to 30 mum for Hg(2)Br(2). AO modulators, deflectors, and AOTFs based on these crystals can operate over a wide spectral range. Single crystals of these materials are being grown and some prototype devices have been fabricated. Results are presented from device characterization for an AO cell fabricated in Hg(2)Cl(2) based on longitudinal acoustic mode propagation. This device was very useful in demonstrating the AO interaction as well as soundness of the transducer bonding technique. Acoustic phase velocity is calculated and measured, diffraction efficiency is obtained from experiments, and the AO figure of merit of the sample is evaluated.

  17. Detection of a Novel Mechanism of Acousto-Optic Modulation of Incoherent Light

    PubMed Central

    Jarrett, Christopher W.; Caskey, Charles F.; Gore, John C.

    2014-01-01

    A novel form of acoustic modulation of light from an incoherent source has been detected in water as well as in turbid media. We demonstrate that patterns of modulated light intensity appear to propagate as the optical shadow of the density variations caused by ultrasound within an illuminated ultrasonic focal zone. This pattern differs from previous reports of acousto-optical interactions that produce diffraction effects that rely on phase shifts and changes in light directions caused by the acoustic modulation. Moreover, previous studies of acousto-optic interactions have mainly reported the effects of sound on coherent light sources via photon tagging, and/or the production of diffraction phenomena from phase effects that give rise to discrete sidebands. We aimed to assess whether the effects of ultrasound modulation of the intensity of light from an incoherent light source could be detected directly, and how the acoustically modulated (AOM) light signal depended on experimental parameters. Our observations suggest that ultrasound at moderate intensities can induce sufficiently large density variations within a uniform medium to cause measurable modulation of the intensity of an incoherent light source by absorption. Light passing through a region of high intensity ultrasound then produces a pattern that is the projection of the density variations within the region of their interaction. The patterns exhibit distinct maxima and minima that are observed at locations much different from those predicted by Raman-Nath, Bragg, or other diffraction theory. The observed patterns scaled appropriately with the geometrical magnification and sound wavelength. We conclude that these observed patterns are simple projections of the ultrasound induced density changes which cause spatial and temporal variations of the optical absorption within the illuminated sound field. These effects potentially provide a novel method for visualizing sound fields and may assist the

  18. Use of acousto-optic tunable filter in fluorescence imaging endoscopy

    NASA Astrophysics Data System (ADS)

    Bouhifd, Mounir; Whelan, Maurice; Aprahamian, Marc

    2003-10-01

    A prototype instrument for fluorescence-based medical diagnostics in vivo is described. The system consists of a rigid endoscope comprising a UV laser-source for fluorescence excitation and a white light source for direct imaging. An acousto-optic tuneable filter (AOTF) is employed as a full-field tuneable bandpass filter. This allows fast continuous or random-access tuning with high filtering efficiency. A study of the diagnostic potential of fluorescence imaging for pancreatitis was conducted on a rat model. In particular, the aim was to detect autofluorescence of endogenous protoporphyrin IX (PpIX) that has been shown to accumulate in early-stage diseased tissue undergoing an inflammatory response.

  19. Chromatic aberrations correction for imaging spectrometer based on acousto-optic tunable filter with two transducers.

    PubMed

    Zhao, Huijie; Wang, Ziye; Jia, Guorui; Zhang, Ying; Xu, Zefu

    2017-10-02

    The acousto-optic tunable filter (AOTF) with wide wavelength range and high spectral resolution has long crystal and two transducers. A longer crystal length leads to a bigger chromatic focal shift and the double-transducer arrangement induces angular mutation in diffracted beam, which increase difficulty in longitudinal and lateral chromatic aberration correction respectively. In this study, the two chromatic aberrations are analyzed quantitatively based on an AOTF optical model and a novel catadioptric dual-path configuration is proposed to correct both the chromatic aberrations. The test results exhibit effectiveness of the optical configuration for this type of AOTF-based imaging spectrometer.

  20. SMILES/AOS: acousto-optical spectrometer for high resolution submillimeter-wave spectroscopy

    NASA Astrophysics Data System (ADS)

    Mazuray, L.; Barthès, J.-C.; Bayle, F.; Castel, D.; Claviere, P.; Delbru, F.; Doittau, P.-O.; Gladin, L.; Guilleux, P.; Halbout, S.; Lavielle, D.; Varin, J.-L.; de Zotti, S.; Rosolen, C.; Ozeki, H.

    2017-11-01

    An acousto-optical spectrometer (AOS) is employed in order to meet scientific mission objectives of submillimeter-wave limb-emission sounder (SMILES) to be aboard the Japanese Experiment Module (JEM) of International space station (ISS). AOS is developed by ASTRIUM for the Japanese space agency (NASDA). The capability of multi channel detection with AOS is suitable for observing multi-chemical species in a wide frequency region. Low noise of the AOS enables us to obtain the spectra with a very high sensitivity. Several technical concerns relating to important instrumental characteristics of AOS are discussed and expected performance of the design are overviewed.

  1. New prototype of acousto-optical radio-wave spectrometer with parallel frequency processing for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Chavez Dagostino, Miguel; Arellanes, Adan O.; Aguirre Lopez, Arturo

    2016-09-01

    We develop a multi-band spectrometer with a few spatially parallel optical arms for the combined processing of their data flow. Such multi-band capability has various applications in astrophysical scenarios at different scales: from objects in the distant universe to planetary atmospheres in the Solar system. Each optical arm exhibits original performances to provide parallel multi-band observations with different scales simultaneously. Similar possibility is based on designing each optical arm individually via exploiting different materials for acousto-optical cells operating within various regimes, frequency ranges and light wavelengths from independent light sources. Individual beam shapers provide both the needed incident light polarization and the required apodization to increase the dynamic range of a system. After parallel acousto-optical processing, data flows are united by the joint CCD matrix on the stage of the combined electronic data processing. At the moment, the prototype combines still three bands, i.e. includes three spatial optical arms. The first low-frequency arm operates at the central frequencies 60-80 MHz with frequency bandwidth 40 MHz. The second arm is oriented to middle-frequencies 350-500 MHz with frequency bandwidth 200-300 MHz. The third arm is intended for ultra-high-frequency radio-wave signals about 1.0-1.5 GHz with frequency bandwidth <300 MHz. To-day, this spectrometer has the following preliminary performances. The first arm exhibits frequency resolution 20 KHz; while the second and third arms give the resolution 150-200 KHz. The numbers of resolvable spots are 1500- 2000 depending on the regime of operation. The fourth optical arm at the frequency range 3.5 GHz is currently under construction.

  2. High power single-longitudinal-mode Ho:YLF unidirectional ring laser based on a composite structure of acousto-optic device and wave plate

    NASA Astrophysics Data System (ADS)

    Dai, T. Y.; Fan, Z. G.; Wu, J.; Ju, Y. L.; Yao, B. Q.; Zhang, Z. G.; Teng, K.; Xu, X. G.; Duan, X. M.

    2017-05-01

    We report a unidirectional single-longitudinal-mode Ho:YLF ring laser. An acousto-optic modulator and two half-wave plates were used to enforce the Ho:YLF ring laser in a unidirectional operation. The single-longitudinal-mode output power could reach 3.73 W successfully when the incident pump power was 16.4 W. The corresponding slope efficiency was 27.1%. The wavelength of the single-longitudinal-mode Ho:YLF ring laser was 2063.8 nm. The M2 factor was 1.12. The results illustrated that the single-longitudinal-mode output power could be further enhanced by increasing the radio frequency power of the acousto-optic modulator.

  3. An experimental distribution of analog and digital information in a hybrid wireless visible light communication system based on acousto-optic modulation and sinusoidal gratings

    NASA Astrophysics Data System (ADS)

    Gómez Colín, R.; García Juárez, A.; Zaldívar Huerta, I. E.; Marquina, A. Vera; García Delgado, L. A.; Leal Cruz, A. L.; Gómez Fuentes, R.

    2016-03-01

    In this paper we propose a photonic architecture as an alternative tool to distribute point to multipoint analog and digital information over a hybrid wireless visible optical communication system. The experimental set-up is composed of a red laser pointer, an acousto-optic modulator, a sinusoidal grating and a photo-detector array. By using a simple and variable interferometric system, diffraction gratings with different spatial frequencies are generated and recorded on a photoemulsion which is composed of vanilla with dichromate gelatin. Analog video and digital information are first transmitted and recovered over a wireless communication system using a microwave carrier at 4.52 GHz which is generated by distributed feedback lasers operating in the low laser threshold current region. Separately, the recovered video information and digital data are combined with a radio frequency signal of 80 MHz, obtaining a subcarrier of information that is imposed on the optical carrier of the pointer laser using an acousto-optic modulator which is operated with an angle of incident light that satisfies the Bragg condition. The modulated optical carrier is sent to a sinusoidal grating, the diffraction pattern is photo-detected using an array of PIN photo-detectors. The use of sinusoidal gratings with acousto-optic modulators allows that number of channels to be increased when both components are placed in cascade.

  4. Acousto-optic Imaging System for In-situ Measurement of the High Temperature Distribution in Micron-size Specimens

    NASA Astrophysics Data System (ADS)

    Machikhin, Alexander S.; Zinin, Pavel V.; Shurygin, Alexander V.

    We developed a unique acousto-optic imaging system for in-situ measurement of high temperature distribution on micron-size specimens. The system was designed to measure temperature distribution inside minerals and functional material phases subjected to high pressure and high temperatures in a diamond anvil cell (DAC) heated by a high powered laser.

  5. Programmable dispersion on a photonic integrated circuit for classical and quantum applications.

    PubMed

    Notaros, Jelena; Mower, Jacob; Heuck, Mikkel; Lupo, Cosmo; Harris, Nicholas C; Steinbrecher, Gregory R; Bunandar, Darius; Baehr-Jones, Tom; Hochberg, Michael; Lloyd, Seth; Englund, Dirk

    2017-09-04

    We demonstrate a large-scale tunable-coupling ring resonator array, suitable for high-dimensional classical and quantum transforms, in a CMOS-compatible silicon photonics platform. The device consists of a waveguide coupled to 15 ring-based dispersive elements with programmable linewidths and resonance frequencies. The ability to control both quality factor and frequency of each ring provides an unprecedented 30 degrees of freedom in dispersion control on a single spatial channel. This programmable dispersion control system has a range of applications, including mode-locked lasers, quantum key distribution, and photon-pair generation. We also propose a novel application enabled by this circuit - high-speed quantum communications using temporal-mode-based quantum data locking - and discuss the utility of the system for performing the high-dimensional unitary optical transformations necessary for a quantum data locking demonstration.

  6. Noise tolerance in wavelength-selective switching of optical differential quadrature-phase-shift-keying pulse train by collinear acousto-optic devices.

    PubMed

    Goto, Nobuo; Miyazaki, Yasumitsu

    2014-06-01

    Optical switching of high-bit-rate quadrature-phase-shift-keying (QPSK) pulse trains using collinear acousto-optic (AO) devices is theoretically discussed. Since the collinear AO devices have wavelength selectivity, the switched optical pulse trains suffer from distortion when the bandwidth of the pulse train is comparable to the pass bandwidth of the AO device. As the AO device, a sidelobe-suppressed device with a tapered surface-acoustic-wave (SAW) waveguide and a Butterworth-type filter device with a lossy SAW directional coupler are considered. Phase distortion of optical pulse trains at 40 to 100  Gsymbols/s in QPSK format is numerically analyzed. Bit-error-rate performance with additive Gaussian noise is also evaluated by the Monte Carlo method.

  7. Early Juno Era Optical Imaging and Analysis of Jupiter's Atmospheric Structure and Color with the NMSU Acousto-optic Imaging Camera

    NASA Astrophysics Data System (ADS)

    Dahl, E.; Chanover, N.; Voelz, D.; Kuehn, D.; Strycker, P.

    2016-12-01

    Jupiter's upper atmosphere is a highly dynamic system in which clouds and storms change color, shape, and size on variable timescales. The exact mechanism by which the deep atmosphere affects these changes in the uppermost cloud deck is still unknown. However, with Juno's arrival in July 2016, it is now possible to take detailed observations of the deep atmosphere with the spacecraft's Microwave Radiometer. By taking detailed optical measurements of Jupiter's uppermost cloud deck in conjunction with these microwave observations, we can provide a context in which to better understand these observations. Ultimately, we can utilize these two complementary datasets in order to thoroughly characterize Jupiter's atmosphere in terms of its vertical cloud structure, color distribution, and dynamical state throughout the Juno era. These optical data will also provide a complement to the near-IR sensitivity of the Jovian InfraRed Auroral Mapper and will expand on the limited spectral coverage of JunoCam. In order to obtain high spectral resolution images of Jupiter's atmosphere in the optical regime we use the New Mexico State University Acousto-optic Imaging Camera (NAIC). NAIC's acousto-optic tunable filter allows us to take hyperspectral image cubes of Jupiter from 450-950 nm at an average spectral resolution (λ/dλ) of 242. We present a preliminary analysis of two datasets obtained with NAIC at the Apache Point Observatory 3.5-m telescope: one pre-Juno dataset from March 2016 and the other from November 2016. From these data we derive low-resolution optical spectra of the Great Red Spot and a representative belt and zone to compare with previous work and laboratory measurements of candidate chromophore materials. Additionally, we compare these two datasets to inspect how the atmosphere has changed since before Juno arrived at Jupiter. NASA supported this work through award number NNX15AP34A.

  8. Acoustic pressure measurement of pulsed ultrasound using acousto-optic diffraction

    NASA Astrophysics Data System (ADS)

    Jia, Lecheng; Chen, Shili; Xue, Bin; Wu, Hanzhong; Zhang, Kai; Yang, Xiaoxia; Zeng, Zhoumo

    2018-01-01

    Compared with continuous ultrasound wave, pulsed ultrasound has been widely used in ultrasound imaging. The aim of this work is to show the applicability of acousto-optic diffraction on pulsed ultrasound transducer. In this paper, acoustic pressure of two ultrasound transducers is measured based on Raman-Nath diffraction. The frequencies of transducers are 5MHz and 10MHz. The pulse-echo method and simulation data are used to evaluate the results. The results show that the proposed method is capable to measure the absolute sound pressure. We get a sectional view of acoustic pressure using a displacement platform as an auxiliary. Compared with the traditional sound pressure measurement methods, the proposed method is non-invasive with high sensitivity and spatial resolution.

  9. Acousto-Optic–Based Wavelength-Comb-Swept Laser for Extended Displacement Measurements

    PubMed Central

    Park, Nam Su; Chun, Soo Kyung; Han, Ga-Hee; Kim, Chang-Seok

    2017-01-01

    We demonstrate a novel wavelength-comb-swept laser based on two intra-cavity filters: an acousto-optic tunable filter (AOTF) and a Fabry-Pérot etalon filter. The AOTF is used for the tunable selection of the output wavelength with time and the etalon filter for the narrowing of the spectral linewidth to extend the coherence length. Compared to the conventional wavelength-swept laser, the acousto-optic–based wavelength-comb-swept laser (WCSL) can extend the measureable range of displacement measurements by decreasing the sensitivity roll-off of the point spread function. Because the AOTF contains no mechanical moving parts to select the output wavelength acousto-optically, the WCSL source has a high wavenumber (k) linearity of R2 = 0.9999 to ensure equally spaced wavelength combs in the wavenumber domain. PMID:28362318

  10. Acousto-Optical Evaluation Of Fiber Size In Wood Pulp

    NASA Astrophysics Data System (ADS)

    Dion, J. L.; Garceau, J. J.; Morissette, J. C.

    1986-10-01

    In the pulp and paper industry, the problem of regular and fast evaluation of wood fiber characteristics such as length and specific area is an important one. With this in view, we have been studying an acousto-optical technique based on the acoustic agglomeration of fibers in a water suspension, where a stationary ultrasonic field is created at about 150 kHz. Under the influence of radiation forces, fibers re-orient themselves parallel to the nodal planes of acoustic pressure, and regroup or agglomerate in these planes in different characteristic times. These are mesured by means of the light scattered at small angles. We have found that these times depend on the size distribution of fibers, particularly length. We present results obtained with an assortment of fiber types, under various experimental conditions which indicate eventual applications in the automatic control of pulp production.

  11. Deep-UV Based Acousto-Optic Tunable Filter for Spectral Sensing Applications

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.

    2006-01-01

    In this paper, recent progress made in the development of quartz and KDP crystal based acousto-optic tunable filters (AOTF) are presented. These AOTFs are developed for operation over deep-UV to near-UV wavelengths of 190 nm to 400 nm. Preliminary output performance measurements of quartz AOTF and design specifications of KDP AOTF are presented. At 355 nm, the quartz AOTF device offered approx.15% diffraction efficiency with a passband full-width-half-maximum (FWHM) of less than 0.0625 nm. Further characterization of quartz AOTF devices at deep-UV wavelengths is progressing. The hermetic packaging of KDP AOTF is nearing completion. The solid-state optical sources being used for excitation include nonlinear optics based high-energy tunable UV transmitters that operate around 320 nm and 308 nm wavelengths, and a tunable deep-UV laser operating over 193 nm to 210 nm. These AOTF devices have been developed as turn-key devices for primarily for space-based chemical and biological sensing applications using laser induced Fluorescence and resonance Raman techniques.

  12. Ultrasound-Mediated Biophotonic Imaging: A Review of Acousto-Optical Tomography and Photo-Acoustic Tomography

    PubMed Central

    Wang, Lihong V.

    2004-01-01

    This article reviews two types of ultrasound-mediated biophotonic imaging–acousto-optical tomography (AOT, also called ultrasound-modulated optical tomography) and photo-acoustic tomography (PAT, also called opto-acoustic or thermo-acoustic tomography)–both of which are based on non-ionizing optical and ultrasonic waves. The goal of these technologies is to combine the contrast advantage of the optical properties and the resolution advantage of ultrasound. In these two technologies, the imaging contrast is based primarily on the optical properties of biological tissues, and the imaging resolution is based primarily on the ultrasonic waves that either are provided externally or produced internally, within the biological tissues. In fact, ultrasonic mediation overcomes both the resolution disadvantage of pure optical imaging in thick tissues and the contrast and speckle disadvantages of pure ultrasonic imaging. In our discussion of AOT, the relationship between modulation depth and acoustic amplitude is clarified. Potential clinical applications of ultrasound-mediated biophotonic imaging include early cancer detection, functional imaging, and molecular imaging. PMID:15096709

  13. Two-dimensional acousto-optic processor using circular antenna array with a Butler matrix

    NASA Astrophysics Data System (ADS)

    Lee, Jim P.

    1992-09-01

    A two-dimensional acousto-optic signal processor is shown to be useful for providing simultaneous spectrum analysis and direction finding of radar signals over an instantaneous field of view of 360 deg. A system analysis with emphasis on the direction-finding aspect of this new architecture is presented. The peak location of the optical pattern provides a direct measure of bearing, independent of signal frequency. In addition, the sidelobe levels of the pattern can be effectively reduced using amplitude weighting. Performance parameters, such as mainlobe beamwidth, peak-sidelobe level, and pointing error, are analyzed as a function of the Gaussian laser illumination profile and the number of channels. Finally, a comparison with a linear antenna array architecture is also discussed.

  14. Acousto-optical interaction of surface acoustic and optical waves in a two-dimensional phoxonic crystal hetero-structure cavity.

    PubMed

    Ma, Tian-Xue; Zou, Kui; Wang, Yue-Sheng; Zhang, Chuanzeng; Su, Xiao-Xing

    2014-11-17

    Phoxonic crystal is a promising material for manipulating sound and light simultaneously. In this paper, we theoretically demonstrate the propagation of acoustic and optical waves along the truncated surface of a two-dimensional square-latticed phoxonic crystal. Further, a phoxonic crystal hetero-structure cavity is proposed, which can simultaneously confine surface acoustic and optical waves. The interface motion and photoelastic effects are taken into account in the acousto-optical coupling. The results show obvious shifts in eigenfrequencies of the photonic cavity modes induced by different phononic cavity modes. The symmetry of the phononic cavity modes plays a more important role in the single-phonon exchange process than in the case of the multi-phonon exchange. Under the same deformation, the frequency shift of the photonic transverse electric mode is larger than that of the transverse magnetic mode.

  15. SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Specialised acousto-optical processor for input, display, and coherent-optical processing of multiparameter information from spaceborne telemetric systems

    NASA Astrophysics Data System (ADS)

    Bykovskii, Yurii A.; Eloev, E. N.; Kukharenko, K. L.; Panin, A. M.; Solodovnikov, N. P.; Torgashin, A. N.; Arestova, E. L.

    1995-10-01

    An acousto-optical system for input, display, and coherent-optical processing of information was implemented experimentally. The information transmission capacity, the structure of the information fluxes, and the efficiency of spaceborne telemetric systems were taken into account. The number of equivalent frequency-resolved channels corresponded to the structure of a telemetric frame of a two-step switch. The number of intensity levels of laser radiation corresponded to the scale of changes in the parameters. Use was made of the technology of a liquid optical contact between a wedge-shaped piezoelectric transducer made of lithium niobate and an anisotropic light-and-sound guide made of paratellurite with asymmetric scattering geometry. The simplest technique for optical filtering of multiparameter signals was analysed.

  16. Secure free-space communication, turbulence mitigation, and other applications using acousto-optic chaos.

    PubMed

    Chatterjee, Monish R; Mohamed, Ali; Almehmadi, Fares S

    2018-04-01

    Use of acousto-optic (A-O) chaos via the feedback loop in a Bragg cell for signal encryption began as a conceptual demonstration around 2008. Radio frequency (RF) chaos from a hybrid A-O feedback device may be used for secure communications of analog and digital signals. In this paper, modulation of RF chaos via first-order feedback is discussed with results corroborated by nonlinear dynamics, bifurcation maps, and Lyapunov analyses. Applications based on encryption with profiled optical beams, and extended to medical and embedded steganographic data, and video signals are discussed. It is shown that the resulting encryption is significantly robust with key tolerances potentially less than 0.1%. Results are also presented for the use of chaotic encryption for image restoration during propagation through atmospheric turbulence.

  17. Acousto-optical imaging using a powerful long pulse laser

    NASA Astrophysics Data System (ADS)

    Rousseau, Guy; Blouin, Alain; Monchalin, Jean-Pierre

    2008-06-01

    Acousto-optical imaging is an emerging biodiagnostic technique which provides an optical spectroscopic signature and a spatial localization of an optically absorbing target embedded in a strongly scattering medium. The transverse resolution of the technique is determined by the lateral extent of ultrasound beam focal zone while the axial resolution is obtained by using short ultrasound pulses. Although very promising for medical diagnostic, the practical application of this technique is presently limited by its poor sensitivity. Moreover, any method to enhance the signal-to-noise ratio must obviously satisfy the in vivo safety limits regarding the acceptable power level of both the ultrasonic pressure wave and the laser beam. In this paper, we propose to improve the sensitivity by using a pulsed single-frequency laser source to raise the optical peak power applied to the scattering medium and to collect more ultrasonically tagged photons. Such a laser source also allows illuminating the tissues mainly during the transit time of the ultrasonic wave to maintain the average optical power below the maximum permissible exposure. In our experiment, a single-frequency Nd:YAG laser emitting 500-μs pulses with a peak power superior to 100 W was used. Photons were tagged in few-cm thick optical phantoms with tone bursts generated by an ultrasonic transducer. Tagged photons were detected with a GaAs photorefractive interferometer characterized by a large optical etendue to process simultaneously a large number of speckle grains. When pumped by high intensity laser pulses, such an interferometer also provides the fast response time essential to obtain an apparatus insensitive to the speckle decorrelation due to mechanical vibrations or tissues movements. The use of a powerful long pulse laser appears promising to enhance the signal level in ultrasound modulated optical imaging. When combined with a photorefractive interferometer of large optical etendue, such a source could

  18. Optical programmable metamaterials

    NASA Astrophysics Data System (ADS)

    Gong, Cheng; Zhang, Nan; Dai, Zijie; Liu, Weiwei

    2018-02-01

    We suggest and demonstrate the concept of optical programmable metamaterials which can configure the device's electromagnetic parameters by the programmable optical stimuli. In such metamaterials, the optical stimuli produced by a FPGA controlled light emitting diode array can switch or combine the resonance modes which are coupled in. As an example, an optical programmable metamaterial terahertz absorber is proposed. Each cell of the absorber integrates four meta-rings (asymmetric 1/4 rings) with photo-resistors connecting the critical gaps. The principle and design of the metamaterials are illustrated and the simulation results demonstrate the functionalities for programming the metamaterial absorber to change its bandwidth and resonance frequency.

  19. Acousto-optic tunable filter chromatic aberration analysis and reduction with auto-focus system

    NASA Astrophysics Data System (ADS)

    Wang, Yaoli; Chen, Yuanyuan

    2018-07-01

    An acousto-optic tunable filter (AOTF) displays optical band broadening and sidelobes as a result of the coupling between the acoustic wave and optical waves of different wavelengths. These features were analysed by wave-vector phase matching between the optical and acoustic waves. A crossed-line test board was imaged by an AOTF multi-spectral imaging system, showing image blurring in the direction of diffraction and image sharpness in the orthogonal direction produced by the greater bandwidth and sidelobes in the former direction. Applying the secondary-imaging principle and considering the wavelength-dependent refractive index, focal length varies over the broad wavelength range. An automatic focusing method is therefore proposed for use in AOTF multi-spectral imaging systems. A new method for image-sharpness evaluation, based on improved Structure Similarity Index Measurement (SSIM), is also proposed, based on the characteristics of the AOTF imaging system. Compared with the traditional gradient operator, as same as it, the new evaluation function realized the evaluation between different image quality, thus could achieve the automatic focusing for different multispectral images.

  20. Simultaneous imaging of cellular morphology and multiple biomarkers using an acousto-optic tunable filter-based bright field microscope.

    PubMed

    Wachman, Elliot S; Geyer, Stanley J; Recht, Joel M; Ward, Jon; Zhang, Bill; Reed, Murray; Pannell, Chris

    2014-05-01

    An acousto-optic tunable filter (AOTF)-based multispectral imaging microscope system allows the combination of cellular morphology and multiple biomarker stainings on a single microscope slide. We describe advances in AOTF technology that have greatly improved spectral purity, field uniformity, and image quality. A multispectral imaging bright field microscope using these advances demonstrates pathology results that have great potential for clinical use.

  1. Feasibility study of complex wavefield retrieval in off-axis acoustic holography employing an acousto-optic sensor

    PubMed Central

    Rodríguez, Guillermo López; Weber, Joshua; Sandhu, Jaswinder Singh; Anastasio, Mark A.

    2011-01-01

    We propose and experimentally demonstrate a new method for complex-valued wavefield retrieval in off-axis acoustic holography. The method involves use of an intensity-sensitive acousto-optic (AO) sensor, optimized for use at 3.3 MHz, to record the acoustic hologram and a computational method for reconstruction of the object wavefield. The proposed method may circumvent limitations of conventional implementations of acoustic holography and may facilitate the development of acoustic-holography-based biomedical imaging methods. PMID:21669451

  2. Time and space integrating acousto-optic folded spectrum processing for SETI

    NASA Technical Reports Server (NTRS)

    Wagner, K.; Psaltis, D.

    1986-01-01

    Time and space integrating folded spectrum techniques utilizing acousto-optic devices (AOD) as 1-D input transducers are investigated for a potential application as wideband, high resolution, large processing gain spectrum analyzers in the search for extra-terrestrial intelligence (SETI) program. The space integrating Fourier transform performed by a lens channels the coarse spectral components diffracted from an AOD onto an array of time integrating narrowband fine resolution spectrum analyzers. The pulsing action of a laser diode samples the interferometrically detected output, aliasing the fine resolution components to baseband, as required for the subsequent charge coupled devices (CCD) processing. The raster scan mechanism incorporated into the readout of the CCD detector array is used to unfold the 2-D transform, reproducing the desired high resolution Fourier transform of the input signal.

  3. High Frequency GaAs Bulk Acousto-Optic Devices For Modulators And Frequency Shifters At 1.3um And 1.5um In Fiber-Optics

    NASA Astrophysics Data System (ADS)

    Soos, J. I.; Rosemeier, R. G.

    1989-02-01

    The edge of a transmission window for a GaAs Bragg cell starts about lum, which allows this material to be used for infrared fiber-optic applications, especially at 1.3um and 1.5um. The single crystal of GaAs is acoustically anisotropic and has the highest figure of merit, M2, along <111> direction for a longitudinal mode sound wave. Recently, Brimrose has designed and fabricated an acousto-optic modulator from GaAs operating at a carrier frequency of 2.3 GHz with a diffraction efficiency of 4%/RF watt.

  4. Acousto-optics bandwidth broadening in a Bragg cell based on arbitrary synthesized signal methods.

    PubMed

    Peled, Itay; Kaminsky, Ron; Kotler, Zvi

    2015-06-01

    In this work, we present the advantages of driving a multichannel acousto-optical deflector (AOD) with a digitally synthesized multifrequency RF signal. We demonstrate a significant bandwidth broadening of ∼40% by providing well-tuned phase control of the array transducers. Moreover, using a multifrequency, complex signal, we manage to suppress the harmonic deflections and return most of the spurious energy to the main beam. This method allows us to operate the AOD with more than an octave of bandwidth with negligible spurious energy going to the harmonic beams and a total bandwidth broadening of over 70%.

  5. Acousto-optic tunable filter spectrometers in space missions [Invited].

    PubMed

    Korablev, Oleg I; Belyaev, Denis A; Dobrolenskiy, Yuri S; Trokhimovskiy, Alexander Y; Kalinnikov, Yuri K

    2018-04-01

    Spectrometers employing acousto-optic tunable filters (AOTFs) rapidly gain popularity in space, and in particular on interplanetary missions. They allow for reducing volume, mass, and complexity of the instrumentation. To date, space operations of 11 AOTF spectrometers are reported in the literature. They were used for analyzing ocean color, greenhouse gases, atmospheres of Mars and Venus, and for lunar mineralogy. More instruments for the Moon, Mars, and asteroid mineralogy are in flight, awaiting launch, or in the state of advanced development. The AOTFs are used in point (pencil-beam) spectrometers for selecting echelle diffraction orders, or in hyper-spectral imagers and microscopes. We review the AOTF-employing devices flown in space or ready to set off. The paper considers basic principles of the AOTF and science applications of the AOTF spectrometers, and describes developed instruments in some detail. We also address some advanced developments for future missions and plans. In addition, we discuss lessons learned during instrument design, build, calibration, and exploitation, and advantages and limitations in implementing the AOTF-based systems in space instrumentation.

  6. The acousto-ultrasonic approach

    NASA Technical Reports Server (NTRS)

    Vary, Alex

    1987-01-01

    The nature and underlying rationale of the acousto-ultrasonic approach is reviewed, needed advanced signal analysis and evaluation methods suggested, and application potentials discussed. Acousto-ultrasonics is an NDE technique combining aspects of acoustic emission methodology with ultrasonic simulation of stress waves. This approach uses analysis of simulated stress waves for detecting and mapping variations of mechanical properties. Unlike most NDE, acousto-ultrasonics is less concerned with flaw detection than with the assessment of the collective effects of various flaws and material anomalies. Acousto-ultrasonics has been applied chiefly to laminated and filament-wound fiber reinforced composites. It has been used to assess the significant strength and toughness reducing effects that can be wrought by combinations of essentially minor flaws and diffuse flaw populations. Acousto-ultrasonics assesses integrated defect states and the resultant variations in properties such as tensile, shear, and flexural strengths and fracture resistance. Matrix cure state, porosity, fiber orientation, fiber volume fraction, fiber-matrix bonding, and interlaminar bond quality are underlying factors.

  7. External cavity quantum cascade lasers with ultra rapid acousto-optic tuning

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

    Lyakh, A., E-mail: alyakh@pranalytica.com; Barron-Jimenez, R.; Dunayevskiy, I.

    2015-04-06

    We report operation of tunable external cavity quantum cascade lasers with emission wavelength controlled by an acousto-optic modulator (AOM). A long-wave infrared quantum cascade laser wavelength tuned from ∼8.5 μm to ∼9.8 μm when the AOM frequency was changed from ∼41MHz to ∼49 MHz. The laser delivered over 350 mW of average power at the center of the tuning curve in a linewidth of ∼4.7 cm{sup −1}. Measured wavelength switching time between any two wavelengths within the tuning range of the QCL was less than 1 μs. Spectral measurements of infrared absorption features of Freon demonstrated a capability of obtaining complete spectral data in less thanmore » 20 μs.« less

  8. Dynamic acousto-optic control of a strongly coupled photonic molecule

    PubMed Central

    Kapfinger, Stephan; Reichert, Thorsten; Lichtmannecker, Stefan; Müller, Kai; Finley, Jonathan J.; Wixforth, Achim; Kaniber, Michael; Krenner, Hubert J.

    2015-01-01

    Strongly confined photonic modes can couple to quantum emitters and mechanical excitations. To harness the full potential in quantum photonic circuits, interactions between different constituents have to be precisely and dynamically controlled. Here, a prototypical coupled element, a photonic molecule defined in a photonic crystal membrane, is controlled by a radio frequency surface acoustic wave. The sound wave is tailored to deliberately switch on and off the bond of the photonic molecule on sub-nanosecond timescales. In time-resolved experiments, the acousto-optically controllable coupling is directly observed as clear anticrossings between the two nanophotonic modes. The coupling strength is determined directly from the experimental data. Both the time dependence of the tuning and the inter-cavity coupling strength are found to be in excellent agreement with numerical calculations. The demonstrated mechanical technique can be directly applied for dynamic quantum gate operations in state-of-the-art-coupled nanophotonic, quantum cavity electrodynamic and optomechanical systems. PMID:26436203

  9. MWIR thermal imaging spectrometer based on the acousto-optic tunable filter.

    PubMed

    Zhao, Huijie; Ji, Zheng; Jia, Guorui; Zhang, Ying; Li, Yansong; Wang, Daming

    2017-09-01

    Mid-wavelength IR (MWIR) thermal imaging spectrometers are widely used in remote sensing, industrial detection, and military applications. The acousto-optic tunable filter (AOTF)-based spectrometer has the advantages of fast tuning, light weight, and no moving parts, which make it ideally suited for MWIR applications. However, when designing an AOTF imaging spectrometer, the traditional method uses a refractive grating or parallel glass model in optical design software to simulate the AOTF, lowering the imaging performance of the optical system. In this paper, an accurate simulating model for an actual MWIR AOTF using the user-defined surface function in ZEMAX is presented, and an AOTF-based MWIR thermal imaging spectrometer is designed and tested successfully. It is based on a MWIR tellurium dioxide (TeO 2 ) AOTF with an operational spectral range from 3.0 to 5.0 μm and a spectral resolution of 30.8 nm at 3.392 μm. The optical system employs a three-mirror off-axis afocal telescope with a 2.4°×2.0° field of view. The operation of the MWIR thermal imaging spectrometer and its image acquisition are computer controlled. Furthermore, the imaging spectrometer is tested in the laboratory, and several experiments are also presented. The experimental results indicate that the proposed AOTF model is efficient, and also show that the imaging spectrometer has the ability to distinguish the real hot target from the interfering target effectively.

  10. High-contrast fast Fourier transform acousto-optical tomography of phantom tissues with a frequency-chirp modulation of the ultrasound.

    PubMed

    Forget, Benoît-Claude; Ramaz, François; Atlan, Michaël; Selb, Juliette; Boccara, Albert-Claude

    2003-03-01

    We report new results on acousto-optical tomography in phantom tissues using a frequency chirp modulation and a CCD camera. This technique allows quick recording of three-dimensional images of the optical contrast with a two-dimensional scan of the ultrasound source in a plane perpendicular to the ultrasonic path. The entire optical contrast along the ultrasonic path is concurrently obtained from the capture of a film sequence at a rate of 200 Hz. This technique reduces the acquisition time, and it enhances the axial resolution and thus the contrast, which are usually poor owing to the large volume of interaction of the ultrasound perturbation.

  11. Performance of continuous wave and acousto-optically Q-switched Tm, Ho: YAP laser pumped by diode laser

    NASA Astrophysics Data System (ADS)

    Li, Guoxing; Xie, Wenqiang; Yang, Xining; Zhang, Ziqiu; Zhang, Hongda; Zhang, Liang

    2018-02-01

    A two-end-pumped a-cut Tm(0.5%), Ho(0.5%):YAP laser output at 2119nm is reported under cryogenic temperature. The maximum output power reached to 7.76W with the incident pump power of 24.2W in CW mode. With the acousto-optically Q-switch, an average power of 7.3W can be obtained, when the pulse repetition frequency was 7.5 kHz. The corresponding optical-to-optical conversion efficiency was 30.2% and the slope efficiency was 31.4%. Then, the laser output characteristics in the repetition frequency of 7.5 kHz and 10kHz were researched. The output power, the optical-to-optical conversion efficiency and slope efficiency were increased with the increase of the repetition frequency. In the same repetition frequency, the pulse duration was decreasing with the growth of the incident pump power.

  12. Exploration of Mars in SPICAM-IR experiment onboard the Mars-Express spacecraft: 1. Acousto-optic spectrometer SPICAM-IR

    NASA Astrophysics Data System (ADS)

    Korablev, O. I.; Bertaux, J. L.; Kalinnikov, Yu. K.; Fedorova, A. A.; Moroz, V. I.; Kiselev, A. V.; Stepanov, A. V.; Grigoriev, A. V.; Zhegulev, V. S.; Rodin, A. V.; Dimarellis, E.; Dubois, J. P.; Reberac, A.; van Ransbeeck, E.; Gondet, B.

    2006-07-01

    The acousto-optic spectrometer of the near infrared range, which is a part of the spectrometer SPICAM onboard the Mars-Express spacecraft, began to operate in the orbit of Mars in January 2004. In the SPICAM experiment, a spectrometer on the basis of an acousto-optic filter was used for the first time to investigate other planets. During one and a half years of operation, the IR channel of SPICAM obtained more than half a million spectra in the 1-1.7 μm range with a resolving power of more than 1500 in different modes of observation: limb, nadir, and solar eclipses. The main goal of the experiment is to study the content of water vapor in the Martian atmosphere by measuring the absorption spectrum in the 1.38 μm band. Characteristics of the instrument (high spectral resolution and signal-to-noise ratio) allow one to solve a number of additional scientific problems including the study of ozone distribution by emission of singlet oxygen (O2 1Δg), detection of the water and carbonic dioxide ices, and also the study of the vertical distribution and optical characteristics of aerosol in the Martian atmosphere. We present a description of the instrument, the results of its ground and in-flight calibrations, and a brief survey of the basic scientific results obtained by the SPICAM spectrometer during a year-and-half of operation.

  13. Laser output power stabilization for direct laser writing system by using an acousto-optic modulator.

    PubMed

    Kim, Dong Ik; Rhee, Hyug-Gyo; Song, Jae-Bong; Lee, Yun-Woo

    2007-10-01

    We present experimental results on the output power stabilization of an Ar(+) laser for a direct laser writing system (LWS). Instability of the laser output power in the LWS cause resolution fluctuations of being fabricated diffractive optical elements or computer-generated holograms. For the purpose of reducing the power fluctuations, we have constituted a feedback loop with an acousto-optic modulator, a photodetector, and a servo controller. In this system, we have achieved the stability of +/-0.20% for 12 min and the relative intensity noise level of 2.1 x 10(-7) Hz(-12) at 100 Hz. In addition, we applied our system to a 2 mW internal mirror He-Ne laser. As a consequence, we achieved the output power stability of +/-0.12% for 25 min.

  14. Acousto-Optic Tunable Filter Spectroscopic Instrumentation for Quantitative Near-Ir Analysis of Organic Materials.

    NASA Astrophysics Data System (ADS)

    Eilert, Arnold James

    1995-01-01

    The utility of near-IR spectroscopy for routine quantitative analyses of a wide variety of compositional, chemical, or physical parameters of organic materials is well understood. It can be used for relatively fast and inexpensive non-destructive bulk material analysis before, during, and after processing. It has been demonstrated as being a particularly useful technique for numerous analytical applications in cereal (food and feed) science and industry. Further fulfillment of the potential of near-IR spectroscopic analysis, both in the process and laboratory environment, is reliant upon the development of instrumentation that is capable of meeting the challenges of increasingly difficult applications. One approach to the development of near-IR spectroscopic instrumentation that holds a great deal of promise is acousto-optic tunable filter (AOTF) technology. A combination of attributes offered by AOTF spectrometry, including speed, optical throughput, wavelength reproducibility, ruggedness (no -moving-parts operation) and flexibility, make it particularly desirable for numerous applications. A series of prototype (research model) acousto -optic tunable filter instruments were developed and tested in order to investigate the feasibility of the technology for quantitative near-IR spectrometry. Development included design, component procurement, assembly and/or configuration of the optical and electronic subsystems of which each functional spectrometer arrangement was comprised, as well as computer interfacing and acquisition/control software development. Investigation of this technology involved an evolution of several operational spectrometer systems, each of which offered improvements over its predecessor. Appropriate testing was conducted at various stages of development. Demonstrations of the potential applicability of our AOTF spectrometer to quantitative process monitoring or laboratory analysis of numerous organic substances, including food materials, were

  15. Piezo-optic and elasto-optic properties of monoclinic triglycine sulfate crystals.

    PubMed

    Mytsyk, Bogdan; Demyanyshyn, Natalya; Erba, Alessandro; Shut, Viktor; Mozzharov, Sergey; Kost, Yaroslav; Mys, Oksana; Vlokh, Rostyslav

    2017-12-01

    For the first time, to the best of our knowledge, we have experimentally determined all of the components of the piezo-optic tensor for monoclinic crystals. This has been implemented on a specific example of triglycine sulfate crystals. Based on the results obtained, the complete elasto-optic tensor has been calculated. Acousto-optic figures of merit (AOFMs) have been estimated for the case of acousto-optic interaction occurring in the principal planes of the optical indicatrix ellipsoid and for geometries in which the highest elasto-optic coefficients are involved as effective parameters. It has been found that the highest AOFM value is equal to 6.8×10 -15   s 3 /kg for the case of isotropic acousto-optic interaction with quasi-longitudinal acoustic waves in the principal planes. This AOFM is higher than the corresponding values typical for canonic acousto-optic materials, which are transparent in the deep ultraviolet spectral range.

  16. Broadly wavelength tunable acousto-optically Q-switched Tm:Lu2SiO5 laser.

    PubMed

    Feng, T; Yang, K; Zhao, S; Zhao, J; Qiao, W; Li, T; Zheng, L; Xu, J

    2014-09-20

    A broadly wavelength tunable acousto-optically Q-switched Tm:Lu2SiO5 (Tm:LSO) laser is presented for the first time, to our best knowledge. The emission wavelength was tuned in a broad spectral region over 111 nm ranging from 1959 to 2070 nm. A shortest pulse duration of 345 ns with beam quality of M(2)≤1.65 was obtained at pulse repetition frequency (PRF) of 1 kHz, corresponding to a maximum single pulse energy of 0.26 mJ and peak power of 0.75 kW. The experimental results indicated that Tm:LSO crystal has outstanding potential for obtaining broadly wavelength tunable and low-PRF laser pulses at 2 μm.

