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Sample records for acousto-optic modulators aom

  1. Note: Laser frequency shifting by using two novel triple-pass acousto-optic modulator configurations

    SciTech Connect

    Carlos-Lopez, E. de; Lopez, J. M.; Lopez, S.; Espinosa, M. G.; Lizama, L. A.

    2012-11-15

    We report the design of two novel triple-pass acousto-optic modulator systems. These designs are extensions of the well known acousto-optic modulator (AOM) double-pass configuration, which eliminates the angle dependence of the diffracted beam with respect to the modulation frequency. In a triple-pass system, however, the frequency dependence of the angle does not disappear but the frequency shift is larger, spanning 3 times the AOM central frequency. In some applications, such as optically pumped Cesium-beam frequency standards, the frequencies of the two laser beams remain fixed and a triple-pass optical system can be used to reduce to one the number of lasers used in such atomic clocks. The two triple-pass configurations use either a retro-reflecting mirror, or a right angle prism to pass for third time the laser beam through the AOM, obtaining diffraction efficiencies of about 27% and 44%, respectively.

  2. Actively mode-locked fiber laser using acousto-optic modulator

    NASA Astrophysics Data System (ADS)

    Nikodem, Michal P.; Sergeant, Hendrik; Kaczmarek, Pawel; Abramski, Krzysztof M.

    2008-12-01

    In recent years we have observed growing interest in mode-locked fiber lasers. Development of erbium doped fiber (EDF) amplifiers and WDM technique made 3rd telecommunication window extremely interesting region for ultrafast optics. The main advantages of fiber lasers i.e. narrow linewidth and wide gain bandwidth make them very attractive sources in various applications. In this paper we present an actively mode-locked erbium doped fiber ring laser. Modelocking is obtained using an acousto-optic modulator (AOM) coupled into the laser cavity. The impact of different parameters (e.g. light polarization, modulation frequency) is investigated. We study mechanisms of controlling the wavelength of the laser.

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

    NASA Astrophysics Data System (ADS)

    Tadesse, Semere A.; Li, Huan; Liu, Qiyu; Li, Mo

    2015-11-01

    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. Our system demonstrates a scalable optomechanical platform where strong acousto-optic coupling between cavity-confined photons and high frequency traveling phonons can be explored.

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

    SciTech Connect

    Tadesse, Semere A.; Li, Huan; Liu, Qiyu; Li, Mo

    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. Our system demonstrates a scalable optomechanical platform where strong acousto-optic coupling between cavity-confined photons and high frequency traveling phonons can be explored.

  5. 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.

  6. In-plane vibration characterization of microelectromechanical systems using acousto-optic modulated partially incoherent stroboscopic imaging

    NASA Astrophysics Data System (ADS)

    Wang, Dung-An; Sheu, Fang-Wen; Chiu, Yen-Sih

    2011-07-01

    A technique using acousto-optic modulated partially incoherent stroboscopic imaging for measurement of in-plane motion of microelectromechanical systems (MEMS) is presented. Vibration measurement is allowed by using flashes of the partially incoherent light source to freeze the positions of the microstructure at 12 equally spaced phases of the vibration period. The first-order diffracted beam taken out by an acousto-optic modulator (AOM) from the light beam of a laser is made partially incoherent by a rotating diffuser and then serves as the stroboscopic light source. Both the MEMS excitation signal and the flash control signal are provided by a dual-channel function generator. The main advantage of this measurement method is the absence of a stroboscopic generator and a high speed digital camera. Microscale prototypes are fabricated and tested. Quantitative estimates of the harmonic responses of the prototypes are obtained from the recorded images. The results agree with those obtained with a commercial MEMS motion analyzer TM with relative errors less than 2%.

  7. Lyapunov exponent of chaos generated by acousto-optic modulators with feedback

    NASA Astrophysics Data System (ADS)

    Ghosh, Anjan K.; Verma, Pramode

    2011-01-01

    Generation of chaos from acousto-optic modulators with an electronic feedback has been studied for several years. Such chaotic signals have an important application in providing secure encryption in free-space optical communication systems. Lyapunov exponent is an important parameter for analysis of chaos generated by a nonlinear system. The Lyapunov exponent of an acousto-optic system is determined and calculated in this paper to understand the dependence of the chaotic response on the system parameters such as bias, feedback gain, input intensity and initial condition exciting the cell. Analysis of chaos using Lyapunov exponent is consistent with bifurcation analysis and is useful in encrypting data signals.