  17. Electro-optic deflectors deliver advantages over acousto-optical deflectors in a high resolution, ultra-fast force-clamp optical trap.

    PubMed

    Woody, Michael S; Capitanio, Marco; Ostap, E Michael; Goldman, Yale E

    2018-04-30

    We characterized experimental artifacts arising from the non-linear response of acousto-optical deflectors (AODs) in an ultra-fast force-clamp optical trap and have shown that using electro-optical deflectors (EODs) instead eliminates these artifacts. We give an example of the effects of these artifacts in our ultra-fast force clamp studies of the interaction of myosin with actin filaments. The experimental setup, based on the concept of Capitanio et al. [Nat. Methods 9, 1013-1019 (2012)] utilizes a bead-actin-bead dumbbell held in two force-clamped optical traps which apply a load to the dumbbell to move it at a constant velocity. When myosin binds to actin, the filament motion stops quickly as the total force from the optical traps is transferred to the actomyosin attachment. We found that in our setup, AODs were unsuitable for beam steering due to non-linear variations in beam intensity and deflection angle as a function of driving frequency, likely caused by low-amplitude standing acoustic waves in the deflectors. These aberrations caused instability in the force feedback loops leading to artifactual jumps in the trap position. We demonstrate that beam steering with EODs improves the performance of our instrument. Combining the superior beam-steering capability of the EODs, force acquisition via back-focal-plane interferometry, and dual high-speed FPGA-based feedback loops, we apply precise and constant loads to study the dynamics of interactions between actin and myosin. The same concept applies to studies of other biomolecular interactions.

  18. All-fiber tunable laser based on an acousto-optic tunable filter and a tapered fiber.

    PubMed

    Huang, Ligang; Song, Xiaobo; Chang, Pengfa; Peng, Weihua; Zhang, Wending; Gao, Feng; Bo, Fang; Zhang, Guoquan; Xu, Jingjun

    2016-04-04

    An all-fiber tunable laser was fabricated based on an acousto-optic tunable filter and a tapered fiber. The structure was of a high signal-to-noise ratio, therefore, no extra gain flattening was needed in the laser. In the experiment, the wavelength of the laser could be tuned from 1532.1 nm to 1570.4 nm with a 3-dB bandwidth of about 0.2 nm. Given enough nonlinearity in the laser cavity, it could also generate a sliding-frequency pulse train. The laser gains advantages of fast tuning and agility in pulse generation, and its simple structure is low cost for practical applications.

  19. Secure chaotic transmission of electrocardiography signals with acousto-optic modulation under profiled beam propagation.

    PubMed

    Almehmadi, Fares S; Chatterjee, Monish R

    2015-01-10

    Electrocardiography (ECG) signals are used for both medical purposes and identifying individuals. It is often necessary to encrypt this highly sensitive information before it is transmitted over any channel. A closed-loop acousto-optic hybrid device acting as a chaotic modulator is applied to ECG signals to achieve this encryption. Recently improved modeling of this approach using profiled optical beams has shown it to be very sensitive to key parameters that characterize the encryption and decryption process, exhibiting its potential for secure transmission of analog and digital signals. Here the encryption and decryption is demonstrated for ECG signals, both analog and digital versions, illustrating strong encryption without significant distortion. Performance analysis pertinent to both analog and digital transmission of the ECG waveform is also carried out using output signal-to-noise, signal-to-distortion, and bit-error-rate measures relative to the key parameters and presence of channel noise in the system.

  20. Exact solution for four-order acousto-optic Bragg diffraction with arbitrary initial conditions.

    PubMed

    Pieper, Ron; Koslover, Deborah; Poon, Ting-Chung

    2009-03-01

    An exact solution to the four-order acousto-optic (AO) Bragg diffraction problem with arbitrary initial conditions compatible with exact Bragg angle incident light is developed. The solution, obtained by solving a 4th-order differential equation, is formalized into a transition matrix operator predicting diffracted light orders at the exit of the AO cell in terms of the same diffracted light orders at the entrance. It is shown that the transition matrix is unitary and that this unitary matrix condition is sufficient to guarantee energy conservation. A comparison of analytical solutions with numerical predictions validates the formalism. Although not directly related to the approach used to obtain the solution, it was discovered that all four generated eigenvalues from the four-order AO differential matrix operator are expressed simply in terms of Euclid's Divine Proportion.

  1. Mid infra-red hyper-spectral imaging with bright super continuum source and fast acousto-optic tuneable filter for cytological applications.

    NASA Astrophysics Data System (ADS)

    Farries, Mark; Ward, Jon; Valle, Stefano; Stephens, Gary; Moselund, Peter; van der Zanden, Koen; Napier, Bruce

    2015-06-01

    Mid-IR imaging spectroscopy has the potential to offer an effective tool for early cancer diagnosis. Current development of bright super-continuum sources, narrow band acousto-optic tunable filters and fast cameras have made feasible a system that can be used for fast diagnosis of cancer in vivo at point of care. The performance of a proto system that has been developed under the Minerva project is described.

  2. Modeling-based design and assessment of an acousto-optic guided high-intensity focused ultrasound system

    PubMed Central

    Adams, Matthew T.; Cleveland, Robin O.; Roy, Ronald A.

    2017-01-01

    Abstract. Real-time acousto-optic (AO) sensing has been shown to noninvasively detect changes in ex vivo tissue optical properties during high-intensity focused ultrasound (HIFU) exposures. The technique is particularly appropriate for monitoring noncavitating lesions that offer minimal acoustic contrast. A numerical model is presented for an AO-guided HIFU system with an illumination wavelength of 1064 nm and an acoustic frequency of 1.1 MHz. To confirm the model’s accuracy, it is compared to previously published experimental data gathered during AO-guided HIFU in chicken breast. The model is used to determine an optimal design for an AO-guided HIFU system, to assess its robustness, and to predict its efficacy for the ablation of large volumes. It was found that a through transmission geometry results in the best performance, and an optical wavelength around 800 nm was optimal as it provided sufficient contrast with low absorption. Finally, it was shown that the strategy employed while treating large volumes with AO guidance has a major impact on the resulting necrotic volume and symmetry. PMID:28114454

  3. Three-dimensional spatiotemporal pulse characterization with an acousto-optic pulse shaper and a Hartmann-Shack wavefront sensor.

    PubMed

    Cousin, Seth L; Bueno, Juan M; Forget, Nicolas; Austin, Dane R; Biegert, J

    2012-08-01

    We demonstrate a simplified arrangement for spatiotemporal ultrashort pulse characterization called Hartmann-Shack assisted, multidimensional, shaper-based technique for electric-field reconstruction. It employs an acousto-optic pulse shaper in combination with a second-order nonlinear crystal and a Hartmann-Shack wavefront sensor. The shaper is used as a tunable bandpass filter, and the wavefronts and intensities of quasimonochromatic spectral slices of the pulse are obtained using the Hartmann-Shack wavefront sensor. The wavefronts and intensities of the spectral slices are related to one another using shaper-assisted frequency-resolved optical gating measurements, performed at particular points in the beam. This enables a three-dimensional reconstruction of the amplitude and phase of the pulse. We present some example pulse measurements and discuss the operating parameters of the device.

  4. Ultra-fast 3D scanning and holographic illumination in non-linear microscopy using acousto-optic deflectors

    NASA Astrophysics Data System (ADS)

    Akemann, Walther; Ventalon, Cathie; Léger, Jean-François; Mathieu, Benjamin; Dieudonné, Stéphane; Blochet, Baptiste; Gigan, Sylvain; Bourdieu, Laurent

    2017-04-01

    Decoding of information in the brain requires the imaging of large neuronal networks using e.g. two-photon microscopy (TPM). Fast control of the focus in 3D can be achieved with phase shaping of the light beam using acoustooptic deflectors (AODs). However, beam shaping using AODs is not straightforward because of non-stationary of acousto-optic diffraction. Here, we demonstrated a new stable AOD-based phase modulator, which operates at a rate of up to about hundred kHz. It provides opportunity for 3D scanning in TPM with the possibility to correct aberrations independently for every focus position or to achieve refocusing of scattered photons in rapidly decorrelating tissues.

  5. Precise Spatiotemporal Control of Optogenetic Activation Using an Acousto-Optic Device

    PubMed Central

    Guo, Yanmeng; Song, Peipei; Zhang, Xiaohui; Zeng, Shaoqun; Wang, Zuoren

    2011-01-01

    Light activation and inactivation of neurons by optogenetic techniques has emerged as an important tool for studying neural circuit function. To achieve a high resolution, new methods are being developed to selectively manipulate the activity of individual neurons. Here, we report that the combination of an acousto-optic device (AOD) and single-photon laser was used to achieve rapid and precise spatiotemporal control of light stimulation at multiple points in a neural circuit with millisecond time resolution. The performance of this system in activating ChIEF expressed on HEK 293 cells as well as cultured neurons was first evaluated, and the laser stimulation patterns were optimized. Next, the spatiotemporally selective manipulation of multiple neurons was achieved in a precise manner. Finally, we demonstrated the versatility of this high-resolution method in dissecting neural circuits both in the mouse cortical slice and the Drosophila brain in vivo. Taken together, our results show that the combination of AOD-assisted laser stimulation and optogenetic tools provides a flexible solution for manipulating neuronal activity at high efficiency and with high temporal precision. PMID:22174813

  6. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

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

    Wang, Wenbo; Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8; Department of Biomedical Engineering, University of British Columbia, KAIS 5500, 2332 Main Mall, Vancouver, British Columbia V6T 1Z4

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra.more » Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.« less

  7. Chaos control and synchronization in Bragg acousto-optic bistable systems driven by a separate chaotic system.

    PubMed

    Wang, Rong; Gao, Jin-Yue

    2005-09-01

    In this paper we propose a new scheme to achieve chaos control and synchronization in Bragg acousto-optic bistable systems. In the scheme, we use the output of one system to drive two identical chaotic systems. Using the maximal conditional Lyapunov exponent (MCLE) as the criterion, we analyze the conditions for realizing chaos synchronization. Numerical calculation shows that the two identical systems in chaos with negative MCLEs and driven by a chaotic system can go into chaotic synchronization whether or not they were in chaos initially. The two systems can go into different periodic states from chaos following an inverse period-doubling bifurcation route as well when driven by a periodic system.

  8. Pure electrical, highly-efficient and sidelobe free coherent Raman spectroscopy using acousto-optics tunable filter (AOTF)

    NASA Astrophysics Data System (ADS)

    Meng, Zhaokai; Petrov, Georgi I.; Yakovlev, Vladislav V.

    2016-02-01

    Fast and sensitive Raman spectroscopy measurements are imperative for a large number of applications in biomedical imaging, remote sensing and material characterization. Stimulated Raman spectroscopy offers a substantial improvement in the signal-to-noise ratio but is often limited to a discrete number of wavelengths. In this report, by introducing an electronically-tunable acousto-optical filter as a wavelength selector, a novel approach to a broadband stimulated Raman spectroscopy is demonstrated. The corresponding Raman shift covers the spectral range from 600 cm-1 to 4500 cm-1, sufficient for probing most vibrational Raman transitions. We validated the use of the new instrumentation to both coherent anti-Stokes scattering (CARS) and stimulated Raman scattering (SRS) spectroscopies.

  9. Spectral shaping of an all-fiber torsional acousto-optic tunable filter.

    PubMed

    Ko, Jeakwon; Lee, Kwang Jo; Kim, Byoung Yoon

    2014-12-20

    Spectral shaping of an all-fiber torsional acousto-optic (AO) tunable filter is studied. The technique is based on the axial modulation of AO coupling strength along a highly birefringent optical fiber, which is achieved by tailoring the outer diameter of the fiber along its propagation axis. Two kinds of filter spectral shaping schemes-Gaussian apodization and matched filtering with triple resonance peaks-are proposed and numerically investigated under realistic experimental conditions: at the 50-cm-long AO interaction length of the fiber and at half of the original fiber diameter as the minimum thickness of the tailored fiber section. The results show that the highest peak of sidelobe spectra in filter transmission is suppressed from 11.64% to 0.54% via Gaussian modulation of the AO coupling coefficient (κ). Matched filtering with triple resonance peaks operating with a single radio frequency signal is also achieved by cosine modulation of κ, of which the modulation period determines the spectral distance between two satellite peaks located in both wings of the main resonance peak. The splitting of two satellite peaks in the filter spectra reaches 48.2 nm while the modulation period varies from 7.7 to 50 cm. The overall peak power of two satellite resonances is calculated to be 22% of the main resonance power. The results confirm the validity and practicality of our approach, and we predict robust and stable operation of the designed all-fiber torsional AO filters.

  10. Advanced fluorescence imaging endoscopy using an acousto-optic tuneable filter

    NASA Astrophysics Data System (ADS)

    Whelan, Maurice P.; Bouhifd, Mounir; Aprahamian, Marc

    2004-07-01

    Two novel prototype instruments for in vivo fluorescence-based medical diagnostics are described. The devices are based on an acousto-optic tuneable filter (AOTF) and can be easily attached to the eyepiece of most commercially available endoscopes. The instruments developed offer significant advantages over typical fixed-filter or filter-wheel fluorescence imaging systems in terms of flexibility, performance and diagnostic potential. Any filtering center-wavelength in the range from 450 to 700 nm can be rapidly selected either by random access or sequential tuning using simple commands delivered over a PC serial interface. In addition, both filtered and unfiltered light can be imaged to facilitate the direct association of fluorescence signals with specific anatomical sites. To demonstrate the system in vivo, a study of the diagnostic potential of fluorescence imaging for pancreatitis was conducted on rats. The aim was to detect extremely low-levels of endogenous protoporphyrin IX (PpIX) that has been shown to accumulate in early-stage diseased tissue undergoing an inflammatory response. Results show clearly that the device is effective in diagnosing mild pancreatitis in rats without the necessity of administering PpIX promoting agents such as ALA. Planning of human clinical trials is currently underway to demonstrate its potential as a tool for non-invasive early diagnosis of gastroenterological diseases.

  11. Ultrafast, large-field multiphoton microscopy based on an acousto-optic deflector and a spatial light modulator.

    PubMed

    Shao, Yonghong; Qin, Wan; Liu, Honghai; Qu, Junle; Peng, Xiang; Niu, Hanben; Gao, Bruce Z

    2012-07-01

    We present an ultrafast, large-field multiphoton excitation fluorescence microscope with high lateral and axial resolutions based on a two-dimensional (2-D) acousto-optical deflector (AOD) scanner and spatial light modulator (SLM). When a phase-only SLM is used to shape the near-infrared light from a mode-locked titanium:sapphire laser into a multifocus array including the 0-order beam, a 136 μm × 136 μm field of view is achieved with a 60× objective using a 2-D AOD scanner without any mechanical scan element. The two-photon fluorescence image of a neuronal network that was obtained using this system demonstrates that our microscopy permits observation of dynamic biological events in a large field with high-temporal and -spatial resolution.

  12. Observation of orbital angular momentum transfer between acoustic and optical vortices in optical fiber.

    PubMed

    Dashti, Pedram Z; Alhassen, Fares; Lee, Henry P

    2006-02-03

    Acousto-optic interaction in optical fiber is examined from the perspective of copropagating optical and acoustic vortex modes. Calculation of the acousto-optic coupling coefficient between different optical modes leads to independent conservation of spin and orbital angular momentum of the interacting photons and phonons. We show that the orbital angular momentum of the acoustic vortex can be transferred to a circularly polarized fundamental optical mode to form a stable optical vortex in the fiber carrying orbital angular momentum. The technique provides a useful way of generating stable optical vortices in the fiber medium.

  13. Detecting Lamb waves with broad-band acousto-ultrasonic signals in composite structures

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.

    1992-01-01

    Lamb waves can be produced and detected in ceramic matrix composites (CMC) and metal matrix composites (MMC) plates using the acousto-ultrasonic configuration employing broadband transducers. Experimental dispersion curves of lowest symmetric and antisymmetric modes behave in a manner analogous to the graphite/polymer theoretical curves. In this study a basis has been established for analyzing Lamb wave velocities for characterizing composite plates. Lamb wave dispersion curves and group velocities were correlated with variations in axial stiffness and shear stiffness in MMC and CMC. For CMC, interfacial shear strength was also correlated with the first antisymmetric Lamb mode.

  14. Quantum optical rotatory dispersion

    PubMed Central

    Tischler, Nora; Krenn, Mario; Fickler, Robert; Vidal, Xavier; Zeilinger, Anton; Molina-Terriza, Gabriel

    2016-01-01

    The phenomenon of molecular optical activity manifests itself as the rotation of the plane of linear polarization when light passes through chiral media. Measurements of optical activity and its wavelength dependence, that is, optical rotatory dispersion, can reveal information about intricate properties of molecules, such as the three-dimensional arrangement of atoms comprising a molecule. Given a limited probe power, quantum metrology offers the possibility of outperforming classical measurements. This has particular appeal when samples may be damaged by high power, which is a potential concern for chiroptical studies. We present the first experiment in which multiwavelength polarization-entangled photon pairs are used to measure the optical activity and optical rotatory dispersion exhibited by a solution of chiral molecules. Our work paves the way for quantum-enhanced measurements of chirality, with potential applications in chemistry, biology, materials science, and the pharmaceutical industry. The scheme that we use for probing wavelength dependence not only allows one to surpass the information extracted per photon in a classical measurement but also can be used for more general differential measurements. PMID:27713928

  15. Faraday anomalous dispersion optical tuners

    NASA Technical Reports Server (NTRS)

    Wanninger, P.; Valdez, E. C.; Shay, T. M.

    1992-01-01

    Common methods for frequency stabilizing diode lasers systems employ gratings, etalons, optical electric double feedback, atomic resonance, and a Faraday cell with low magnetic field. Our method, the Faraday Anomalous Dispersion Optical Transmitter (FADOT) laser locking, is much simpler than other schemes. The FADOT uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. This method is vibration insensitive, thermal expansion effects are minimal, and the system has a frequency pull in range of 443.2 GHz (9A). Our technique is based on the Faraday anomalous dispersion optical filter. This method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters. We present the first theoretical model for the FADOT and compare the calculations to our experimental results.

  16. Potentials of acousto-optical spectrum analysis on a basis of a novel algorithm of the collinear wave heterodyning in a large-aperture KRS-5 crystalline cell

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Maximov, Jewgenij; Bliznetsov, Alexej M.; Sanchez Perez, Karla J.

    2011-03-01

    The technique under proposal for a precise spectrum analysis within an algorithm of the collinear wave heterodyning implies a two-stage integrated processing, namely, the wave heterodyning of a signal in a square-law nonlinear medium and then the optical processing in the same solid state cell. The technical advantage of this approach lies in providing a direct multichannel parallel processing of ultra-high-frequency radio-wave signals with essentially improved frequency resolution. This technique imposes specific requirements on the cell's material. We focus our attention on the solid solutions of thallium chalcogenides and take the TlBr-TlI (thallium bromine-thallium iodine) solution, which forms KRS-5 cubic-symmetry crystals with the mass-ratio 58% of TlBr to 42% of TlI. Analysis shows that the acousto-optical cell made of a KRS-5 crystal oriented along the [111]-axis and the corresponding longitudinal elastic mode for producing the dynamic diffractive grating can be exploited. With the acoustic velocity of about 1.92 × 105 cm/s and attenuation of ~10 dB/(cm GHz2), a similar cell is capable of providing an optical aperture of ~5.0 cm and one of the highest figures of acousto-optical merit in solid states in the visible range. Such a cell is rather desirable for the application to direct 5000-channel parallel spectrum analysis with an improved up to 10-5 relative frequency resolution.

  17. Optical Signal Processing

    DTIC Science & Technology

    1990-02-28

    domain; we therefore conclude that um dioxide ( TeO2 ) is used in a slow shear wave mode; in this case we might have W - 50 MHz and T - 40 As d (4) I so...8 and L = 5.1 mm. fiber-to-fiber coupling loss and inefficiency in The acousto-optic cell is made from flint glass and has acousto-optic diffraction...The mode mismatch loss can be estimated using well-known optical fiber splice Flint glass I loss theory; reflection and restricted-aperture related

  18. Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Huber, Robert D.; Green, Robert E., Jr.

    1990-01-01

    The acousto-ultrasonic method has proven to be a most interesting technique for nondestructive evaluation of the mechanical properties of a variety of materials. Use of the technique or a modification thereof, has led to correlation of the associated stress wave factor with mechanical properties of both metals and composite materials. The method is applied to the nondestructive evaluation of selected fiber reinforced structural composites. For the first time, conventional piezoelectric transducers were replaced with laser beam ultrasonic generators and detectors. This modification permitted true non-contact acousto-ultrasonic measurements to be made, which yielded new information about the basic mechanisms involved as well as proved the feasibility of making such non-contact measurements on terrestrial and space structures and heat engine components. A state-of-the-art laser based acousto-ultrasonic system, incorporating a compact pulsed laser and a fiber-optic heterodyne interferometer, was delivered to the NASA Lewis Research Center.

  19. Tuning group-velocity dispersion by optical force.

    PubMed

    Jiang, Wei C; Lin, Qiang

    2013-07-15

    We propose an optomechanical approach for dispersion dynamic tuning and microengineering by taking advantage of the optical force in nano-optomechanical structures. Simulations of a suspended coupled silicon waveguide show that the zero-dispersion wavelength can be tuned by 40 nm by an optical pump power of 3 mW. Our approach exhibits great potential for broad applications in dispersion-sensitive processes, which not only offers a new root toward versatile tunable nonlinear photonics but may also open up a great avenue toward a new regime of nonlinear dynamics coupling between nonlinear optical and optomechanical effects.

  20. Faraday anomalous dispersion optical filters

    NASA Technical Reports Server (NTRS)

    Shay, T. M.; Yin, B.

    1992-01-01

    The present calculations of the performance of Faraday anomalous dispersion optical filters (FADOF) on IR transitions indicate that such filters may furnish high transmission, narrow-pass bandwidth, and low equivalent noise bandwidth under optimum operating conditions. A FADOF consists of an atomic vapor cell between crossed polarizers that are subject to a dc magnetic field along the optical path; when linearly polarized light travels along the direction of the magnetic field through the dispersive atomic vapor, a polarization rotation occurs. If FADOF conditions are suitably adjusted, a maximum transmission with very narrow bandwidth is obtained.

  1. Field-programmable logic devices with optical input-output.

    PubMed

    Szymanski, T H; Saint-Laurent, M; Tyan, V; Au, A; Supmonchai, B

    2000-02-10

    A field-programmable logic device (FPLD) with optical I/O is described. FPLD's with optical I/O can have their functionality specified in the field by means of downloading a control-bit stream and can be used in a wide range of applications, such as optical signal processing, optical image processing, and optical interconnects. Our device implements six state-of-the-art dynamically programmable logic arrays (PLA's) on a 2 mm x 2 mm die. The devices were fabricated through the Lucent Technologies-Advanced Research Projects Agency-Consortium for Optical and Optoelectronic Technologies in Computing (Lucent/ARPA/COOP) workshop by use of 0.5-microm complementary metal-oxide semiconductor-self-electro-optic device technology and were delivered in 1998. All devices are fully functional: The electronic data paths have been verified at 200 MHz, and optical tests are pending. The device has been programmed to implement a two-stage optical switching network with six 4 x 4 crossbar switches, which can realize more than 190 x 10(6) unique programmable input-output permutations. The same device scaled to a 2 cm x 2 cm substrate could support as many as 4000 optical I/O and 1 Tbit/s of optical I/O bandwidth and offer fully programmable digital functionality with approximately 110,000 programmable logic gates. The proposed optoelectronic FPLD is also ideally suited to realizing dense, statically reconfigurable crossbar switches. We describe an attractive application area for such devices: a rearrangeable three-stage optical switch for a wide-area-network backbone, switching 1000 traffic streams at the OC-48 data rate and supporting several terabits of traffic.

  2. Analysis of Non-contact Acousto Thermal Signature Data (Postprint)

    DTIC Science & Technology

    2016-02-01

    AFRL-RX-WP-JA-2016-0321 ANALYSIS OF NON- CONTACT ACOUSTO-THERMAL SIGNATURE DATA (POSTPRINT) Amanda K. Criner AFRL/RX...October 2014 – 16 September 2015 4. TITLE AND SUBTITLE ANALYSIS OF NON- CONTACT ACOUSTO-THERMAL SIGNATURE DATA (POSTPRINT) 5a. CONTRACT NUMBER...words) The non- contact acousto-thermal signature (NCATS) is a nondestructive evaluation technique with potential to detect fatigue in materials such as

  3. Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection

    NASA Technical Reports Server (NTRS)

    Huber, Robert D.; Green, Robert E., Jr.; Vary, Alex; Kautz, Harold

    1990-01-01

    Presented in viewgraph format, the possibility of using laser generation and detection of ultrasound to replace piezoelectric transducers for the acousto-ultrasonic technique is advanced. The advantages and disadvantages of laser acousto-ultrasonics are outlined. Laser acousto-ultrasonics complements standard piezoelectric acousto-ultrasonics and offers non-contact nondestructive evaluation.

  4. Continuous-wave and acousto-optically Q-switched 1066 nm laser performance of a novel Nd:GdTaO4 crystal

    NASA Astrophysics Data System (ADS)

    Ma, Yufei; He, Ying; Peng, Zhenfang; Sun, Haiyue; Peng, Fang; Yan, Renpeng; Li, Xudong; Yu, Xin; Zhang, Qingli; Ding, Shoujun

    2018-05-01

    A diode-pumped acousto-optically (AO) Q-switched 1066 nm laser with a novel Nd:GdTaO4 crystal was demonstrated for the first time to the best of our knowledge. The optimization selection of output coupler was carried out in the continuous-wave (CW) operation. After that the pulsed Nd:GdTaO4 laser performances using different modulation repetition rates of 10 kHz and 20 kHz were investigated. At an absorbed pump power of 10 W and repetition rates of 10 kHz, the obtained minimum pulse width was 28 ns and the maximum peak power was 5.4 kW.

  5. Simultaneous and co-localized acousto-optic measurements of spectral and temporal properties of diffusive media

    NASA Astrophysics Data System (ADS)

    Balberg, Michal; Shechter, Revital; Girshovitz, Pinhas; Breskin, Ilan; Fantini, Sergio

    2017-02-01

    Acousto-optic (AO) modulation of light is used to extract both temporal and spectral information of diffusive media such as biological tissue, where they provide measures of blood flow and oxygen saturation of hemoglobin, respectively. The temporal information is extracted from the width of the power spectrum of the light intensity, whereas the spectral information is calculated from the spatial decay of the cross correlation between the light intensity and the generated ultrasonic signal. The ultrasonic signal is a coded phase modulated signal with a narrow autocorrelation, enabling localization of the measurement volume. Two different liquid phantoms are used, with similar scattering but different absorption properties. The difference in absorption calculated with the AO signal is compared to calculations based on the modified Beer Lambert law. As the same AO signal is used to extract both modalities, it might be used to extract hemodynamic related changes in the brain for diagnostic and functional assessment.

  6. Acousto-optic devices for operation with 2μm fibre lasers

    NASA Astrophysics Data System (ADS)

    Ward, J. D.; Stevens, G.; Shardlow, P. C.

    2016-03-01

    Fibre lasers operating in the 2μm region are of increasing interest for a range of applications, including laser machining and biomedical systems. The large mode area compared to 1μm fibre lasers combined with operation in an "eye-safe" region of the spectrum makes them particularly attractive. When developing fibre lasers at 1μm and 1·5μm manufacturers were able to call upon enabling technologies used by the telecoms industry, but at longer wavelengths, including 2μm, many such components are either unavailable or immature. We report on recent developments of Acousto-Optic Modulators and Tunable Filters that are specifically optimised for use with fibre systems operating at or around 2μm. AO devices are interesting due to their ability to conserve spatial-coherence, making them appropriate for use with single-mode optical fibres. We describe how the choice of interaction medium is an important consideration, particularly affecting the drive power and the polarisation behaviour of the device - the latter being an important parameter when used in a fibre system. We also describe two designs of AO Tunable Filter intended for laser tuning. Both designs have been demonstrated intracavity in 2μm fibre lasers. The first gives exceptionally narrow resolution (δλ/λ<0·1%). The second design is of a novel type of AOTF where a matched pair of AOTFs is configured to give a substantially net zero frequency-shift with little or no loss of pointing stability, any minor deviations in manufacture being self-compensated. Furthermore, small controlled frequency-shifts (up to about 10kHz) may be introduced with little or no detriment to the alignment of the system.

  7. Spectra analysis of nonuniform FBG-based acousto-optic modulator by using Fourier mode coupling theory.

    PubMed

    Liu, Chao; Pei, Li; Li, Zhuoxuan; Ning, Tigang; Yu, Shaowei; Kang, Zexin

    2013-05-10

    Fourier mode coupling theory was first employed in the spectral analysis of several nonuniform fiber Bragg grating (FBG)-based acousto-optic modulators (NU-FBG-AOMs) with the effects of Gaussian-apodization (GA), phase shift (PS), and linear chirp (LC). Because of the accuracy and simplicity of the algorithm applied in this model, the modulation performances of these modulators can be acquired effectively and efficiently. Based on the model, the reflected spectra of these modulators were simulated under various acoustic frequencies and acoustically induced strains. The simulation results of the GA-FBG-AOM and PS-FBG-AOM showed that the wavelength spacing between the primary reflection peak and the secondary reflection peak is proportional to the acoustic frequency, and the reflectivity of reflection peaks depends on the acoustically induced strains. But for the LC-FBG-AOM, the wavelength spacing between the neighboring reflection peaks increased linearly and inversely with the acoustic frequency, and the extinction ratio of each peak relates to the acoustically induced strain. These numerical analysis results, which were effectively used in the designs and fabrications of these NU-FBG-AOMs, can broaden the AOM-based application scope and shed light on the performance optimization of optical wavelength-division multiplex system.

  8. Carrier-envelope phase stabilization and control using a transmission grating compressor and an AOPDF.

    PubMed

    Canova, Lorenzo; Chen, Xiaowei; Trisorio, Alexandre; Jullien, Aurélie; Assion, Andreas; Tempea, Gabriel; Forget, Nicolas; Oksenhendler, Thomas; Lopez-Martens, Rodrigo

    2009-05-01

    Carrier-envelope phase (CEP) stabilization of a femtosecond chirped-pulse amplification system featuring a compact transmission grating compressor is demonstrated. The system includes two amplification stages and routinely generates phase-stable (approximately 250 mrad rms) 2 mJ, 25 fs pulses at 1 kHz. Minimizing the optical pathway in the compressor enables phase stabilization without feedback control of the grating separation or beam pointing. We also demonstrate for the first time to the best of our knowledge, out-of-loop control of the CEP using an acousto-optic programmable dispersive filter inside the laser chain.

  9. Monitoring synaptic and neuronal activity in 3D with synthetic and genetic indicators using a compact acousto-optic lens two-photon microscope☆

    PubMed Central

    Fernández-Alfonso, Tomás; Nadella, K.M. Naga Srinivas; Iacaruso, M. Florencia; Pichler, Bruno; Roš, Hana; Kirkby, Paul A.; Silver, R. Angus

    2014-01-01

    Background Two-photon microscopy is widely used to study brain function, but conventional microscopes are too slow to capture the timing of neuronal signalling and imaging is restricted to one plane. Recent development of acousto-optic-deflector-based random access functional imaging has improved the temporal resolution, but the utility of these technologies for mapping 3D synaptic activity patterns and their performance at the excitation wavelengths required to image genetically encoded indicators have not been investigated. New method Here, we have used a compact acousto-optic lens (AOL) two-photon microscope to make high speed [Ca2+] measurements from spines and dendrites distributed in 3D with different excitation wavelengths (800–920 nm). Results We show simultaneous monitoring of activity from many synaptic inputs distributed over the 3D arborisation of a neuronal dendrite using both synthetic as well as genetically encoded indicators. We confirm the utility of AOL-based imaging for fast in vivo recordings by measuring, simultaneously, visually evoked responses in 100 neurons distributed over a 150 μm focal depth range. Moreover, we explore ways to improve the measurement of timing of neuronal activation by choosing specific regions within the cell soma. Comparison with existing methods These results establish that AOL-based 3D random access two-photon microscopy has a wider range of neuroscience applications than previously shown. Conclusions Our findings show that the compact AOL microscope design has the speed, spatial resolution, sensitivity and wavelength flexibility to measure 3D patterns of synaptic and neuronal activity on individual trials. PMID:24200507

  10. Depth discrimination in acousto-optic cerebral blood flow measurement simulation

    NASA Astrophysics Data System (ADS)

    Tsalach, A.; Schiffer, Z.; Ratner, E.; Breskin, I.; Zeitak, R.; Shechter, R.; Balberg, M.

    2016-03-01

    Monitoring cerebral blood flow (CBF) is crucial, as inadequate perfusion, even for relatively short periods of time, may lead to brain damage or even death. Thus, significant research efforts are directed at developing reliable monitoring tools that will enable continuous, bed side, simple and cost-effective monitoring of CBF. All existing non invasive bed side monitoring methods, which are mostly NIRS based, such as Laser Doppler or DCS, tend to underestimate CBF in adults, due to the indefinite effect of extra-cerebral tissues on the obtained signal. If those are to find place in day to day clinical practice, the contribution of extra-cerebral tissues must be eliminated and data from the depth (brain) should be extracted and discriminated. Recently, a novel technique, based on ultrasound modulation of light was developed for non-invasive, continuous CBF monitoring (termed ultrasound-tagged light (UTL or UT-NIRS)), and shown to correlate with readings of 133Xe SPECT and laser Doppler. We have assembled a comprehensive computerized simulation, modeling this acousto-optic technique in a highly scattering media. Using the combination of light and ultrasound, we show how depth information may be extracted, thus distinguishing between flow patterns taking place at different depths. Our algorithm, based on the analysis of light modulated by ultrasound, is presented and examined in a computerized simulation. Distinct depth discrimination ability is presented, suggesting that using such method one can effectively nullify the extra-cerebral tissues influence on the obtained signals, and specifically extract cerebral flow data.

  11. Thermo-acousto-photonics for noncontact temperature measurement in silicon wafer processing

    NASA Astrophysics Data System (ADS)

    Suh, Chii-Der S.; Rabroker, G. Andrew; Chona, Ravinder; Burger, Christian P.

    1999-10-01

    A non-contact thermometry technique has been developed to characterize the thermal state of silicon wafers during rapid thermal processing. Information on thermal variations is obtained from the dispersion relations of the propagating waveguide mode excited in wafers using a non-contact, broadband optical system referred to as Thermal Acousto- Photonics for Non-Destructive Evaluation. Variations of thermo-mechanical properties in silicon wafers are correlated to temperature changes by performing simultaneous time-frequency analyses on Lamb waveforms acquired with a fiber-tip interferometer sensor. Experimental Lamb wave data collected for cases ranging from room temperature to 400 degrees C is presented. The results show that the temporal progressions of all spectral elements found in the fundamental antisymmetric mode are strong functions of temperature. This particular attribute is exploited to achieve a thermal resolution superior to the +/- 5 degrees C attainable through current pyrometric techniques. By analyzing the temperature-dependent group velocity of a specific frequency component over the temperature range considered and then comparing the results to an analytical model developed for silicon wafers undergoing annealing, excellent agreement was obtained. Presented results demonstrate the feasibility of applying laser-induced stress waves as a temperature diagnostic during rapid thermal processing.

  12. Voltage-programmable liquid optical interface

    NASA Astrophysics Data System (ADS)

    Brown, C. V.; Wells, G. G.; Newton, M. I.; McHale, G.

    2009-07-01

    Recently, there has been intense interest in photonic devices based on microfluidics, including displays and refractive tunable microlenses and optical beamsteerers that work using the principle of electrowetting. Here, we report a novel approach to optical devices in which static wrinkles are produced at the surface of a thin film of oil as a result of dielectrophoretic forces. We have demonstrated this voltage-programmable surface wrinkling effect in periodic devices with pitch lengths of between 20 and 240 µm and with response times of less than 40 µs. By a careful choice of oils, it is possible to optimize either for high-amplitude sinusoidal wrinkles at micrometre-scale pitches or more complex non-sinusoidal profiles with higher Fourier components at longer pitches. This opens up the possibility of developing rapidly responsive voltage-programmable, polarization-insensitive transmission and reflection diffraction devices and arbitrary surface profile optical devices.

  13. Dispersion and dispersion slope compensation impact on high channel bit rate optical signal transmission degradation

    NASA Astrophysics Data System (ADS)

    Hamidine, Mahamadou; Yuan, Xiuhua

    2011-11-01

    In this article a numerical simulation is carried out on a single channel optical transmission system with channel bit rate greater than 40 Gb/s to investigate optical signal degradation due to the impact of dispersion and dispersion slope of both transmitting and dispersion compensating fibers. By independently varying the input signal power and the dispersion slope of both transmitting and dispersion compensating fibers of an optical link utilizing a channel bit rate of 86 Gb/s, a good quality factor (Q factor) is obtained with a dispersion slope compensation ratio change of +/-10% for a faithful transmission. With this ratio change a minimum Q factor of 16 dB is obtained in the presence of amplifier noise figure of 5 dB and fiber nonlinearities effects at input signal power of 5 dBm and 3 spans of 100 km standard single mode fiber with a dispersion (D) value of 17 ps/nm.km.

  14. Generalized dispersive wave emission in nonlinear fiber optics.

    PubMed

    Webb, K E; Xu, Y Q; Erkintalo, M; Murdoch, S G

    2013-01-15

    We show that the emission of dispersive waves in nonlinear fiber optics is not limited to soliton-like pulses propagating in the anomalous dispersion regime. We demonstrate, both numerically and experimentally, that pulses propagating in the normal dispersion regime can excite resonant dispersive radiation across the zero-dispersion wavelength into the anomalous regime.

  15. A modeling-based assessment of acousto-optic sensing for monitoring high-intensity focused ultrasound lesion formation

    NASA Astrophysics Data System (ADS)

    Adams, Matthew Tyler

    Real-time acousto-optic (AO) sensing---a dual-wave modality that combines ultrasound with diffuse light to probe the optical properties of turbid media---has been demonstrated to non-invasively detect changes in ex vivo tissue optical properties during high-intensity focused ultrasound (HIFU) exposure. The AO signal indicates the onset of lesion formation and predicts resulting lesion volumes. Although proof-of-concept experiments have been successful, many of the underlying parameters and mechanisms affecting thermally induced optical property changes and the AO detectability of HIFU lesion formation are not well understood. In thesis, a numerical simulation was developed to model the AO sensing process and capture the relevant acoustic, thermal, and optical transport processes. The simulation required data that described how optical properties changed with heating. Experiments were carried out where excised chicken breast was exposed to thermal bath heating and changes in the optical absorption and scattering spectra (500 nm--1100 nm) were measured using a scanning spectrophotometer and an integrating sphere assembly. Results showed that the standard thermal dose model currently used for guiding HIFU treatments needs to be adjusted to describe thermally induced optical property changes. To model the entire AO process, coupled models were used for ultrasound propagation, tissue heating, and diffusive light transport. The angular spectrum method was used to model the acoustic field from the HIFU source. Spatial-temporal temperature elevations induced by the absorption of ultrasound were modeled using a finite-difference time-domain solution to the Pennes bioheat equation. The thermal dose model was then used to determine optical properties based on the temperature history. The diffuse optical field in the tissue was then calculated using a GPU-accelerated Monte Carlo algorithm, which accounted for light-sound interactions and AO signal detection. The simulation was

  16. Post-Flight Test Results of Acousto-Optic Modulator Devices Subjected to Space Exposure

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.; Trivedi, Sudhir; Rosemeier, Jolanta; Diestler, Mark

    2014-01-01

    The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. MISSE missions provide an opportunity for developing space qualifiable materials. Several laser and lidar components were sent by NASA Langley Research Center (LaRC) as a part of the MISSE 7 mission. The MISSE 7 module was transported to the international space station (ISS) via STS 129 mission that was launched on Nov 16, 2009. Later, the MISSE 7 module was brought back to the earth via the STS 134 that landed on June 1, 2011. The MISSE 7 module that was subjected to exposure in a space environment for more than one and a half years included fiber laser, solid-state laser gain materials, detectors, and semiconductor laser diode. Performance testing of these components is now progressing. In this paper, the results of performance testing of a laser diode module sent by NASA Langley Research Center on MISSE 7 mission will be discussed. This paper will present the comparison of pre-flight and post-flight performance of two different COTS acousto-optic modulator (AOM) devices. Post-flight measurements indicate that these two devices did not undergo any significant performance degradation.

  17. Post-flight test results of acousto-optic modulator devices subjected to space exposure

    NASA Astrophysics Data System (ADS)

    Prasad, Narasimha S.; Trivedi, Sudhir; Rosemeier, Jolanta; Diestler, Mark

    2014-09-01

    The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. MISSE missions provide an opportunity for developing space qualifiable materials. Several laser and lidar components were sent by NASA Langley Research Center (LaRC) as a part of the MISSE 7 mission. The MISSE 7 module was transported to the international space station (ISS) via STS 129 mission that was launched on Nov 16, 2009. Later, the MISSE 7 modulewas brought back to the earth via the STS 134 that landed on June 1, 2011. The MISSE 7 module that was subjected to exposure in space environment for more than one and a half year included fiber laser, solid-state laser gain materials, detectors, and semiconductor laser diode. Performance testing of these components is now progressing. In this paper, the results of performance testing of a laser diode module sent by NASA Langley Research Center on MISSE 7 mission will be discussed. This paper will present the comparison of pre-flight and post-flight performance of two different COTS acousto-optic modulator devices. Post-flight measurements indicate that these two devices did not undergo any significant performance degradation.

  18. Detecting Lamb waves with broadband acousto-ultrasonic signals in composite structures

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.

    1992-01-01

    Lamb waves can be produced and detected in ceramic matrix composites (CMC) and metal matrix composites (MMC) plates using the acousto-ultrasonic configuration employing broadband transducers. Experimental dispersion curves of lowest symmetric and lowest antisymmetric modes behave in a manner analogous to the graphite/polymer theoretical curves. In this study a basis has been established for analyzing Lamb wave velocities for characterizing composite plates. Lamb wave disperison curves and group velocities were correlated with variations in axial stiffness and shear stiffness in MMC and CMC. For CMCs, interfacial shear strength was also correlated with the first antisymmetric Lamb mode.

  19. Feasibility of Dual Optics/Ultrasound Imaging and Contrast Media for the Detection and Characterization of Prostate Cancer

    DTIC Science & Technology

    2009-03-01

    acousto - optic effect will be used to only modulate light (at the ultrasound frequency) which propagates through a small ultrasound focal zone. This...DOD Idea Development Award is concerned with the development of a novel acousto - optic detection idea based on quadrature measurements with a gain...perform acousto - optic molecular imaging of prostate cancer with incoherent photons using endogenous contrast, e.g. hypoxia, and with fluorescent probes and microbubbles for increased specificity and signal enhancement.

  20. Optical Sensing Device Containing Fiber Bragg Gratings

    DTIC Science & Technology

    2000-08-01

    Fabry - Perot (SFP) filter-based interrogation (Kersey et al. Opt. Lett.. 18, 1370-2. 1993), tunable acousto-optic filter inteiTOgation (Geiger et al...a tunable Fabry - Perot filter, and a tunable acousto-optical filter. Alternatively, scanning filter 28 can be omitted in device 10 of the present...invention when broadband light source 20 is a tunable broadband light source. More preferably, scanning filter 28 is a tunable Fabry - Perot filter

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

    NASA Technical Reports Server (NTRS)

    1963-01-01

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

  2. Investigation on dispersion in the active optical waveguide resonator

    NASA Astrophysics Data System (ADS)

    Qiu, Zihan; Gao, Yining; Xie, Wei

    2018-03-01

    Introducing active gain in the optical waveguide resonator not only compensates the loss, but also can change the dispersion relationship in the ring resonator. It is demonstrated that the group delay time is negative when the resonator is in the undercoupled condition, which also means the resonator exhibits the fast light effect. Theoretical analysis indicates that fast light effect due to anomalous dispersion, would be manipulated by the gain coefficient controlled by the input pump light power and that fast light would enhance scale factor of the optical resonant gyroscope. Resonance optical gyroscope (ROG)'s scale factor for measuring rotation rate is enhanced by anomalous dispersion with superluminal light propagation. The sensitivity of ROG could be enhanced by anomalous dispersion by coupled resonators even considering the effect of anomalous dispersion and propagation gain on broadened linewidth, and this could result in at least two orders of magnitude enhancement in sensitivity.

  3. Optical Channelizer Evaluation Using Empirical Data and Simulation

    NASA Technical Reports Server (NTRS)

    Ivancic,William D.

    1998-01-01

    Westinghouse Electric Corporation Division under NASA contract NAS3-25865 developed a proof-of-concept (POC) multichannel demultiplexer implemented as an acousto-optic radiofrequency (RF) with a spectrum analyzer. A detailed analysis of the experimental results indicate that the expected degradation caused by the acousto-optical channelizer is approximately 2.0 dB degradation at 10(exp -5) bit-error rate (BER) and 3.0 dB degradation at 10(exp -8) BER. This degradation may be quite acceptable when considering the excellent volume, mass, and power characteristics of acousto-optical channelizing relative to other technologies. In addition, system performance can be greatly improved by using digital pulse shaping in the modem and increasing the channel spacing from 40 to 45 kHz for 64 kbps quadrature phase-shift keying (QPSK) modulation.

  4. A potassium Faraday anomalous dispersion optical filter

    NASA Technical Reports Server (NTRS)

    Yin, B.; Shay, T. M.

    1992-01-01

    The characteristics of a potassium Faraday anomalous dispersion optical filter operating on the blue and near infrared transitions are calculated. The results show that the filter can be designed to provide high transmission, very narrow pass bandwidth, and low equivalent noise bandwidth. The Faraday anomalous dispersion optical filter (FADOF) provides a narrow pass bandwidth (about GHz) optical filter for laser communications, remote sensing, and lidar. The general theoretical model for the FADOF has been established in our previous paper. In this paper, we have identified the optimum operational conditions for a potassium FADOF operating on the blue and infrared transitions. The signal transmission, bandwidth, and equivalent noise bandwidth (ENBW) are also calculated.

  5. Advanced instrumentation for acousto-ultrasonic based structural health monitoring

    NASA Astrophysics Data System (ADS)

    Smithard, Joel; Galea, Steve; van der Velden, Stephen; Powlesland, Ian; Jung, George; Rajic, Nik

    2016-04-01

    Structural health monitoring (SHM) systems using structurally-integrated sensors potentially allow the ability to inspect for damage in aircraft structures on-demand and could provide a basis for the development of condition-based maintenance approaches for airframes. These systems potentially offer both substantial cost savings and performance improvements over conventional nondestructive inspection (NDI). Acousto-ultrasonics (AU), using structurallyintegrated piezoelectric transducers, offers a promising basis for broad-field damage detection in aircraft structures. For these systems to be successfully applied in the field the hardware for AU excitation and interrogation needs to be easy to use, compact, portable, light and, electrically and mechanically robust. Highly flexible and inexpensive instrumentation for basic background laboratory investigations is also required to allow researchers to tackle the numerous scientific and engineering issues associated with AU based SHM. The Australian Defence Science and Technology Group (DST Group) has developed the Acousto Ultrasonic Structural health monitoring Array Module (AUSAM+), a compact device for AU excitation and interrogation. The module, which has the footprint of a typical current generation smart phone, provides autonomous control of four send and receive piezoelectric elements, which can operate in pitch-catch or pulse-echo modes and can undertake electro-mechanical impedance measurements for transducer and structural diagnostics. Modules are designed to operate synchronously with other units, via an optical link, to accommodate larger transducer arrays. The module also caters for fibre optic sensing of acoustic waves with four intensity-based optical inputs. Temperature and electrical resistance strain gauge inputs as well as external triggering functionality are also provided. The development of a Matlab hardware object allows users to easily access the full hardware functionality of the device and

  6. Design specification of an acousto-optic spectrum analyzer that could be used as an auxiliary receiver for CANEWS

    NASA Astrophysics Data System (ADS)

    Studenny, John; Johnstone, Eric

    1991-01-01

    The acousto-optic spectrum analyzer has undergone a theoretical design review and a basic parameter tradeoff analysis has been performed. The main conclusion is that for the given scenario of a 55 dB dynamic range and for a one-second temporal resolution, a 3.9 MHz resolution is a reasonable compromise with respect to current technology. Additional configurations are suggested. Noise testing of the signal detection processor algorithm was conducted. Additive white Gaussian noise was introduced to pure data. As expected, the tradeoff was between algorithm sensitivity and false alarms. No additional algorithm improvements could be made. The algorithm was observed to be robust, provided that the noise floor was set at a proper level. The digitization scheme was mainly driven by hardware constraints. To implement an analog to digital conversion scheme that linearly covers a 55 dB dynamic range would require a minimum of 17 bits. The general consensus was that 17 bits would be untenable for very large scale integration.

  7. Bubble-on-fiber (BoF): a built-in tunable broadband acousto-optic sensor for liquid-immersible in situ measurements.

    PubMed

    Xu, Hongsong; Wang, Guanyu; Ma, Jun; Jin, Long; Oh, Kyunghwan; Guan, Bai-Ou

    2018-04-30

    A new type of tunable broadband fiber-optic acousto-optic sensor was experimentally demonstrated by utilizing a bubble-on-fiber (BoF) interferometer. A single micro-bubble was generated by injecting a heating laser at λ = 980 nm on the metalized facet of an optical fiber. The BoF formed a spherical micro-cavity in water whose acoustic deformation was precisely detected by using a narrowband DFB laser at 1550 nm. The heating light and the interrogating light were fed into a single fiber probe by wavelength division multiplexing (WDM) realizing a small footprint all-fiber configuration. The diameter of the BoF was stabilized with a variation less than 0.5 nm by fast servo-control of the heating laser power. The stabilized BoF served as a Fabry-Pérot cavity that can be deformed by acoustic perturbation, and a minimum detectable pressure level of as low as ~1 mPa/Hz 1/2 was achieved in a frequency range of over 60 kHz in water at room temperature. Our proposed BoF technology can provide a tunable, flexible and all-fiber solution to detect minute acoustically driven perturbations combining high-precision interferometry. Due to the very small form-factor, the technique can find applications of liquid-immersible in situ measurements in bio-molecular/cell detection and biochemical phenomena study.

  8. SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Semiconductor-laser Fourier processors of electric signals

    NASA Astrophysics Data System (ADS)

    Blok, A. S.; Bukhenskii, A. F.; Krupitskii, É. I.; Morozov, S. V.; Pelevin, V. Yu; Sergeenko, T. N.; Yakovlev, V. I.

    1995-10-01

    An investigation is reported of acousto-optical and fibre-optic Fourier processors of electric signals, based on semiconductor lasers. A description is given of practical acousto-optical processors with an analysis band 120 MHz wide, a resolution of 200 kHz, and 7 cm × 8 cm × 18 cm dimensions. Fibre-optic Fourier processors are considered: they represent a new class of devices which are promising for the processing of gigahertz signals.

  9. Construction, alignment, and implementation of an acousto-optical deflector-based system for patterned uncaging with ultraviolet light.

    PubMed

    Civillico, Eugene F; Shoham, Shy; O'Connor, Daniel H; Sarkisov, Dmitry V; Wang, Samuel S-H

    2012-08-01

    The method of patterned photoactivation is a natural fit for the study of neuronal dendritic integration. Photoactivatable molecules that influence a wide range of extracellular and intracellular neurophysiological functions are available. The choice of photosensitive molecules depends on the research question and will influence the design of the experimental apparatus. An acousto-optical deflector (AOD)-based system can be used for rapid ultraviolet (UV) photolysis in arbitrary spatial and temporal patterns. Photolysis-activated "caged" diffusible molecules or newer light-sensitive membrane proteins can be used in this system. This protocol describes the addition of a UV beam for uncaging to a homebuilt two-photon microscope. The goal is to get UV light from the light source (laser) to the approximate center of the objective's back aperture, passing through a pair of perpendicularly oriented AODs along the way. The protocol also describes the fine alignment of the UV beam and the implementation of AOD-based beam steering. Performing the final alignment with the beam passing through the AODs will ensure that the system is optimized for the idiosyncrasies of the crystals.

  10. Spectral characterization of near-infrared acousto-optic tunable filter (AOTF) hyperspectral imaging systems using standard calibration materials.

    PubMed

    Bürmen, Miran; Pernuš, Franjo; Likar, Boštjan

    2011-04-01

    In this study, we propose and evaluate a method for spectral characterization of acousto-optic tunable filter (AOTF) hyperspectral imaging systems in the near-infrared (NIR) spectral region from 900 nm to 1700 nm. The proposed spectral characterization method is based on the SRM-2035 standard reference material, exhibiting distinct spectral features, which enables robust non-rigid matching of the acquired and reference spectra. The matching is performed by simultaneously optimizing the parameters of the AOTF tuning curve, spectral resolution, baseline, and multiplicative effects. In this way, the tuning curve (frequency-wavelength characteristics) and the corresponding spectral resolution of the AOTF hyperspectral imaging system can be characterized simultaneously. Also, the method enables simple spectral characterization of the entire imaging plane of hyperspectral imaging systems. The results indicate that the method is accurate and efficient and can easily be integrated with systems operating in diffuse reflection or transmission modes. Therefore, the proposed method is suitable for characterization, calibration, or validation of AOTF hyperspectral imaging systems. © 2011 Society for Applied Spectroscopy

  11. Improved Measurement of Dispersion in an Optical Fiber

    NASA Technical Reports Server (NTRS)

    Huang, Shouhua; Le, Thanh; Maleki, Lute

    2004-01-01

    An improved method of measuring chromatic dispersion in an optical fiber or other device affords a lower (relative to prior such methods) limit of measurable dispersion. This method is a modified version of the amplitude-modulation (AM) method, which is one of the prior methods. In comparison with the other prior methods, the AM method is less complex. However, the AM method is limited to dispersion levels . 160 ps/nm and cannot be used to measure the symbol of the dispersion. In contrast, the present modified version of the AM method can be used to measure the symbol of the symbol of the dispersion and affords a measurement range from about 2 ps/nm to several thousand ps/nm with a resolution of 0.27 ps/nm or finer. The figure schematically depicts the measurement apparatus. The source of light for the measurement is a laser, the wavelength of which is monitored by an optical spectrum analyzer. A light-component analyzer amplitude-modulates the light with a scanning radio-frequency signal. The modulated light is passed through a buffer (described below) and through the device under test (e.g., an optical fiber, the dispersion of which one seeks to measure), then back to the light-component analyzer for spectrum analysis. Dispersion in the device under test gives rise to phase shifts among the carrier and the upper and lower sideband components of the modulated signal. These phase shifts affect the modulation-frequency component of the output of a photodetector exposed to the signal that emerges from the device under test. One of the effects is that this component goes to zero periodically as the modulation frequency is varied.

  12. High-Performance Scanning Acousto-Ultrasonic System

    NASA Technical Reports Server (NTRS)

    Roth, Don; Martin, Richard; Kautz, Harold; Cosgriff, Laura; Gyekenyesi, Andrew

    2006-01-01

    A high-performance scanning acousto-ultrasonic system, now undergoing development, is designed to afford enhanced capabilities for imaging microstructural features, including flaws, inside plate specimens of materials. The system is expected to be especially helpful in analyzing defects that contribute to failures in polymer- and ceramic-matrix composite materials, which are difficult to characterize by conventional scanning ultrasonic techniques and other conventional nondestructive testing techniques. Selected aspects of the acousto-ultrasonic method have been described in several NASA Tech Briefs articles in recent years. Summarizing briefly: The acousto-ultrasonic method involves the use of an apparatus like the one depicted in the figure (or an apparatus of similar functionality). Pulses are excited at one location on a surface of a plate specimen by use of a broadband transmitting ultrasonic transducer. The stress waves associated with these pulses propagate along the specimen to a receiving transducer at a different location on the same surface. Along the way, the stress waves interact with the microstructure and flaws present between the transducers. The received signal is analyzed to evaluate the microstructure and flaws. The specific variant of the acousto-ultrasonic method implemented in the present developmental system goes beyond the basic principle described above to include the following major additional features: Computer-controlled motorized translation stages are used to automatically position the transducers at specified locations. Scanning is performed in the sense that the measurement, data-acquisition, and data-analysis processes are repeated at different specified transducer locations in an array that spans the specimen surface (or a specified portion of the surface). A pneumatic actuator with a load cell is used to apply a controlled contact force. In analyzing the measurement data for each pair of transducer locations in the scan, the total

  13. Photon dispersion associated with optic-vibrations

    NASA Astrophysics Data System (ADS)

    Feng, P. X.

    1999-05-01

    In this communication, an effect of the damping coefficient on the dielectric function and dispersion is discussed. We recalculate Li's result [Li Xin-Qi, Yasuhiko Arakawa, Solid State Commun., 108 (1998) 211] and present a more general dielectric function associated with optic-vibrations. The relation between the phonon wavevector and the dispersion has also been obtained. The theoretical results show that the wavevector will obviously affect the profile of the dielectric function and result in the peak of the profile shift and increasing.

  14. Evaluation of material dispersion using a nanosecond optical pulse radiator.

    PubMed

    Horiguchi, M; Ohmori, Y; Miya, T

    1979-07-01

    To study the material dispersion effects on graded-index fibers, a method for measuring the material dispersion in optical glass fibers has been developed. Nanosecond pulses in the 0.5-1.7-microm region are generated by a nanosecond optical pulse radiator and grating monochromator. These pulses are injected into a GeO(2)-P(2)0(5)-doped silica graded-index fiber. Relative time delay changes between different wavelengths are used to determine material dispersion, core glass refractive index, material group index, and optimum profile parameter of the graded-index fiber. From the measured data, the optimum profile parameter on the GeO(2)-P(2)O(5)-doped silica graded-index fiber could be estimated to be 1.88 at 1.27 microm of the material dispersion free wavelength region and 1.82 at 1.55 microm of the lowest-loss wavelength region in silica-based optical fiber waveguides.

  15. Integrated optical signal processing with magnetostatic waves

    NASA Technical Reports Server (NTRS)

    Fisher, A. D.; Lee, J. N.

    1984-01-01

    Magneto-optical devices based on Bragg diffraction of light by magnetostatic waves (MSW's) offer the potential of large time-bandwidth optical signal processing at microwave frequencies of 1 to 20 GHz and higher. A thin-film integrated-optical configuration, with the interacting MSW and guided-optical wave both propagating in a common ferrite layer, is necessary to avoid shape-factor demagnetization effects. The underlying theory of the MSW-optical interaction is outlined, including the development of expressions for optical diffraction efficiency as a function of MSW power and other relevant parameters. Bradd diffraction of guided-optical waves by transversely-propagating magnetostatic waves and collinear TE/TM mode conversion included by MSW's have been demonstrated in yttrium iron garnet (YIG) thin films. Diffraction levels as large as 4% (7 mm interaction length) and a modulation dynamic range of approx 30 dB have been observed. Advantages of these MSW-based devices over the analogous acousto-optical devices include: much greater operating frequencies, tunability of the MSW dispersion relation by varying either the RF frequency or the applied bias magnetic field, simple broad-band MSW transducer structures (e.g., a single stripline), and the potential for very high diffraction efficiencies.

  16. Subcarrier multiplexing tolerant dispersion transmission system employing optical broadband sources.

    PubMed

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2009-03-16

    This paper presents a novel SCM optical transmission system for next-generation WDM-PONs combining broadband optical sources and a Mach-Zehnder interferometric structure. The approach leeds to transport RF signals up to 50 GHz being compatible with RoF systems since a second configuration has been proposed in order to overcome dispersion carrier suppression effect using DSB modulation. The theoretical analysis validates the potentiality of the system also considering the effects of the dispersion slope over the transmission window. (c) 2009 Optical Society of America

  17. Nondestructive evaluation/characterization of composite materials and structures using the acousto-ultrasonic techniques

    NASA Technical Reports Server (NTRS)

    Dos Reis, H. L. M.; Vary, A.

    1988-01-01

    This paper introduces the nature and the underlying rational of the acousto-ultrasonic stress wave factor technique and some of its applications to composite materials and structures. Furthermore, two examples of successful application of the acousto-ultrasonic technique are presented in detail. In the first example, the acousto-ultrasonic technique is used to evaluate the adhesive bond strength between rubber layers and steel plates, and in the seocnd example the tehcnique is used to monitor progressive damage in wire rope.

  18. Optical fiber dispersion characterization study

    NASA Technical Reports Server (NTRS)

    Geeslin, A.; Arriad, A.; Riad, S. M.; Padgett, M. E.

    1979-01-01

    The theory, design, and results of optical fiber pulse dispersion measurements are considered. Both the hardware and software required to perform this type of measurement are described. Hardware includes a thermoelectrically cooled injection laser diode source, an 800 GHz gain bandwidth produce avalanche photodiode and an input mode scrambler. Software for a HP 9825 computer includes fast Fourier transform, inverse Fourier transform, and optimal compensation deconvolution. Test set construction details are also included. Test results include data collected on a 1 Km fiber, a 4 Km fiber, a fused spliced, eight 600 meter length fibers concatenated to form 4.8 Km, and up to nine optical connectors.

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

    PubMed

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

    2005-12-12

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

  20. Faraday anomalous dispersion optical filters

    NASA Technical Reports Server (NTRS)

    Shay, T. M.; Yin, B.; Alvarez, L. S.

    1993-01-01

    The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.

  1. Applied optics. Multiwavelength achromatic metasurfaces by dispersive phase compensation.

    PubMed

    Aieta, Francesco; Kats, Mikhail A; Genevet, Patrice; Capasso, Federico

    2015-03-20

    The replacement of bulk refractive optical elements with diffractive planar components enables the miniaturization of optical systems. However, diffractive optics suffers from large chromatic aberrations due to the dispersion of the phase accumulated by light during propagation. We show that this limitation can be overcome with an engineered wavelength-dependent phase shift imparted by a metasurface, and we demonstrate a design that deflects three wavelengths by the same angle. A planar lens without chromatic aberrations at three wavelengths is also presented. Our designs are based on low-loss dielectric resonators, which introduce a dense spectrum of optical modes to enable dispersive phase compensation. The suppression of chromatic aberrations in metasurface-based planar photonics will find applications in lightweight collimators for displays, as well as chromatically corrected imaging systems. Copyright © 2015, American Association for the Advancement of Science.

  2. Electrodeless-discharge-vapor-lamp-based Faraday anomalous-dispersion optical filter.

    PubMed

    Sun, Qinqing; Zhuang, Wei; Liu, Zhiwen; Chen, Jingbiao

    2011-12-01

    We report an excited-state Faraday anomalous-dispersion optical filter operating on the rubidium 5P(3/2)-5D(5/2) transition (775.9 nm in vacuum) without the use of a pump laser. An electrodeless discharge vapor lamp is employed to replace the Rb vapor cell in a traditional Faraday anomalous-dispersion optical filter system. Atoms can be excited by power rather than a complex frequency-locked pump laser. A proof-of-concept experimental demonstration with a maximum transmission of 1.9% and a filter bandwidth of 650 MHz is presented. © 2011 Optical Society of America

  3. Dispersion-engineered and highly nonlinear microstructured polymer optical fibres

    NASA Astrophysics Data System (ADS)

    Frosz, Michael H.; Nielsen, Kristian; Hlubina, Petr; Stefani, Alessio; Bang, Ole

    2009-05-01

    We demonstrate dispersion-engineering of microstructured polymer optical fibres (mPOFs) made of poly(methyl methacrylate) (PMMA). A significant shift of the total dispersion from the material dispersion is confirmed through measurement of the mPOF dispersion using white-light spectral interferometry. The influence of strong loss peaks on the dispersion (through the Kramers-Kronig relations) is investigated theoretically. It is found that the strong loss peaks of PMMA above 1100 nm can significantly modify the dispersion, while the losses below 1100 nm only modify the dispersion slightly. To increase the nonlinearity of the mPOFs we investigated doping of PMMA with the highly-nonlinear dye Disperse Red 1. Both doping of a PMMA cane and direct doping of a PMMA mPOF was performed.

  4. Grating-based real-time smart optics for biomedicine and communications

    NASA Astrophysics Data System (ADS)

    Yaqoob, Zahid

    Novel photonic systems are proposed and experimentally validated using active as well as passive wavelength dispersive optical devices in unique fashions to solve important system level application problems in biomedicine and laser communications. Specifically for the first time are proposed, high dynamic range variable optical attenuators (VOAs) using bulk acousto-optics (AO). These AO-based architectures have excellent characteristics such as high laser damage threshold (e.g., 1 Watt CW laser power operations), large (e.g., >40 dB) dynamic range, and microsecond domain attenuation setting speed. The demonstrated architectures show potentials for compact, low static insertion loss, and low power VOA designs for wavelength division multiplexed (WDM) fiber-optic communication networks and high speed photonic signal processing for optical and radio frequency (RF) radar and electronic warfare (EW). Acoustic diffraction of light in isotropic media has been manipulated to design and demonstrate on a proof-of-principle basis, the first bulk AO-based optical coherence tomography (OCT) system for high-resolution sub-surface tissue diagnostics. As opposed to the current OCT systems that use mechanical means to generate optical delays, both free-space as well as fiber-optic AO-based OCT systems utilize unique electronically-controlled acousto-optically switched no-moving parts optical delay lines and therefore promise microsecond speed OCT data acquisition rates. The proposed OCT systems also feature high (e.g., >100 MHz) intermediate frequency for low 1/f noise heterodyne detection. For the first time, two agile laser beam steering schemes that are members of a new beam steering technology known as Multiplexed-Optical Scanner Technology (MOST) are theoretically investigated and experimentally demonstrated. The new scanner technologies are based on wavelength and space manipulations and possess remarkable features such as a no-moving parts fast (e.g., microseconds domain or

  5. Spatial and temporal pulse propagation for dispersive paraxial optical systems.

    PubMed

    Marcus, G

    2016-04-04

    The formalism for pulse propagation through dispersive paraxial optical systems first presented by Kostenbauder (IEEE J. Quant. Elec.261148-1157 (1990)) using 4 × 4 ray-pulse matrices is extended to 6 × 6 matrices and includes non-separable spatial-temporal couplings in both transverse dimensions as well as temporal dispersive effects up to a quadratic phase. The eikonal in a modified Huygens integral in the Fresnell approximation is derived and can be used to propagate pulses through complicated dispersive optical systems within the paraxial approximation. In addition, a simple formula for the propagation of ultrashort pulses having a Gaussian profile both spatially and temporally is presented.

  6. Optically Driven Q-Switches For Lasers

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid

    1994-01-01

    Optically driven Q-switches for pulsed lasers proposed, taking place of acousto-optical, magneto-optical, and electro-optical switches. Optical switching beams of proposed Q-switching most likely generated in pulsed diode lasers or light-emitting diodes, outputs of which are amplitude-modulated easily by direct modulation of relatively small input currents. Energy efficiencies exceed those of electrically driven Q-switches.

  7. Acousto-optical and SAW propagation characteristics of temperature stable multilayered structures based on LiNbO3 and diamond

    NASA Astrophysics Data System (ADS)

    Shandilya, Swati; Sreenivas, K.; Gupta, Vinay

    2008-01-01

    Theoretical studies on the surface acoustic wave (SAW) properties of c-axis oriented LiNbO3/IDT/diamond and diamond/IDT/128° rotated Y-X cut LiNbO3 multilayered structures have been considered. Both layered structures exhibit a positive temperature coefficient of delay (TCD) characteristic, and a zero TCD device is obtained after integrating with an over-layer of either tellurium dioxide (TeO2) or silicon dioxide (SiO2). The presence of a TeO2 over-layer enhanced the electromechanical coupling coefficients of both multilayered structures, which acts as a better temperature compensation layer than SiO2. The temperature stable TeO2/LiNbO3/IDT/diamond layered structure exhibits good electromechanical coefficient and higher phase velocity for SAW device applications. On the other hand, a high acousto-optical (AO) figure of merit (30-37) × 10-15 s3 kg-1 has been obtained for the temperature stable SiO2/diamond/IDT/LiNbO3 layered structure indicating a promising device structure for AO applications.

  8. Towards Terawatt Sub-Cycle Long-Wave Infrared Pulses via Chirped Optical Parametric Amplification and Indirect Pulse Shaping

    PubMed Central

    Yin, Yanchun; Chew, Andrew; Ren, Xiaoming; Li, Jie; Wang, Yang; Wu, Yi; Chang, Zenghu

    2017-01-01

    We present an approach for both efficient generation and amplification of 4–12 μm pulses by tailoring the phase matching of the nonlinear crystal Zinc Germanium Phosphide (ZGP) in a narrowband-pumped optical parametric chirped pulse amplifier (OPCPA) and a broadband-pumped dual-chirped optical parametric amplifier (DC-OPA), respectively. Preliminary experimental results are obtained for generating 1.8–4.2 μm super broadband spectra, which can be used to seed both the signal of the OPCPA and the pump of the DC-OPA. The theoretical pump-to-idler conversion efficiency reaches 27% in the DC-OPA pumped by a chirped broadband Cr2+:ZnSe/ZnS laser, enabling the generation of  Terawatt-level 4–12 μm pulses with an available large-aperture ZGP. Furthermore, the 4–12 μm idler pulses can be compressed to sub-cycle pulses by compensating the tailored positive chirp of the idler pulses using the bulk compressor NaCl, and by indirectly controlling the higher-order idler phase through tuning the signal (2.4–4.0 μm) phase with a commercially available acousto-optic programmable dispersive filter (AOPDF). A similar approach is also described for generating high-energy 4–12 μm sub-cycle pulses via OPCPA pumped by a 2 μm Ho:YLF laser. PMID:28367966

  9. 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

  10. All-optical control of group velocity dispersion in tellurite photonic crystal fibers.

    PubMed

    Liu, Lai; Tian, Qijun; Liao, Meisong; Zhao, Dan; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

    2012-12-15

    We demonstrate all-optical control of group velocity dispersion (GVD) via optical Kerr effect in highly nonlinear tellurite photonic crystal fibers. The redshift of the zero-dispersion wavelength is over 307 nm, measured by soliton self-frequency shift cancellation, when the pump peak power of a 1.56 μm femtosecond fiber laser is increased to 11.6 kW. The all-optical control of GVD not only offers a new platform for constructing all-optical-control photonic devices but also promises a new class of experiments in nonlinear fiber optics and light-matter interactions.

  11. Pump-probe micro-spectroscopy by means of an ultra-fast acousto-optics delay line.

    PubMed

    Audier, Xavier; Balla, Naveen; Rigneault, Hervé

    2017-01-15

    We demonstrate femtosecond pump-probe transient absorption spectroscopy using a programmable dispersive filter as an ultra-fast delay line. Combined with fast synchronous detection, this delay line allows for recording of 6 ps decay traces at 34 kHz. With such acquisition speed, we perform single point pump-probe spectroscopy on bulk samples in 80 μs and hyperspectral pump-probe imaging over a field of view of 100 μm in less than a second. The usability of the method is illustrated in a showcase experiment to image and discriminate between two pigments in a mixture.

  12. Spatial and temporal pulse propagation for dispersive paraxial optical systems

    DOE PAGES

    Marcus, G.

    2016-04-01

    The formalism for pulse propagation through dispersive paraxial optical systems first presented by Kostenbauder (IEEE J. Quant. Elec. 261148–1157 (1990)) using 4 × 4 ray-pulse matrices is extended to 6 × 6 matrices and includes non-separable spatial-temporal couplings in both transverse dimensions as well as temporal dispersive effects up to a quadratic phase. The eikonal in a modified Huygens integral in the Fresnell approximation is derived and can be used to propagate pulses through complicated dispersive optical systems within the paraxial approximation. Additionally, a simple formula for the propagation of ultrashort pulses having a Gaussian profile both spatially and temporallymore » is presented.« less

  13. Spatial and temporal pulse propagation for dispersive paraxial optical systems

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

    Marcus, G.

    The formalism for pulse propagation through dispersive paraxial optical systems first presented by Kostenbauder (IEEE J. Quant. Elec. 261148–1157 (1990)) using 4 × 4 ray-pulse matrices is extended to 6 × 6 matrices and includes non-separable spatial-temporal couplings in both transverse dimensions as well as temporal dispersive effects up to a quadratic phase. The eikonal in a modified Huygens integral in the Fresnell approximation is derived and can be used to propagate pulses through complicated dispersive optical systems within the paraxial approximation. Additionally, a simple formula for the propagation of ultrashort pulses having a Gaussian profile both spatially and temporallymore » is presented.« less

  14. Throughput and latency programmable optical transceiver by using DSP and FEC control.

    PubMed

    Tanimura, Takahito; Hoshida, Takeshi; Kato, Tomoyuki; Watanabe, Shigeki; Suzuki, Makoto; Morikawa, Hiroyuki

    2017-05-15

    We propose and experimentally demonstrate a proof-of-concept of a programmable optical transceiver that enables simultaneous optimization of multiple programmable parameters (modulation format, symbol rate, power allocation, and FEC) for satisfying throughput, signal quality, and latency requirements. The proposed optical transceiver also accommodates multiple sub-channels that can transport different optical signals with different requirements. Multi-degree-of-freedom of the parameters often leads to difficulty in finding the optimum combination among the parameters due to an explosion of the number of combinations. The proposed optical transceiver reduces the number of combinations and finds feasible sets of programmable parameters by using constraints of the parameters combined with a precise analytical model. For precise BER prediction with the specified set of parameters, we model the sub-channel BER as a function of OSNR, modulation formats, symbol rates, and power difference between sub-channels. Next, we formulate simple constraints of the parameters and combine the constraints with the analytical model to seek feasible sets of programmable parameters. Finally, we experimentally demonstrate the end-to-end operation of the proposed optical transceiver with offline manner including low-density parity-check (LDPC) FEC encoding and decoding under a specific use case with latency-sensitive application and 40-km transmission.

  15. Synthesis and optical characterization of LiKB4O7, Li2B6O10, and LiCsB6O10 glasses.

    PubMed

    Adamiv, V; Teslyuk, I; Dyachok, Ya; Romanyuk, G; Krupych, O; Mys, O; Martynyuk-Lototska, I; Burak, Ya; Vlokh, R

    2010-10-01

    In the current work we report on the synthesis of LiKB(4)O(7), Li(2)B(6)O(10), and LiCsB(6)O(10) borate glasses. The results for their piezo-optic, acousto-optic, acoustic, elastic, refractive, optical transmission, and optical resistance properties are also presented. It is shown that some of these glasses represent efficient acousto-optic materials that are transparent down to the vacuum ultraviolet range and highly resistant to laser radiation.

  16. Dispersion analysis and measurement of potassium tantalate niobate crystals by broadband optical interferometers.

    PubMed

    Ren, Jian

    2017-01-10

    Electro-optic crystals, such as potassium tantalate niobate [KTa1-xNbxO3(KTN)], are enabling materials for many optical devices. Their utility in broadband applications heavily depends on their dispersion property. To this end, an analysis of dispersion mismatch in broadband optical interferometers is first presented. Then a method utilizing polynomial phase fitting to measure the dispersion property of materials composing the arms of an interferometer is introduced. As a demonstration, an interferometry system based on optical coherence tomography (OCT) was built, where, for the first time, the group velocity dispersion of a KTN crystal around 1310 nm was measured and numerically compensated for OCT imaging. Several advantages over a widely used method in OCT, which is based on metric functions, are discussed. The results show the fitting method can provide a more reliable measurement with reduced computation complexity.

  17. Optical programmable Boolean logic unit.

    PubMed

    Chattopadhyay, Tanay

    2011-11-10

    Logic units are the building blocks of many important computational operations likes arithmetic, multiplexer-demultiplexer, radix conversion, parity checker cum generator, etc. Multifunctional logic operation is very much essential in this respect. Here a programmable Boolean logic unit is proposed that can perform 16 Boolean logical operations from a single optical input according to the programming input without changing the circuit design. This circuit has two outputs. One output is complementary to the other. Hence no loss of data can occur. The circuit is basically designed by a 2×2 polarization independent optical cross bar switch. Performance of the proposed circuit has been achieved by doing numerical simulations. The binary logical states (0,1) are represented by the absence of light (null) and presence of light, respectively.

  18. Methods and optical fibers that decrease pulse degradation resulting from random chromatic dispersion

    DOEpatents

    Chertkov, Michael; Gabitov, Ildar

    2004-03-02

    The present invention provides methods and optical fibers for periodically pinning an actual (random) accumulated chromatic dispersion of an optical fiber to a predicted accumulated dispersion of the fiber through relatively simple modifications of fiber-optic manufacturing methods or retrofitting of existing fibers. If the pinning occurs with sufficient frequency (at a distance less than or are equal to a correlation scale), pulse degradation resulting from random chromatic dispersion is minimized. Alternatively, pinning may occur quasi-periodically, i.e., the pinning distance is distributed between approximately zero and approximately two to three times the correlation scale.

  19. Noncontact acousto-ultrasonics using laser generation and laser interferometric detection

    NASA Technical Reports Server (NTRS)

    Green, Robert E., Jr.; Huber, Robert D.

    1991-01-01

    A compact, portable fiber-optic heterodyne interferometer designed to detect out-of-plane motion on surfaces is described. The interferometer provides a linear output for displacements over a broad frequency range and can be used for ultrasonic, acoustic emission, and acousto-ultrasonic (AU) testing. The interferometer in conjunction with a compact pulsed Nd:YAG laser represents a noncontact testing system. This system was tested to determine its usefulness for the AU technique. The results obtained show that replacement of conventional piezoelectric transducers (PZT) with a laser generation/detection system make it possible to carry out noncontact AU measurements. The waveforms recorded were 5 MHZ PZT-generated ultrasound propagating through an aluminum block, detection of the acoustic emission event, and laser AU waveforms from graphite-epoxy laminates and a filament-wound composite.

  20. Optical reversible programmable Boolean logic unit.

    PubMed

    Chattopadhyay, Tanay

    2012-07-20

    Computing with reversibility is the only way to avoid dissipation of energy associated with bit erase. So, a reversible microprocessor is required for future computing. In this paper, a design of a simple all-optical reversible programmable processor is proposed using a polarizing beam splitter, liquid crystal-phase spatial light modulators, a half-wave plate, and plane mirrors. This circuit can perform 16 logical operations according to three programming inputs. Also, inputs can be easily recovered from the outputs. It is named the "reversible programmable Boolean logic unit (RPBLU)." The logic unit is the basic building block of many complex computational operations. Hence the design is important in sense. Two orthogonally polarized lights are defined here as two logical states, respectively.

  1. Double Q-switch Ho:Sc2SiO5 laser by acousto-optic modulator combined with Cr2+:ZnSe saturable absorber

    NASA Astrophysics Data System (ADS)

    Yang, Xiao-tao; Zhang, Peng; Xie, Wen-qiang; Li, Lin-jun

    2018-01-01

    A double Q-switch (DQS) Ho:Sc2SiO5 laser modulated by a acousto-optic modulators (AOM) combined with a Cr2+:ZnSe saturable absorber (SA) was reported for the first time. The actively Q-switch (AQS) and passively Q-switch (PQS) were also studied. For the DQS mode, a maximum average output power of 2.49 W under the incident pump power of 12.5 W was obtained, corresponding to a slope efficiency of 24%. The characteristics of the DQS Ho:SSO laser versus different repetition frequencies (RF) of the AOM were researched. The maximum single-pulse energy of the DQS Ho:SSO laser was calculated to 1.98 mJ. The maximum peak power of the DQS Ho:SSO laser was 49.5 kW. The output beam quality factor M2 of DQS Ho:SSO laser was measured to be 1.15 with the highest peak power by knife-edge method at different positions.

  2. Polarization Dependence Suppression of Optical Fiber Grating Sensor in a π-Shifted Sagnac Loop Interferometer

    PubMed Central

    Son, Jaebum; Lee, Min-Kyoung; Jeong, Myung Yung; Kim, Chang-Seok

    2010-01-01

    In the sensing applications of optical fiber grating, it is necessary to reduce the transmission-type polarization dependence to isolate the sensing parameter. It is experimentally shown that the polarization-dependent spectrum of acousto-optic long-period fiber grating sensors can be suppressed in the transmission port of a π-shifted Sagnac loop interferometer. General expressions for the transmittance and reflectance are derived for transmission-type, reflection-type, and partially reflecting/transmitting-type polarization-dependent optical devices. The compensation of polarization dependence through the counter propagation in the Sagnac loop interferometer is quantitatively measured for a commercial in-line polarizer and an acousto-optic long-period fiber grating sensor. PMID:22399884

  3. 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)

  4. Integrated all-optical programmable logic array based on semiconductor optical amplifiers.

    PubMed

    Dong, Wenchan; Huang, Zhuyang; Hou, Jie; Santos, Rui; Zhang, Xinliang

    2018-05-01

    The all-optical programmable logic array (PLA) is one of the most important optical complex logic devices that can implement combinational logic functions. In this Letter, we propose and experimentally demonstrate an integrated all-optical PLA at the operation speed of 40 Gb/s. The PLA mainly consists of a delay interferometer (DI) and semiconductor optical amplifiers (SOAs) of different lengths. The DI is used to pre-code the input signals and improve the reconfigurability of the scheme. The longer SOAs are nonlinear media for generating canonical logic units (CLUs) using four-wave mixing. The shorter SOAs are used to select the appropriate CLUs by changing the working states; then reconfigurable logic functions can be output directly. The results show that all the CLUs are realized successfully, and the optical signal-to-noise ratios are above 22 dB. The exclusive NOR gate and exclusive OR gate are experimentally demonstrated based on output CLUs.

  5. International Conference on Integrated Optical Circuit Engineering, 1st, Cambridge, MA, October 23-25, 1984, Proceedings

    NASA Astrophysics Data System (ADS)

    Ostrowsky, D. B.; Sriram, S.

    Aspects of waveguide technology are explored, taking into account waveguide fabrication techniques in GaAs/GaAlAs, the design and fabrication of AlGaAs/GaAs phase couplers for optical integrated circuit applications, ion implanted GaAs integrated optics fabrication technology, a direct writing electron beam lithography based process for the realization of optoelectronic integrated circuits, and advances in the development of semiconductor integrated optical circuits for telecommunications. Other subjects examined are related to optical signal processing, optical switching, and questions of optical bistability and logic. Attention is given to acousto-optic techniques in integrated optics, acousto-optic Bragg diffraction in proton exchanged waveguides, optical threshold logic architectures for hybrid binary/residue processors, integrated optical modulation and switching, all-optic logic devices for waveguide optics, optoelectronic switching, high-speed photodetector switching, and a mechanical optical switch.

  6. Full-frame, programmable hyperspectral imager

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

    Love, Steven P.; Graff, David L.

    A programmable, many-band spectral imager based on addressable spatial light modulators (ASLMs), such as micro-mirror-, micro-shutter- or liquid-crystal arrays, is described. Capable of collecting at once, without scanning, a complete two-dimensional spatial image with ASLM spectral processing applied simultaneously to the entire image, the invention employs optical assemblies wherein light from all image points is forced to impinge at the same angle onto the dispersing element, eliminating interplay between spatial position and wavelength. This is achieved, as examples, using telecentric optics to image light at the required constant angle, or with micro-optical array structures, such as micro-lens- or capillary arrays,more » that aim the light on a pixel-by-pixel basis. Light of a given wavelength then emerges from the disperser at the same angle for all image points, is collected at a unique location for simultaneous manipulation by the ASLM, then recombined with other wavelengths to form a final spectrally-processed image.« less

  7. Optical simulation of quantum algorithms using programmable liquid-crystal displays

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

    Puentes, Graciana; La Mela, Cecilia; Ledesma, Silvia

    2004-04-01

    We present a scheme to perform an all optical simulation of quantum algorithms and maps. The main components are lenses to efficiently implement the Fourier transform and programmable liquid-crystal displays to introduce space dependent phase changes on a classical optical beam. We show how to simulate Deutsch-Jozsa and Grover's quantum algorithms using essentially the same optical array programmed in two different ways.

  8. All optical programmable logic array (PLA)

    NASA Astrophysics Data System (ADS)

    Hiluf, Dawit

    2018-03-01

    A programmable logic array (PLA) is an integrated circuit (IC) logic device that can be reconfigured to implement various kinds of combinational logic circuits. The device has a number of AND and OR gates which are linked together to give output or further combined with more gates or logic circuits. This work presents the realization of PLAs via the physics of a three level system interacting with light. A programmable logic array is designed such that a number of different logical functions can be combined as a sum-of-product or product-of-sum form. We present an all optical PLAs with the aid of laser light and observables of quantum systems, where encoded information can be considered as memory chip. The dynamics of the physical system is investigated using Lie algebra approach.

  9. Dispersion control with a Fourier-domain optical delay line in a fiber-optic imaging interferometer.

    PubMed

    Lee, Kye-Sung; Akcay, A Ceyhun; Delemos, Tony; Clarkson, Eric; Rolland, Jannick P

    2005-07-01

    Recently, Fourier-domain (FD) optical delay lines (ODLs) were introduced for high-speed scanning and dispersion compensation in imaging interferometry. We investigate the effect of first- and second-order dispersion on the photocurrent signal associated with an optical coherence imaging system implemented with a single-mode fiber, a superluminescent diode centered at 950 nm +/- 35 nm, a FD ODL, a mirror, and a layered LiTAO3 that has suitable dispersion characteristics to model a skin specimen. We present a practical and useful method to minimize the effect of dispersion through the interferometer and the specimen combined, as well as to quantify the results using two general metrics for resolution. Theoretical and associated experimental results show that, under the optimum solution, the maximum broadening of the point-spread function through a 1-mm-deep specimen is limited to 57% of its original rms width value (i.e., 8.1 microm optimal, 12.7 microm at maximum broadening) compared with approximately 110% when compensation is performed without the specimen taken into account.