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

    SciTech Connect

    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)

  9. Two-dimensional refractive index modulation by phased array transducers in acousto-optic deflectors.

    PubMed

    Wang, Tiansi; Zhang, Chong; Aleksov, Aleksandar; Salama, Islam; Kar, Aravinda

    2017-01-20

    Acousto-optic deflectors are photonic devices that are used for scanning high-power laser beams in advanced microprocessing applications such as marking and direct writing. The operation of conventional deflectors mostly relies on one-dimensional sinusoidal variation of the refractive index in an acousto-optic medium. Sometimes static phased array transducers, such as step configuration or planar configuration transducer architecture, are used to tilt the index modulation planes for achieving higher performance and higher resolution than a single transducer AO device. However, the index can be modulated in two dimensions, and the modulation plane can be tilted arbitrarily by creating dynamic phase gratings in the medium using phased array transducers. This type of dynamic two-dimensional acousto-optic deflector can provide better performance using, for example, a large deflection angle and high diffraction efficiency. This paper utilizes an ultrasonic beam steering approach to study the two-dimensional strain-induced index modulation due to the photoelastic effect. The modulation is numerically simulated, and the effects of various parameters, such as the operating radiofrequency of the transducers, the ultrasonic beam steering angle, and different combinations of pressure on each element of the transducer array, are demonstrated.

  10. 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

  11. Fiber-optic tunable multiwavelength variable attenuator and routing module designs that use bulk acousto-optics.

    PubMed

    Riza, Nabeel A; Mughal, M Junaid

    2005-02-10

    A compact fiber-coupled bulk acousto-optical multiwavelength variable optical attenuator module design that uses a retroreflective double-pass geometry within a single bulk acousto-optic tunable filter device is presented. The proposed attenuator module demonstrates a high 17-dB notch dynamic range at a low 100-mW drive power and uses a single bulk collinear-interaction acousto-optic tunable-filter device. Experiments show a low (<1.8-dB) fiber-to-fiber insertion loss with a fast 34-micros speed within a wide 1520-1640-nm agile multinotch band. The basic broadband attenuator module design is extended to allow for efficient architectures for routing modules such as agile drop filters, analog hitless tap filters, and digital add-drop switches.

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

    SciTech Connect

    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.

  13. Addressable, large-field second harmonic generation microscopy based on 2D acousto-optical deflector and spatial light modulator.

    PubMed

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

    2012-09-01

    We present an addressable, large-field second harmonic generation microscope by combining a 2D acousto-optical deflector with a spatial light modulator. The SLM shapes an incoming mode-locked, near-infrared Ti:Sapphire laser beam into a multifocus array, which can be rapidly scanned by changing the incident angle of the laser beam using a 2D acousto-optical deflector. Compared to the single-beam-scan technique, the multifocus array scan can increase the scanning rate and the field-of-view size with the multi-region imaging ability.

  14. Addressable, large-field second harmonic generation microscopy based on 2D acousto-optical deflector and spatial light modulator

    PubMed Central

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

    2013-01-01

    We present an addressable, large-field second harmonic generation microscope by combining a 2D acousto-optical deflector with a spatial light modulator. The SLM shapes an incoming mode-locked, near-infrared Ti:Sapphire laser beam into a multifocus array, which can be rapidly scanned by changing the incident angle of the laser beam using a 2D acousto-optical deflector. Compared to the single-beam-scan technique, the multifocus array scan can increase the scanning rate and the field-of-view size with the multi-region imaging ability. PMID:24307756

  15. Mode locking of an all-fiber laser by acousto-optic superlattice modulation.

    PubMed

    Cuadrado-Laborde, C; Diez, A; Delgado-Pinar, M; Cruz, J L; Andrés, M V

    2009-04-01

    Active mode locking of an erbium-doped all-fiber laser with a Bragg-grating-based acousto-optic modulator is demonstrated. The fiber Bragg grating was acoustically modulated by a standing longitudinal elastic wave, which periodically modulates the sidebands at twice the acoustic frequency. The laser has a Fabry-Perot configuration in which cavity loss modulation is achieved by tuning the output fiber Bragg grating to one of the acoustically induced sidebands. Optical pulses at 9 MHz repetition rate, 120 mW peak power, and 780 ps temporal width were obtained. The output results to be stable and has a timing jitter below 40 ps. The measured linewidth, 2.8 pm, demonstrates that these pulses are transform limited.