  10. Uni-directional optical pulses, temporal propagation, and spatial and temporal dispersion

    NASA Astrophysics Data System (ADS)

    Kinsler, P.

    2018-02-01

    I derive a temporally propagated uni-directional optical pulse equation valid in the few cycle limit. Temporal propagation is advantageous because it naturally preserves causality, unlike the competing spatially propagated models. The exact coupled bi-directional equations that this approach generates can be efficiently approximated down to a uni-directional form in cases where an optical pulse changes little over one optical cycle. They also permit a direct term-to-term comparison of the exact bi-directional theory with its corresponding approximate uni-directional theory. Notably, temporal propagation handles dispersion in a different way, and this difference serves to highlight existing approximations inherent in spatially propagated treatments of dispersion. Accordingly, I emphasise the need for future work in clarifying the limitations of the dispersion conversion required by these types of approaches; since the only alternative in the few cycle limit may be to resort to the much more computationally intensive full Maxwell equation solvers.

  11. Wavelength-Scanning SPR Imaging Sensors Based on an Acousto-Optic Tunable Filter and a White Light Laser

    PubMed Central

    Zeng, Youjun; Wang, Lei; Wu, Shu-Yuen; He, Jianan; Qu, Junle; Li, Xuejin; Ho, Ho-Pui; Gu, Dayong; Gao, Bruce Zhi; Shao, Yonghong

    2017-01-01

    A fast surface plasmon resonance (SPR) imaging biosensor system based on wavelength interrogation using an acousto-optic tunable filter (AOTF) and a white light laser is presented. The system combines the merits of a wide-dynamic detection range and high sensitivity offered by the spectral approach with multiplexed high-throughput data collection and a two-dimensional (2D) biosensor array. The key feature is the use of AOTF to realize wavelength scan from a white laser source and thus to achieve fast tracking of the SPR dip movement caused by target molecules binding to the sensor surface. Experimental results show that the system is capable of completing a SPR dip measurement within 0.35 s. To the best of our knowledge, this is the fastest time ever reported in the literature for imaging spectral interrogation. Based on a spectral window with a width of approximately 100 nm, a dynamic detection range and resolution of 4.63 × 10−2 refractive index unit (RIU) and 1.27 × 10−6 RIU achieved in a 2D-array sensor is reported here. The spectral SPR imaging sensor scheme has the capability of performing fast high-throughput detection of biomolecular interactions from 2D sensor arrays. The design has no mechanical moving parts, thus making the scheme completely solid-state. PMID:28067766

  12. Optical data packet synchronization and multiplexing using a tunable optical delay based on wavelength conversion and inter-channel chromatic dispersion.

    PubMed

    Fazal, Irfan; Yilmaz, Omer; Nuccio, Scott; Zhang, Bo; Willner, Alan E; Langrock, Carsten; Fejer, Martin M

    2007-08-20

    10 Gb/s non-return-to-zero (NRZ) on-off keyed (OOK) optical data packets are synchronized and time-multiplexed using a 26-ns tunable all-optical delay line. The delay element is based on wavelength conversion in periodically poled lithium niobate (PPLN) waveguides, inter-channel chromatic dispersion in dispersion compensating fiber (DCF) and intra-channel dispersion compensation with a chirped fiber Bragg grating (FBG). Delay reconfiguration time is measured to be less than 300 ps.

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

    DOEpatents

    Hendrix, J.L.

    1995-04-11

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

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

    DOEpatents

    Hendrix, James L.

    1995-01-01

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

  15. Absorbing Boundary Conditions For Optical Pulses In Dispersive, Nonlinear Materials

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Kwak, Dochan (Technical Monitor)

    1995-01-01

    This paper will present results in computational nonlinear optics. An algorithm will be described that provides absorbing boundary conditions for optical pulses in dispersive, nonlinear materials. A new numerical absorber at the boundaries has been developed that is responsive to the spectral content of the pulse. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of "light bullet" like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. Comparisons will be shown of calculations that use the standard boundary conditions and the new ones.

  16. Efficient calculation of higher-order optical waveguide dispersion.

    PubMed

    Mores, J A; Malheiros-Silveira, G N; Fragnito, H L; Hernández-Figueroa, H E

    2010-09-13

    An efficient numerical strategy to compute the higher-order dispersion parameters of optical waveguides is presented. For the first time to our knowledge, a systematic study of the errors involved in the higher-order dispersions' numerical calculation process is made, showing that the present strategy can accurately model those parameters. Such strategy combines a full-vectorial finite element modal solver and a proper finite difference differentiation algorithm. Its performance has been carefully assessed through the analysis of several key geometries. In addition, the optimization of those higher-order dispersion parameters can also be carried out by coupling to the present scheme a genetic algorithm, as shown here through the design of a photonic crystal fiber suitable for parametric amplification applications.

  17. Optical Spatial integration methods for ambiguity function generation

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  18. All-optical central-frequency-programmable and bandwidth-tailorable radar

    PubMed Central

    Zou, Weiwen; Zhang, Hao; Long, Xin; Zhang, Siteng; Cui, Yuanjun; Chen, Jianping

    2016-01-01

    Radar has been widely used for military, security, and rescue purposes, and modern radar should be reconfigurable at multi-bands and have programmable central frequencies and considerable bandwidth agility. Microwave photonics or photonics-assisted radio-frequency technology is a unique solution to providing such capabilities. Here, we demonstrate an all-optical central-frequency-programmable and bandwidth-tailorable radar architecture that provides a coherent system and utilizes one mode-locked laser for both signal generation and reception. Heterodyning of two individually filtered optical pulses that are pre-chirped via wavelength-to-time mapping generates a wideband linearly chirped radar signal. The working bands can be flexibly tailored with the desired bandwidth at a user-preferred carrier frequency. Radar echoes are first modulated onto the pre-chirped optical pulse, which is also used for signal generation, and then stretched in time or compressed in frequency several fold based on the time-stretch principle. Thus, digitization is facilitated without loss of detection ability. We believe that our results demonstrate an innovative radar architecture with an ultra-high-range resolution. PMID:26795596

  19. Improved performance of analog and digital acousto-optic modulation with feedback under profiled beam propagation for secure communication using chaos

    NASA Astrophysics Data System (ADS)

    Almehmadi, Fares S.; Chatterjee, Monish R.

    2014-12-01

    Using intensity feedback, the closed-loop behavior of an acousto-optic hybrid device under profiled beam propagation has been recently shown to exhibit wider chaotic bands potentially leading to an increase in both the dynamic range and sensitivity to key parameters that characterize the encryption. In this work, a detailed examination is carried out vis-à-vis the robustness of the encryption/decryption process relative to parameter mismatch for both analog and pulse code modulation signals, and bit error rate (BER) curves are used to examine the impact of additive white noise. The simulations with profiled input beams are shown to produce a stronger encryption key (i.e., much lower parametric tolerance thresholds) relative to simulations with uniform plane wave input beams. In each case, it is shown that the tolerance for key parameters drops by factors ranging from 10 to 20 times below those for uniform plane wave propagation. Results are shown to be at consistently lower tolerances for secure transmission of analog and digital signals using parameter tolerance measures, as well as BER performance measures for digital signals. These results hold out the promise for considerably greater information transmission security for such a system.

  20. Noncontact Acousto-Ultrasonic Testing With Laser Beams

    NASA Technical Reports Server (NTRS)

    Huber, Robert D.; Green, Robert E., Jr.

    1994-01-01

    Laser beams used to excite and detect acoustic waves in specimens. Laser/acousto-ultrasonic technique entails no mechanical contact between specimens and testing apparatus. Apparatus located at relatively large distances (meters) from specimens, making it possible to test specimens too hot for contact measurements or located in inaccessible places, vacuums, or hostile environments.

  1. 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.

  2. Numerical dispersion compensation for Partial Coherence Interferometry and Optical Coherence Tomography.

    PubMed

    Fercher, A; Hitzenberger, C; Sticker, M; Zawadzki, R; Karamata, B; Lasser, T

    2001-12-03

    Dispersive samples introduce a wavelength dependent phase distortion to the probe beam. This leads to a noticeable loss of depth resolution in high resolution OCT using broadband light sources. The standard technique to avoid this consequence is to balance the dispersion of the sample byarrangingadispersive materialinthereference arm. However, the impact of dispersion is depth dependent. A corresponding depth dependent dispersion balancing technique is diffcult to implement. Here we present a numerical dispersion compensation technique for Partial Coherence Interferometry (PCI) and Optical Coherence Tomography (OCT) based on numerical correlation of the depth scan signal with a depth variant kernel. It can be used a posteriori and provides depth dependent dispersion compensation. Examples of dispersion compensated depth scan signals obtained from microscope cover glasses are presented.

  3. Large tunable optical delays via self-phase modulation and dispersion

    NASA Astrophysics Data System (ADS)

    Okawachi, Yoshitomo; Sharping, Jay E.; Xu, Chris; Gaeta, Alexander L.

    2006-12-01

    We demonstrate all-optically tunable delays in optical fiber via a dispersive stage and two stages of nonlinear spectral broadening and filtering. With this scheme, we achieve continuously tunable delays of 3.5- ps pulses and advancements over a total range of more than 1200 pulsewidths. Our technique is applicable to a wide range of pulse durations and delays.

  4. Pigment dispersion syndrome associated with optic nerve melanocytoma.

    PubMed

    Asorey-García, A; Méndez-Hernández, C D; Santos-Bueso, E; García-Feijoo, J

    2015-10-01

    A 60-year old patient was referred for cataract surgery. The examination showed retrokeratic pigment in the left eye, which had an intraocular pressure of 24 mm Hg. The funduscopy showed a brown lesion on the left optic disk, with adjacent vitreous seeding of pigment. The patient was thus diagnosed with secondary pigment dispersion syndrome due to optic disk melanocytoma. Although melanocytoma is most commonly a benign, stationary tumor, it may present with major complications leading to significant visual loss. A patient with melanocytoma of the optic disk should be examined periodically. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  5. Femtosecond Mode-locked Fiber Laser at 1 μm Via Optical Microfiber Dispersion Management.

    PubMed

    Wang, Lizhen; Xu, Peizhen; Li, Yuhang; Han, Jize; Guo, Xin; Cui, Yudong; Liu, Xueming; Tong, Limin

    2018-03-16

    Mode-locked Yb-doped fiber lasers around 1 μm are attractive for high power applications and low noise pulse train generation. Mode-locked fiber lasers working in soliton and stretched-pulse regime outperform others in terms of the laser noise characteristics, mechanical stability and easy maintenance. However, conventional optical fibers always show a normal group velocity dispersion around 1 μm, leading to the inconvenience for necessary dispersion management. Here we show that optical microfibers having a large anomalous dispersion around 1 μm can be integrated into mode-locked Yb-doped fiber lasers with ultralow insertion loss down to -0.06 dB, enabling convenient dispersion management of the laser cavity. Besides, optical microfibers could also be adopted to spectrally broaden and to dechirp the ultrashort pulses outside the laser cavity, giving rise to a pulse duration of about 110 fs. We believe that this demonstration may facilitate all-fiber format high-performance ultrashort pulse generation at 1 μm and may find applications in precision measurements, large-scale facility synchronization and evanescent-field-based optical sensing.

  6. All-optical observation and reconstruction of spin wave dispersion

    PubMed Central

    Hashimoto, Yusuke; Daimon, Shunsuke; Iguchi, Ryo; Oikawa, Yasuyuki; Shen, Ka; Sato, Koji; Bossini, Davide; Tabuchi, Yutaka; Satoh, Takuya; Hillebrands, Burkard; Bauer, Gerrit E. W.; Johansen, Tom H.; Kirilyuk, Andrei; Rasing, Theo; Saitoh, Eiji

    2017-01-01

    To know the properties of a particle or a wave, one should measure how its energy changes with its momentum. The relation between them is called the dispersion relation, which encodes essential information of the kinetics. In a magnet, the wave motion of atomic spins serves as an elementary excitation, called a spin wave, and behaves like a fictitious particle. Although the dispersion relation of spin waves governs many of the magnetic properties, observation of their entire dispersion is one of the challenges today. Spin waves whose dispersion is dominated by magnetostatic interaction are called pure-magnetostatic waves, which are still missing despite of their practical importance. Here, we report observation of the band dispersion relation of pure-magnetostatic waves by developing a table-top all-optical spectroscopy named spin-wave tomography. The result unmasks characteristics of pure-magnetostatic waves. We also demonstrate time-resolved measurements, which reveal coherent energy transfer between spin waves and lattice vibrations. PMID:28604690

  7. Blind third-order dispersion estimation based on fractional Fourier transformation for coherent optical communication

    NASA Astrophysics Data System (ADS)

    Yang, Lin; Guo, Peng; Yang, Aiying; Qiao, Yaojun

    2018-02-01

    In this paper, we propose a blind third-order dispersion estimation method based on fractional Fourier transformation (FrFT) in optical fiber communication system. By measuring the chromatic dispersion (CD) at different wavelengths, this method can estimation dispersion slope and further calculate the third-order dispersion. The simulation results demonstrate that the estimation error is less than 2 % in 28GBaud dual polarization quadrature phase-shift keying (DP-QPSK) and 28GBaud dual polarization 16 quadrature amplitude modulation (DP-16QAM) system. Through simulations, the proposed third-order dispersion estimation method is shown to be robust against nonlinear and amplified spontaneous emission (ASE) noise. In addition, to reduce the computational complexity, searching step with coarse and fine granularity is chosen to search optimal order of FrFT. The third-order dispersion estimation method based on FrFT can be used to monitor the third-order dispersion in optical fiber system.

  8. Grayness-dependent emission of dispersive waves from dark solitons in optical fibers.

    PubMed

    Marest, T; Arabí, C Mas; Conforti, M; Mussot, A; Milián, C; Skryabin, D V; Kudlinski, A

    2018-04-01

    We report the experimental observation of dispersive wave emission from gray solitons propagating in the normal dispersion region of an optical fiber. Besides observing for the first time, to the best of our knowledge, the emission of a dispersive wave from an isolated dark soliton, we show that the dispersive wave frequency and amplitude strongly depend on soliton grayness. This process can be explained by the higher-order dispersion contribution into the phase-matching condition and the grayness of the soliton. Numerical simulations and theoretical predictions are in good agreement with the experiments.

  9. Acousto-ultrasonic evaluation of ceramic matrix composite materials

    NASA Technical Reports Server (NTRS)

    Dosreis, Henrique L. M.

    1991-01-01

    Acousto-ultrasonic nondestructive evaluation of ceramic composite specimens with a lithium-alumino-silicate glass matrix reinforced with unidirectional silicon carbide (NICALON) fibers was conducted to evaluate their reserve of strength. Ceramic composite specimens with different amount of damage were prepared by four-point cyclic fatigue loading of the specimens at 500 C for a different number of cycles. The reserve of strength of the specimens was measured as the maximum bending stress recorded during four-pointed bending test with the load monotonically increased until failure occurs. It was observed that the reserve of strength did not correlate with the number of fatigue cycles. However, it was also observed that higher values of the stress wave factor measurements correspond to higher values of the reserve of strength test data. Therefore, these results show that the acousto-ultrasonic approach has the potential of being used to monitor damage and to estimate the reserve of strength of ceramic composites.

  10. Optical Rotatory Dispersion: New Twists on AN Old Topic

    NASA Astrophysics Data System (ADS)

    Vaccaro, Patrick

    2017-06-01

    Among the many physicochemical properties used to distinguish chiral molecules, perhaps none has had as profound and sustained an impact in the realm of chemistry as the characteristic interactions that take place with polarized light. Of special note is the dispersive (non-resonant) phenomenon of circular birefringence (CB), the manifestation of which first was reported over two centuries ago and which still is employed routinely - in the more familiar guise of specific optical rotation - to gauge the enantiomeric purity of the products emerging from asymmetric syntheses. Concerted experimental and theoretical efforts designed to probe such electronic optical activity in isolated chiral molecules will be presented, with special emphasis directed towards the marked influence that intramolecular (vibrational and conformational) dynamics and intermolecular (environmental) perturbations can exert upon the intrinsic chiroptical response. Requisite isolated-molecule measurements have been made possible by our continuing development of cavity ring-down polarimetry (CRDP), an ultrasensitive polarimetric scheme that has permitted the first quantitative analyses of optical rotatory dispersion (ORD or wavelength-resolved CB) to be performed in rarefied (gaseous) media. Various technical aspects of CRDP will be discussed to illustrate the unique capabilities and practical limitations afforded by this novel methodology. Comparison of specific rotation values acquired for a broad spectrum of rigid and flexible chiral species under complementary isolated and solvated conditions will highlight the intimate coupling that exists among electronic and nuclear degrees of freedom as well as the pronounced, yet oftentimes counterintuitive, effects incurred by subtle solute-solvent interactions. The disparate nature of optical activity extracted from different surroundings will be demonstrated, with quantum-chemical calculations serving to elucidate the structural, electronic, and

  11. The Rb 780-nanometer Faraday anomalous dispersion optical filter: Theory and experiment

    NASA Technical Reports Server (NTRS)

    Yin, B.; Alvarez, L. S.; Shay, T. M.

    1994-01-01

    The Faraday anomalous dispersion optical filter may provide ultra-high background noise rejection for free-space laser communications systems. The theoretical model for the filter is reported. The experimental measurements and their comparison with theoretical results are discussed. The results show that the filter can provide a 56-dB solar background noise rejection with about a 2-GHz transmission bandwidth and no image degradation. To further increase the background noise rejection, a composite Zeeman and Faraday anomalous dispersion optical filter is designed and experimentally demonstrated.

  12. A programmable light engine for quantitative single molecule TIRF and HILO imaging.

    PubMed

    van 't Hoff, Marcel; de Sars, Vincent; Oheim, Martin

    2008-10-27

    We report on a simple yet powerful implementation of objective-type total internal reflection fluorescence (TIRF) and highly inclined and laminated optical sheet (HILO, a type of dark-field) illumination. Instead of focusing the illuminating laser beam to a single spot close to the edge of the microscope objective, we are scanning during the acquisition of a fluorescence image the focused spot in a circular orbit, thereby illuminating the sample from various directions. We measure parameters relevant for quantitative image analysis during fluorescence image acquisition by capturing an image of the excitation light distribution in an equivalent objective backfocal plane (BFP). Operating at scan rates above 1 MHz, our programmable light engine allows directional averaging by circular spinning the spot even for sub-millisecond exposure times. We show that restoring the symmetry of TIRF/HILO illumination reduces scattering and produces an evenly lit field-of-view that affords on-line analysis of evanescnt-field excited fluorescence without pre-processing. Utilizing crossed acousto-optical deflectors, our device generates arbitrary intensity profiles in BFP, permitting variable-angle, multi-color illumination, or objective lenses to be rapidly exchanged.

  13. Filter-Based Dispersion-Managed Versatile Ultrafast Fibre Laser

    PubMed Central

    Peng, Junsong; Boscolo, Sonia

    2016-01-01

    We present the operation of an ultrafast passively mode-locked fibre laser, in which flexible control of the pulse formation mechanism is readily realised by an in-cavity programmable filter the dispersion and bandwidth of which can be software configured. We show that conventional soliton, dispersion-managed (DM) soliton (stretched-pulse) and dissipative soliton mode-locking regimes can be reliably targeted by changing the filter’s dispersion and bandwidth only, while no changes are made to the physical layout of the laser cavity. Numerical simulations are presented which confirm the different nonlinear pulse evolutions inside the laser cavity. The proposed technique holds great potential for achieving a high degree of control over the dynamics and output of ultrafast fibre lasers, in contrast to the traditional method to control the pulse formation mechanism in a DM fibre laser, which involves manual optimisation of the relative length of fibres with opposite-sign dispersion in the cavity. Our versatile ultrafast fibre laser will be attractive for applications requiring different pulse profiles such as in optical signal processing and optical communications. PMID:27183882

  14. Programmable diffractive optical elements for extending the depth of focus in ophthalmic optics

    NASA Astrophysics Data System (ADS)

    Romero, Lenny A.; Millán, María. S.; Jaroszewicz, Zbigniew; Kołodziejczyk, Andrzej

    2015-01-01

    The depth of focus (DOF) defines the axial range of high lateral resolution in the image space for object position. Optical devices with a traditional lens system typically have a limited DOF. However, there are applications such as in ophthalmology, which require a large DOF in comparison to a traditional optical system, this is commonly known as extended DOF (EDOF). In this paper we explore Programmable Diffractive Optical Elements (PDOEs), with EDOF, as an alternative solution to visual impairments, especially presbyopia. These DOEs were written onto a reflective liquid cystal on silicon (LCoS) spatial light modulator (SLM). Several designs of the elements are analyzed: the Forward Logarithmic Axicon (FLAX), the Axilens (AXL), the Light sword Optical Element (LSOE), the Peacock Eye Optical Element (PE) and Double Peacock Eye Optical Element (DPE). These elements focus an incident plane wave into a segment of the optical axis. The performances of the PDOEs are compared with those of multifocal lenses. In all cases, we obtained the point spread function and the image of an extended object. The results are presented and discussed.

  15. Electro-Optic Effects in Colloidal Dispersion of Metal Nano-Rods in Dielectric Fluid

    PubMed Central

    Golovin, Andrii B.; Xiang, Jie; Park, Heung-Shik; Tortora, Luana; Nastishin, Yuriy A.; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

    2011-01-01

    In modern transformation optics, one explores metamaterials with properties that vary from point to point in space and time, suitable for application in devices such as an “optical invisibility cloak” and an “optical black hole”. We propose an approach to construct spatially varying and switchable metamaterials that are based on colloidal dispersions of metal nano-rods (NRs) in dielectric fluids, in which dielectrophoretic forces, originating in the electric field gradients, create spatially varying configurations of aligned NRs. The electric field controls orientation and concentration of NRs and thus modulates the optical properties of the medium. Using gold (Au) NRs dispersed in toluene, we demonstrate electrically induced change in refractive index on the order of 0.1. PMID:28879997

  16. Optical signal processing

    NASA Astrophysics Data System (ADS)

    Vanderlugt, A.

    1993-07-01

    A quasi-realtime adaptive processing system was used to correct the multipath distortion found in wideband digital radios. The measured power spectral density of the input signal was used to adaptively select one of eight equalization filters which reduce the residual distortion to less than 3.6 dB even for the most severe channel distortion. A related adaptive system was used for signal excision in which we removed narrowband interference from wideband signals with minimum signal distortion. An 8x8 acousto-optic switch in a multimode fiber-optic system was built. Insertion loss is approximately 2-4 dB, signal-to-crosstalk ratio is better than 25 dB, and the reconfiguration time is 880 nsec. Short pulses were detected by using the Fresnel transform. Pulses as short as the theoretical limit of 20 nanoseconds were detected for this system, and separated by as little as 60 nanoseconds or by as much as 17 nanoseconds. All possible acousto-optic scanning configurations were considered and classified into four basic types. A consistent set of design relationships for each of the scanning configurations was developed and presented in both tabular and graphic forms from which a preliminary design is obtained.

  17. Bright and dark solitons in the normal dispersion regime of inhomogeneous optical fibers: Soliton interaction and soliton control

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

    Liu Wenjun; Tian Bo, E-mail: tian.bupt@yahoo.com.c; State Key Laboratory of Software Development Environment, Beijing University of Aeronautics and Astronautics, Beijing 100191

    2010-08-15

    Symbolically investigated in this paper is a nonlinear Schroedinger equation with the varying dispersion and nonlinearity for the propagation of optical pulses in the normal dispersion regime of inhomogeneous optical fibers. With the aid of the Hirota method, analytic one- and two-soliton solutions are obtained. Relevant properties of physical and optical interest are illustrated. Different from the previous results, both the bright and dark solitons are hereby derived in the normal dispersion regime of the inhomogeneous optical fibers. Moreover, different dispersion profiles of the dispersion-decreasing fibers can be used to realize the soliton control. Finally, soliton interaction is discussed withmore » the soliton control confirmed to have no influence on the interaction. The results might be of certain value for the study of the signal generator and soliton control.« less

  18. Theoretical model for a Faraday anomalous dispersion optical filter

    NASA Technical Reports Server (NTRS)

    Yin, B.; Shay, T. M.

    1991-01-01

    A model for the Faraday anomalous dispersion optical filter is presented. The model predicts a bandwidth of 0.6 GHz and a transmission peak of 0.98 for a filter operating on the Cs (D2) line. The model includes hyperfine effects and is valid for arbitrary magnetic fields.

  19. Optical solitons, explicit solutions and modulation instability analysis with second-order spatio-temporal dispersion

    NASA Astrophysics Data System (ADS)

    Inc, Mustafa; Isa Aliyu, Aliyu; Yusuf, Abdullahi; Baleanu, Dumitru

    2017-12-01

    This paper obtains the dark, bright, dark-bright or combined optical and singular solitons to the nonlinear Schrödinger equation (NLSE) with group velocity dispersion coefficient and second-order spatio-temporal dispersion coefficient, which arises in photonics and waveguide optics and in optical fibers. The integration algorithm is the sine-Gordon equation method (SGEM). Furthermore, the explicit solutions of the equation are derived by considering the power series solutions (PSS) theory and the convergence of the solutions is guaranteed. Lastly, the modulation instability analysis (MI) is studied based on the standard linear-stability analysis and the MI gain spectrum is obtained.

  20. Integrated Electro-optical Laser-Beam Scanners

    NASA Technical Reports Server (NTRS)

    Boord, Warren T.

    1990-01-01

    Scanners using solid-state devices compact, consume little power, and have no moving parts. Integrated electro-optical laser scanner, in conjunction with external lens, points outgoing beam of light in any number of different directions, depending on number of upper electrodes. Offers beam-deflection angles larger than those of acousto-optic scanners. Proposed for such diverse applications as nonimpact laser printing, color imaging, ranging, barcode reading, and robotic vision.

  1. Emission of dispersive waves from a train of dark solitons in optical fibers.

    PubMed

    Marest, T; Mas Arabí, C; Conforti, M; Mussot, A; Milián, C; Skryabin, D V; Kudlinski, A

    2016-06-01

    We report the experimental observation of multiple dispersive waves (DWs) emitted in the anomalous dispersion region of an optical fiber from a train of dark solitons. Each DW can be associated to one dark soliton of the train, using phase-matching arguments involving higher-order dispersion and soliton velocity. For a large number of dark solitons (>10), we observe the formation of a continuum associated with the efficient emission of DWs.

  2. Specifications of the International Cooperation Administration for DDT water-dispersible powder for use in malaria control programmes

    PubMed Central

    Pearce, George W.; Gooden, E. L.; Johnson, Donald R.

    1959-01-01

    Background information is presented on the development of specifications for 75% DDT water-dispersible powder for use in malaria control programmes supported by the International Cooperation Administration (ICA) of the United States Government. Early difficulties with DDT powders used in these programmes were investigated and it was found that the most critical requirements involved packaging, suspensibility and storage stability. ICA specifications were evolved to meet these requirements. The suspensibility test developed is described, and the importance of inspection of the material procured is discussed. PMID:14431217

  3. Plasmonic Gold Nanorod Dispersions with Electrical and Optical Tunability

    NASA Astrophysics Data System (ADS)

    Grabowski, Christopher; Mahoney, Clare; Park, Kyoungweon; Jawaid, Ali; White, Timothy; Vaia, Richard

    The transmissive, absorptive, electrical, and thermal properties of plasmonic gold nanorods (NRs) have led to their employment in a broad range of applications. These electro-optical properties - governed by their size, shape, and composition - are widely and precisely tunable during synthesis. Gold NRs show promise for large scale optical elements as they have been demonstrated to align faster than liquid crystal films (μs) at low fields (1 V/ μm). Successfully dispersing a high volume fraction of gold NRs requires a strategy to control particle-particle separation and thus avoid aggregation. Herein, we discuss the role of theta temperature and the ability to swell or collapse the chains of polymer-grafted gold NRs to alter the interaction potential between particles. UV-Vis spectroscopy, scattering, and electrical susceptibility characterization methods were employed to determine nanoparticle dispersion along with the degree of gold NR alignment. The development of new agile photonic materials, controllable with both light and electric fields, will help address emerging needs in laser hardening (agile filters) and variable transmission visors.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  5. Soliton Perturbation Theory for Dispersion-Managed Optical Fibers

    NASA Astrophysics Data System (ADS)

    Kohl, Russell; Milovic, Daniela; Zerrad, Essaid; Biswas, Anjan

    This paper studies the propagation of solitons through optical fibers with dispersion management. The adiabatic variation of the soliton parameters, due to the presence of perturbation terms, is obtained. The dynamics is studied for the case of polarization-preserving fibers, while the types of pulses that are considered here are Gaussian, super-Gaussian and supersech. The perturbation terms that are taken into consideration are both local and nonlocal.

  6. Transply crack density detection by acousto-ultrasonics

    NASA Technical Reports Server (NTRS)

    Hemann, John H.; Bowles, Kenneth J.; Kautz, Harold; Cavano, Paul

    1987-01-01

    The acousto-ultrasonic method was applied to a PMR-15 8-harness, satin Celion 3000 fabric composite to determine the extent of transply cracking. A six-ply 0/90 laminate was also subjected to mechanical loading, which induced transply cracking. The stress wave factor (SWF) is defined as the energy contained in the received signal from a 2.25-MHz center frequency transducer. The correlation of the SWF with transply crack density is shown.

  7. Normal dispersion femtosecond fiber optical parametric oscillator.

    PubMed

    Nguyen, T N; Kieu, K; Maslov, A V; Miyawaki, M; Peyghambarian, N

    2013-09-15

    We propose and demonstrate a synchronously pumped fiber optical parametric oscillator (FOPO) operating in the normal dispersion regime. The FOPO generates chirped pulses at the output, allowing significant pulse energy scaling potential without pulse breaking. The output average power of the FOPO at 1600 nm was ∼60  mW (corresponding to 1.45 nJ pulse energy and ∼55% slope power conversion efficiency). The output pulses directly from the FOPO were highly chirped (∼3  ps duration), and they could be compressed outside of the cavity to 180 fs by using a standard optical fiber compressor. Detailed numerical simulation was also performed to understand the pulse evolution dynamics around the laser cavity. We believe that the proposed design concept is useful for scaling up the pulse energy in the FOPO using different pumping wavelengths.

  8. Are There Optical Solitary Wave Solutions in Linear Media with Group Velocity Dispersion?

    NASA Technical Reports Server (NTRS)

    Li, Zhonghao; Zhou, Guosheng

    1996-01-01

    A generalized exact optical bright solitary wave solution in a three dimensional dispersive linear medium is presented. The most interesting property of the solution is that it can exist in the normal group-velocity-dispersion (GVD) region. In addition, another peculiar feature is that it may achieve a condition of 'zero-dispersion' to the media so that a solitary wave of arbitrarily small amplitude may be propagated with no dependence on is pulse width.

  9. Graphene and silver-nanoprism dispersion for printing optically-transparent electrodes

    NASA Astrophysics Data System (ADS)

    Sinar, Dogan; Knopf, George K.; Nikumb, Suwas

    2017-02-01

    Optically transparent electrodes (OTEs) are used for bioelectronics, touch screens, visual displays, and photovoltaic cells. Although the conductive coating for these electrodes is often composed of indium tin oxide (ITO), indium is a very expensive material and thin ITO films are relatively brittle compared to conductive polymer or graphene thin films. An alternative highly conductive optically transparent thin film based on a graphene (G) and silver-nanoprism (AgNP) dispersion is introduced in this paper. The aqueous G ink is first synthesized using carboxymethyl cellulose (CMC) as a stabilizing agent. Silver (Ag) nanoprisms are then prepared separately by a simple thermal process which involves the reduction of silver nitrate by sodium borohydride. These Ag nanoprisms are only a few nanometers thick but have relatively large surface areas (>1000 nm2). As a consequence, the nanoprisms provide more efficient injection of free carriers to the G layer. The concentrated G-AgNP dispersions are then deposited on optically transparent glass and polyimide substrates using an inkjet printer with a HP6602A print head. After printing, these optically thin films can be thermally treated to further increase electrical conductivity. Thermal treatment decomposes CMC which frees elemental carbon from polymer chain and, simultaneously, causes the film to become hydrophobic. Preliminary experiments demonstrate that the G-AgNP films on glass substrates exhibit high conductivity at 70% transparency (550 nm). Additional tests on the Gr-AgNP thin films printed on polymide substrates show mechanical stability under bending with minimal reduction in electrical conductivity or optical transparency.

  10. Optically-programmable nonlinear photonic component for dielectric-loaded plasmonic circuitry.

    PubMed

    Krasavin, Alexey V; Randhawa, Sukanya; Bouillard, Jean-Sebastien; Renger, Jan; Quidant, Romain; Zayats, Anatoly V

    2011-12-05

    We demonstrate both experimentally and numerically a compact and efficient, optically tuneable plasmonic component utilizing a surface plasmon polariton ring resonator with nonlinearity based on trans-cis isomerization in a polymer material. We observe more than 3-fold change between high and low transmission states of the device at milliwatt control powers (∼100 W/cm2 by intensity), with the performance limited by switching speed of the material. Such plasmonic components can be employed in optically programmable and reconfigurable integrated photonic circuitry.

  11. Optical measurements in evolving dispersed pipe flows

    NASA Astrophysics Data System (ADS)

    Voulgaropoulos, Victor; Angeli, Panagiota

    2017-12-01

    Optical laser-based techniques and an extensive data analysis methodology have been developed to acquire flow and separation characteristics of concentrated liquid-liquid dispersions. A helical static mixer was used at the inlet of an acrylic 4 m long horizontal pipe to actuate the dispersed flows at low mixture velocities. The organic (913 kg m^{-3}, 0.0046 Pa s) and aqueous phases (1146 kg m^{-3}, 0.0084 Pa s) were chosen to have matched refractive indices. Measurements were conducted at 15 and 135 equivalent pipe diameters downstream the inlet. Planar laser induced fluorescence (PLIF) measurements illustrated the flow structures and provided the local in-situ holdup profiles. It was found that along the pipe the drops segregate and in some cases coalesce either with other drops or with the corresponding continuous phase. A multi-level threshold algorithm was developed to measure the drop sizes from the PLIF images. The velocity profiles in the aqueous phase were measured with particle image velocimetry (PIV), while the settling velocities of the organic dispersed drops were acquired with particle tracking velocimetry (PTV). It was also possible to capture coalescence events of a drop with an interface over time and to acquire the instantaneous velocity and vorticity fields in the coalescing drop.

  12. Optical Properties of Nanocellulose Dispersions in Water, Dimethylformamide and Poly(Methyl Methacrylate)

    DTIC Science & Technology

    2013-10-01

    measurements for cellulose and PMMA thin- films . ..13  v List of Tables Table 1. Recorded optical data for nanocellulose in water...applications beyond thin films . In particular, the effects of nanocellulose fibers in higher concentrations, processed in different solvents, and...Optical Properties of Nanocellulose Dispersions in Water, Dimethylformamide and Poly(Methyl Methacrylate) by James F. Snyder, Joshua Steele

  13. Infrared fiber optic focal plane dispersers

    NASA Technical Reports Server (NTRS)

    Goebel, J. H.

    1981-01-01

    Far infrared transmissive fiber optics as a component in the design of integrated far infrared focal plane array utilization is discussed. A tightly packed bundle of fibers is placed at the focal plane, where an array of infrared detectors would normally reside, and then fanned out in two or three dimensions to individual detectors. Subsequently, the detectors are multiplexed by cryogenic electronics for relay of the data. A second possible application is frequency up-conversion (v sub 1 + v sub 2 = v sub 3), which takes advantage of the nonlinear optical index of refraction of certain infrared transmissive materials in fiber form. Again, a fiber bundle is utilized as above, but now a laser of frequency v sub 1 is mixed with the incoming radiation of frequency v sub 1 within the nonlinear fiber material. The sum, v sub 2 is then detected by near infrared or visible detectors which are more sensitive than those available at v sub 2. Due to the geometrical size limitations of detectors such as photomultipliers, the focal plane dispersal technique is advantageous for imaging up-conversion.

  14. Longitudinal measurement of chromatic dispersion along an optical fiber transmission system with a new correction factor

    NASA Astrophysics Data System (ADS)

    Abbasi, Madiha; Imran Baig, Mirza; Shafique Shaikh, Muhammad

    2013-12-01

    At present existence OTDR based techniques have become a standard practice for measuring chromatic dispersion distribution along an optical fiber transmission link. A constructive measurement technique has been offered in this paper, in which a four wavelength bidirectional optical time domain reflectometer (OTDR) has been used to compute the chromatic dispersion allocation beside an optical fiber transmission system. To improve the correction factor a novel formulation has been developed, which leads to an enhanced and defined measurement. The investigational outcomes obtained are in good harmony.

  15. Photorefractive Integrators and Correlators

    DTIC Science & Technology

    1992-12-01

    The use of photorefractive crystals as optically addressed time integrating spatial light modulators in acousto - optic signal processing applications...adaptive acousto - optic processor. These results demonstrated the feasibility of using photorefractives for such applications.... Photorefractive, Acousto - optic processor.

  16. Digital algorithm for dispersion correction in optical coherence tomography for homogeneous and stratified media.

    PubMed

    Marks, Daniel L; Oldenburg, Amy L; Reynolds, J Joshua; Boppart, Stephen A

    2003-01-10

    The resolution of optical coherence tomography (OCT) often suffers from blurring caused by material dispersion. We present a numerical algorithm for computationally correcting the effect of material dispersion on OCT reflectance data for homogeneous and stratified media. This is experimentally demonstrated by correcting the image of a polydimethyl siloxane microfludic structure and of glass slides. The algorithm can be implemented using the fast Fourier transform. With broad spectral bandwidths and highly dispersive media or thick objects, dispersion correction becomes increasingly important.

  17. Digital Algorithm for Dispersion Correction in Optical Coherence Tomography for Homogeneous and Stratified Media

    NASA Astrophysics Data System (ADS)

    Marks, Daniel L.; Oldenburg, Amy L.; Reynolds, J. Joshua; Boppart, Stephen A.

    2003-01-01

    The resolution of optical coherence tomography (OCT) often suffers from blurring caused by material dispersion. We present a numerical algorithm for computationally correcting the effect of material dispersion on OCT reflectance data for homogeneous and stratified media. This is experimentally demonstrated by correcting the image of a polydimethyl siloxane microfludic structure and of glass slides. The algorithm can be implemented using the fast Fourier transform. With broad spectral bandwidths and highly dispersive media or thick objects, dispersion correction becomes increasingly important.

  18. Dispersion management for a sub-10-fs, 10 TW optical parametric chirped-pulse amplifier.

    PubMed

    Tavella, Franz; Nomura, Yutaka; Veisz, Laszlo; Pervak, Vladimir; Marcinkevicius, Andrius; Krausz, Ferenc

    2007-08-01

    We report the amplification of three-cycle, 8.5 fs optical pulses in a near-infrared noncollinear optical parametric chirped-pulse amplifier (OPCPA) up to energies of 80 mJ. Improved dispersion management in the amplifier by means of a combination of reflection grisms and a chirped-mirror stretcher allowed us to recompress the amplified pulses to within 6% of their Fourier limit. The novel ultrabroad, ultraprecise dispersion control technology presented in this work opens the way to scaling multiterawatt technology to even shorter pulses by optimizing the OPCPA bandwidth.

  19. The effect of broadened linewidth induced by dispersion on the performance of resonant optical gyroscope

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Li, Wenxiu; Han, Peng; Chang, Xiaoyang; Liu, Jiaming; Lin, Jian; Xue, Xia; Zhu, Fang; Yang, Yang; Liu, Xiaojing; Zhang, Xiaofu; Huang, Anping; Xiao, Zhisong; Fang, Jiancheng

    2018-01-01

    Anomalous dispersion enhancement physical mechanism for Sagnac effect is described by special relativity derivation, and three kinds of definitions of minimum detectable angular rate of resonance optical gyroscope (ROG) are compared and the relations among them are investigated. The effect of linewidth broadening induced by anomalous dispersion on the sensitivity of ROG is discussed in this paper. Material dispersion-broadened resonance linewidth deteriorates the performance of a passive ROG and dispersion enhancement effect, while the sensitivity of a structural dispersion ROG is enhanced by two orders of magnitude even considering the dispersion-broadened resonance linewidth.

  20. Constraining the CMB optical depth through the dispersion measure of cosmological radio transients

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

    Fialkov, A.; Loeb, A., E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu

    2016-05-01

    The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we showmore » that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.« less

  1. Universal dispersion model for characterization of optical thin films over wide spectral range: Application to magnesium fluoride

    NASA Astrophysics Data System (ADS)

    Franta, Daniel; Nečas, David; Giglia, Angelo; Franta, Pavel; Ohlídal, Ivan

    2017-11-01

    Optical characterization of magnesium fluoride thin films is performed in a wide spectral range from far infrared to extreme ultraviolet (0.01-45 eV) utilizing the universal dispersion model. Two film defects, i.e. random roughness of the upper boundaries and defect transition layer at lower boundary are taken into account. An extension of universal dispersion model consisting in expressing the excitonic contributions as linear combinations of Gaussian and truncated Lorentzian terms is introduced. The spectral dependencies of the optical constants are presented in a graphical form and by the complete set of dispersion parameters that allows generating tabulated optical constants with required range and step using a simple utility in the newAD2 software package.

  2. Femtosecond parabolic pulse shaping in normally dispersive optical fibers.

    PubMed

    Sukhoivanov, Igor A; Iakushev, Sergii O; Shulika, Oleksiy V; Díez, Antonio; Andrés, Miguel

    2013-07-29

    Formation of parabolic pulses at femtosecond time scale by means of passive nonlinear reshaping in normally dispersive optical fibers is analyzed. Two approaches are examined and compared: the parabolic waveform formation in transient propagation regime and parabolic waveform formation in the steady-state propagation regime. It is found that both approaches could produce parabolic pulses as short as few hundred femtoseconds applying commercially available fibers, specially designed all-normal dispersion photonic crystal fiber and modern femtosecond lasers for pumping. The ranges of parameters providing parabolic pulse formation at the femtosecond time scale are found depending on the initial pulse duration, chirp and energy. Applicability of different fibers for femtosecond pulse shaping is analyzed. Recommendation for shortest parabolic pulse formation is made based on the analysis presented.

  3. Determination of dispersive optical constants of nanocrystalline CdSe (nc-CdSe) thin films

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

    Sharma, Kriti; Al-Kabbi, Alaa S.; Saini, G.S.S.

    2012-06-15

    Highlights: ► nc-CdSe thin films are prepared by thermal vacuum evaporation technique. ► TEM analysis shows NCs are spherical in shape. ► XRD reveals the hexagonal (wurtzite) crystal structure of nc-CdSe thin films. ► The direct optical bandgap of nc-CdSe is 2.25 eV in contrast to bulk (1.7 eV). ► Dispersion of refractive index is discussed in terms of Wemple–DiDomenico single oscillator model. -- Abstract: The nanocrystalline thin films of CdSe are prepared by thermal evaporation technique at room temperature. These thin films are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-raymore » diffraction (XRD) and photoluminescence spectroscopy (PL). The transmission spectra are recorded in the transmission range 400–3300 nm for nc-CdSe thin films. Transmittance measurements are used to calculate the refractive index (n) and absorption coefficient (α) using Swanepoel's method. The optical band gap (E{sub g}{sup opt}) has been determined from the absorption coefficient values using Tauc's procedure. The optical constants such as extinction coefficient (k), real (ε{sub 1}) and imaginary (ε{sub 2}) dielectric constants, dielectric loss (tan δ), optical conductivity (σ{sub opt}), Urbach energy (E{sub u}) and steepness parameter (σ) are also calculated for nc-CdSe thin films. The normal dispersion of refractive index is described using Wemple–DiDomenico single-oscillator model. Refractive index dispersion is further analysed to calculate lattice dielectric constant (ε{sub L}).« less

  4. Acousto-mechanical and thermal properties of clotted blooda)

    PubMed Central

    Nahirnyak, Volodymyr M.; Yoon, Suk Wang; Holland, Christy K.

    2007-01-01

    The efficacy of ultrasound-assisted thrombolysis as an adjunct treatment of ischemic stroke is being widely investigated. To determine the role of ultrasound hyperthermia in the process of blood clot disruption, the acousto-mechanical and thermal properties of clotted blood were measured in vitro, namely, density, speed of sound, frequency-dependent attenuation, specific heat, and thermal conductivity. The amplitude coefficient of attenuation of the clots was determined for 120 kHz, 1.0 MHz, and 3.5 MHz ultrasound at room temperature (20±2 °C). The attenuation coefficient ranged from 0.10 to 0.30 Np/cm in porcine clots and from 0.09 to 0.23 Np/cm in human clots. The experimentally determined values of specific heat and thermal conductivity for porcine clotted blood are (3.2±0.5)×103 J/kg·K and 0.55±0.13 W/m·K, respectively, and for human clotted blood are (3.5±0.8)×103 J/kg·K and 0.59±0.11 W/m·K, respectively. Measurements of the acousto-mechanical and thermal properties of clotted blood can be helpful in theoretical modeling of ultrasound hyperthermia in ultrasound-assisted thrombolysis and other high-intensity focused ultrasound applications. PMID:16838520

  5. Analysis of Acousto-Optic Errors in Laser Gyroscopes.

    DTIC Science & Technology

    1982-12-01

    2 2 Sagnac’s Interferometer ................................ 4 3 Harress ’ Prism Ring.................................... 5 4...years before Sagnac’s experiment, Harress , a German graduate student formed a ring of partially reflecting prisms to measure the dispersive properties of...glass (Figure 3). Harress noticed a fringe shift when he rotated the ring, and he assumed that the shift was caused by the *dragging" of the light

  6. Feasibility study of parallel optical correlation-decoding analysis of lightning

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

    Descour, M.R.; Sweatt, W.C.; Elliott, G.R.

    The optical correlator described in this report is intended to serve as an attention-focusing processor. The objective is to narrowly bracket the range of a parameter value that characterizes the correlator input. The input is a waveform collected by a satellite-borne receiver. In the correlator, this waveform is simultaneously correlated with an ensemble of ionosphere impulse-response functions, each corresponding to a different total-electron-count (TEC) value. We have found that correlation is an effective method of bracketing the range of TEC values likely to be represented by the input waveform. High accuracy in a computational sense is not required of themore » correlator. Binarization of the impulse-response functions and the input waveforms prior to correlation results in a lower correlation-peak-to-background-fluctuation (signal-to-noise) ratio than the peak that is obtained when all waveforms retain their grayscale values. The results presented in this report were obtained by means of an acousto-optic correlator previously developed at SNL as well as by simulation. An optical-processor architecture optimized for 1D correlation of long waveforms characteristic of this application is described. Discussions of correlator components, such as optics, acousto-optic cells, digital micromirror devices, laser diodes, and VCSELs are included.« less

  7. Fully digital programmable optical frequency comb generation and application.

    PubMed

    Yan, Xianglei; Zou, Xihua; Pan, Wei; Yan, Lianshan; Azaña, José

    2018-01-15

    We propose a fully digital programmable optical frequency comb (OFC) generation scheme based on binary phase-sampling modulation, wherein an optimized bit sequence is applied to phase modulate a narrow-linewidth light wave. Programming the bit sequence enables us to tune both the comb spacing and comb-line number (i.e., number of comb lines). The programmable OFCs are also characterized by ultra-flat spectral envelope, uniform temporal envelope, and stable bias-free setup. Target OFCs are digitally programmed to have 19, 39, 61, 81, 101, or 201 comb lines and to have a 100, 50, 20, 10, 5, or 1 MHz comb spacing. As a demonstration, a scanning-free temperature sensing system using a proposed OFC with 1001 comb lines was also implemented with a sensitivity of 0.89°C/MHz.

  8. Frequency multiplexed long range swept source optical coherence tomography

    PubMed Central

    Zurauskas, Mantas; Bradu, Adrian; Podoleanu, Adrian Gh.

    2013-01-01

    We present a novel swept source optical coherence tomography configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire multiple B-scans originating from different depths. The sensitivity range of the configuration is evaluated while acquiring five simultaneous B-scans. Then the configuration is employed to demonstrate long range B-scan imaging by combining two simultaneous B-scans from a mouse head sample. PMID:23760762

  9. Optically buffered Jones-matrix-based multifunctional optical coherence tomography with polarization mode dispersion correction

    PubMed Central

    Hong, Young-Joo; Makita, Shuichi; Sugiyama, Satoshi; Yasuno, Yoshiaki

    2014-01-01

    Polarization mode dispersion (PMD) degrades the performance of Jones-matrix-based polarization-sensitive multifunctional optical coherence tomography (JM-OCT). The problem is specially acute for optically buffered JM-OCT, because the long fiber in the optical buffering module induces a large amount of PMD. This paper aims at presenting a method to correct the effect of PMD in JM-OCT. We first mathematically model the PMD in JM-OCT and then derive a method to correct the PMD. This method is a combination of simple hardware modification and subsequent software correction. The hardware modification is introduction of two polarizers which transform the PMD into global complex modulation of Jones matrix. Subsequently, the software correction demodulates the global modulation. The method is validated with an experimentally obtained point spread function with a mirror sample, as well as by in vivo measurement of a human retina. PMID:25657888

  10. A novel optical millimeter-wave signal generation approach to overcome chromatic dispersion

    NASA Astrophysics Data System (ADS)

    Liang, Dong; Jiang, Wei; Tan, Qinggui; Zhu, Zhongbo; Liu, Feng

    2014-06-01

    In this paper, a novel frequency octupling approach for optical millimeter-wave signal generation to overcome chromatic dispersion is proposed and demonstrated. The frequency octupling mm-wave with the baseband signal carried only by -4th order sideband is generated by properly adjusting a series of parameters, which are the modulation constant, the gain of baseband signal, the direct current bias and the different phase of the modulation arms. As the optical millimeter-wave signal is transmitted along the fiber, there is no time shift caused by chromatic dispersion. Theoretical analyses and simulated results show that when the optical mm-wave carrying 2.5 Gbps baseband signal transmits a distance of over 110 km, the eye diagram still keeps open and clear. The power penalty is about 0.4 dB after the optical signal transmits over 40 km. In additions, given the +4th order sideband carries no data, a full-duplex RoF link based on wavelength reuse is built for the uplink. The bidirectional 2.5 Gbps baseband signal could successfully transmit over 40 km with about 0.8 dB power penalty in the simulation. Both theoretical analyses and simulation results show that the full-duplex RoF link has good performance.

  11. Theoretical analyses of resonant frequency shift in anomalous dispersion enhanced resonant optical gyroscopes.

    PubMed

    Lin, Jian; Liu, Jiaming; Zhang, Hao; Li, Wenxiu; Zhao, Lu; Jin, Junjie; Huang, Anping; Zhang, Xiaofu; Xiao, Zhisong

    2016-12-12

    Rigorous expressions of resonant frequency shift (RFS) in anomalous dispersion enhanced resonant optical gyroscopes (ADEROGs) are deduced without making approximation, which provides a precise theoretical guidance to achieve ultra-sensitive ADEROGs. A refractive index related modification factor is introduced when considering special theory of relativity (STR). We demonstrate that the RFS will not be "infinitely large" by using critical anomalous dispersion (CAD) and negative modification does not exist, which make the mechanism of anomalous dispersion enhancement clear and coherent. Although step change of RFS will happen when the anomalous dispersion condition varies, the amplification of RFS is limited by attainable variation of refractive index in practice. Moreover, it is shown that the properties of anomalous dispersion will influence not only the amplification of RFS, but also the detection range of ADEROGs.

  12. Tissue dispersion measurement techniques using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Photiou, Christos; Pitris, Costas

    2017-02-01

    Dispersion, a result of wavelength-dependent index of refraction variations, causes pulse-width broadening with detrimental effects in many pulsed-laser applications. It is also considered to be one of the major causes of resolution degradation in Optical Coherence Tomography (OCT). However, dispersion is material dependent and, in tissue, Group Velocity Dispersion (GVD) could be used, for example, to detect changes associated with early cancer and result in more accurate disease diagnosis. In this summary we compare different techniques for estimating the GVD from OCT images, in order to evaluate their accuracy and applicability in highly scattering samples such as muscle and adipose tissue. The methods investigated included estimation of the GVD from (i) the point spread function (PSF) degradation, (ii) the shift (walk-off) between images taken at different center wavelengths and (iii) the second derivative of the spectral phase. The measurements were degraded by the presence of strong Mie scattering and speckle noise with the most robust being the PSF degradation and the least robust the phase derivative method. If the GVD is to be used to provide sensitive diagnostic information from highly scattering human tissues, it would be preferable to use the resolution degradation as an estimator of GVD.

  13. Removing the depth-degeneracy in optical frequency domain imaging with frequency shifting

    PubMed Central

    Yun, S. H.; Tearney, G. J.; de Boer, J. F.; Bouma, B. E.

    2009-01-01

    A novel technique using an acousto-optic frequency shifter in optical frequency domain imaging (OFDI) is presented. The frequency shift eliminates the ambiguity between positive and negative differential delays, effectively doubling the interferometric ranging depth while avoiding image cross-talk. A signal processing algorithm is demonstrated to accommodate nonlinearity in the tuning slope of the wavelength-swept OFDI laser source. PMID:19484034

  14. Simultaneous chromatic dispersion monitoring and optical modulation format identification utilizing four wave mixing

    NASA Astrophysics Data System (ADS)

    Cui, Sheng; Qiu, Chen; Ke, Changjian; He, Sheng; Liu, Deming

    2015-11-01

    This paper presents a method which is able to monitor the chromatic dispersion (CD) and identify the modulation format (MF) of optical signals simultaneously. This method utilizes the features of the output curve of the highly sensitive all-optical CD monitor based on four wave mixing (FWM). From the symmetric center of the curve CD can be estimated blindly and independently, while from the profile and convergence region of the curve ten commonly used modulation formats can be recognized with simple algorithm based on maximum correlation classifier. This technique does not need any high speed optoelectronics and has no limitation on signal rate. Furthermore it can tolerate large CD distortions and is robust to polarization mode dispersion (PMD) and amplified spontaneous emission (ASE) noise.

  15. Programmable masks for optical information processing

    NASA Technical Reports Server (NTRS)

    Goebel, J. H.; Matsumoto, T.; Mina, C.; Welch, J.

    1984-01-01

    Research in progress at NASA Ames Research Center on programmable masks is discussed in this paper. One type is a large area format liquid crystal mask intended for binary optical computation problems. To date, an on-off contrast ratio of 500:1 has been achieved at a switching rate of 1 Hz. With a 32 x 32 format, a ratio 10 to the 4th power:1 is desirable. The switching contrast is entirely dependent on the polarized quality; therefore, it is believed that 10 to the 4th power:1 in transmission is possible. Larger format masks are under development. An application to Hadamard transform polarized imagery at wavelengths of 1.0 to 2.0 micrometers, which is competitive with the best monolithic infrared detector arrays, is discussed.

  16. Magneto-optical characterization of colloidal dispersions. Application to nickel nanoparticles.

    PubMed

    Pascu, Oana; Caicedo, José Manuel; Fontcuberta, Josep; Herranz, Gervasi; Roig, Anna

    2010-08-03

    We report here on a fast magneto-optical characterization method for colloidal liquid dispersions of magnetic nanoparticles. We have applied our methodology to Ni nanoparticles with size equal or below 15 nm synthesized by a ligand stabilized solution-phase synthesis. We have measured the magnetic circular dichroism (MCD) of colloidal dispersions and found that we can probe the intrinsic magnetic properties within a wide concentration range, from 10(-5) up to 10(-2) M, with sensitivity to concentrations below 1 microg/mL of magnetic Ni particles. We found that the measured MCD signal scales up with the concentration thus providing a means of determining the concentration values of highly diluted dispersions. The methodology presented here exhibits large flexibility and versatility and might be suitable to study either fundamental problems related to properties of nanosize particles including surface related effects which are highly relevant for magnetic colloids in biomedical applications or to be applied to in situ testing and integration in production lines.

  17. Optical Distance Measurement Device And Method Thereof

    DOEpatents

    Bowers, Mark W.

    2004-06-15

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

  18. Dispersive optical solitons and modulation instability analysis of Schrödinger-Hirota equation with spatio-temporal dispersion and Kerr law nonlinearity

    NASA Astrophysics Data System (ADS)

    Inc, Mustafa; Aliyu, Aliyu Isa; Yusuf, Abdullahi; Baleanu, Dumitru

    2018-01-01

    This paper obtains the dark, bright, dark-bright or combined optical and singular solitons to the perturbed nonlinear Schrödinger-Hirota equation (SHE) with spatio-temporal dispersion (STD) and Kerr law nonlinearity in optical fibers. The integration algorithm is the Sine-Gordon equation method (SGEM). Furthermore, the modulation instability analysis (MI) of the equation is studied based on the standard linear-stability analysis and the MI gain spectrum is got.

  19. Programmable logic controller optical fibre sensor interface module

    NASA Astrophysics Data System (ADS)

    Allwood, Gary; Wild, Graham; Hinckley, Steven

    2011-12-01

    Most automated industrial processes use Distributed Control Systems (DCSs) or Programmable Logic Controllers (PLCs) for automated control. PLCs tend to be more common as they have much of the functionality of DCSs, although they are generally cheaper to install and maintain. PLCs in conjunction with a human machine interface form the basis of Supervisory Control And Data Acquisition (SCADA) systems, combined with communication infrastructure and Remote Terminal Units (RTUs). RTU's basically convert different sensor measurands in to digital data that is sent back to the PLC or supervisory system. Optical fibre sensors are becoming more common in industrial processes because of their many advantageous properties. Being small, lightweight, highly sensitive, and immune to electromagnetic interference, means they are an ideal solution for a variety of diverse sensing applications. Here, we have developed a PLC Optical Fibre Sensor Interface Module (OFSIM), in which an optical fibre is connected directly to the OFSIM located next to the PLC. The embedded fibre Bragg grating sensors, are highly sensitive and can detect a number of different measurands such as temperature, pressure and strain without the need for a power supply.

  20. Development of acousto-optic spatial light modulator unit for effective control of light beam intensity and diffraction angle in 3D holographic display applications

    NASA Astrophysics Data System (ADS)

    Kondalkar, Vijay V.; Ryu, Geonhee; Lee, Yongbeom; Lee, Keekeun

    2018-07-01

    An acousto-optic (AO) based holographic display unit was developed using surface acoustic wave (SAW) with different wavelength to modulate the diffraction angles, intensities, and phases of light. The new configurations were employed to control two beams simultaneously by using a single chirp inter-digital transducer (IDT), and a micro-lens array was integrated at the end of the waveguide layer to focus the diffracted light on to the screen. Two incident light beams were simultaneously modulated by using different refractive grating periods generated from chirp IDT. A diffraction angle of about 5° was obtained by using a SAW with a frequency of 430 MHz. The increase in the SAW input power enhances the diffraction efficiency of the light beam at the exit. The obtained maximum diffraction efficiency is ~70% at a frequency of 430 MHz. The sloped shape of the waveguide entrance and a tall rounded Ni poles help in coupling the incident light to the waveguide layer. The diffracted beam was collected through the lens, which increased the intensity of light in the viewing plane. COMSOL multi-physics and coupling of mode (COM) modeling were performed to predict the device performance and compared with the experimental results.

  1. Dispersion dependence of second-order refractive index and complex third-order optical susceptibility in oxide glasses

    NASA Astrophysics Data System (ADS)

    Abdel Wahab, F. A.; El-Diasty, Fouad; Abdel-Baki, Manal

    2009-10-01

    A method correlates Fresnel-based spectrophotometric measurements and Lorentz dispersion theory is presented to study the dispersion of nonlinear optical parameters in particularly oxide glasses in a very wide range of angular frequency. The second-order refractive index and third-order optical susceptibility of Cr-doped glasses are determined from linear refractive index. Furthermore, both real and imaginary components of the complex susceptibility are carried out. The study reveals the importance of determining the dispersion of nonlinear absorption (two-photon absorption coefficient) to find the maximum resonant and nonresonant susceptibilities of investigated glasses. The present method is applied on Cr-doped lithium aluminum silicate (LAS) glasses due to their semiconductor-like behavior and also to their application in laser industry.

  2. Efficient dynamic coherence transfer relying on offset locking using optical phase-locked loop

    NASA Astrophysics Data System (ADS)

    Xie, Weilin; Dong, Yi; Bretenaker, Fabien; Shi, Hongxiao; Zhou, Qian; Xia, Zongyang; Qin, Jie; Zhang, Lin; Lin, Xi; Hu, Weisheng

    2018-01-01

    We design and experimentally demonstrate a highly efficient coherence transfer based on composite optical phaselocked loop comprising multiple feedback servo loops. The heterodyne offset-locking is achieved by conducting an acousto-optic frequency shifter in combination with the current tuning and the temperature controlling of the semiconductor laser. The adaptation of the composite optical phase-locked loop enables the tight coherence transfer from a frequency comb to a semiconductor laser in a fully dynamic manner.

  3. Optical Interarray Processing.

    DTIC Science & Technology

    1980-03-01

    of around 30 frames/sec. One dimensional input transducers such as acousto-optic Bragg cells have much higher frame rates. For example, a TeO2 Bragg...Conventional manufacturing processes such as grinding and polish- ing a glass piece would be difficult if not impossible to apply to the fabrication of such...time-bandwidth product (TBW). An acoustic shear wave in a TeO2 Bragg cell will propagate with a speed of 617 meters/ sec, while the practical physical

  4. Two-Phonon Absorption

    ERIC Educational Resources Information Center

    Hamilton, M. W.

    2007-01-01

    A nonlinear aspect of the acousto-optic interaction that is analogous to multi-photon absorption is discussed. An experiment is described in which the second-order acousto-optically scattered intensity is measured and found to scale with the square of the acoustic intensity. This experiment using a commercially available acousto-optic modulator is…

  5. Acousto-thermometric recovery of the deep temperature profile using heat conduction equations

    NASA Astrophysics Data System (ADS)

    Anosov, A. A.; Belyaev, R. V.; Vilkov, V. A.; Dvornikova, M. V.; Dvornikova, V. V.; Kazanskii, A. S.; Kuryatnikova, N. A.; Mansfel'd, A. D.

    2012-09-01

    In a model experiment using the acousto-thermographic method, deep temperature profiles varying in time are recovered. In the recovery algorithm, we used a priori information in the form of a requirement that the calculated temperature must satisfy the heat conduction equation. The problem is reduced to determining two parameters: the initial temperature and the temperature conductivity coefficient of the object under consideration (the plasticine band). During the experiment, there was independent inspection using electronic thermometers mounted inside the plasticine. The error in the temperature conductivity coefficient was about 17% and the error in initial temperature determination was less than one degree. Such recovery results allow application of this approach to solving a number of medical problems. It is experimentally proved that acoustic irregularities influence the acousto-thermometric results as well. It is shown that in the chosen scheme of experiment (which corresponds to measurements of human muscle tissue), this influence can be neglected.

  6. Multiscale dispersion-state characterization of nanocomposites using optical coherence tomography

    PubMed Central

    Schneider, Simon; Eppler, Florian; Weber, Marco; Olowojoba, Ganiu; Weiss, Patrick; Hübner, Christof; Mikonsaari, Irma; Freude, Wolfgang; Koos, Christian

    2016-01-01

    Nanocomposite materials represent a success story of nanotechnology. However, development of nanomaterial fabrication still suffers from the lack of adequate analysis tools. In particular, achieving and maintaining well-dispersed particle distributions is a key challenge, both in material development and industrial production. Conventional methods like optical or electron microscopy need laborious, costly sample preparation and do not permit fast extraction of nanoscale structural information from statistically relevant sample volumes. Here we show that optical coherence tomography (OCT) represents a versatile tool for nanomaterial characterization, both in a laboratory and in a production environment. The technique does not require sample preparation and is applicable to a wide range of solid and liquid material systems. Large particle agglomerates can be directly found by OCT imaging, whereas dispersed nanoparticles are detected by model-based analysis of depth-dependent backscattering. Using a model system of polystyrene nanoparticles, we demonstrate nanoparticle sizing with high accuracy. We further prove the viability of the approach by characterizing highly relevant material systems based on nanoclays or carbon nanotubes. The technique is perfectly suited for in-line metrology in a production environment, which is demonstrated using a state-of-the-art compounding extruder. These experiments represent the first demonstration of multiscale nanomaterial characterization using OCT. PMID:27557544

  7. Multiscale dispersion-state characterization of nanocomposites using optical coherence tomography.

    PubMed

    Schneider, Simon; Eppler, Florian; Weber, Marco; Olowojoba, Ganiu; Weiss, Patrick; Hübner, Christof; Mikonsaari, Irma; Freude, Wolfgang; Koos, Christian

    2016-08-25

    Nanocomposite materials represent a success story of nanotechnology. However, development of nanomaterial fabrication still suffers from the lack of adequate analysis tools. In particular, achieving and maintaining well-dispersed particle distributions is a key challenge, both in material development and industrial production. Conventional methods like optical or electron microscopy need laborious, costly sample preparation and do not permit fast extraction of nanoscale structural information from statistically relevant sample volumes. Here we show that optical coherence tomography (OCT) represents a versatile tool for nanomaterial characterization, both in a laboratory and in a production environment. The technique does not require sample preparation and is applicable to a wide range of solid and liquid material systems. Large particle agglomerates can be directly found by OCT imaging, whereas dispersed nanoparticles are detected by model-based analysis of depth-dependent backscattering. Using a model system of polystyrene nanoparticles, we demonstrate nanoparticle sizing with high accuracy. We further prove the viability of the approach by characterizing highly relevant material systems based on nanoclays or carbon nanotubes. The technique is perfectly suited for in-line metrology in a production environment, which is demonstrated using a state-of-the-art compounding extruder. These experiments represent the first demonstration of multiscale nanomaterial characterization using OCT.

  8. Optical gyroscope with controllable dispersion in four wave mixing regime.

    NASA Astrophysics Data System (ADS)

    Mikhailov, Eugeniy; Wolfe, Owen; Du, Shuangli; Rochester, Simon; Budker, Dmitry; Novikova, Irina

    2016-05-01

    We present our work towards realization of the fast-light gyroscope prototype, in which the sensitivity enhancement (compared to a regular laser gyroscopes) is achieved by adjusting the intra-cavity dispersion. We discuss schematics and underlying nonlinear effects leading to the negative dispersion in Rb vapor: level structure, optically addressed transitions, and configuration of the resonant cavity. We investigate dependence of the pulling factor (i.e., the ratio of the lasing frequency shift with the change of the cavity length to the equivalent resonance frequency shift in the empty cavity) on pump lasers detunings, power, and density of the atomic vapor. The observation of the pulling factor exceeding unity implies the gyroscope sensitivity improvement over the regular system This work is supported by Naval Air Warfare Center STTR program N68335-11-C-0428.

  9. Acousto-ultrasonic decay in metal matrix composite panels

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.

    1995-01-01

    Acousto-ultrasonic (A-U) decay rates (UD) were measured in metal matrix composite (MMC) panels. The MMC panels had fiber architectures and cross-sectional thicknesses corresponding to those designed for aerospace turbine engine structures. The wavelength-to-thickness ratio produced by the combination of experimental frequency setting conditions and specimen geometry was found to be a key parameter for identifying optimum conditions for UD measurements. The ratio was shown to be a useful rule of thumb when applied to ceramic matrix composites (CMC)s and monolithic thermo-plastics.

  10. Applications of a nanocomposite-inspired in-situ broadband ultrasonic sensor to acousto-ultrasonics-based passive and active structural health monitoring.

    PubMed

    Liu, Menglong; Zeng, Zhihui; Xu, Hao; Liao, Yaozhong; Zhou, Limin; Zhang, Zhong; Su, Zhongqing

    2017-07-01

    A novel nanocomposite-inspired in-situ broadband ultrasonic sensor previously developed, with carbon black as the nanofiller and polyvinylidene fluoride as the matrix, was networked for acousto-ultrasonic wave-based passive and active structural health monitoring (SHM). Being lightweight and small, this kind of sensor was proven to be capable of perceiving strain perturbation in virtue of the tunneling effect in the formed nanofiller conductive network when acousto-ultrasonic waves traverse the sensor. Proof-of-concept validation was implemented, to examine the sensor performance in responding to acousto-ultrasonic waves in a broad frequency regime: from acoustic emission (AE) of lower frequencies to guided ultrasonic waves (GUWs) of higher frequencies. Results have demonstrated the high fidelity, ultrafast response and high sensitivity of the sensor to acousto-ultrasonic waves up to 400kHz yet with an ultra-low magnitude (of the order of micro-strain). The sensor is proven to possess sensitivity and accuracy comparable with commercial piezoelectric ultrasonic transducers, whereas with greater flexibility in accommodating curved structural surfaces. Application paradigms of using the sensor for damage evaluation have spotlighted the capability of the sensor in compromising "sensing cost" with "sensing effectiveness" for passive AE- or active GUW-based SHM. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Parallel Optical Random Access Memory (PORAM)

    NASA Technical Reports Server (NTRS)

    Alphonse, G. A.

    1989-01-01

    It is shown that the need to minimize component count, power and size, and to maximize packing density require a parallel optical random access memory to be designed in a two-level hierarchy: a modular level and an interconnect level. Three module designs are proposed, in the order of research and development requirements. The first uses state-of-the-art components, including individually addressed laser diode arrays, acousto-optic (AO) deflectors and magneto-optic (MO) storage medium, aimed at moderate size, moderate power, and high packing density. The next design level uses an electron-trapping (ET) medium to reduce optical power requirements. The third design uses a beam-steering grating surface emitter (GSE) array to reduce size further and minimize the number of components.

  12. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, A.J.; Butler, M.A.; Sinclair, M.B.; Senturia, S.D.

    1998-05-26

    An electrically-programmable diffraction grating is disclosed. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers). 14 figs.

  13. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, Antonio J.; Butler, Michael A.; Sinclair, Michael B.; Senturia, Stephen D.

    1998-01-01

    An electrically-programmable diffraction grating. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers).

  14. Optical soliton solutions for the higher-order dispersive cubic-quintic nonlinear Schrödinger equation

    NASA Astrophysics Data System (ADS)

    Inc, Mustafa; Yusuf, Abdullahi; Aliyu, Aliyu Isa; Baleanu, Dumitru

    2017-12-01

    In this paper, we analyze new optical soliton solutions to the higher-order dispersive cubic-quintic nonlinear Schrödinger equation (NLSE) using three integration schemes. The schemes used in this paper are modified tanh-coth (MTC), extended Jacobi elliptic function expansion (EJEF), and two variable (G‧ / G , 1 / G) -expansion methods. We obtain new solutions that to the best of our knowledge do not exist previously. The obtained solutions includes bright, dark, combined bright-dark, singular as well as periodic waves solitons. The obtained solutions may be used to explain and understand the physical nature of the wave spreads in the most dispersive optical medium. Some interesting figures for the physical interpretation of the obtained solutions are also presented.

  15. Frequency hopping due to acousto-electric interaction in ZnO based surface acoustic wave oscillator

    NASA Astrophysics Data System (ADS)

    Dasgupta, Daipayan; Sreenivas, K.

    2011-08-01

    A 36 MHz surface acoustic wave delay line based oscillator has been used to study the effect of acousto-electric interaction due to photo generated charge carriers in rf sputtered ZnO film under UV illumination (λ = 365 nm, 20-100 μW/cm2). Design aspects for developing a delay line based SAW oscillator are specified. The observed linear downshift in frequency (2.2 to 19.0 kHz) with varying UV intensity (20-100 μW/cm2) is related to the fractional velocity change due to acousto-electric interaction. UV illumination level of 100 μW/cm2 leads to a characteristic frequency hopping behavior arising due to a change in the oscillation criteria, and is attributed to the complex interplay between the increased attenuation and velocity shift.

  16. Theory of dispersive microlenses

    NASA Technical Reports Server (NTRS)

    Herman, B.; Gal, George

    1993-01-01

    A dispersive microlens is a miniature optical element which simultaneously focuses and disperses light. Arrays of dispersive mircolenses have potential applications in multicolor focal planes. They have a 100 percent optical fill factor and can focus light down to detectors of diffraction spot size, freeing up areas on the focal plane for on-chip analog signal processing. Use of dispersive microlenses allows inband color separation within a pixel and perfect scene registration. A dual-color separation has the potential for temperature discrimination. We discuss the design of dispersive microlenses and present sample results for efficient designs.

  17. Hyperbranched-polymer dispersed nanocomposite volume gratings for holography and diffractive optics

    NASA Astrophysics Data System (ADS)

    Tomita, Yasuo; Takeuchi, Shinsuke; Oyaizu, Satoko; Urano, Hiroshi; Fukamizu, Taka-aki; Nishimura, Naoya; Odoi, Keisuke

    2016-10-01

    We review our experimental investigations of photopolymerizable nanoparticle-polymer composites (NPCs) for holography and diffractive optics. Various types of hyperbranched polymer (HBP) were systhesized and used as transporting organic nanoparticles. These HBPs include hyperbranched poly(ethyl methacrylate) (HPEMA), hyperbranched polystyrene (HPS) and hyperbranched triazine/aromatic polymer units (HTA) whose refractive indices are 1.51, 1.61 and 1.82, respectively. Each HBP was dispersed in (meth)acrylate monomer whose refractive index was so chosen that a refractive index difference between HBP and the formed polymer was large. Such monomer-HBP syrup was mixed with a titanocene photoinitiator for volume holographic recording in the green. We used a two-beam interference setup to write an unslanted transmission volume grating at grating spacing of 1 μm and at a wavelength of 532 nm. It is shown that NPC volume gratings with the saturated refractive index modulation amplitudes as large as 0.008, 0.004 and 0.02 can be recorded in NPCs incorporated with HPEMA, HPS and HTA at their optimum concentrations of 34, 34 and 25 vol.%, respectively. We show the usefulness of HBP-dispersed NPC volume gratings for holographic applications such as holographic data storage and diffractive optical devices.

  18. Bacteriorhodopsin films for optical signal processing and data storage

    NASA Technical Reports Server (NTRS)

    Walkup, John F. (Principal Investigator); Mehrl, David J. (Principal Investigator)

    1996-01-01

    This report summarizes the research results obtained on NASA Ames Grant NAG 2-878 entitled 'Investigations of Bacteriorhodopsin Films for Optical Signal Processing and Data Storage.' Specifically we performed research, at Texas Tech University, on applications of Bacteriorhodopisin film to both (1) dynamic spatial filtering and (2) holographic data storage. In addition, measurements of the noise properties of an acousto-optical matrix-vestor multiplier built for NASA Ames by Photonic Systems Inc. were performed at NASA Ames' Photonics Laboratory. This research resulted in two papers presented at major optical data processing conferences and a journal paper which is to appear in APPLIED OPTICS. A new proposal for additional BR research has recently been submitted to NASA Ames Research Center.

  19. Optical spectroscopy and velocity dispersions of galaxy clusters from the SPT-SZ survey

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

    Ruel, J.; Bayliss, M.; Bazin, G.

    2014-09-01

    We present optical spectroscopy of galaxies in clusters detected through the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). We report our own measurements of 61 spectroscopic cluster redshifts, and 48 velocity dispersions each calculated with more than 15 member galaxies. This catalog also includes 19 dispersions of SPT-observed clusters previously reported in the literature. The majority of the clusters in this paper are SPT-discovered; of these, most have been previously reported in other SPT cluster catalogs, and five are reported here as SPT discoveries for the first time. By performing a resampling analysis of galaxy velocities, we findmore » that unbiased velocity dispersions can be obtained from a relatively small number of member galaxies (≲ 30), but with increased systematic scatter. We use this analysis to determine statistical confidence intervals that include the effect of membership selection. We fit scaling relations between the observed cluster velocity dispersions and mass estimates from SZ and X-ray observables. In both cases, the results are consistent with the scaling relation between velocity dispersion and mass expected from dark-matter simulations. We measure a ∼30% log-normal scatter in dispersion at fixed mass, and a ∼10% offset in the normalization of the dispersion-mass relation when compared to the expectation from simulations, which is within the expected level of systematic uncertainty.« less

  20. Acoustic-optic spectrometer. 1: Noise contributions and system consideration

    NASA Technical Reports Server (NTRS)

    Chin, G.

    1984-01-01

    An acousto-optic spectrometer (AOS) used as an IF spectrometer to a heterodyne receiver is modeled as a total power multi-channel integrating receiver. Systematic noise contributions common to all total power, time integrating receivers, as well as noise terms unique to the use of optical elements and photo-detectors in an AOS are identified and discussed. In addition, degradation of signal-to-noise ratio of an unbalanced Dicke receiver compared to a balanced Dicke receiver is found to be due to gain calibration processing and is not an instrumental effect.

  1. Heterodyne detection using spectral line pairing for spectral phase encoding optical code division multiple access and dynamic dispersion compensation.

    PubMed

    Yang, Yi; Foster, Mark; Khurgin, Jacob B; Cooper, A Brinton

    2012-07-30

    A novel coherent optical code-division multiple access (OCDMA) scheme is proposed that uses spectral line pairing to generate signals suitable for heterodyne decoding. Both signal and local reference are transmitted via a single optical fiber and a simple balanced receiver performs sourceless heterodyne detection, canceling speckle noise and multiple-access interference (MAI). To validate the idea, a 16 user fully loaded phase encoded system is simulated. Effects of fiber dispersion on system performance are studied as well. Both second and third order dispersion management is achieved by using a spectral phase encoder to adjust phase shifts of spectral components at the optical network unit (ONU).

  2. Programmable Bidirectional Folding of Metallic Thin Films for 3D Chiral Optical Antennas.

    PubMed

    Mao, Yifei; Zheng, Yun; Li, Can; Guo, Lin; Pan, Yini; Zhu, Rui; Xu, Jun; Zhang, Weihua; Wu, Wengang

    2017-05-01

    3D structures with characteristic lengths ranging from nanometer to micrometer scale often exhibit extraordinary optical properties, and have been becoming an extensively explored field for building new generation nanophotonic devices. Albeit a few methods have been developed for fabricating 3D optical structures, constructing 3D structures with nanometer accuracy, diversified materials, and perfect morphology is an extremely challenging task. This study presents a general 3D nanofabrication technique, the focused ion beam stress induced deformation process, which allows a programmable and accurate bidirectional folding (-70°-+90°) of various metal and dielectric thin films. Using this method, 3D helical optical antennas with different handedness, improved surface smoothness, and tunable geometries are fabricated, and the strong optical rotation effects of single helical antennas are demonstrated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Fast and wide tuning wavelength-swept source based on dispersion-tuned fiber optical parametric oscillator.

    PubMed

    Zhou, Yue; Cheung, Kim K Y; Li, Qin; Yang, Sigang; Chui, P C; Wong, Kenneth K Y

    2010-07-15

    We demonstrate a dispersion-tuned fiber optical parametric oscillator (FOPO)-based swept source with a sweep rate of 40 kHz and a wavelength tuning range of 109 nm around 1550 nm. The cumulative speed exceeds 4,000,000 nm/s. The FOPO is pumped by a sinusoidally modulated pump, which is driven by a clock sweeping linearly from 1 to 1.0006 GHz. A spool of dispersion-compensating fiber is added inside the cavity to perform dispersion tuning. The instantaneous linewidth is 0.8 nm without the use of any wavelength selective element inside the cavity. 1 GHz pulses with pulse width of 150 ps are generated.

  4. Klein tunneling and electron optics in Dirac-Weyl fermion systems with tilted energy dispersion

    NASA Astrophysics Data System (ADS)

    Nguyen, V. Hung; Charlier, J.-C.

    2018-06-01

    The transport properties of relativisticlike fermions have been extensively studied in solid-state systems with isotropic energy dispersions. Recently, several two-dimensional and three-dimensional Dirac-Weyl (DW) materials exhibiting tilted energy dispersions around their DW cones have been explored. Here, we demonstrate that such a tilt character could induce drastically different transport phenomena, compared to the isotropic-dispersion cases. Indeed, the Klein tunneling of DW fermions of opposite chiralities is predicted to appear along two separated oblique directions. In addition, valley filtering and beam splitting effects are easily tailored by dopant engineering techniques whereas the refraction of electron waves at a (p -n )-doped interface is dramatically modified by the tilt, thus paving the way for emerging applications in electron optics and valleytronics.

  5. The Abcd Formula of Phase Definition in Optical Interferometry: Combined Effect of Air Dispersion and Broad Passband

    NASA Astrophysics Data System (ADS)

    Mathar, Richard J.

    Long-baseline interferometry detects fringes created by superposition of two beams of light collected by two telescopes pointing into a common direction. The external path difference is commonly compensated by adding a variable optical path length (delay) through air for one beam such that the optical path difference between the beams remains close to zero near the detector. The ABCD formula assigns a (wrapped) phase to the signals A to D of an interference pattern shifted by multiples of 90 degrees in phase. We study the interplay between a broad spectral passband of the optics and the dispersion of the air in the compensating delay, which leads to small deviations between the ABCD phase and the reduced, monochromatic group-delay representation of the wave packets. This adds dispersion to the effects that have been discussed for evacuated interferometers before (Milman 2005).

  6. Effects of fourth-order dispersion in very high-speed optical time-division multiplexed transmission.

    PubMed

    Capmany, J; Pastor, D; Sales, S; Ortega, B

    2002-06-01

    We present a closed-form expression for computation of the output pulse's rms time width in an optical fiber link with up to fourth-order dispersion (FOD) by use of an optical source with arbitrary linewidth and chirp parameters. We then specialize the expression to analyze the effect of FOD on the transmission of very high-speed linear optical time-division multiplexing systems. By suitable source chirping, FOD can be compensated for to an upper link-length limit above which other techniques must be employed. Finally, a design formula to estimate the maximum attainable bit rate limited by FOD as a function of the link length is also presented.

  7. Tunable terahertz reflection spectrum based on band gaps of GaP materials excited by ultrasonic

    NASA Astrophysics Data System (ADS)

    Cui, H.; Zhang, X. B.; Wang, X. F.; Wang, G. Q.

    2018-02-01

    Tunable terahertz (THz) reflection spectrum, ranged from 0.2 to 8 THz, in band gaps of gallium phosphide (GaP) materials excited by ultrasonic is investigated in the present paper, in which tunable ultrasonic and terahertz wave collinear transmission in the same direction is postulated. Numerical simulation results show that, under the acousto-optic interaction, band gaps of transverse optical phonon polariton dispersion curves are turned on, this leads to a dis-propagation of polariton in GaP bulk. On the other side, GaP material has less absorption to THz wave according to experimental studies, as indicates that THz wave could be reflected by the band gaps spontaneously. The band gaps width and acousto-optic coupling strength are proportional with ultrasonic frequency and its intensity in ultrasonic frequency range of 0-250 MHz, in which low-frequency branch of transverse optical phonon polariton dispersion curves demonstrate periodicity and folding as well as. With the increase of ultrasonic frequency, frequency of band gap is blue-shifted, and total reflectivity decreased with -1-order and -2-order reflectivity decrease. The band gaps converge to the restrahlen band infinitely with frequency of ultrasonic exceeding over 250 MHz, total reflectivity of which is attenuated. As is show above, reflection of THz wave can be accommodated by regulating the frequency and its intensity of ultrasonic frequency. Relevant technology may be available in tunable THz frequency selection and filtering.

  8. Morphological and electro optic studies of polymer dispersed liquid crystal in reverse mode

    NASA Astrophysics Data System (ADS)

    Sharma, Vandna; Kumar, Pankaj; Chinky, Malik, Praveen; Raina, K. K.

    2018-05-01

    Present work deals with reverse mode polymer dispersed liquid crystals (PDLCs) sensitive to electric field. Contrary to the conventional PDLCs operate from opaque (OFF state) to transparent state (ON state) with the application of field, reverse mode PDLCs work in transparent to opaque state. Reverse mode PDLC composed of nematic LC and UV curable optical adhesive polymer were prepared by the polymerization induced phase separation. The polarizing optical microscope study shows the vertical alignment of LCs within droplets with initial dark state under cross polarizers and confirms preliminary natural transparent state. The electro optic (EO) results show that the reverse mode PDLC lowered the threshold and operating voltages significantly compared with reported values. The contrast ratio of the film was also studied.

  9. Dispersion-based stimulated Raman scattering spectroscopy, holography, and optical coherence tomography

    PubMed Central

    Robles, Francisco E.; Fischer, Martin C.; Warren, Warren S.

    2016-01-01

    Stimulated Raman scattering (SRS) enables fast, high resolution imaging of chemical constituents important to biological structures and functional processes, both in a label-free manner and using exogenous biomarkers. While this technology has shown remarkable potential, it is currently limited to point scanning and can only probe a few Raman bands at a time (most often, only one). In this work we take a fundamentally different approach to detecting the small nonlinear signals based on dispersion effects that accompany the loss/gain processes in SRS. In this proof of concept, we demonstrate that the dispersive measurements are more robust to noise compared to amplitude-based measurements, which then permit spectral or spatial multiplexing (potentially both, simultaneously). Finally, we illustrate how this method may enable different strategies for biochemical imaging using phase microscopy and optical coherence tomography. PMID:26832279

  10. The serpentine optical waveguide: engineering the dispersion relations and the stopped light points.

    PubMed

    Scheuer, Jacob; Weiss, Ori

    2011-06-06

    We present a study a new type of optical slow-light structure comprising a serpentine shaped waveguide were the loops are coupled. The dispersion relation, group velocity and GVD are studied analytically using a transfer matrix method and numerically using finite difference time domain simulations. The structure exhibits zero group velocity points at the ends of the Brillouin zone, but also within the zone. The position of mid-zone zero group velocity point can be tuned by modifying the coupling coefficient between adjacent loops. Closed-form analytic expressions for the dispersion relations, group velocity and the mid-zone zero v(g) points are found and presented.