  16. Acousto-optic gyrotropic-crystal-based modulator with a rotating polarisation vector

    NASA Astrophysics Data System (ADS)

    Kotov, V. M.; Averin, S. V.; Kotov, E. V.; Voronko, A. I.; Tikhomirov, S. A.

    2017-02-01

    We study the influence of ellipticity of gyrotropic-crystal eigenwaves on the output characteristics of an acousto-optic (AO) modulator based on the interferometer scheme. The schemes of AO modulators are considered, which provide the polarisation vector rotation frequency fn/2, where f is the frequency of the acoustic wave, and n is the integer. Preference is given to the scheme combining cascade and polarisation-independent diffraction. An experimental layout of the AO modulator operating at f = 44.5 MHz is described, the modulation frequency of the output laser light intensity being 89 MHz. The frequency of the electrical signal from the photodetector is equal to 179.5 MHz.

  17. Actively mode-locked fiber ring laser by intermodal acousto-optic modulation.

    PubMed

    Bello-Jiménez, M; Cuadrado-Laborde, C; Sáez-Rodríguez, D; Diez, A; Cruz, J L; Andrés, M V

    2010-11-15

    We report an actively mode-locked fiber ring laser. A simple and low-insertion-loss acousto-optic modulator driven by standing flexural waves, which couples core-to-cladding modes in a standard single-mode optical fiber, is used as an active mechanism for mode locking. Among the remarkable features of the modulator, we mention its high modulation depth (72%), broad bandwidth (187 GHz), easy tunability in the optical wavelength, and low insertion losses (0.7 dB). The narrowest optical pulses obtained were of 95 ps time width, 21 mW peak power, repetition rate of 4.758 MHz, and 110 mW of pump power.

  18. Acousto-Optic Modulation and Optoacoustic Gating in Piezo-Optomechanical Circuits

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    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 optoacoustic 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 modeled through the coupled mode equations of cavity optomechanics.

  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. Stabilisation of a fibre frequency synthesiser using acousto-optical and electro-optical modulators

    NASA Astrophysics Data System (ADS)

    Koliada, N. A.; Nyushkov, B. N.; Pivtsov, V. S.; Dychkov, A. S.; Farnosov, S. A.; Denisov, V. I.; Bagayev, S. N.

    2016-12-01

    A fibre-optic frequency synthesiser is developed that is stabilised to the optical frequency standard based on molecular iodine ({\\text{Nd : YAG/I}}2). The possibility of transferring stability of the optical frequency standard to other optical frequencies in the IR range 1 - 2 \\unicode{956}{\\text{m}} and to the RF range by using synthesiser phase-locked loops (PLLs) with acousto-optical and electro-optical modulators is experimentally demonstrated. The additive instability introduced into the optical frequency comb of the synthesiser (which arises due to PLL residual random errors) is several orders less than the intrinsic instability of the reference optical frequency standard employed (i.e., is noticeably less than 1 × 10-13 for 1 {\\text{s}} and 5 × 10-15 for 1000 {\\text{s}}).

  1. Gain-switched Ho:YAG ceramic laser with an acousto-optic modulator

    NASA Astrophysics Data System (ADS)

    Zhang, Jianing; Shen, Deyuan; Zhang, Jian; Tang, Dingyuan; Chen, Hao

    2016-04-01

    We demonstrate a gain-switched Ho:YAG ceramic laser in-band pumped by an acousto-optically modulated thulium fiber laser at ˜1908 nm. The laser pulse repetition rate could be tuned continuously from 60 to 100 kHz with the pulse energy kept constant for a certain pump power level. The shortest pulse width of 204 ns and a maximum peak power of 75 W have been obtained at 60 kHz under the maximum pump power level of 11 W. A maximum average output power of 1.4 W has been achieved with a pulse repetition rate of 100 kHz, corresponding to a slope efficiency of 57% with respect to the incident pump power. The prospects for further improvement in laser performance are discussed.