  11. 40-fs hydrogen Raman laser

    NASA Astrophysics Data System (ADS)

    Didenko, N. V.; Konyashchenko, A. V.; Kostryukov, P. V.; Losev, L. L.; Pazyuk, V. S.; Tenyakov, S. Yu; Molchanov, V. Ya; Chizhikov, S. I.; Yushkov, K. B.

    2015-12-01

    40-fs first Stokes pulses at a wavelength of 1.2 μm were generated in a hydrogen SRS-converter pumped by orthogonally polarised double chirped pulses of a Ti : sapphire laser. To obtain a Stokes pulse close to a transform-limited one, a programmed acousto-optic dispersive delay line was placed between the master oscillator and regenerative amplifier. The energy efficiency of Stokes radiation conversion reached 22%.

  12. Dispersion-optimized optical fiber for high-speed long-haul dense wavelength division multiplexing transmission

    NASA Astrophysics Data System (ADS)

    Wu, Jindong; Chen, Liuhua; Li, Qingguo; Wu, Wenwen; Sun, Keyuan; Wu, Xingkun

    2011-07-01

    Four non-zero-dispersion-shifted fibers with almost the same large effective area (Aeff) and optimized dispersion properties are realized by novel index profile designing and modified vapor axial deposition and modified chemical vapor deposition processes. An Aeff of greater than 71 μm2 is obtained for the designed fibers. Three of the developed fibers with positive dispersion are improved by reducing the 1550nm dispersion slope from 0.072ps/nm2/km to 0.063ps/nm2/km or 0.05ps/nm2/km, increasing the 1550nm dispersion from 4.972ps/nm/km to 5.679ps/nm/km or 7.776ps/nm/km, and shifting the zero-dispersion wavelength from 1500nm to 1450nm. One of these fibers is in good agreement with G655D and G.656 fibers simultaneously, and another one with G655E and G.656 fibers; both fibers are beneficial to high-bit long-haul dense wavelength division multiplexing systems over S-, C-, and L-bands. The fourth developed fiber with negative dispersion is also improved by reducing the 1550nm dispersion slope from 0.12ps/nm2/km to 0.085ps/nm2/km, increasing the 1550nm dispersion from -4ps/nm/km to -6.016ps/nm/km, providing facilities for a submarine transmission system. Experimental measurements indicate that the developed fibers all have excellent optical transmission and good macrobending and splice performances.

  13. Optical characteristics of particles produced using electroerosion dispersion of titanium in hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Pyachin, S. A.; Burkov, A. A.; Makarevich, K. S.; Zaitsev, A. V.; Karpovich, N. F.; Ermakov, M. A.

    2016-07-01

    Titanium oxide particles are produced using electric-discharge dispersion of titanium in aqueous solution of hydrogen peroxide. Electron vacuum microscopy, X-ray diffraction, and diffuse reflection spectroscopy are used to study the morphology, composition, and optical characteristics of the erosion particles. It has been demonstrated that the particles consist of titanium and titanium oxides with different valences. The edge of the optical absorption is located in the UV spectral range. The band gap is 3.35 eV for indirect transitions and 3.87 eV for direct allowed transitions. The band gap decreases due to the relatively long heating in air at a temperature of 480-550°C, so that powder oxide compositions can be obtained, the optical characteristics of which are similar to optical characteristics of anatase. The erosion products are completely oxidized to rutile after annealing in air at a temperature of 1000°C.

  14. Spatial Phase Coding for Incoherent Optical Processors

    NASA Technical Reports Server (NTRS)

    Tigin, D. V.; Lavrentev, A. A.; Gary, C. K.

    1994-01-01

    In this paper we introduce spatial phase coding of incoherent optical signals for representing signed numbers in optical processors and present an experimental demonstration of this coding technique. If a diffraction grating, such as an acousto-optic cell, modulates a stream of light, the image of the grating can be recovered from the diffracted beam. The position of the grating image, or more precisely its phase, can be used to denote the sign of the number represented by the diffracted light. The intensity of the light represents the magnitude of the number. This technique is more economical than current methods in terms of the number of information channels required to represent a number and the amount of post processing required.

  15. A preliminary investigation of acousto-ultrasonic NDE of metal matrix composite test specimens

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.; Lerch, Brad A.

    1991-01-01

    Acousto-ultrasonic (AU) measurements were performed on a series of tensile specimens composed of 8 laminated layers of continuous, SiC fiber reinforced Ti-15-3 matrix. The following subject areas are covered: AU signal analysis; tensile behavior; AU and interrupted tensile tests; AU and thermally cycled specimens; AU and stiffness; and AU and specimen geometry.

  16. Dynamic ultrasound modulated optical tomography by self-referenced photorefractive holography.

    PubMed

    Benoit a la Guillaume, Emilie; Bortolozzo, Umberto; Huignard, Jean-Pierre; Residori, Stefania; Ramaz, Francois

    2013-02-01

    Photorefractive Bi(12)SiO(20) single crystal is used for acousto-optic imaging in thick scattering media in the green part of the spectrum, in an adaptive speckle correlation configuration. Light fields at the output of the scattering sample exhibit typical speckle grains of 1 μm size within the volume of the nonlinear crystal. This heterogeneous illumination induces a complex refractive index structure without applying a reference beam on the crystal, leading to a self-referenced diffraction correlation scheme. We demonstrate that this simple and robust configuration is able to perform axially resolved ultrasound modulated optical tomography of thick scattering media with an improved optical etendue.

  17. Scalable fabrication of a hybrid field-effect and acousto-electric device by direct growth of monolayer MoS2/LiNbO3

    PubMed Central

    Preciado, Edwin; Schülein, Florian J.R.; Nguyen, Ariana E.; Barroso, David; Isarraraz, Miguel; von Son, Gretel; Lu, I-Hsi; Michailow, Wladislaw; Möller, Benjamin; Klee, Velveth; Mann, John; Wixforth, Achim; Bartels, Ludwig; Krenner, Hubert J.

    2015-01-01

    Lithium niobate is the archetypical ferroelectric material and the substrate of choice for numerous applications including surface acoustic wave radio frequencies devices and integrated optics. It offers a unique combination of substantial piezoelectric and birefringent properties, yet its lack of optical activity and semiconducting transport hamper application in optoelectronics. Here we fabricate and characterize a hybrid MoS2/LiNbO3 acousto-electric device via a scalable route that uses millimetre-scale direct chemical vapour deposition of MoS2 followed by lithographic definition of a field-effect transistor structure on top. The prototypical device exhibits electrical characteristics competitive with MoS2 devices on silicon. Surface acoustic waves excited on the substrate can manipulate and probe the electrical transport in the monolayer device in a contact-free manner. We realize both a sound-driven battery and an acoustic photodetector. Our findings open directions to non-invasive investigation of electrical properties of monolayer films. PMID:26493867

  18. Acousto-ultrasonic system for the inspection of composite armored vehicles

    NASA Astrophysics Data System (ADS)

    Godinez, Valery F.; Carlos, Mark F.; Delamere, Michael; Hoch, William; Fotopoulos, Christos; Dai, Weiming; Raju, Basavaraju B.

    2001-04-01

    In this paper the design and implementation of a unique acousto-ultrasonics system for the inspection of composite armored vehicles is discussed. The system includes a multi-sensor probe with a position-tracking device mounted on a computer controlled scanning bridge. The system also includes an arbitrary waveform generator with a multiplexer and a multi-channel acoustic emission board capable of simultaneously collecting and processing up to four acoustic signals in real time. C-scans of an armored vehicle panel with defects are presented.

  19. Smart Optical Composite Materials: Dispersions of Metal-Organic Framework@Superparamagnetic Microrods for Switchable Isotropic-Anisotropic Optical Properties.

    PubMed

    Mandel, Karl; Granath, Tim; Wehner, Tobias; Rey, Marcel; Stracke, Werner; Vogel, Nicolas; Sextl, Gerhard; Müller-Buschbaum, Klaus

    2017-01-24

    A smart optical composite material with dynamic isotropic and anisotropic optical properties by combination of luminescence and high reflectivity was developed. This combination enables switching between luminescence and angle-dependent reflectivity by changing the applied wavelength of light. The composite is formed as anisotropic core/shell particles by coating superparamagnetic iron oxide-silica microrods with a layer of the luminescent metal-organic framework (MOF) 3 ∞ [Eu 2 (BDC) 3 ]·2DMF·2H 2 O (BDC 2- = 1,4-benzenedicarboxylate). The composite particles can be rotated by an external magnet. Their anisotropic shape causes changes in the reflectivity and diffraction of light depending on the orientation of the composite particle. These rotation-dependent optical properties are complemented by an isotropic luminescence resulting from the MOF shell. If illuminated by UV light, the particles exhibit isotropic luminescence while the same sample shows anisotropic optical properties when illuminated with visible light. In addition to direct switching, the optical properties can be tailored continuously between isotropic red emission and anisotropic reflection of light if the illuminating light is tuned through fractions of both UV and visible light. The integration and control of light emission modes within a homogeneous particle dispersion marks a smart optical material, addressing fundamental directions for research on switchable multifunctional materials. The material can function as an optic compass or could be used as an optic shutter that can be switched by a magnetic field, e.g., for an intensity control for waveguides in the visible range.

  20. Acousto-ultrasonics to Assess Material and Structural Properties

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.

    2002-01-01

    This report was created to serve as a manual for applying the Acousto-Ultrasonic NDE method, as practiced at NASA Glenn, to the study of materials and structures for a wide range of applications. Three state of the art acousto-ultrasonic (A-U) analysis parameters, ultrasonic decay (UD) rate, mean time (or skewing factor, "s"), and the centroid of the power spectrum, "f(sub c)," have been studied and applied at GRC for NDE interrogation of various materials and structures of aerospace interest. In addition to this, a unique application of Lamb wave analysis is shown. An appendix gives a brief overview of Lamb Wave analysis. This paper presents the analysis employed to calculate these parameters and the development and reasoning behind their use. It also discusses the planning of A-U measurements for materials and structures to be studied. Types of transducer coupling are discussed including contact and non-contact via laser and air. Experimental planning includes matching transducer frequency range to material and geometry of the specimen to be studied. The effect on results of initially zeroing the DC component of the ultrasonic waveform is compared with not doing so. A wide range of interrogation problems are addressed via the application of these analysis parameters to real specimens is shown for five cases: Case 1: Differences in density in [0] SiC/RBSN ceramic matrix composite. Case 2: Effect of tensile fatigue cycling in [+/-45] SiC/SiC ceramic matrix composite. Case 3: Detecting creep life, and failure, in Udimet 520 Nickel-Based Super Alloy. Case 4: Detecting Surface Layer Formation in T-650-35/PMR-15 Polymer Matrix Composites Panels due to Thermal Aging. Case 5: Detecting Spin Test Degradation in PMC Flywheels. Among these cases a wide range of materials and geometries are studied.

  1. Single-pulse and burst-mode ablation of gold films measured by quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Andrusyak, Oleksiy G.; Bubelnik, Matthew; Mares, Jeremy; McGovern, Theresa; Siders, Craig W.

    2005-02-01

    Femtosecond ablation has several distinct advantages: the threshold energy fluence for the onset of damage and ablation is orders of magnitude less than for traditional nanosecond laser machining, and by virtue of the rapid material removal of approximately an optical penetration depth per pulse, femtosecond machined cuts can be cleaner and more precise than those made with traditional nanosecond or longer pulse lasers. However, in many materials of interest, especially metals, this limits ablation rates to 10-100 nm/pulse. We present the results of using multiple pulse bursts to significantly increase the per-burst ablation rate compared to a single pulse with the same integrated energy, while keeping the peak intensity of each individual pulse below the air ionization limit. Femtosecond ablation with pulses centered at 800-nm having integrated energy of up to 30 mJ per pulse incident upon thin gold films was measured via resonance frequency shifts in a gold-electrode-coated quartz-crystal oscillator. Measurements were performed using Michelson-interferometer-based burst generators, with up to 2 ns pulse separations, as well as pulse shaping by programmable acousto-optic dispersive filter (Dazzler from FastLite) with up to 2 ps pulse separations.

  2. Spectral splitting of optical pulses inside a dispersive medium at a temporal boundary

    DOE PAGES

    Plansinis, Brent W.; Donaldson, William R.; Agrawal, Govind P.

    2016-11-07

    We show numerically that the spectrum of an optical pulse splits into multiple, widely separated, spectral bands when it arrives at a temporal boundary across which refractive index changes suddenly. At the same time, the pulse breaks into several temporally separated pulses traveling at different speeds. The number of such pulses depends on the dispersive properties of the medium. We study the effect of second- and third-order dispersion in detail but also consider briefly the impact of other higher-order terms. As a result, a temporal waveguide formed with two temporal boundaries can reflect the temporally separated pulses again and again,more » increasing the number of pulses trapped within the temporal waveguide.« less

  3. Acoustic emission and acousto-ultrasonic techniques for wood and wood-based composites: a review

    Treesearch

    Sumire Kawamoto; R. Sam Williams

    2002-01-01

    This review focuses on the feasibility of acoustic emission (AE) and acousto-ultrasonic (AU) techniques for monitoring defects in wood, particularly during drying. The advantages and disadvantages of AE and AU techniques are described. Particular emphasis is placed on the propagation and attenuation of ultrasonic waves in wood and the associated measurement problems....

  4. MO-A-BRD-01: An Investigation of the Dynamic Response of a Novel Acousto-Optic Liquid Crystal Detector for Full-Field Transmission Ultrasound Breast Imaging

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

    Rosenfield, J.R.; La Riviere, P.J.; Sandhu, J.S.

    Purpose: To characterize the dynamic response of a novel acousto-optic (AO) liquid crystal detector for high-resolution transmission ultrasound breast imaging. Transient and steady-state lesion contrast were investigated to identify optimal transducer settings for our prototype imaging system consistent with the FDA limits of 1 W/cm{sup 2} and 50 J/cm{sup 2} on the incident acoustic intensity and the transmitted acoustic energy flux density. Methods: We have developed a full-field transmission ultrasound breast imaging system that uses monochromatic plane-wave illumination to acquire projection images of the compressed breast. The acoustic intensity transmitted through the breast is converted into a visual image bymore » a proprietary liquid crystal detector operating on the basis of the AO effect. The dynamic response of the AO detector in the absence of an imaged breast was recorded by a CCD camera as a function of the acoustic field intensity and the detector exposure time. Additionally, a stereotactic needle biopsy breast phantom was used to investigate the change in opaque lesion contrast with increasing exposure time for a range of incident acoustic field intensities. Results: Using transducer voltages between 0.3 V and 0.8 V and exposure times of 3 minutes, a unique one-to-one mapping of incident acoustic intensity to steady-state optical brightness in the AO detector was observed. A transfer curve mapping acoustic intensity to steady-state optical brightness shows a high-contrast region analogous to the linear portion of the Hurter-Driffield curves of radiography. Using transducer voltages between 1 V and 1.75 V and exposure times of 90 s, the lesion contrast study demonstrated increasing lesion contrast with increasing breast exposure time and acoustic field intensity. Lesion-to-background contrast on the order of 0.80 was observed. Conclusion: Maximal lesion contrast in our prototype system can be obtained using the highest acoustic field intensity and

  5. Determination of plate wave velocities and diffuse field decay rates with braod-band acousto-ultrasonic signals

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.

    1993-01-01

    Lowest symmetric and lowest antisymmetric plate wave modes were excited and identified in broad-band acousto-ultrasonic (AU) signals collected from various high temperature composite materials. Group velocities have been determined for these nearly nondispersive modes. An algorithm has been developed and applied to determine phase velocities and hence dispersion curves for the frequency ranges of the broad-band pulses. It is demonstrated that these data are sensitive to changes in the various stiffness moduli of the materials, in agreement by analogy, with the theoretical and experimental results of Tang and Henneke on fiber reinforced polymers. Diffuse field decay rates have been determined in the same specimen geometries and AU configuration as for the plate wave measurements. These decay rates are of value in assessing degradation such as matrix cracking in ceramic matrix composites. In addition, we verify that diffuse field decay rates respond to fiber/matrix interfacial shear strength and density in ceramic matrix composites. This work shows that velocity/stiffness and decay rate measurements can be obtained in the same set of AU experiments for characterizing materials and in specimens with geometries useful for mechanical measurements.

  6. Interaction and dispersion of waveguide modes in an optical fiber with microirregularities of the core surface

    NASA Astrophysics Data System (ADS)

    Zadorin, A. S.; Kruglov, R. S.; Surkova, G. A.

    2012-08-01

    A self-consistent linear model is proposed for the transformation of the average intensity of the mode spectrum I( z) of the waveguide field in a multimode optical fiber with a stepped refractive index profile and the core having a rough surface. The model is based on the concept of the intermodal dispersion matrix of an elementary segment of the fiber, ∆, whose elements characterize the mutual transfer of energy between the waveguide modes, as well as their conversion to radiation modes on the specified interval. On this basis, the features of the transformation of the mode spectrum I( z) in a multimode optical fiber with a stepped refractive index profile are considered that is due to the effects of multiple dispersion of the signal by the stochastic irregularities of the duct. The effect of self-filtering of I( z) is described that results in the formation of a stable (normalized) distribution I*. The features of the normalization of the radiative damping of a group of modes I i ( z) in an optical fiber are considered.

  7. Integrated optical maze

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

    Roos, E.V.; Hendrix, J.L.

    1994-06-01

    Improvements to Nuclear Weapons Surety through the development of new detonation control techniques incorporating electro-optic technology are reviewed and proposed in this report. The results of the Kansas City Division`s (KCD`s) literature and vendor search, potential system architecture synthesis, and device test results are the basis of this report. This study has revealed several potential reconfigureable optical interconnect architectures that meet Los Alamos National Laboratory`s preliminary performance specifications. Several planer and global architectures have the potential for meeting the Department of Energy`s applications. Preliminary conclusions on the proposed architectures are discussed. The planer approach of monolithic GaAs amplifier switch arraysmore » is the leading candidate because it meets most of the specifications now. LiNbO{sub 3} and LiTaO{sub 3} planer tree switch arrays are the second choice because they meet all the specifications except for laser power transmission. Although not atop choice, acousto-optical free space switch arrays have been considered and meet most of the specifications. Symmetric-Self Electro-Optic Effect Devices (S-SEED) free space switch arrays are being considered and have excellent potential for smart reconfigureable optical interconnects in the future.« less

  8. Measuring the Dispersion Curve of a PMMA-Fibre Optic Cable Using a Dye Laser

    ERIC Educational Resources Information Center

    Zorba, Serkan; Farah, Constantine; Pant, Ravi

    2010-01-01

    An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and…

  9. Laser control of natural disperse systems

    NASA Astrophysics Data System (ADS)

    Vlasova, Olga L.; Bezrukova, Alexandra G.

    2003-10-01

    Different water disperse systems were studied by integral (spectroturbidemetry) and differential light scattering method with a laser as a source of light. The investigation done concerns the state of kaolin dispersions at storage and under dilution as an example of mineral dispersion systems such as natural water. The role of some light scattering parameters for an optical analysis of water dispersions, like the dispersion of erythrocytes and bacterial cells -Escherichia coli is discussed. The results obtained can help to elaborate the methods for on-line optical control fo natural disperse systems (water, air) with mineral and biological particles.

  10. The application of digital image analysis for blood typing: the comparison of anti-A and anti-B monoclonal antibodies activity with standard hemagglutinating sera

    NASA Astrophysics Data System (ADS)

    Medvedeva, Maria F.; Doubrovski, Valery A.

    2017-03-01

    The resolution of the acousto-optical method for blood typing was estimated experimentally by means of two types of reagents: monoclonal antibodies and standard hemagglutinating sera. The peculiarity of this work is the application of digital photo images processing by pixel analysis previously proposed by the authors. The influence of the concentrations of reagents, of blood sample, which is to be tested, as well as of the duration of the ultrasonic action on the biological object upon the resolution of acousto-optical method were investigated. The optimal experimental conditions to obtain maximum of the resolution of the acousto-optical method were found, it creates the prerequisites for a reliable blood typing. The present paper is a further step in the development of acousto-optical method for determining human blood groups.

  11. Nonlinear optical microscopy for immunoimaging: a custom optimized system of high-speed, large-area, multicolor imaging

    PubMed Central

    Li, Hui; Cui, Quan; Zhang, Zhihong; Luo, Qingming

    2015-01-01

    Background The nonlinear optical microscopy has become the current state-of-the-art for intravital imaging. Due to its advantages of high resolution, superior tissue penetration, lower photodamage and photobleaching, as well as intrinsic z-sectioning ability, this technology has been widely applied in immunoimaging for a decade. However, in terms of monitoring immune events in native physiological environment, the conventional nonlinear optical microscope system has to be optimized for live animal imaging. Generally speaking, three crucial capabilities are desired, including high-speed, large-area and multicolor imaging. Among numerous high-speed scanning mechanisms used in nonlinear optical imaging, polygon scanning is not only linearly but also dispersion-freely with high stability and tunable rotation speed, which can overcome disadvantages of multifocal scanning, resonant scanner and acousto-optical deflector (AOD). However, low frame rate, lacking large-area or multicolor imaging ability make current polygonbased nonlinear optical microscopes unable to meet the requirements of immune event monitoring. Methods We built up a polygon-based nonlinear optical microscope system which was custom optimized for immunoimaging with high-speed, large-are and multicolor imaging abilities. Results Firstly, we validated the imaging performance of the system by standard methods. Then, to demonstrate the ability to monitor immune events, migration of immunocytes observed by the system based on typical immunological models such as lymph node, footpad and dorsal skinfold chamber are shown. Finally, we take an outlook for the possible advance of related technologies such as sample stabilization and optical clearing for more stable and deeper intravital immunoimaging. Conclusions This study will be helpful for optimizing nonlinear optical microscope to obtain more comprehensive and accurate information of immune events. PMID:25694951

  12. Single-mode dispersive waves and soliton microcomb dynamics

    PubMed Central

    Yi, Xu; Yang, Qi-Fan; Zhang, Xueyue; Yang, Ki Youl; Li, Xinbai; Vahala, Kerry

    2017-01-01

    Dissipative Kerr solitons are self-sustaining optical wavepackets in resonators. They use the Kerr nonlinearity to both compensate dispersion and offset optical loss. Besides providing insights into nonlinear resonator physics, they can be applied in frequency metrology, precision clocks, and spectroscopy. Like other optical solitons, the dissipative Kerr soliton can radiate power as a dispersive wave through a process that is the optical analogue of Cherenkov radiation. Dispersive waves typically consist of an ensemble of optical modes. Here, a limiting case is studied in which the dispersive wave is concentrated into a single cavity mode. In this limit, its interaction with the soliton induces hysteresis behaviour in the soliton's spectral and temporal properties. Also, an operating point of enhanced repetition-rate stability occurs through balance of dispersive-wave recoil and Raman-induced soliton-self-frequency shift. The single-mode dispersive wave can therefore provide quiet states of soliton comb operation useful in many applications. PMID:28332495

  13. Transfer function of radio over fiber multimode fiber optic links considering third-order dispersion.

    PubMed

    Capmany, J; Gasulla, Ivana

    2007-08-20

    Although a considerable number of multimode fiber (MMF) links operate in a wavelength region around 850 nm where chromatic dispersion of a given modal group mu is described adequately by the second derivative beta(mu) (2) of the propagation constant beta(mu)(omega), there is also an increasing interest in MMF links transmitting in the second spectral window (@1300nm) where this second derivative vanishes being thus necessary to consider the third derivative beta(mu) (3) in the evaluation of the transfer function of the multimode fiber link. We present in this paper, for the first time to our knowledge, an analytical model for the transfer function of a multimode fiber (MMF) optic link taken into account the impact of third-order dispersion. The model extends the operation of a previously reported one for second-order dispersion. Our results show that the performance of broadband radio over fiber transmission through middle-reach distances can be improved by working at the minimum-dispersion wavelength as long as low-linewidth lasers are employed.

  14. Chromatic dispersion estimation based on heterodyne detection for coherent optical communication systems

    NASA Astrophysics Data System (ADS)

    Li, Yong; Yang, Aiying; Guo, Peng; Qiao, Yaojun; Lu, Yueming

    2018-01-01

    We propose an accurate and nondata-aided chromatic dispersion (CD) estimation method involving the use of the cross-correlation function of two heterodyne detection signals for coherent optical communication systems. Simulations are implemented to verify the feasibility of the proposed method for 28-GBaud coherent systems with different modulation formats. The results show that the proposed method has high accuracy for measuring CD and has good robustness against laser phase noise, amplified spontaneous emission noise, and nonlinear impairments.

  15. High transmittance optical films based on quantum dot doped nanoscale polymer dispersed liquid crystals

    NASA Astrophysics Data System (ADS)

    Gandhi, Sahil Sandesh; Chien, Liang-Chy

    2016-04-01

    We propose a simple way to fabricate highly transparent nanoscale polymer dispersed liquid crystal (nano-PDLC) films between glass substrates and investigate their incident angle dependent optical transmittance properties with both collimated and Lambertian intensity distribution light sources. We also demonstrate that doping nano-PDLC films with 0.1% InP/ZnS core/shell quantum dots (QD) results in a higher optical transmittance. This work lays the foundation for such nanostructured composites to potentially serve as roll-to-roll coatable light extraction or brightness enhancement films in emissive display applications, superior to complex nanocorrugation techniques proposed in the past.

  16. Optical transmission testing based on asynchronous sampling techniques: images analysis containing chromatic dispersion using convolutional neural network

    NASA Astrophysics Data System (ADS)

    Mrozek, T.; Perlicki, K.; Tajmajer, T.; Wasilewski, P.

    2017-08-01

    The article presents an image analysis method, obtained from an asynchronous delay tap sampling (ADTS) technique, which is used for simultaneous monitoring of various impairments occurring in the physical layer of the optical network. The ADTS method enables the visualization of the optical signal in the form of characteristics (so called phase portraits) that change their shape under the influence of impairments such as chromatic dispersion, polarization mode dispersion and ASE noise. Using this method, a simulation model was built with OptSim 4.0. After the simulation study, data were obtained in the form of images that were further analyzed using the convolutional neural network algorithm. The main goal of the study was to train a convolutional neural network to recognize the selected impairment (distortion); then to test its accuracy and estimate the impairment for the selected set of test images. The input data consisted of processed binary images in the form of two-dimensional matrices, with the position of the pixel. This article focuses only on the analysis of images containing chromatic dispersion.

  17. On-chip optical mode conversion based on dynamic grating in photonic-phononic hybrid waveguide

    PubMed Central

    Chen, Guodong; Zhang, Ruiwen; Sun, Junqiang

    2015-01-01

    We present a scheme for reversible and tunable on-chip optical mode conversion based on dynamic grating in a hybrid photonic-phononic waveguide. The dynamic grating is built up through the acousto-optic effect and the theoretical model of the optical mode conversion is developed by considering the geometrical deformation and refractive index change. Three kinds of mode conversions are able to be realized using the same hybrid waveguide structure in a large bandwidth by only changing the launched acoustic frequency. The complete mode conversion can be achieved by choosing a proper acoustic power under a given waveguide length. PMID:25996236

  18. On compensation of four wave mixing effect in dispersion managed hybrid WDM-OTDM multicast overlay system with optical phase conjugation modules

    NASA Astrophysics Data System (ADS)

    Singh, Sukhbir; Singh, Surinder

    2017-11-01

    This paper investigated the effect of FWM and its suppression using optical phase conjugation modules in dispersion managed hybrid WDM-OTDM multicast overlay system. Interaction between propagating wavelength signals at higher power level causes new FWM component generation that can significant limit the system performance. OPC module consists of the pump signal and 0.6 km HNLF implemented in midway of optical link to generate destructive phase FWM components. Investigation revealed that by use of even OPC module in optical link reduces the FWM power and mitigate the interaction between wavelength signals at variable signal input power, dispersion parameter (β2) and transmission distance. System performance comparison is also made between without DM-OPC module, with DM and with DM-OPC module in scenario of FWM tolerance. The BER performance of hybrid WDM-OTDM multicast system using OPC module is improved by multiplication factor of 2 as comparable to dispersion managed and coverage distance is increased by factor of 2 as in Singh and Singh (2016).

  19. Practical implementation of spectral-intensity dispersion-canceled optical coherence tomography with artifact suppression

    NASA Astrophysics Data System (ADS)

    Shirai, Tomohiro; Friberg, Ari T.

    2018-04-01

    Dispersion-canceled optical coherence tomography (OCT) based on spectral intensity interferometry was devised as a classical counterpart of quantum OCT to enhance the basic performance of conventional OCT. In this paper, we demonstrate experimentally that an alternative method of realizing this kind of OCT by means of two optical fiber couplers and a single spectrometer is a more practical and reliable option than the existing methods proposed previously. Furthermore, we develop a recipe for reducing multiple artifacts simultaneously on the basis of simple averaging and verify experimentally that it works successfully in the sense that all the artifacts are mitigated effectively and only the true signals carrying structural information about the sample survive.

  20. Optical implementation of systolic array processing

    NASA Technical Reports Server (NTRS)

    Caulfield, H. J.; Rhodes, W. T.; Foster, M. J.; Horvitz, S.

    1981-01-01

    Algorithms for matrix vector multiplication are implemented using acousto-optic cells for multiplication and input data transfer and using charge coupled devices detector arrays for accumulation and output of the results. No two dimensional matrix mask is required; matrix changes are implemented electronically. A system for multiplying a 50 component nonnegative real vector by a 50 by 50 nonnegative real matrix is described. Modifications for bipolar real and complex valued processing are possible, as are extensions to matrix-matrix multiplication and multiplication of a vector by multiple matrices.

  1. Compact first and second order polarization mode dispersion emulator

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Li, Shiguang; Yang, Changxi

    2005-08-01

    We propose a 1st and 2nd order polarization mode dispersion emulator (PMDE) with one variable differential group delay (DGD) element using birefringence crystals and four polarization controllers (PCs). Monte Carlo simulations demonstrate that the output 1st and 2nd order polarization mode dispersion (PMD) generated by the PMDE consists with statistic theory. Compared with former PMDEs, this design is tunable, lower-cost, and more integrated for fabrication, which shows response time of 150 ?s, response frequency of 3.8 kHz, working wavelength of 1550 nm, total power consumption of less than 3 W, working range of 0---84 ps and 0---3600 ps2 for 1st and 2nd order PMD emulation, respectively. Also, it is programmable and can be controlled by either singlechip or computer. It can be applied to study the outage probability of optical communication systems due to PMD effect and the effectiveness of PMD compensation.

  2. Imaging of optically diffusive media by use of opto-elastography

    NASA Astrophysics Data System (ADS)

    Bossy, Emmanuel; Funke, Arik R.; Daoudi, Khalid; Tanter, Mickael; Fink, Mathias; Boccara, Claude

    2007-02-01

    We present a camera-based optical detection scheme designed to detect the transient motion created by the acoustic radiation force in elastic media. An optically diffusive tissue mimicking phantom was illuminated with coherent laser light, and a high speed camera (2 kHz frame rate) was used to acquire and cross-correlate consecutive speckle patterns. Time-resolved transient decorrelations of the optical speckle were measured as the results of localised motion induced in the medium by the radiation force and subsequent propagating shear waves. As opposed to classical acousto-optic techniques which are sensitive to vibrations induced by compressional waves at ultrasonic frequencies, the proposed technique is sensitive only to the low frequency transient motion induced in the medium by the radiation force. It therefore provides a way to assess both optical and shear mechanical properties.

  3. LASER APPLICATIONS AND OTHER ASPECTS OF QUANTUM ELECTRONICS Measurement of angular parameters of divergent optical radiation by light diffraction on sound

    NASA Astrophysics Data System (ADS)

    Kotov, V. M.; Averin, S. V.; Shkerdin, G. N.

    2010-12-01

    A method is proposed to measure the scattering angle of optical radiation, the method employing two Bragg diffraction processes in which divergent optical radiation propagates close to the optical axis of a uniaxial crystal, while the acoustic wave — orthogonally to this axis. The method does not require additional angular tuning of the acousto-optic cell. We suggest using a mask to measure the light divergence that is larger than the angle of Bragg scattering. The method can be used to measure the size of the polished glass plate inhomogeneities.

  4. Full distortion induced by dispersion evaluation and optical bandwidth constraining of fiber Bragg grating demultiplexers over analogue SCM systems.

    PubMed

    Martinez, Alfonso; Pastor, Daniel; Capmany, Jose

    2002-12-30

    We provide a full analysis of the distortion effects produced by the first and second order in-band dispersion of fiber Bragg grating based optical demultiplexers over analogue SCM (Sub Carrier Multiplexed) signals. Optical bandwidth utilization ranges for Dense WDM network are calculated considering different SCM system cases of frequency extension and modulation conditions.

  5. Programmable diffractive lens for ophthalmic application

    NASA Astrophysics Data System (ADS)

    Millán, María S.; Pérez-Cabré, Elisabet; Romero, Lenny A.; Ramírez, Natalia

    2014-06-01

    Pixelated liquid crystal displays have been widely used as spatial light modulators to implement programmable diffractive optical elements, particularly diffractive lenses. Many different applications of such components have been developed in information optics and optical processors that take advantage of their properties of great flexibility, easy and fast refreshment, and multiplexing capability in comparison with equivalent conventional refractive lenses. We explore the application of programmable diffractive lenses displayed on the pixelated screen of a liquid crystal on silicon spatial light modulator to ophthalmic optics. In particular, we consider the use of programmable diffractive lenses for the visual compensation of refractive errors (myopia, hypermetropia, astigmatism) and presbyopia. The principles of compensation are described and sketched using geometrical optics and paraxial ray tracing. For the proof of concept, a series of experiments with artificial eye in optical bench are conducted. We analyze the compensation precision in terms of optical power and compare the results with those obtained by means of conventional ophthalmic lenses. Practical considerations oriented to feasible applications are provided.

  6. Modeling of dispersion and nonlinear characteristics of tapered photonic crystal fibers for applications in nonlinear optics

    NASA Astrophysics Data System (ADS)

    Pakarzadeh, H.; Rezaei, S. M.

    2016-01-01

    In this article, we investigate for the first time the dispersion and the nonlinear characteristics of the tapered photonic crystal fibers (PCFs) as a function of length z, via solving the eigenvalue equation of the guided mode using the finite-difference frequency-domain method. Since the structural parameters such as the air-hole diameter and the pitch of the microstructured cladding change along the tapered PCFs, dispersion and nonlinear properties change with the length as well. Therefore, it is important to know the exact behavior of such fiber parameters along z which is necessary for nonlinear optics applications. We simulate the z dependency of the zero-dispersion wavelength, dispersion slope, effective mode area, nonlinear parameter, and the confinement loss along the tapered PCFs and propose useful relations for describing dispersion and nonlinear parameters. The results of this article, which are in a very good agreement with the available experimental data, are important for simulating pulse propagation as well as investigating nonlinear effects such as supercontinuum generation and parametric amplification in tapered PCFs.

  7. Pulse duration dependent nonlinear optical response in black phosphorus dispersions

    NASA Astrophysics Data System (ADS)

    Tang, Shana; He, Zhiliang; Liang, Guowen; Chen, Si; Ge, Yanqi; Sang, David K.; Lu, Jianxin; Lu, Shunbin; Wen, Qiao; Zhang, Han

    2018-01-01

    Black phosphorus (BP), is the most thermodynamically stable allotrope of phosphorus, the narrow direct band gap and the strong light-matter interaction make BP a promising nonlinear optical (NLO) nano-material. In this paper, we use the open aperture Z- scan method to measure the NLO property of BP dispersion. Saturable absorption was observed in the BP material through the excitation of Ti: sapphire laser at 800 nm. Three different excitation pulse duration (100 fs, 1 ps and 10 ps) were used in the experiments, and BP exhibited different NLO performance. The results show that nonlinear absorption coefficient and figure of merit of BP nanosheets are proportional to the pulse duration while saturable intensity is opposite to pulse duration.

  8. Wide-aperture TeO₂ AOTF at low temperatures: operation and survival.

    PubMed

    Mantsevich, S N; Korablev, O I; Kalinnikov, Yu K; Ivanov, A Yu; Kiselev, A V

    2015-05-01

    The effect of temperature on the performance in a wide-angle paratellurite acousto-optic tunable filter (AOTF) is analyzed on the example of two different AOTF configurations. The present study is a by-product of the AOTF characterization for space-borne applications. The two AOTFs serve as dispersion elements in spectrometers for Moon and Mars space missions. The operation of the AO filters was tested in the range of -50° to+40°C; we have also demonstrated the survival of an AOTF device at -130°C. The phase matching ultrasound frequency varies with temperature within 2.5×10(-5) K(-1) and 6.6×10(-5) K(-1). We link this temperature shift to elastic characteristics of the TeO2, and demonstrate that it is mostly explained by the temperature modification of the slow acoustic wave velocity. We point out the best reference describing experimental results (Silvestrova et al., 1987). A generalization is made for all wide-angle acousto-optic tunable filters based on tellurium dioxide crystal. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Digital micromirror devices: principles and applications in imaging.

    PubMed

    Bansal, Vivek; Saggau, Peter

    2013-05-01

    A digital micromirror device (DMD) is an array of individually switchable mirrors that can be used in many advanced optical systems as a rapid spatial light modulator. With a DMD, several implementations of confocal microscopy, hyperspectral imaging, and fluorescence lifetime imaging can be realized. The DMD can also be used as a real-time optical processor for applications such as the programmable array microscope and compressive sensing. Advantages and disadvantages of the DMD for these applications as well as methods to overcome some of the limitations will be discussed in this article. Practical considerations when designing with the DMD and sample optical layouts of a completely DMD-based imaging system and one in which acousto-optic deflectors (AODs) are used in the illumination pathway are also provided.

  10. Characterization of Ultrafast Laser Pulses using a Low-dispersion Frequency Resolved Optical Grating Spectrometer

    NASA Astrophysics Data System (ADS)

    Whitelock, Hope; Bishop, Michael; Khosravi, Soroush; Obaid, Razib; Berrah, Nora

    2016-05-01

    A low dispersion frequency-resolved optical gating (FROG) spectrometer was designed to characterize ultrashort (<50 femtosecond) laser pulses from a commercial regenerative amplifier, optical parametric amplifier, and a home-built non-colinear optical parametric amplifier. This instrument splits a laser pulse into two replicas with a 90:10 intensity ratio using a thin pellicle beam-splitter and then recombines the pulses in a birefringent medium. The instrument detects a wavelength-sensitive change in polarization of the weak probe pulse in the presence of the stronger pump pulse inside the birefringent medium. Scanning the time delay between the two pulses and acquiring spectra allows for characterization of the frequency and time content of ultrafast laser pulses, that is needed for interpretation of experimental results obtained from these ultrafast laser systems. Funded by the DoE-BES, Grant No. DE-SC0012376.

  11. Modeling dispersive coupling and losses of localized optical and mechanical modes in optomechanical crystals

    NASA Astrophysics Data System (ADS)

    Eichenfield, Matt; Chan, Jasper; Safavi-Naeini, Amir H.; Vahala, Kerry J.; Painter, Oskar

    2009-10-01

    Periodically structured materials can sustain both optical and mechanical excitations which are tailored by the geometry. Here we analyze the properties of dispersively coupled planar photonic and phononic crystals: optomechanical crystals. In particular, the properties of co-resonant optical and mechanical cavities in quasi-1D (patterned nanobeam) and quasi-2D (patterned membrane) geometries are studied. It is shown that the mechanical Q and optomechanical coupling in these structures can vary by many orders of magnitude with modest changes in geometry. An intuitive picture is developed based upon a perturbation theory for shifting material boundaries that allows the optomechanical properties to be designed and optimized. Several designs are presented with mechanical frequency ~ 1-10 GHz, optical Q-factor Qo > 10^7, motional masses meff 100 femtograms, optomechanical coupling length LOM < 5 microns, and a radiation-limited mechanical Q-factor Qm > 10^7.

  12. Refractive-index dispersion measurement of bulk optical materials using a fiber raman laser widely tunable in the visible and near-infrared

    NASA Astrophysics Data System (ADS)

    Ilev, Ilko K.; Kumagai, Hiroshi; Toyoda, Koichi

    1997-01-01

    We propose a simple, highly sensitive fiber-optic autocollimation method for refractive-index dispersion measurement of solid-state and liquid bulk optical materials using a double-pass fiber Raman laser with Littrow-prism-tuned emission. The optical fiber is a key element of the scheme and serves simultaneously as a point laser source for the test, as a highly sensitive point receiver (or spatial filter) of the autocollimation backreflectance signal and as a medium for nonlinear frequency conversion and generation of a broadband continuum spectrum. When the Raman medium is a graded-index multimode fiber with powerful pumping (over 100 kW) using the second harmonic of a Q-switched Nd:YAG laser (λp=532nm), we obtain widely tunable (0.54-1.01 μm) generation in both the visible and near-IR ranges. The results obtained in the refractive-index dispersion measurements are fitted to the Sellmeier dispersion equation and the standard deviation of the experimental data from the analytical curve does not exceed 5x10-5.

  13. Dispersal of Engineered Male Aedes aegypti Mosquitoes.

    PubMed

    Winskill, Peter; Carvalho, Danilo O; Capurro, Margareth L; Alphey, Luke; Donnelly, Christl A; McKemey, Andrew R

    2015-11-01

    Aedes aegypti, the principal vector of dengue fever, have been genetically engineered for use in a sterile insect control programme. To improve our understanding of the dispersal ecology of mosquitoes and to inform appropriate release strategies of 'genetically sterile' male Aedes aegypti detailed knowledge of the dispersal ability of the released insects is needed. The dispersal ability of released 'genetically sterile' male Aedes aegypti at a field site in Brazil has been estimated. Dispersal kernels embedded within a generalized linear model framework were used to analyse data collected from three large scale mark release recapture studies. The methodology has been applied to previously published dispersal data to compare the dispersal ability of 'genetically sterile' male Aedes aegypti in contrasting environments. We parameterised dispersal kernels and estimated the mean distance travelled for insects in Brazil: 52.8 m (95% CI: 49.9 m, 56.8 m) and Malaysia: 58.0 m (95% CI: 51.1 m, 71.0 m). Our results provide specific, detailed estimates of the dispersal characteristics of released 'genetically sterile' male Aedes aegypti in the field. The comparative analysis indicates that despite differing environments and recapture rates, key features of the insects' dispersal kernels are conserved across the two studies. The results can be used to inform both risk assessments and release programmes using 'genetically sterile' male Aedes aegypti.

  14. Q-switched Nd:YAG optical vortex lasers.

    PubMed

    Kim, D J; Kim, J W; Clarkson, W A

    2013-12-02

    Q-switched operation of a high-quality Nd:YAG optical vortex laser with the first order Laguerre-Gaussian mode and well-determined helical wavefronts using a fiber-based pump beam conditioning scheme is reported. A simple two-mirror resonator incorporating an acousto-optic Q-switch was employed, along with an etalon and a Brewster plate to enforce the particular helicity of the output. The laser yielded Q-switched pulses with ~250 μJ pulse energy and ~33 ns pulse duration (FWHM) at a 0.1 kHz repetition rate for 5.1 W of absorbed pump power. The handedness of the helical wavefronts was preserved regardless of the repetition rates. The prospects of further power scaling and improved laser performance are discussed.

  15. Direct RF A-O Processor Spectrum Analyzer.

    DTIC Science & Technology

    1981-08-01

    The primary objective was to develop and demonstrate design approach, along with the associated processing technologies, for a wideband acousto optic Bragg...cell spectrum analyzer. The signal processor used to demonstrate feasibility of the technical approach consisted of two bulk wave acousto optic deflectors

  16. Exploration of operator method digital optical computers for application to NASA

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Digital optical computer design has been focused primarily towards parallel (single point-to-point interconnection) implementation. This architecture is compared to currently developing VHSIC systems. Using demonstrated multichannel acousto-optic devices, a figure of merit can be formulated. The focus is on a figure of merit termed Gate Interconnect Bandwidth Product (GIBP). Conventional parallel optical digital computer architecture demonstrates only marginal competitiveness at best when compared to projected semiconductor implements. Global, analog global, quasi-digital, and full digital interconnects are briefly examined as alternative to parallel digital computer architecture. Digital optical computing is becoming a very tough competitor to semiconductor technology since it can support a very high degree of three dimensional interconnect density and high degrees of Fan-In without capacitive loading effects at very low power consumption levels.

  17. Simulation of time-dispersion spectral device with sample spectra accumulation

    NASA Astrophysics Data System (ADS)

    Zhdanov, Arseny; Khansuvarov, Ruslan; Korol, Georgy

    2014-09-01

    This research is conducted in order to design a spectral device for light sources power spectrum analysis. The spectral device should process radiation from sources, direct contact with radiation of which is either impossible or undesirable. Such sources include jet blast of an aircraft, optical radiation in metallurgy and textile industry. In proposed spectral device optical radiation is guided out of unfavorable environment via a piece of optical fiber with high dispersion. It is necessary for analysis to make samples of analyzed radiation as short pulses. Dispersion properties of such optical fiber cause spectral decomposition of input optical pulses. The faster time of group delay vary the stronger the spectral decomposition effect. This effect allows using optical fiber with high dispersion as a major element of proposed spectral device. Duration of sample must be much shorter than group delay time difference of a dispersive system. In the given frequency range this characteristic has to be linear. The frequency range is 400 … 500 THz for typical optical fiber. Using photonic-crystal fiber (PCF) gives much wider spectral range for analysis. In this paper we propose simulation of single pulse transmission through dispersive system with linear dispersion characteristic and quadratic-detected output responses accumulation. During simulation we propose studying influence of optical fiber dispersion characteristic angle on spectral measurement results. We also consider pulse duration and group delay time difference impact on output pulse shape and duration. Results show the most suitable dispersion characteristic that allow choosing the structure of PCF - major element of time-dispersion spectral analysis method and required number of samples for reliable assessment of measured spectrum.

  18. Optical pattern recognition architecture implementing the mean-square error correlation algorithm

    DOEpatents

    Molley, Perry A.

    1991-01-01

    An optical architecture implementing the mean-square error correlation algorithm, MSE=.SIGMA.[I-R].sup.2 for discriminating the presence of a reference image R in an input image scene I by computing the mean-square-error between a time-varying reference image signal s.sub.1 (t) and a time-varying input image signal s.sub.2 (t) includes a laser diode light source which is temporally modulated by a double-sideband suppressed-carrier source modulation signal I.sub.1 (t) having the form I.sub.1 (t)=A.sub.1 [1+.sqroot.2m.sub.1 s.sub.1 (t)cos (2.pi.f.sub.o t)] and the modulated light output from the laser diode source is diffracted by an acousto-optic deflector. The resultant intensity of the +1 diffracted order from the acousto-optic device is given by: I.sub.2 (t)=A.sub.2 [+2m.sub.2.sup.2 s.sub.2.sup.2 (t)-2.sqroot.2m.sub.2 (t) cos (2.pi.f.sub.o t] The time integration of the two signals I.sub.1 (t) and I.sub.2 (t) on the CCD deflector plane produces the result R(.tau.) of the mean-square error having the form: R(.tau.)=A.sub.1 A.sub.2 {[T]+[2m.sub.2.sup.2.multidot..intg.s.sub.2.sup.2 (t-.tau.)dt]-[2m.sub.1 m.sub.2 cos (2.tau.f.sub.o .tau.).multidot..intg.s.sub.1 (t)s.sub.2 (t-.tau.)dt]} where: s.sub.1 (t) is the signal input to the diode modulation source: s.sub.2 (t) is the signal input to the AOD modulation source; A.sub.1 is the light intensity; A.sub.2 is the diffraction efficiency; m.sub.1 and m.sub.2 are constants that determine the signal-to-bias ratio; f.sub.o is the frequency offset between the oscillator at f.sub.c and the modulation at f.sub.c +f.sub.o ; and a.sub.o and a.sub.1 are constant chosen to bias the diode source and the acousto-optic deflector into their respective linear operating regions so that the diode source exhibits a linear intensity characteristic and the AOD exhibits a linear amplitude characteristic.

  19. Controllable vacuum-induced diffraction of matter-wave superradiance using an all-optical dispersive cavity

    NASA Astrophysics Data System (ADS)

    Su, Shih-Wei; Lu, Zhen-Kai; Gou, Shih-Chuan; Liao, Wen-Te

    2016-10-01

    Cavity quantum electrodynamics (CQED) has played a central role in demonstrating the fundamental principles of the quantum world, and in particular those of atom-light interactions. Developing fast, dynamical and non-mechanical control over a CQED system is particularly desirable for controlling atomic dynamics and building future quantum networks at high speed. However conventional mirrors do not allow for such flexible and fast controls over their coupling to intracavity atoms mediated by photons. Here we theoretically investigate a novel all-optical CQED system composed of a binary Bose-Einstein condensate (BEC) sandwiched by two atomic ensembles. The highly tunable atomic dispersion of the CQED system enables the medium to act as a versatile, all-optically controlled atomic mirror that can be employed to manipulate the vacuum-induced diffraction of matter-wave superradiance. Our study illustrates a innovative all-optical element of atomtroics and sheds new light on controlling light-matter interactions.

  20. Analytical study of acoustically perturbed Brillouin active magnetized semiconductor plasma

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

    Shukla, Arun, E-mail: arunshuklaujn@gmail.com; Jat, K. L.

    2015-07-31

    An analytical study of acoustically perturbed Brillouin active magnetized semiconductor plasma has been reported. In the present analytical investigation, the lattice displacement, acousto-optical polarization, susceptibility, acousto-optical gain constant arising due to the induced nonlinear current density and acousto-optical process are deduced in an acoustically perturbed Brillouin active magnetized semiconductor plasma using the hydrodynamical model of plasma and coupled mode scheme. The influence of wave number and magnetic field has been explored. The analysis has been applied to centrosymmetric crystal. Numerical estimates are made for n-type InSb crystal duly irradiated by a frequency doubled 10.6 µm CO{sub 2} laser. It is foundmore » that lattice displacement, susceptibility and acousto-optical gain increase linearly with incident wave number and applied dc magnetic field, while decrease with scattering angle. The gain also increases with electric amplitude of incident laser beam. Results are found to be well in agreement with available literature.« less

  1. Optical mass memory investigation

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The MASTER 1 optical mass storage system advanced working model (AWM) was designed to demonstrate recording and playback of imagery data and to enable quantitative data to be derived as to the statistical distribution of raw errors experienced through the system. The AWM consists of two subsystems, the recorder and storage and retrieval. The recorder subsystem utilizes key technologies such as an acoustic travelling wave lens to achieve recording of digital data on fiche at a rate of 30 Mbits/sec, whereas the storage and retrieval reproducer subsystem utilizes a less complex optical system that employs an acousto-optical beam deflector to achieve data readout at a 5 Mbits/sec rate. The system has the built in capability for detecting and collecting error statistics. The recorder and storage and retrieval subsystems operate independent of one another and are each constructed in modular form with each module performing independent functions. The operation of each module and its interface to other modules is controlled by one controller for both subsystems.

  2. Programmable Colored Illumination Microscopy (PCIM): A practical and flexible optical staining approach for microscopic contrast enhancement

    NASA Astrophysics Data System (ADS)

    Zuo, Chao; Sun, Jiasong; Feng, Shijie; Hu, Yan; Chen, Qian

    2016-03-01

    Programmable colored illumination microscopy (PCIM) has been proposed as a flexible optical staining technique for microscopic contrast enhancement. In this method, we replace the condenser diaphragm of a conventional microscope with a programmable thin film transistor-liquid crystal display (TFT-LCD). By displaying different patterns on the LCD, numerous established imaging modalities can be realized, such as bright field, dark field, phase contrast, oblique illumination, and Rheinberg illuminations, which conventionally rely on intricate alterations in the respective microscope setups. Furthermore, the ease of modulating both the color and the intensity distribution at the aperture of the condenser opens the possibility to combine multiple microscopic techniques, or even realize completely new methods for optical color contrast staining, such as iridescent dark-field and iridescent phase-contrast imaging. The versatility and effectiveness of PCIM is demonstrated by imaging of several transparent colorless specimens, such as unstained lung cancer cells, diatom, textile fibers, and a cryosection of mouse kidney. Finally, the potentialities of PCIM for RGB-splitting imaging with stained samples are also explored by imaging stained red blood cells and a histological section.

  3. Optical parameters and dispersion behavior of potassium magnesium chloride sulfate single crystals doped with Co+2 ions

    NASA Astrophysics Data System (ADS)

    Abu El-Fadl, A.; Abd-Elsalam, A. M.

    2018-05-01

    Single crystals of potassium magnesium chloride sulfate (KMCS) doped with cobalt ions were grown by slow cooling method. Powder XRD study confirmed the monoclinic structure of the grown crystals. The functional group vibrations were checked through FTIR spectroscopy measurements. In optical studies, the absorbance behavior of the crystals and their optical energy gap were established by Tauc plot. The refractive index, the extinction coefficient and other optical constants were calculated for the grown crystals. The normal dispersion of the refractive index was analyzed according to single oscillator Sellmeier's model. The Urbach's rule was applied to analyze the localized states density in the forbidden gap.

  4. Acoustic dispersive prism.

    PubMed

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R

    2016-01-07

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  5. High repetition frequency PPMgOLN mid-infrared optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Liu, J.; Liu, Q.; Yan, X.; Chen, H.; Gong, M.

    2010-09-01

    A mid-infrared optical parametric oscillator (OPO) with the idler wavelengths of 3591 nm, 3384 nm, and 3164 nm at the repetition of 76.8 kHz is reported, and a high repetition frequency acousto-optic Q-switched Nd:YVO4 laser is used as the pump source. The OPO is designed as an external non-colinear single-resonator optical parametric oscillator. When the power of the pump light is 25.1 W, the idler with the wavelength of 3164 nm and the power of 4.3 W is generated. The corresponding signal light is 1603 nm with the power of 3.1 W. The efficiency from 1064 nm to 3160 nm can reach as high as 17.1%, and the efficiency of the OPO is 29.5%.

  6. Heterodyne interferometer with angstrom-level periodic nonlinearity

    DOEpatents

    Schmitz, Tony L.; Beckwith, John F.

    2005-01-25

    Displacement measuring interferometer systems and methods are disclosed. One or more acousto-optic modulators for receiving a laser light beam from a laser light source can be utilized to split the laser light beam into two or more laser light beams, while spatially separating frequencies thereof. One or more reflective mechanisms can be utilized to reflect one or more of the laser light beams back to the acousto-optic modulator. Interference of two or more of the laser light beams generally at the acousto-optic modulator can provide an interfered laser light beam thereof. A detector for receiving the interfered laser light beam can be utilized to provide interferometer measurement data.

  7. Dispersion management with metamaterials

    DOEpatents

    Tassin, Philippe; Koschny, Thomas; Soukoulis, Costas M.

    2017-03-07

    An apparatus, system, and method to counteract group velocity dispersion in fibers, or any other propagation of electromagnetic signals at any wavelength (microwave, terahertz, optical, etc.) in any other medium. A dispersion compensation step or device based on dispersion-engineered metamaterials is included and avoids the need of a long section of specialty fiber or the need for Bragg gratings (which have insertion loss).

  8. Analytical expressions for the nonlinear interference in dispersion managed transmission coherent optical systems

    NASA Astrophysics Data System (ADS)

    Qiao, Yaojun; Li, Ming; Yang, Qiuhong; Xu, Yanfei; Ji, Yuefeng

    2015-01-01

    Closed-form expressions of nonlinear interference of dense wavelength-division-multiplexed (WDM) systems with dispersion managed transmission (DMT) are derived. We carry out a simulative validation by addressing an ample and significant set of the Nyquist-WDM systems based on polarization multiplexed quadrature phase-shift keying (PM-QPSK) subcarriers at a baud rate of 32 Gbaud per channel. Simulation results show the simple closed-form analytical expressions can provide an effective tool for the quick and accurate prediction of system performance in DMT coherent optical systems.

  9. Noncontact Acousto-Ultrasonics for Material Characterization

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.

    1998-01-01

    A NdYAG 1064 nm, laser pulse was employed to produce ultrasonic waves in specimens of SiC/SiC and SiC/Ti 6-4 composites which are high temperature materials of interest for aerospace applications. Air coupled transducers were used to detect and collect the signals used for acousto-ultrasonic analysis. Conditions for detecting ultrasonic decay signals were examined. The results were compared to those determined on the same specimens with contact coupling. Some non-contact measurements were made employing conventional air focused detectors. Others were performed with a more novel micromachined capacitance transducer. Concerns of the laser-in technology include potential destructiveness of the laser pulse. Repeated laser pulsing at the same location does lead to deterioration of the ultrasonic signal in some materials, but seems to recover with time. Also, unlike contact AU, the frequency regime employed is a function of laser-material interaction rather than the choice of transducers. Concerns of the air coupled-out technology include the effect of air attenuation. This imposes a practical upper limit to frequency of detection. In the case of the experimental specimens studied ultrasonic decay signals could be imaged satisfactorily.

  10. A coherent light scanner for optical processing of large format transparencies

    NASA Technical Reports Server (NTRS)

    Callen, W. R.; Weaver, J. E.; Shackelford, R. G.; Walsh, J. R.

    1975-01-01

    A laser scanner is discussed in which the scanning beam is random-access addressable and perpendicular to the image input plane and the irradiance of the scanned beam is controlled so that a constant average irradiance is maintained after passage through the image plane. The scanner's optical system and design are described, and its performance is evaluated. It is noted that with this scanner, data in the form of large-format transparencies can be processed without the expense, space, maintenance, and precautions attendant to the operation of a high-power laser with large-aperture collimating optics. It is shown that the scanned format as well as the diameter of the scanning beam may be increased by simple design modifications and that higher scan rates can be achieved at the expense of resolution by employing acousto-optic deflectors with different relay optics.

  11. Noise study of all-normal dispersion supercontinuum sources for potential application in optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Gonzalo, I. B.; Engelsholm, R. D.; Bang, O.

    2018-03-01

    Commercially available silica-fiber-based and ultra-broadband supercontinuum (SC) sources are typically generated by pumping close to the zero-dispersion wavelength (ZDW) of a photonic crystal fiber (PCF), using high-power picosecond or nanosecond laser pulses. Despite the extremely broad bandwidths, such sources are characterized by large intensity fluctuations, limiting their performance for applications in imaging such as optical coherence tomography (OCT). An approach to eliminate the influence of noise sensitive effects is to use a so-called all-normal dispersion (ANDi) fiber, in which the dispersion is normal for all the wavelengths of interest. Pumping these types of fibers with short enough femtosecond pulses allows to suppress stimulated Raman scattering (SRS), which is known to be as noisy process as modulation instability (MI), and coherent SC is generated through self-phase modulation (SPM) and optical wave breaking (OWB). In this study, we show the importance of the pump laser and fiber parameters in the design of low-noise ANDi based SC sources, for application in OCT. We numerically investigate the pulse-to-pulse fluctuations of the SC, calculating the relative intensity noise (RIN) as a function of the pump pulse duration and fiber length. Furthermore, we experimentally demonstrate the role of the fiber length on the RIN of the ANDi SC, validating the results calculated numerically. In the end, we compare the RIN of a commercial SC source based on MI and the ANDi SC source developed here, which shows better noise performance when it is carefully designed.

  12. Simulation of heating by optical absorption in nanoparticle dispersions (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Olbricht, Benjamin C.

    2017-02-01

    With the proliferation of highly confined, nanophotonic waveguides and laser sources with increasing intensity, the effects of laser heating will begin to greatly impact the materials used in optical applications. In order to better understand the mechanism of laser heating, its timescales, and the dispersion of heat into the material, simulations of nanoparticles in various media are presented. A generic model to describe a variety of nanoparticle shapes and sizes is desirable to describe complex phenomenon. These particles are dispersed into various solids, liquids, or gases depending on the application. To simulate nanoparticles and their interaction with their host material, the Finite Element Method (FEM) is used. Heat transfer following an absorption event is also described by a parabolic partial differential equation, and transient solutions are generated in response to continuous, pulsed, or modulated laser radiation. The simplest physical system described by FEM is that of a broadly-absorbing round-shaped nanoparticle dispersed in viscous host fluid or solid. Many experimental and theoretical studies conveniently describe a very similar system: a carbon "black" nanoparticle suspended in water. This material is well-known to exhibit nonlinear behavior when a laser pulse carrying 0.7 J/cm2 is incident on the material. For this process the FEM simulations agree with experimental results to show that a pulse of this fluence is capable of heating the solvent elements adjacent to the nanoparticle to their boiling point. This creates nonlinear scattering which is empirically observed as a nonlinear decrease in the transmitted power at this input fluence.

  13. Manipulation of Micro Scale Particles in Optical Traps Using Programmable Spatial Light Modulation

    NASA Technical Reports Server (NTRS)

    Seibel, Robin E.; Decker, Arthur J. (Technical Monitor)

    2003-01-01

    1064 nm light, from an Nd:YAG laser, was polarized and incident upon a programmable parallel aligned liquid crystal spatial light modulator (PAL-SLM), where it was phase modulated according to the program controlling the PAL-SLM. Light reflected from the PAL-SLM was injected into a microscope and focused. At the focus, multiple optical traps were formed in which 9.975 m spheres were captured. The traps and the spheres were moved by changing the program of the PAL-SLM. The motion of ordered groups of micro particles was clearly demonstrated.

  14. Dispersed Fringe Sensing Analysis - DFSA

    NASA Technical Reports Server (NTRS)

    Sigrist, Norbert; Shi, Fang; Redding, David C.; Basinger, Scott A.; Ohara, Catherine M.; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.; Spechler, Joshua A.

    2012-01-01

    Dispersed Fringe Sensing (DFS) is a technique for measuring and phasing segmented telescope mirrors using a dispersed broadband light image. DFS is capable of breaking the monochromatic light ambiguity, measuring absolute piston errors between segments of large segmented primary mirrors to tens of nanometers accuracy over a range of 100 micrometers or more. The DFSA software tool analyzes DFS images to extract DFS encoded segment piston errors, which can be used to measure piston distances between primary mirror segments of ground and space telescopes. This information is necessary to control mirror segments to establish a smooth, continuous primary figure needed to achieve high optical quality. The DFSA tool is versatile, allowing precise piston measurements from a variety of different optical configurations. DFSA technology may be used for measuring wavefront pistons from sub-apertures defined by adjacent segments (such as Keck Telescope), or from separated sub-apertures used for testing large optical systems (such as sub-aperture wavefront testing for large primary mirrors using auto-collimating flats). An experimental demonstration of the coarse-phasing technology with verification of DFSA was performed at the Keck Telescope. DFSA includes image processing, wavelength and source spectral calibration, fringe extraction line determination, dispersed fringe analysis, and wavefront piston sign determination. The code is robust against internal optical system aberrations and against spectral variations of the source. In addition to the DFSA tool, the software package contains a simple but sophisticated MATLAB model to generate dispersed fringe images of optical system configurations in order to quickly estimate the coarse phasing performance given the optical and operational design requirements. Combining MATLAB (a high-level language and interactive environment developed by MathWorks), MACOS (JPL s software package for Modeling and Analysis for Controlled Optical

  15. High-resolution (>5 800 time-bandwidth product) shear mode TeO2 deflector

    NASA Astrophysics Data System (ADS)

    Soos, Jolanta I.; Caviris, Nicholas P.; Phuvan, Sonlinh

    1992-12-01

    Acousto-optic deflectors play an important role in optical signal processing systems due to their real time processing capabilities, as well as their conversion capabilities of a function of time to a function of space and time. In this work Brimrose investigated the design and fabrication of state-of-the-art, very large time-bandwidth acousto-optic devices from TeO2 single crystals.

  16. A Column Dispersion Experiment.

    ERIC Educational Resources Information Center

    Corapcioglu, M. Y.; Koroglu, F.

    1982-01-01

    Crushed glass and a Rhodamine B solution are used in a one-dimensional optically scanned column experiment to study the dispersion phenomenon in porous media. Results indicate that the described model gave satisfactory results and that the dispersion process in this experiment is basically convective. (DC)

  17. High-Q photonic resonators and electro-optic coupling using silicon-on-lithium-niobate

    PubMed Central

    Witmer, Jeremy D.; Valery, Joseph A.; Arrangoiz-Arriola, Patricio; Sarabalis, Christopher J.; Hill, Jeff T.; Safavi-Naeini, Amir H.

    2017-01-01

    Future quantum networks, in which superconducting quantum processors are connected via optical links, will require microwave-to-optical photon converters that preserve entanglement. A doubly-resonant electro-optic modulator (EOM) is a promising platform to realize this conversion. Here, we present our progress towards building such a modulator by demonstrating the optically-resonant half of the device. We demonstrate high quality (Q) factor ring, disk and photonic crystal resonators using a hybrid silicon-on-lithium-niobate material system. Optical Q factors up to 730,000 are achieved, corresponding to propagation loss of 0.8 dB/cm. We also use the electro-optic effect to modulate the resonance frequency of a photonic crystal cavity, achieving a electro-optic modulation coefficient between 1 and 2 pm/V. In addition to quantum technology, we expect that our results will be useful both in traditional silicon photonics applications and in high-sensitivity acousto-optic devices. PMID:28406177

  18. High-Q photonic resonators and electro-optic coupling using silicon-on-lithium-niobate

    NASA Astrophysics Data System (ADS)

    Witmer, Jeremy D.; Valery, Joseph A.; Arrangoiz-Arriola, Patricio; Sarabalis, Christopher J.; Hill, Jeff T.; Safavi-Naeini, Amir H.

    2017-04-01

    Future quantum networks, in which superconducting quantum processors are connected via optical links, will require microwave-to-optical photon converters that preserve entanglement. A doubly-resonant electro-optic modulator (EOM) is a promising platform to realize this conversion. Here, we present our progress towards building such a modulator by demonstrating the optically-resonant half of the device. We demonstrate high quality (Q) factor ring, disk and photonic crystal resonators using a hybrid silicon-on-lithium-niobate material system. Optical Q factors up to 730,000 are achieved, corresponding to propagation loss of 0.8 dB/cm. We also use the electro-optic effect to modulate the resonance frequency of a photonic crystal cavity, achieving a electro-optic modulation coefficient between 1 and 2 pm/V. In addition to quantum technology, we expect that our results will be useful both in traditional silicon photonics applications and in high-sensitivity acousto-optic devices.

  19. Dark soliton synthesis using an optical pulse synthesizer and transmission through a normal-dispersion optical fiber.

    PubMed

    Kashiwagi, Ken; Mozawa, Kiyonobu; Tanaka, Yosuke; Kurokawa, Takashi

    2013-12-16

    We precisely generate dark solitons using an optical pulse synthesizer (OPS) at a repetition rate of 25 GHz and experimentally investigate soliton transmission through a normal-dispersion fiber. Because of their particular waveform, there are not many experimental studies. The OPS provides frequency-domain line-by-line modulation and produces arbitrary pulse waveforms. The soliton waveform has an intensity contrast greater than 20 dB. At certain input peak power, the pulse exhibits soliton transmission and maintains its initial waveform. The power agrees with soliton transmission theory. We confirm that the π phase shift at the center of the dark soliton is maintained after transmission through the fiber. We also investigate the influence of stimulated Brillouin scattering for long-distance transmission.

  20. Optics outreach in Irish context

    NASA Astrophysics Data System (ADS)

    McHugh, Emer; Smith, Arlene

    2009-06-01

    The Applied Optics Group, National University of Ireland Galway is a research centre involved in programmes that cover a wide variety of topics in applied optics and imaging science, including smart optics, adaptive optics, optical scattering and propagation, and engineering optics. The Group have also developed significant outreach programmes both in Primary and Post-Primary schools. It is recognised that there is a need for innovation in Science Education in Ireland and we are committed to working extensively with schools. The main aim of these outreach programmes is to increase awareness and interest in science with students and enhance the communication skills of the researchers working in the Group. The education outreach team works closely with the relevant teachers in both Primary and Post-Primary schools to design and develop learning initiatives to match the needs of the target group of students. The learning programmes are usually delivered in the participating schools during normal class time by a team of Applied Optics specialists. We are involved in running these programmes in both Primary and Post-Primary schools where the programmes are tailored to the curriculum and concentrating on optics and light. The students may also visit the Groups research centre where presentations and laboratory tours are arranged.

  1. Dispersion analysis of collagen fiber networks in cervical tissue using optical coherence tomography (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Gan, Yu; Yao, Wang; Myers, Kristin M.; Vink, Joy Y.; Wapner, Ronald J.; Hendon, Christine P.

    2016-02-01

    Understanding the human cervical collagen fiber network is critical to delineating the physiology of cervical remodeling during pregnancy. Previously, we presented our methodology to study the ultrastructure of collagen fibers over an entire field of transverse slices of human cervix tissue using optical coherence tomography. Here, we present a pixel-wise fiber orientation method to enable dispersion analysis on entire slices of human cervical tissues. We obtained en face images that were parallel to the surface. In each en face image, we masked the collagen fiber region based on signal noise ratio. Then, we extracted fiber orientations in each pixel using a weighted summation scheme and generated a pixel-wise directionality map within the entire region. The weight was determined by intensity variations between a pixel of interest and its neighboring pixels and their corresponding distances. We divided the directionality map into regions of 400 μm × 400 μm along radial direction in all four quadrants. In each region, we fit von-Mises distribution to fiber orientations of pixels with mode θ and dispersion b. We compared dispersions among regions and samples. Using IRB approved protocols, we obtained whole transverse slices of cervical tissue from pregnant (n = 2) and non-pregnant (n = 13) women. We observed higher dispersion in pregnant samples compared to non-pregnant samples and higher dispersions in patient's right/left zones than posterior/anterior zones within an axial slice. Future studies will analyze how collagen fiber dispersion patterns change from the internal to the external os.

  2. Structure and optical properties of noble metal and oxide nanoparticles dispersed in various polysaccharide biopolymers

    NASA Astrophysics Data System (ADS)

    Djoković, V.; Božanic, D. K.; Vodnik, V. V.; Krsmanović, R. M.; Trandafilovic, L. V.; Dimitrijević-Branković, S.

    2011-10-01

    We present the results on the structure and the optical properties of noble metal (Ag, Au) and oxide (ZnO) nanoparticles synthesized by various methods in different polysaccharide matrices such as chitosan, glycogen, alginate and starch. The structure of the obtained nanoparticles was studied in detail with microscopic techniques (TEM, SEM), while the XPS spectroscopy was used to investigate the effects at the nanoparticle-biomolecule interfaces. The antimicrobial activity of the nanocomposite films with Ag nanoparticles was tested against the Staphylococcus aureus, Escherichia coli and Candida albicans pathogens. In addition, we will present the results on the structure and optical properties of the tryptophan amino acid functionalized silver nanoparticles dispersed in water soluble polymer matrices.

  3. Feasibility of Dual Optics/Ultrasound Imaging and Contrast Media for the Detection and Characterization of Prostate Cancer

    DTIC Science & Technology

    2010-03-01

    ultrasound microbubbles and generation of higher harmonic modulation. We also demonstrated acousto- optic detection with a novel SPAD detector. During...NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON USAMRMC a. REPORT U b. ABSTRACT U c . THIS PAGE U UU 27 19b. TELEPHONE NUMBER (include...pass Filter Digital Scope Silicon Photodetector (a) (b) ( c ) Figure 2a) Experimental set-up for detection of ultrasound-modulated

  4. Megahertz-resolution programmable microwave shaper.

    PubMed

    Li, Jilong; Dai, Yitang; Yin, Feifei; Li, Wei; Li, Ming; Chen, Hongwei; Xu, Kun

    2018-04-15

    A novel microwave shaper is proposed and demonstrated, of which the microwave spectral transfer function could be fully programmable with high resolution. We achieve this by bandwidth-compressed mapping a programmable optical wave-shaper, which has a lower frequency resolution of tens of gigahertz, to a microwave one with resolution of tens of megahertz. This is based on a novel technology of "bandwidth scaling," which employs bandwidth-stretched electronic-to-optical conversion and bandwidth-compressed optical-to-electronic conversion. We demonstrate the high resolution and full reconfigurability experimentally. Furthermore, we show the group delay variation could be greatly enlarged after mapping; this is then verified by the experiment with an enlargement of 194 times. The resolution improvement and group delay magnification significantly distinguish our proposal from previous optics-to-microwave spectrum mapping.

  5. Effects of gold nanoparticles on the electro-optical properties of a polymer dispersed liquid crystal

    NASA Astrophysics Data System (ADS)

    Hinojosa, A.; Shive, C.; Sharma, Suresh

    2010-03-01

    We have studied the electro-optical properties of a polymer-dispersed liquid crystal (PDLC) as functions of relative concentrations of gold nanoparticles. PDLC samples were synthesized between indium-tin-oxide (ITO) coated glass slides, separated by SiO2 spacers, by using liquid crystal E44, a monofunctional acrylic oligomer (CN135), and a tetrafunctional crosslinker (SR295). A UV photoinitiator (SR1124) was used to facilitate the curing of the monomer exposed to UV radiation from a Hg spectral lamp. A He-Ne laser was used to measure optical transmission through the PDLC as a function of applied ac electric field (1 kHz). The PDLC without gold nanoparticles shows the expected behavior; transmission through the PDLC increases from a minimum (opaque) to a maximum (transparent) with increasing electric field. The electro-optical behavior of the PDLC is altered significantly (e. g., relatively low switching field) upon addition of relatively low concentrations of gold nanoparticles into the starting PDLC syrup. We present electro-optical data as functions of gold nanoparticle concentration and discuss possible mechanism to understand our results.

  6. Novel applications of the dispersive optical model

    NASA Astrophysics Data System (ADS)

    Dickhoff, W. H.; Charity, R. J.; Mahzoon, M. H.

    2017-03-01

    A review of recent developments of the dispersive optical model (DOM) is presented. Starting from the original work of Mahaux and Sartor, several necessary steps are developed and illustrated which increase the scope of the DOM allowing its interpretation as generating an experimentally constrained functional form of the nucleon self-energy. The method could therefore be renamed as the dispersive self-energy method. The aforementioned steps include the introduction of simultaneous fits of data for chains of isotopes or isotones allowing a data-driven extrapolation for the prediction of scattering cross sections and level properties in the direction of the respective drip lines. In addition, the energy domain for data was enlarged to include results up to 200 MeV where available. An important application of this work was implemented by employing these DOM potentials to the analysis of the (d, p) transfer reaction using the adiabatic distorted wave approximation. We review these calculations which suggest that physically meaningful results are easier to obtain by employing DOM ingredients as compared to the traditional approach which relies on a phenomenologically-adjusted bound-state wave function combined with a global (nondispersive) optical-model potential. Application to the exotic 132Sn nucleus also shows great promise for the extrapolation of DOM potentials towards the drip line with attendant relevance for the physics of FRIB. We note that the DOM method combines structure and reaction information on the same footing providing a unique approach to the analysis of exotic nuclei. We illustrate the importance of abandoning the custom of representing the non-local Hartree-Fock (HF) potential in the DOM by an energy-dependent local potential as it impedes the proper normalization of the solution of the Dyson equation. This important step allows for the interpretation of the DOM potential as representing the nucleon self-energy permitting the calculations of

  7. Optically Programmable Field Programmable Gate Arrays (FPGA) Systems

    DTIC Science & Technology

    2004-01-01

    VCSEL requires placing the array far enough as to overlap the entire footprint of the signal beam in order to record the hologram. Therefore, these...hologram that self-focuses, due to phase -conjugation, on the array of detectors in the chip. VC A 10 m m 10 mm 18mm 16mm SEL RRAY OPTICAL MEMORY LOGIC...the VCSEL array , the chip and the optical material, and the requirements they have to meet for their use in the OPGA system. Section

  8. Multichannel optical sensing device

    DOEpatents

    Selkowitz, S.E.

    1985-08-16

    A multichannel optical sensing device is disclosed, for measuring the outdoor sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optical elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

  9. Multichannel optical sensing device

    DOEpatents

    Selkowitz, Stephen E.

    1990-01-01

    A multichannel optical sensing device is disclosed, for measuring the outr sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optic elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

  10. Development of a High Performance Acousto-ultrasonic Scan System

    NASA Technical Reports Server (NTRS)

    Roth, D. J.; Martin, R. E.; Harmon, L. M.; Gyekenyesi, A. L.; Kautz, H. E.

    2002-01-01

    Acousto-ultrasonic (AU) interrogation is a single-sided nondestructive evaluation (NDE) technique employing separated sending and receiving transducers. It is used for assessing the microstructural condition/distributed damage state of the material between the transducers. AU is complementary to more traditional NDE methods such as ultrasonic c-scan, x-ray radiography, and thermographic inspection that tend to be used primarily for discrete flaw detection. Through its history, AU has been used to inspect polymer matrix composite, metal matrix composite, ceramic matrix composite, and even monolithic metallic materials. The development of a high-performance automated AU scan system for characterizing within-sample microstructural and property homogeneity is currently in a prototype stage at NASA. In this paper, a review of essential AU technology is given. Additionally, the basic hardware and software configuration, and preliminary results with the system, are described.

  11. Elastic and photo-elastic characteristics of laser crystals potassium rare-earth tungstates KRE(WO₄)₂, where RE=Y, Yb, Gd and Lu.

    PubMed

    Mazur, M M; Velikovskiy, D Yu; Mazur, L I; Pavluk, A A; Pozhar, V E; Pustovoit, V I

    2014-07-01

    The elastic and photo-elastic characteristics of four laser crystals KY(WO₄)₂, KGd(WO₄)₂, KYb(WO₄)₂, and KLu(WO₄)₂ are presented. The first pair was reported early, and the last two materials have been investigated for the first time. The full matrix of elastic constants of these monoclinic crystals has been determined. Also, acousto-optical figure of merit for all the basic geometries of isotropic diffraction has been measured. It is proved that potassium rare-earth tungstates has rather good acousto-optical properties and particularly can take place of fused silica in technical applications required high power laser radiation. All the results demonstrate good prospect of these optically bi-axial laser crystals for development of new effective acousto-optical devices. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Thermally and optically tunable lasing properties from dye-doped holographic polymer dispersed liquid crystal in capillaries

    NASA Astrophysics Data System (ADS)

    Chen, Maozhou; Dai, Haitao; Wang, Dongshuo; Yang, Yue; Luo, Dan; Zhang, Xiaodong; Liu, Changlong

    2018-03-01

    In this paper, we investigated tunable lasing properties from the dye-doped holographic polymer dispersed liquid crystal (HPDLC) gratings in capillaries with thermal and optical manners. The thermally tunable range of the lasing from the dye-doped HPDLC reached 8.60 nm with the temperature ranging from 23 °C to 50 °C. The optically tunable laser emission was achieved by doping azo-dye in HPDLC. The transition of azo-dye from trans- to cis-state could induce the reorientation of LC molecules after UV light irradiation, which resulted in the variation of refractive index contrast of LC-rich/polymer-rich layer in HPDLC. Experimentally, the emission wavelength of lasing showed a blueshift (about 2 nm) coupled with decreasing output intensities. The tunable laser based on HPDLC may enable more applications in laser displays, optical communication, biosensors, etc.

  13. Soliton's eigenvalue based analysis on the generation mechanism of rogue wave phenomenon in optical fibers exhibiting weak third order dispersion.

    PubMed

    Weerasekara, Gihan; Tokunaga, Akihiro; Terauchi, Hiroki; Eberhard, Marc; Maruta, Akihiro

    2015-01-12

    One of the extraordinary aspects of nonlinear wave evolution which has been observed as the spontaneous occurrence of astonishing and statistically extraordinary amplitude wave is called rogue wave. We show that the eigenvalues of the associated equation of nonlinear Schrödinger equation are almost constant in the vicinity of rogue wave and we validate that optical rogue waves are formed by the collision between quasi-solitons in anomalous dispersion fiber exhibiting weak third order dispersion.

  14. On the dispersion management of fluorite whispering-gallery mode resonators for Kerr optical frequency comb generation in the telecom and mid-infrared range.

    PubMed

    Lin, Guoping; Chembo, Yanne K

    2015-01-26

    Optical whispering gallery mode (WGM) resonators have been very attracting platforms for versatile Kerr frequency comb generations. We report a systematic study on the material dispersion of various optical materials that are capable of supporting quality factors above 109. Using an analytical approximation of WGM resonant frequencies in disk resonators, we investigate the effect of the geometry and transverse mode order on the total group-velocity dispersion (GVD). We demonstrate that the major radii and the radial mode indices play an important role in tailoring the GVD of WGM resonators. In particular, our study shows that in WGM disk-resonators, the polar families of modes have very similar GVD, while the radial families of modes feature dispersion values that can differ by up to several orders of magnitude. The effect of these giant dispersion shifts are experimentally evidenced in Kerr comb generation with magnesium fluoride. From a more general perspective, this critical feature enables to push the zero-dispersion wavelength of fluorite crystals towards the mid-infrared (mid-IR) range, thereby allowing for efficient Kerr comb generation in that spectral range. We show that barium fluoride is the most interesting crystal in this regard, due to its zero dispersion wavelength (ZDW) at 1.93 μm and an optimal dispersion profile in the mid-IR regime. We expect our results to facilitate the design of different platforms for Kerr frequency comb generations in both telecommunication and mid-IR spectral ranges.

  15. Ring-laser gyroscope system using dispersive element(s)

    NASA Technical Reports Server (NTRS)

    Smith, David D. (Inventor)

    2010-01-01

    A ring-laser gyroscope system includes a ring-laser gyroscope (RLG) and at least one dispersive element optically coupled to the RLG's ring-shaped optical path. Each dispersive element has a resonant frequency that is approximately equal to the RLG's lasing frequency. A group index of refraction defined collectively by the dispersive element(s) has (i) a real portion that is greater than zero and less than one, and (ii) an imaginary portion that is less than zero.

  16. Tetravalent chromium (Cr(4+)) as laser-active ion for tunable solid-state lasers

    NASA Technical Reports Server (NTRS)

    Seas, A.; Petricevic, V.; Alfano, Robert R.

    1992-01-01

    Generation of femtosecond pulses from a continuous-wave mode-locked chromium-doped forsterite (Cr(4+):Mg2SiO4) laser has been accomplished. The forsterite laser was actively mode-locked using an acousto-optic modulator operating at 78 MHz with two Brewster high-dispersion glass prisms for intra-cavity chirp compensation. Transform-limited sub-100-fs pulses were routinely generated in the TEM(sub 00) mode with 85 mW of continuous power (with 1 percent output coupler), tunable over 1230-1280 nm. The shortest pulses of 60-fs pulsewidth were measured.

  17. Fiber optic monitoring device

    DOEpatents

    Samborsky, James K.

    1993-01-01

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  18. Viscoelastic characterization of dispersive media by inversion of a general wave propagation model in optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Zvietcovich, Fernando; Rolland, Jannick P.; Grygotis, Emma; Wayson, Sarah; Helguera, Maria; Dalecki, Diane; Parker, Kevin J.

    2018-02-01

    Determining the mechanical properties of tissue such as elasticity and viscosity is fundamental for better understanding and assessment of pathological and physiological processes. Dynamic optical coherence elastography uses shear/surface wave propagation to estimate frequency-dependent wave speed and Young's modulus. However, for dispersive tissues, the displacement pulse is highly damped and distorted during propagation, diminishing the effectiveness of peak tracking approaches. The majority of methods used to determine mechanical properties assume a rheological model of tissue for the calculation of viscoelastic parameters. Further, plane wave propagation is sometimes assumed which contributes to estimation errors. To overcome these limitations, we invert a general wave propagation model which incorporates (1) the initial force shape of the excitation pulse in the space-time field, (2) wave speed dispersion, (3) wave attenuation caused by the material properties of the sample, (4) wave spreading caused by the outward cylindrical propagation of the wavefronts, and (5) the rheological-independent estimation of the dispersive medium. Experiments were conducted in elastic and viscous tissue-mimicking phantoms by producing a Gaussian push using acoustic radiation force excitation, and measuring the wave propagation using a swept-source frequency domain optical coherence tomography system. Results confirm the effectiveness of the inversion method in estimating viscoelasticity in both the viscous and elastic phantoms when compared to mechanical measurements. Finally, the viscoelastic characterization of collagen hydrogels was conducted. Preliminary results indicate a relationship between collagen concentration and viscoelastic parameters which is important for tissue engineering applications.

  19. Radioracemization and radiation-induced chiral amplification of chiral terpenes measured by optical rotatory dispersion (ORD) spectroscopy

    NASA Astrophysics Data System (ADS)

    Cataldo, Franco; Ursini, Ornella; Angelini, Giancarlo

    2008-08-01

    For the first time the radioracemization of α(+)pinene and α(-)pinene, of turpentine and of R(-)- α-phellandrene has been studied by optical rotatory dispersion (ORD) spectroscopy. For all these compounds, the radioracemization implies a shift of the ORD curves toward lower levels of specific optical rotation. The radioracemization degree ( RR) has been defined and calculated for all the compounds studied. It has been found that for radiation dose of 1 MGy the radioracemization degree is about 4.5% for the compound with the highest optical purity and reaches 7-8% for the less optically pure compounds, demonstrating that impurities can affect greatly the radioracemization. In contrast with the general radioracemization effect exerted by high-energy radiation on chiral molecules, β(-)pinene, β(+)pinene when irradiated show an increment of their specific optical rotation. This fact has been measured for the first time by ORD spectroscopy and the amplification degree of chirality can reach 1000% in the near UV. This phenomenon is due to the formation of a chiral polymer, poly- β-pinene, which forms a solution with the monomer enhancing its optical activity. The implications for the theories of the origin of life of such unexpected phenomenon are discussed briefly.

  20. Two-photon microscope for multisite microphotolysis of caged neurotransmitters in acute brain slices

    PubMed Central

    Losavio, Bradley E.; Iyer, Vijay; Saggau, Peter

    2009-01-01

    We developed a two-photon microscope optimized for physiologically manipulating single neurons through their postsynaptic receptors. The optical layout fulfills the stringent design criteria required for high-speed, high-resolution imaging in scattering brain tissue with minimal photodamage. We detail the practical compensation of spectral and temporal dispersion inherent in fast laser beam scanning with acousto-optic deflectors, as well as a set of biological protocols for visualizing nearly diffraction-limited structures and delivering physiological synaptic stimuli. The microscope clearly resolves dendritic spines and evokes electrophysiological transients in single neurons that are similar to endogenous responses. This system enables the study of multisynaptic integration and will assist our understanding of single neuron function and dendritic computation. PMID:20059271

  1. The Influence of Finite-size Sources in Acousto-ultrasonics

    NASA Technical Reports Server (NTRS)

    Pavlakovic, Brian N.; Rose, Joseph L.

    1994-01-01

    This work explores the effects that the finite normal axisymmetric traction loading of an infinite isotropic plate has on wave propagation in acousto-ultrasonics (AU), in which guided waves are created using two normal incidence transducers. Although the work also addresses the effects of the transducer pressure distribution and pulse shape, this thesis concentrates on two main questions: how does the transducer's diameter control the phase velocity and frequency spectrum of the response, and how does the plate thickness relate to the plate's excitability? The mathematics of the time-harmonic solution and the physical principles and the practical considerations for AU wave generation are explained. Transient sources are modeled by the linear superposition of the time-harmonic solutions found using the Hankel transform and they are then compared to experimental data to provide insight into the relation between the size of the transducer and the preferred phase velocity.

  2. Dispersion relations for circular single and double dusty plasma chains

    NASA Astrophysics Data System (ADS)

    Tkachenko, D. V.; Sheridan, T. E.; Misko, V. R.

    2011-10-01

    We derive dispersion relations for a system of identical particles confined in a two-dimensional annular harmonic well and which interact through a Yukawa potential, e.g., a dusty plasma ring. When the particles are in a single chain (i.e., a one-dimensional ring), we find a longitudinal acoustic mode and a transverse optical mode which show approximate agreement with the dispersion relation for a straight configuration for large radii of the ring. When the radius decreases, the dispersion relations modify: there appears an anticrossing of the modes near the crossing point resulting in a frequency gap between the lower and upper branches of the modified dispersion relations. For the double chain (i.e., a two-dimensional zigzag configuration), the dispersion relation has four branches: longitudinal acoustic and optical and transverse acoustic and optical.

  3. Quantitative dispersion microscopy

    PubMed Central

    Fu, Dan; Choi, Wonshik; Sung, Yongjin; Yaqoob, Zahid; Dasari, Ramachandra R.; Feld, Michael

    2010-01-01

    Refractive index dispersion is an intrinsic optical property and a useful source of contrast in biological imaging studies. In this report, we present the first dispersion phase imaging of living eukaryotic cells. We have developed quantitative dispersion microscopy based on the principle of quantitative phase microscopy. The dual-wavelength quantitative phase microscope makes phase measurements at 310 nm and 400 nm wavelengths to quantify dispersion (refractive index increment ratio) of live cells. The measured dispersion of living HeLa cells is found to be around 1.088, which agrees well with that measured directly for protein solutions using total internal reflection. This technique, together with the dry mass and morphology measurements provided by quantitative phase microscopy, could prove to be a useful tool for distinguishing different types of biomaterials and studying spatial inhomogeneities of biological samples. PMID:21113234

  4. Expanded all-optical programmable logic array based on multi-input/output canonical logic units.

    PubMed

    Lei, Lei; Dong, Jianji; Zou, Bingrong; Wu, Zhao; Dong, Wenchan; Zhang, Xinliang

    2014-04-21

    We present an expanded all-optical programmable logic array (O-PLA) using multi-input and multi-output canonical logic units (CLUs) generation. Based on four-wave mixing (FWM) in highly nonlinear fiber (HNLF), two-input and three-input CLUs are simultaneously achieved in five different channels with an operation speed of 40 Gb/s. Clear temporal waveforms and wide open eye diagrams are successfully observed. The effectiveness of the scheme is validated by extinction ratio and optical signal-to-noise ratio measurements. The computing capacity, defined as the total amount of logic functions achieved by the O-PLA, is discussed in detail. For a three-input O-PLA, the computing capacity of the expanded CLUs-PLA is more than two times as large as that of the standard CLUs-PLA, and this multiple will increase to more than three and a half as the idlers are individually independent.

  5. 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.

  6. Coherent optical frequency transfer over 50-km physical distance using a 120-km-long installed telecom fiber network.

    PubMed

    Musha, Mitsuru; Hong, Feng-Lei; Nakagawa, Ken'ichi; Ueda, Ken-ichi

    2008-10-13

    Optical frequency at 1542 nm was coherently transferred over a 120-km-long installed telecom fiber network between two cities (Tsukuba and Tokyo) in Japan separated by more than 50 km. The phase noise induced by the fiber length fluctuations was actively reduced by using a fiber stretcher and an acousto-optic modulator. The fractional frequency instability of the one-way transmitted light was reduced down to less than 8.0 x 10(-16) at an averaging time of 1s, which is limited by the theoretical limit deduced from the length and the intrinsic noise of the fiber.

  7. Engineering ultra-flattened normal dispersion photonic crystal fiber with silica material

    NASA Astrophysics Data System (ADS)

    Ferhat, Mohamed Lamine; Cherbi, Lynda; Bahloul, Lies; Hariz, Abdelhafid

    2017-05-01

    The tailoring of the group velocity dispersion (GVD) of an optical fiber is critical in many applications, influence on the bandwidth of information transmission in optical communication systems, successful utilization of nonlinear optical properties in applications such as supercontinuum generation, wavelength conversion and harmonic generation via stimulated Raman scattering ...In this work, we propose a design of ultra-flattened photonic crystal fiber by changing the diameter of the air holes of the cladding rings. The geometry is composed of only four rings, hexagonal structure of air holes and silica as background of the solid core. As a result, we present structures with broadband flat normal dispersion on many wavelengths bands useful for several applications. We obtain flat normal dispersion over 1000 nm broadband flat normal dispersion below -7 [ps/nm.km], and ultra-flat near zero normal dispersion below -0.2 [ps/nm.km] over 150 nm. The modeled photonic crystal fiber would be valuable for the fabrication of ultra-flattened-dispersion fibers, and have potential applications in wide-band high-speed optical communication systems, supercontinuum generation and many other applications.

  8. Dispersion relations for circular single and double dusty plasma chains

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

    Tkachenko, D. V.; Misko, V. R.; Sheridan, T. E.

    2011-10-15

    We derive dispersion relations for a system of identical particles confined in a two-dimensional annular harmonic well and which interact through a Yukawa potential, e.g., a dusty plasma ring. When the particles are in a single chain (i.e., a one-dimensional ring), we find a longitudinal acoustic mode and a transverse optical mode which show approximate agreement with the dispersion relation for a straight configuration for large radii of the ring. When the radius decreases, the dispersion relations modify: there appears an anticrossing of the modes near the crossing point resulting in a frequency gap between the lower and upper branchesmore » of the modified dispersion relations. For the double chain (i.e., a two-dimensional zigzag configuration), the dispersion relation has four branches: longitudinal acoustic and optical and transverse acoustic and optical.« less

  9. Dispersions of Semiconductor Nanoparticles in Thermotropic Liquid Crystal: From Optical Modification to Assisted Self-Assembly

    NASA Astrophysics Data System (ADS)

    Rodarte, Andrea L.

    The interaction of semiconducting quantum dot nanoparticles (QDs) within thermotropic liquid crystalline (LC) materials are studied in this thesis. LC materials are ideal for bottom-up organization of nanoparticles as an active matrix that can be externally manipulated via electric or magnetic fields. In addition, the optical properties of QDs can be modified by the surrounding LC resulting in novel devices such as a quantum dot/liquid crystal laser. The first system studies the dispersion of spherical nanoparticles in the phase. The dispersion is investigated with the use of polarized optical microscopy, fluorescence microscopy and confocal scanning microscopy. Quantum dots well dispersed in the isotropic phase are expelled from ordered domains of LC at the phase transition. Under controlled conditions, the majority of QDs in the system can form ordered three dimensional assemblies that are situated at defect points in the liquid crystal. The internal order of the assemblies is probed utilizing Forster resonance energy transfer (FRET), combined with small angle X-ray scattering (SAXS). Furthermore, the location of these assemblies can be predetermined with the use of beads as defect nucleation points in the cell. The interaction of QDs in a cholesteric liquid crystal (CLC) is also investigated. The reflection band created by the periodic change of index of refraction in a planar aligned CLC acts as a 1-D photonic cavity when the CLC is doped with a low concentration of QDs. A Cano-wedge cell varies the pitch of the CLC leading to the formation of Grandjean steps. This spatially tunes the photonic stop band, changing the resonance condition and continuously altering both the emission wavelength and polarization state of the QD ensemble. Using high resolution spatially and spectrally resolved photoluminescence measurements, the emission is shown to be elliptically polarized and that the tilt of the ellipse, while dependent on the emission wavelength, additionally

  10. Investigation of pH and temperature on optical rotatory dispersion for noninvasive glucose monitoring

    NASA Astrophysics Data System (ADS)

    Baba, Justin S.; Meledeo, Adam; Cameron, B. D.; Cote, Gerard L.

    2001-06-01

    The widespread occurrence of diabetes mellitus and the severity of its associated complications necessitate the development of non-invasive blood glucose measurement devices in an attempt to improve treatment regimens and curb the complications associated with this disease. One method showing promise in this endeavor utilizes optical polarimetry to monitor blood glucose levels indirectly by measuring glucose rotation of polarized light, which is a direct indication of glucose concentration, in the aqueous humor of the eye. The presence of other optically active (chiral) components in the aqueous humor of the eye have the potential to confound the glucose measurement of optical rotation when using a single wavelength polarimeter. Thus, this has led to the recent investigation of multispectral polarimetric systems which have the potential to enable the removal of confounder contributions to the net observed optical rotation, therefore, increasing glucose specificity and reducing glucose prediction errors. Such polarimetric systems take advantage of the uniqueness in the rotation of polarized light, as a function of wavelength, by the chiral molecule of interest. This is commonly referred to as the optical rotatory dispersion (ORD) spectra of the chiral molecule. ORD characterization of the chiral molecules within the aqueous humor is necessary for determining the optimum number of wavelengths needed to reduce glucose prediction errors; however, this information is often only given at the sodium-D line (589 nm) in the literature. This report describes the system we designed and built to measure ORD spectra for glucose and for albumin, the main optical confounder within the aqueous humor, as well as our investigation of the effects of temperature and pH on these ORD spectra.

  11. Photonic fractional Fourier transformer with a single dispersive device.

    PubMed

    Cuadrado-Laborde, C; Carrascosa, A; Díez, A; Cruz, J L; Andres, M V

    2013-04-08

    In this work we used the temporal analog of spatial Fresnel diffraction to design a temporal fractional Fourier transformer with a single dispersive device, in this way avoiding the use of quadratic phase modulators. We demonstrate that a single dispersive passive device inherently provides the fractional Fourier transform of an incident optical pulse. The relationships linking the fractional Fourier transform order and scaling factor with the dispersion parameters are derived. We first provide some numerical results in order to prove the validity of our proposal, using a fiber Bragg grating as the dispersive device. Next, we experimentally demonstrate the feasibility of this proposal by using a spool of a standard optical fiber as the dispersive device.

  12. Effect of cross-phase-modulation-induced polarization scattering on optical polarization mode dispersion compensation in wavelength-division-multiplexed systems

    NASA Astrophysics Data System (ADS)

    Xie, Chongjin; Möller, Lothar; Kilper, Daniel C.; Mollenauer, Linn F.

    2003-12-01

    Interchannel cross-phase-modulation-induced polarization scattering (XPMIPS) and its effect on the performance of optical polarization mode dispersion (PMD) compensation in wavelength-division-multiplexed (WDM) systems are studied. The level of XPMIPS in long-haul WDM transmission systems is theoretically quantified, and its effect on optical PMD compensation is evaluated with numerical simulations. We show that in 10-Gbit/s ultra-long-haul dense WDM systems XPMIPS could reduce the PMD compensation efficiency by 50%, whereas for 40-Gbit/s systems the effect of XPMIPS is smaller.

  13. Fluence compensated photoacoustic tomography in small animals (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hussain, Altaf; Pool, Martin; Daoudi, Khalid; de Vries, Liesbeth G.; Steenbergen, Wiendelt

    2017-03-01

    Light fluence inside turbid media can be experimentally mapped by measuring ultrasonically modulated light (Acousto-optics). To demonstrate the feasibility of fluence corrected Photoacoustic (PA) imaging, we have realized a tri-modality (i.e. photoacoustic, acousto-optic and ultrasound) tomographic small animal imaging system. Wherein PA imaging provides high resolution map of absorbed optical energy density, Acousto-optics yields the fluence distribution map in the corresponding PA imaging plane and Ultrasound provides morphological information. Further, normalization of the PA image with the acousto-optically measured fluence map results in an image that directly represents the optical absorption. Human epidermal growth factor receptor 2 (HER2) is commonly found overexpressed in human cancers, among which breast cancers, resulting in a more aggressive tumor phenotype. Identification of HER2-expression is clinically relevant, because cancers overexpressing this marker are amenable to HER2-directed therapies, among which antibodies trastuzumab and pertuzumab. Here, we investigate the feasibility and advantage of acousto-optically assisted fluence compensated PA imaging over PA imaging alone in visualizing and quantifying HER2 expression. For this experiment, nude mice were xenografted with human breast cancer cell lines SKBR3 and BT474 (both HER2 overexpressing), as well as HER2-negative MDA-MB-231. To visualize HER2 expression in these mice, HER2 monoclonal antibody pertuzumab (Perjeta®, Roche), was conjugated to near-infrared dye IRDye 800CW (800CW, LICOR Biosciences) at a ratio of 1∶2 antibody to 800CW. When xenograft tumors measured ≥ 100 mm3, mice received 100 µg 800CW-pertuzumab intravenously. Three days post injection, mice were scanned for fluorescence signal with an IVIS scanner. After fluorescence scans, mice were euthanized and imaged in our PA tomographic imaging system.

  14. Influence of gamma ray irradiation and annealing temperature on the optical constants and spectral dispersion parameters of metal-free and zinc tetraphenylporphyrin thin films: A comparative study.

    PubMed

    Zeyada, H M; Makhlouf, M M; El-Nahass, M M

    2015-09-05

    In this work, we report on the effect of γ-ray irradiation and annealing temperature on the optical properties of metal-free tetraphenylporphyrin, H2TPP, and zinc tetraphenylporphyrin, ZnTPP, thin films. Thin films of H2TPP and ZnTPP were successfully prepared by the thermal evaporation technique. The optical properties of H2TPP and ZnTPP films were investigated using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in the wavelength range from 200 to 2500 nm. The absorption spectra of H2TPP showed four absorption bands, namely the Q, B, N and M bands. The effect of inserting Zn atom into the cavity of porphyrin macrocycle in ZnTPP molecule distorted the Q and B bands, reduced the width of absorption region and influenced the optical constants and dispersion parameters. In all conditions, the type of electron transition is indirect allowed transition. Anomalous dispersion is observed in the absorption region but normal dispersion occurs in the transparent region of spectra. We adopted multi-oscillator model and the single oscillator model to interpret the anomalous and normal dispersion, respectively. We have found that the annealing temperature has mostly the opposite effect of γ-ray irradiation on absorption and dispersion characteristics of these films. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Variational principles for dissipative (sub)systems, with applications to the theory of linear dispersion and geometrical optics

    DOE PAGES

    Dodin, I. Y.; Zhmoginov, A. I.; Ruiz, D. E.

    2017-02-24

    Applications of variational methods are typically restricted to conservative systems. Some extensions to dissipative systems have been reported too but require ad hoc techniques such as the artificial doubling of the dynamical variables. We propose a different approach. Here, we show that for a broad class of dissipative systems of practical interest, variational principles can be formulated using constant Lagrange multipliers and Lagrangians nonlocal in time, which allow treating reversible and irreversible dynamics on the same footing. A general variational theory of linear dispersion is formulated as an example. Particularly, we present a variational formulation for linear geometrical optics inmore » a general dissipative medium, which is allowed to be nonstationary, inhomogeneous, anisotropic, and exhibit both temporal and spatial dispersion simultaneously.« less

  16. DOC II 32-bit digital optical computer: optoelectronic hardware and software

    NASA Astrophysics Data System (ADS)

    Stone, Richard V.; Zeise, Frederick F.; Guilfoyle, Peter S.

    1991-12-01

    This paper describes current electronic hardware subsystems and software code which support OptiComp's 32-bit general purpose digital optical computer (DOC II). The reader is referred to earlier papers presented in this section for a thorough discussion of theory and application regarding DOC II. The primary optoelectronic subsystems include the drive electronics for the multichannel acousto-optic modulators, the avalanche photodiode amplifier, as well as threshold circuitry, and the memory subsystems. This device utilizes a single optical Boolean vector matrix multiplier and its VME based host controller interface in performing various higher level primitives. OptiComp Corporation wishes to acknowledge the financial support of the Office of Naval Research, the National Aeronautics and Space Administration, the Rome Air Development Center, and the Strategic Defense Initiative Office for the funding of this program under contracts N00014-87-C-0077, N00014-89-C-0266 and N00014-89-C- 0225.

  17. Co-dispersion of plasmonic nanorods in thermotropic nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Sheetah, Ghadah; Liu, Qinkun; Smalukh, Ivan

    Colloidal dispersions of plasmonic metal nanoparticles in liquid crystals promise the capability of pre-engineering tunable optical properties of mesostructured metal-dielectric composites. Recently, concentrated dispersions of anisotropic gold, silver, and metal alloy nanoparticles in nematic hosts have been achieved and successfully controlled by low-voltage fields. However, to enable versatile designs of material behavior of the composites, simultaneous co-dispersion of anisotropic particles with different shapes, alignment properties, and compositions are often needed. We achieve such co-dispersions and explore their switching characteristics in response to external stimuli like light and electric fields. We demonstrated that spectral characteristics of co-dispersions of multiple types of anisotropic nanoparticles in a common nematic host provides unprecedented variety of electrically- and optically-tunable material behavior, with a host of potential practical applications in electro-optic devices and displays Ghadah acknowledges support from the King Faisal University (KFU) graduate fellowship.

  18. Multi-arm spectrometer for parallel frequency analysis of radio-wave signals oriented to astronomical observations

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Chavez Dagostino, Miguel; Arellanes, Adan Omar; Tepichin Rodriguez, Eduardo

    2017-08-01

    We describe a potential prototype of modern spectrometer based on acousto-optical technique with three parallel optical arms for analysis of radio-wave signals specific to astronomical observations. Each optical arm exhibits original performances to provide parallel multi-band observations with different scales simultaneously. Similar multi-band instrument is able to realize measurements within various scenarios from planetary atmospheres to attractive objects in the distant Universe. The arrangement under development has two novelties. First, each optical arm represents an individual spectrum analyzer with its individual performances. Such an approach is conditioned by exploiting various materials for acousto-optical cells operating within various regimes, frequency ranges, and light wavelengths from independent light sources. Individually produced beam shapers give both the needed incident light polarization and the required apodization for light beam to increase the dynamic range of the system as a whole. After parallel acousto-optical processing, a few data flows from these optical arms are united by the joint CCD matrix on the stage of the combined extremely high-bit rate electronic data processing that provides the system performances as well. The other novelty consists in the usage of various materials for designing wide-aperture acousto-optical cells exhibiting the best performances within each of optical arms. Here, one can mention specifically selected cuts of tellurium dioxide, bastron, and lithium niobate, which overlap selected areas within the frequency range from 40 MHz to 2.0 GHz. Thus one yields the united versatile instrument for comprehensive studies of astronomical objects simultaneously with precise synchronization in various frequency ranges.

  19. Real time acousto-ultrasonic NDE technique for monitoring damage in ceramic composites under dynamic loads

    NASA Technical Reports Server (NTRS)

    Tiwari, Anil

    1995-01-01

    Research effort was directed towards developing a near real-time, acousto-ultrasonic (AU), nondestructive evaluation (NDE) tool to study the failure mechanisms of ceramic composites. Progression of damage is monitored in real-time by observing the changes in the received AU signal during the actual test. During the real-time AU test, the AU signals are generated and received by the AU transducers attached to the specimen while it is being subjected to increasing quasi-static loads or cyclic loads (10 Hz, R = 1.0). The received AU signals for 64 successive pulses were gated in the time domain (T = 40.96 micro sec) and then averaged every second over ten load cycles and stored in a computer file during fatigue tests. These averaged gated signals are representative of the damage state of the specimen at that point of its fatigue life. This is also the first major attempt in the development and application of real-time AU for continuously monitoring damage accumulation during fatigue without interrupting the test. The present work has verified the capability of the AU technique to assess the damage state in silicon carbide/calcium aluminosilicate (SiC/CAS) and silicon carbide/ magnesium aluminosilicate (SiC/MAS) ceramic composites. Continuous monitoring of damage initiation and progression under quasi-static ramp loading in tension to failure of unidirectional and cross-ply SiC/CAS and quasi-isotropic SiC/MAS ceramic composite specimens at room temperature was accomplished using near real-time AU parameters. The AU technique was shown to be able to detect the stress levels for the onset and saturation of matrix cracks, respectively. The critical cracking stress level is used as a design stress for brittle matrix composites operating at elevated temperatures. The AU technique has found that the critical cracking stress level is 10-15% below the level presently obtained for design purposes from analytical models. An acousto-ultrasonic stress-strain response (AUSSR) model

  20. On the local field method with the account of spatial dispersion. Application to the optical activity theory

    NASA Astrophysics Data System (ADS)

    Tyu, N. S.; Ekhilevsky, S. G.

    1992-07-01

    For the perfect molecular crystals the equations of the local field method (LFM) with the account of spatial dispersion are formulated. They are used to derive the expression for the crystal polarizability tensor. For the first time within the framework of this method the formula for the gyrotropy tensor of an arbitrary optically active molecular crystal is obtained. This formula is analog of well known relationships of Lorentz-Lorenz.

  1. Characterization of Acousto-Electric Cluster and Array Levitation and its Application to Evaporation

    NASA Technical Reports Server (NTRS)

    Robert E. Apfel; Zheng, Yibing

    2000-01-01

    An acousto-electric levitator has been developed to study the behavior of liquid drop and solid particle clusters and arrays. Unlike an ordinary acoustic levitator that uses only a standing acoustic wave to levitate a single drop or particle, this device uses an extra electric static field and the acoustic field simultaneously to generate and levitate charged drops in two-dimensional arrays in air without any contact to a solid surface. This cluster and array generation (CAG) instrument enables us to steadily position drops and arrays to study the behavior of multiple drop and particle systems such as spray and aerosol systems relevant to the energy, environmental, and material sciences.

  2. Fully-elastic multi-granular network with space/frequency/time switching using multi-core fibres and programmable optical nodes.

    PubMed

    Amaya, N; Irfan, M; Zervas, G; Nejabati, R; Simeonidou, D; Sakaguchi, J; Klaus, W; Puttnam, B J; Miyazawa, T; Awaji, Y; Wada, N; Henning, I

    2013-04-08

    We present the first elastic, space division multiplexing, and multi-granular network based on two 7-core MCF links and four programmable optical nodes able to switch traffic utilising the space, frequency and time dimensions with over 6000-fold bandwidth granularity. Results show good end-to-end performance on all channels with power penalties between 0.75 dB and 3.7 dB.

  3. Hollow cathode lamp based Faraday anomalous dispersion optical filter.

    PubMed

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-07-15

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the (88)Sr (5s(2))(1)S0 - (5s5p)(1)P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization.

  4. Hollow cathode lamp based Faraday anomalous dispersion optical filter

    NASA Astrophysics Data System (ADS)

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-07-01

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the 88Sr (5s2)1S0 - (5s5p)1P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization.

  5. Hollow cathode lamp based Faraday anomalous dispersion optical filter

    PubMed Central

    Pan, Duo; Xue, Xiaobo; Shang, Haosen; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2016-01-01

    The Faraday anomalous dispersion optical filter (FADOF), which has acquired wide applications, is mainly limited to some gaseous elements and low melting-point metals before, for the restriction of the attainable atomic density. In conventional FADOF systems a high atomic density is usually achieved by thermal equilibrium at the saturated vapor pressure, hence for elements with high melting-points a high temperature is required. To avoid this restriction, we propose a scheme of FADOF based on the hollow cathode lamp (HCL), instead of atomic vapor cells. Experimental results in strontium atoms verified this scheme, where a transmission peak corresponding to the 88Sr (5s2)1S0 − (5s5p)1P1 transition (461 nm) is obtained, with a maximum transmittance of 62.5% and a bandwith of 1.19 GHz. The dependence of transmission on magnetic field and HCL discharge current is also studied. Since the state-of-art commercial HCLs cover about 70 elements, this scheme can greatly expand the applications of FADOFs, and the abundant atomic transitions they provide bring the HCL based FADOFs potential applications for frequency stabilization. PMID:27418112

  6. Programmable Iterative Optical Image And Data Processing

    NASA Technical Reports Server (NTRS)

    Jackson, Deborah J.

    1995-01-01

    Proposed method of iterative optical image and data processing overcomes limitations imposed by loss of optical power after repeated passes through many optical elements - especially, beam splitters. Involves selective, timed combination of optical wavefront phase conjugation and amplification to regenerate images in real time to compensate for losses in optical iteration loops; timing such that amplification turned on to regenerate desired image, then turned off so as not to regenerate other, undesired images or spurious light propagating through loops from unwanted reflections.

  7. A technique for individual atom delivery into a crossed vortex bottle beam trap using a dynamic 1D optical lattice.

    PubMed

    Dinardo, Brad A; Anderson, Dana Z

    2016-12-01

    We describe a system for loading a single atom from a reservoir into a blue-detuned crossed vortex bottle beam trap using a dynamic 1D optical lattice. The lattice beams are frequency chirped using acousto-optic modulators, which causes the lattice to move along its axial direction and behave like an optical conveyor belt. A stationary lattice is initially loaded with approximately 6000 atoms from a reservoir, and the conveyor belt transports them 1.1 mm from the reservoir to a bottle beam trap, where a single atom is loaded via light-assisted collisions. Photon counting data confirm that an atom can be delivered and loaded into the bottle beam trap 13.1% of the time.

  8. Acousto-Ultrasonic analysis of failure in ceramic matrix composite tensile specimens

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.; Chulya, Abhisak

    1993-01-01

    Three types of acousto-ultrasonic (AU) measurements, stress-wave factor (SWF), lowest antisymmetric plate mode group velocity (VS), and lowest symmetric plate mode group velocity (VL), were performed on specimens before and after tensile failure. Three different Nicalon fiber architectures with ceramic matrices were tested. These composites were categorized as 1D (unidirectional fiber orientation) SiC/CAS glass ceramic, and 2D and 3D woven SiC/SiC ceramic matrix materials. SWF was found to be degraded after tensile failure in all three material categories. VS was found to be degraded only in the 1D SiC/CAS. VL was difficult to determine on the irregular specimen surfaces but appeared unchanged on all failed specimens. 3D woven specimens with heat-treatment at high temperature exhibited degradation only in SWF.

  9. Spatial dispersion in atom-surface quantum friction

    DOE PAGES

    Reiche, D.; Dalvit, D. A. R.; Busch, K.; ...

    2017-04-15

    We investigate the influence of spatial dispersion on atom-surface quantum friction. We show that for atom-surface separations shorter than the carrier's mean free path within the material, the frictional force can be several orders of magnitude larger than that predicted by local optics. In addition, when taking into account spatial dispersion effects, we show that the commonly used local thermal equilibrium approximation underestimates by approximately 95% the drag force, obtained by employing the recently reported nonequilibrium fluctuation-dissipation relation for quantum friction. Unlike the treatment based on local optics, spatial dispersion in conjunction with corrections to local thermal equilibrium change notmore » only the magnitude but also the distance scaling of quantum friction.« less

  10. First operations of the SOIR occultation infrared spectrometer in Venus orbit.

    NASA Astrophysics Data System (ADS)

    Nevejans, D.; Neefs, E.; Vandaele, A. C.; Muller, C.; Fussen, D.; Berkenbosch, S.; Clairquin, R.; Korablev, O.; Federova, A.; Bertaux, J. L.

    Since May 2006, the Venus-Express spacecraft is in its nominal orbit around VENUS and the SPICAV optical package has begun to acquire spectra. The SOIR extension to SPICAV is an echelle spectrometer associated to an AOTF (Acousto-Optical Tunable Filter) for the order selection, which performs solar occultation measurements in the IR region (2.2-4.3 µm) at a resolution of 0.1 cm-1 . The detailed optical study and design as well as the manufacturing were performed at the BIRA/IASB in collaboration with its industrial partners OIP and PEDEO. It was funded by the Belgian Federal Science Policy Office under the ESA PRODEX programme. The wavelength range allows a detailed chemical inventory of the Venus atmosphere above the cloud layer with an emphasis on vertical distribution of gases. The first results look promising and will be qualitatively presented.

  11. High speed line-scan confocal imaging of stimulus-evoked intrinsic optical signals in the retina

    PubMed Central

    Li, Yang-Guo; Liu, Lei; Amthor, Franklin; Yao, Xin-Cheng

    2010-01-01

    A rapid line-scan confocal imager was developed for functional imaging of the retina. In this imager, an acousto-optic deflector (AOD) was employed to produce mechanical vibration- and inertia-free light scanning, and a high-speed (68,000 Hz) linear CCD camera was used to achieve sub-cellular and sub-millisecond spatiotemporal resolution imaging. Two imaging modalities, i.e., frame-by-frame and line-by-line recording, were validated for reflected light detection of intrinsic optical signals (IOSs) in visible light stimulus activated frog retinas. Experimental results indicated that fast IOSs were tightly correlated with retinal stimuli, and could track visible light flicker stimulus frequency up to at least 2 Hz. PMID:20125743

  12. SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Optoelectronic processors with scanning CCD photodetectors

    NASA Astrophysics Data System (ADS)

    Esepkina, N. A.; Lavrov, A. P.; Anan'ev, M. N.; Blagodarnyi, V. S.; Ivanov, S. I.; Mansyrev, M. I.; Molodyakov, S. A.

    1995-10-01

    Two new types of optoelectronic radio-signal processors were investigated. Charge-coupled device (CCD) photodetectors are used in these processors under continuous scanning conditions, i.e. in a time delay and storage mode. One of these processors is based on a CCD photodetector array with a reference-signal amplitude transparency and the other is an adaptive acousto-optical signal processor with linear frequency modulation. The processor with the transparency performs multichannel discrete—analogue convolution of an input signal with a corresponding kernel of the transformation determined by the transparency. If a light source is an array of light-emitting diodes of special (stripe) geometry, the optical stages of the processor can be made from optical fibre components and the whole processor then becomes a rigid 'sandwich' (a compact hybrid optoelectronic microcircuit). A report is given also of a study of a prototype processor with optical fibre components for the reception of signals from a system with antenna aperture synthesis, which forms a radio image of the Earth.

  13. Optically programmable encoder based on light propagation in two-dimensional regular nanoplates.

    PubMed

    Li, Ya; Zhao, Fangyin; Guo, Shuai; Zhang, Yongyou; Niu, Chunhui; Zeng, Ruosheng; Zou, Bingsuo; Zhang, Wensheng; Ding, Kang; Bukhtiar, Arfan; Liu, Ruibin

    2017-04-07

    We design an efficient optically controlled microdevice based on CdSe nanoplates. Two-dimensional CdSe nanoplates exhibit lighting patterns around the edges and can be realized as a new type of optically controlled programmable encoder. The light source is used to excite the nanoplates and control the logical position under vertical pumping mode by the objective lens. At each excitation point in the nanoplates, the preferred light-propagation routes are along the normal direction and perpendicular to the edges, which then emit out from the edges to form a localized lighting section. The intensity distribution around the edges of different nanoplates demonstrates that the lighting part with a small scale is much stronger, defined as '1', than the dark section, defined as '0', along the edge. These '0' and '1' are the basic logic elements needed to compose logically functional devices. The observed propagation rules are consistent with theoretical simulations, meaning that the guided-light route in two-dimensional semiconductor nanoplates is regular and predictable. The same situation was also observed in regular CdS nanoplates. Basic theoretical analysis and experiments prove that the guided light and exit position follow rules mainly originating from the shape rather than material itself.

  14. Full color laser projection display using Kr-Ar laser (white laser) beam-scanning technology

    NASA Astrophysics Data System (ADS)

    Kim, Yonghoon; Lee, Hang W.; Cha, Seungnam; Lee, Jin-Ho; Park, Youngjun; Park, Jungho; Hong, Sung S.; Hwang, Young M.

    1997-07-01

    Full color laser projection display is realized on the large screen using a krypton-argon laser (white laser) as a light source, and acousto-optic devices as light modulators. The main wavelengths of red, green and blue color are 647, 515, and 488 nm separated by dichroic mirrors which are designed to obtain the best performance for the s-polarized beam with the 45 degree incident angle. The separated beams are modulated by three acousto-optic modulators driven by rf drivers which has energy level of 1 watt at 144 MHz and recombined by dichroic mirrors again. Acousto-optic modulators (AOM) are fabricated to satisfy high diffraction efficiency over 80% and fast rising time less than 50 ns at the video bandwidth of 5 MHz. The recombined three beams (RGB) are scanned by polygonal mirrors for horizontal lines and a galvanometer for vertical lines. The photodiode detection for monitoring of rotary polygonal mirrors is adopted in this system for the compensation of the tolerance in the mechanical scanning to prevent the image joggling in the horizontal direction. The laser projection display system described in this paper is expected to apply HDTV from the exploitation of the acousto- optic modulator with the video bandwidth of 30 MHz.

  15. Dispersion compensation of fiber optic communication system with direct detection using artificial neural networks (ANNs)

    NASA Astrophysics Data System (ADS)

    Maghrabi, Mahmoud M. T.; Kumar, Shiva; Bakr, Mohamed H.

    2018-02-01

    This work introduces a powerful digital nonlinear feed-forward equalizer (NFFE), exploiting multilayer artificial neural network (ANN). It mitigates impairments of optical communication systems arising due to the nonlinearity introduced by direct photo-detection. In a direct detection system, the detection process is nonlinear due to the fact that the photo-current is proportional to the absolute square of the electric field intensity. The proposed equalizer provides the most efficient computational cost with high equalization performance. Its performance is comparable to the benchmark compensation performance achieved by maximum-likelihood sequence estimator. The equalizer trains an ANN to act as a nonlinear filter whose impulse response removes the intersymbol interference (ISI) distortions of the optical channel. Owing to the proposed extensive training of the equalizer, it achieves the ultimate performance limit of any feed-forward equalizer (FFE). The performance and efficiency of the equalizer is investigated by applying it to various practical short-reach fiber optic communication system scenarios. These scenarios are extracted from practical metro/media access networks and data center applications. The obtained results show that the ANN-NFFE compensates for the received BER degradation and significantly increases the tolerance to the chromatic dispersion distortion.

  16. Characterization and enhanced nonlinear optical limiting response in carbon nanodots dispersed in solid-state hybrid organically modified silica gel glasses

    NASA Astrophysics Data System (ADS)

    Huang, Li; Zheng, Chan; Guo, Qiaohang; Huang, Dongdong; Wu, Xiukai; Chen, Ling

    2018-02-01

    Freely dispersed carbon nanodots (CNDs) were introduced into a 3-glycidoxy-propyltrimethoxysilane modified silicate gel glass (i.e. an organically modified silica or ORMOSIL) by a highly efficient and simple sol-gel process, which could be easily extended to prepare functional molecules/nanoparticles solid state optoelectronic devices. Scanning electron microscope imaging, Fourier transform infrared spectroscopy, pore structure measurements, ultraviolet-visible spectroscopy, and fluorescence spectroscopy were used to investigate the surface characteristics, structure, texture, and linear optical properties of the CND/SiO2 ORMOSIL gel glasses. Images and UV/Vis spectra confirmed the successful dispersion of CNDs in the ORMOSIL gel glass. The surface characteristics and pore structure of the host SiO2 matrix were markedly changed through the introduction of the CNDs. The linear optical properties of the guest CNDs were also affected by the sol-gel procedure. The nonlinear optical (NLO) properties of the CNDs were investigated by a nanosecond open-aperture Z-scan technique at 532 nm both in liquid and solid matrices. We found that the NLO response of the CNDs was considerably improved after their incorporation into the ORMOSIL gel glasses. Possible enhancement mechanisms were also explored. The nonlinear extinction coefficient gradually increased while the optical limiting (OL) threshold decreased as the CND doping level was increased. This result suggests that the NLO and OL properties of the composite gel glasses can be optimized by tuning the concentration of CNDs in the gel glass matrix. Our findings show that CND/SiO2 ORMOSIL gel glasses are promising candidates for optical limiters to protect sensitive instruments and human eyes from damage caused by high power lasers.

  17. The cubic-quintic-septic complex Ginzburg-Landau equation formulation of optical pulse propagation in 3D doped Kerr media with higher-order dispersions

    NASA Astrophysics Data System (ADS)

    Djoko, Martin; Kofane, T. C.

    2018-06-01

    We investigate the propagation characteristics and stabilization of generalized-Gaussian pulse in highly nonlinear homogeneous media with higher-order dispersion terms. The optical pulse propagation has been modeled by the higher-order (3+1)-dimensional cubic-quintic-septic complex Ginzburg-Landau [(3+1)D CQS-CGL] equation. We have used the variational method to find a set of differential equations characterizing the variation of the pulse parameters in fiber optic-links. The variational equations we obtained have been integrated numerically by the means of the fourth-order Runge-Kutta (RK4) method, which also allows us to investigate the evolution of the generalized-Gaussian beam and the pulse evolution along an optical doped fiber. Then, we have solved the original nonlinear (3+1)D CQS-CGL equation with the split-step Fourier method (SSFM), and compare the results with those obtained, using the variational approach. A good agreement between analytical and numerical methods is observed. The evolution of the generalized-Gaussian beam has shown oscillatory propagation, and bell-shaped dissipative optical bullets have been obtained under certain parameter values in both anomalous and normal chromatic dispersion regimes. Using the natural control parameter of the solution as it evolves, named the total energy Q, our numerical simulations reveal the existence of 3D stable vortex dissipative light bullets, 3D stable spatiotemporal optical soliton, stationary and pulsating optical bullets, depending on the used initial input condition (symmetric or elliptic).

  18. Wideband spectrum analysis of ultra-high frequency radio-wave signals due to advanced one-phonon non-collinear anomalous light scattering.

    PubMed

    Shcherbakov, Alexandre S; Arellanes, Adan Omar

    2017-04-20

    We present a principally new acousto-optical cell providing an advanced wideband spectrum analysis of ultra-high frequency radio-wave signals. For the first time, we apply a recently developed approach with the tilt angle to a one-phonon non-collinear anomalous light scattering. In contrast to earlier cases, now one can exploit a regime with the fixed optical wavelength for processing a great number of acoustic frequencies simultaneously in the linear regime. The chosen rutile-crystal combines a moderate acoustic velocity with low acoustic attenuation and allows us wide-band data processing within GHz-frequency acoustic waves. We have created and experimentally tested a 6-cm aperture rutile-made acousto-optical cell providing the central frequency 2.0 GHz, frequency bandwidth ∼0.52  GHz with the frequency resolution about 68.3 kHz, and ∼7620 resolvable spots. A similar cell permits designing an advanced ultra-high-frequency arm within a recently developed multi-band radio-wave acousto-optical spectrometer for astrophysical studies. This spectrometer is intended to operate with a few parallel optical arms for processing the multi-frequency data flows within astrophysical observations. Keeping all the instrument's advantages of the previous schematic arrangement, now one can create the highest-frequency arm using the developed rutile-based acousto-optical cell. It permits optimizing the performances inherent in that arm via regulation of both the central frequency and the frequency bandwidth for spectrum analysis.

  19. Ophthalmic compensation of visual ametropia based on a programmable diffractive lens

    NASA Astrophysics Data System (ADS)

    Millán, Maria S.; Pérez-Cabré, Elisabet; Romero, Lenny A.; Ramírez, Natalia

    2013-11-01

    Pixelated liquid crystal displays have been widely used as spatial light modulators to implement programmable diffractive optical elements (DOEs), particularly diffractive lenses. Many different applications of such components have been developed in information optics and optical processors that take advantage of their properties of great flexibility, easy and fast refreshment, and multiplexing capability in comparison with equivalent conventional refractive lenses. In this paper, we explore the application of programmable diffractive lenses displayed on the pixelated screen of a liquid crystal on silicon spatial light modulator (LCoS-SLM) to ophthalmic optics. In particular, we consider the use of programmable diffractive lenses for the visual compensation of some refractive errors (myopia, hyperopia). The theoretical principles of compensation are described and sketched using geometrical optics and paraxial ray tracing. A series of experiments with artificial eye in optical bench are conducted to analyze the compensation accuracy in terms of optical power and to compare the results with those obtained by means of conventional ophthalmic lenses. Practical considerations oriented to feasible applications are provided.

  20. Synthesis of transparent dispersions of aluminium hydroxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Wang, Jie-Xin; Wang, Dan; Zeng, Xiao-Fei; Clarke, Stuart M.; Chen, Jian-Feng

    2018-07-01

    Transparent dispersions of inorganic nanoparticles are attractive materials in many fields. However, a facile method for preparing such dispersions of aluminium hydroxide nanoparticles is yet to be realized. Here, we report a direct reactive method to prepare transparent dispersions of pseudo-boehmite nanoparticles (1 wt%) without any surface modification, and with an average particle size of 80 nm in length and 10 nm in width, as well as excellent optical transparency over 94% in the visible range. Furthermore, transparent dispersions of boehmite nanoparticles (1.5 wt%) were also achieved after an additional hydrothermal treatment. However, the optical transparency of dispersions decreased with the rise of hydrothermal temperature and the shape of particles changed from rhombs to hexagons. In particular, monodisperse hexagonal boehmite nanoplates with an average lateral size of 58 nm and a thickness of 12.5 nm were obtained at a hydrothermal temperature of 220 °C. The selectivity of crystal growth direction was speculated as the possible formation mechanism of these as-prepared aluminium hydroxide nanoparticles. Besides, two values of 19.6 wt% and 14.64 wt% were separately measured for the weight loss of pseudo-boehmite and boehmite nanoparticles after a continuous heating, indicating their potential flame-resistant applications in the fabrication of plastic electronics and optical devices with high transparency.