  2. High-peak-power sub-nanosecond intracavity KTiOPO4 optical parametric oscillator pumped by a dual-loss modulated laser with acousto-optic modulator and single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Qiao, Junpeng; Zhao, Shengzhi; Yang, Kejian; Zhao, Jia; Li, Guiqiu; Li, Dechun; Li, Tao; Qiao, Wenchao; Lu, Jianren; Wang, Yonggang; Chu, Hongwei; Luan, Chao

    2016-08-01

    A high-peak-power low-repetition-rate sub-nanosecond intracavity KTiOPO4 (KTP) optical parametric oscillator (OPO) pumped by a doubly Q-switched and mode-locked (QML) YVO4/Nd:YVO4 laser with an acousto-optic modulator (AOM) and a single-walled carbon nanotube saturable absorber (SWCNT-SA) has been demonstrated. A maximum output power of 373 mW at a signal wavelength of 1570 nm was obtained. The smallest pulse width, highest pulse energy, and greatest peak power of mode-locking pulses were estimated to be 119 ps, 124 µJ, and 1.04 MW, respectively, under a maximum incident pump power of 8.3 W and an AOM repetition rate of 2 kHz. This OPO operation paves a simple way to produce eye-safe laser sources at 1570 nm with low repetition rates, small pulse widths, and high peak powers.

  3. Self-acousto-optic modulation and orthogonality violation in the transverse modes of a broad-area Nd-doped yttrium-aluminum-garnet single-shot laser

    SciTech Connect

    Soler Rus, M. Odin; Cabrera-Granado, E.; Guerra Perez, J. M.

    2011-05-15

    Self-acousto-optic Raman-Nath modulation and nonorthogonal transversal modes are found in a broad-area Nd:YAG single-shot laser. The device is free from the thermal-induced effects previously related to orthogonality violation and the acousto-optic modulation comes from a shock wave produced by the discharge of the flash lamps that optically pump the laser. The experimental findings are reproduced by a general model of a class B laser.

  4. High coherent bi-chromatic laser with gigahertz splitting produced by the high diffraction orders of acousto-optic modulator used for coherent population trapping experiments.

    PubMed

    Yun, Peter; Tan, Bozhong; Deng, Wei; Gu, Sihong

    2011-12-01

    To prepare the coherent population trapping (CPT) states with rubidium and cesium, the commonly used atoms in CPT studies, a coherent bi-chromatic light field with frequency difference of several GHz is a basic requirement. With a 200 MHz center frequency acousto-optic modulator (AOM), we have realized bi-chromatic laser fields with several GHz frequency splits through high diffraction orders. We have experimentally studied the coherence between two frequency components of a bi-chromatic laser beam, which is composed of ±6 orders with frequency split of 3 GHz diffracted from the same laser beam, and the measured residual phase noise is Δφ(2)<0.019 rad(2). The bi-chromatic laser fields were used to prepare CPT states with (85)Rb and (87)Rb atoms, and high contrast CPT signals were obtained. For CPT states preparation, our study result shows that it is a feasible approach to generate the bi-chromatic light field with larger frequency splits through high diffraction orders of AOM.

  5. Acousto-Optic Adaptive Processing (AOAP).

    DTIC Science & Technology

    1983-12-01

    I ~.sls Phe Report December 1963 •- ACOUSTO - OPTIC ADAPTIVE <PROCESSING (AOAP) General Electric Company W. A. Penn, D. R. Morgan, A. Aridgides and M. L...numnber) Optical signal processing Acousto - optical modulators Adaptive signal processing - Adaptive sidelobe cancellation 20. ABSTRACT (Contnue an...required operations of multiplication and time delay are provided by acousto - optical (AO) delay lines. The required time integraticO is provided by

  6. Dual-loss-modulated Q-switched Tm:LuAG laser with AOM and monolayer graphene.

    PubMed

    Luan, Chao; Yang, Ke Jian; Zhao, Jia; Zhao, Sheng Zhi; Qiao, Wen Chao; Li, Tao; Feng, Tian Li; Liu, Cheng; Qiao, Jun Peng; Zheng, Li He; Xu, Jun; Wang, Qing Guo; Su, Liang Bi

    2015-09-20

    A laser-diode-pumped dual-loss-modulated Q-switching Tm:LuAG laser with an acousto-optic modulator (AOM) and monolayer graphene saturable absorber (SA) around 2 μm is presented for the first time to the best of our knowledge. The average output power and the pulse widths for different repetition rates have been measured. In comparison with the singly Q-switching laser with AOM or with monolayer graphene SA, the dual-loss-modulated Q-switching laser could generate shorter pulse width and higher peak power. The maximum pulse width compression ratio was found to be 3.11, and the highest peak power was enhanced 97.4 times. The experimental results show that the dual-loss-modulated technology is an efficient method for compressing the pulse width, improving the peak power, and enhancing the pulse stability for the Q-switched lasers at 2 μm.

  7. Dependence of integrated acousto-optical devices with one and two modulated arms on the static phase difference.

    PubMed

    Fan, Guofang; Li, Yuan; Hu, Chunguang; Lei, Lihua; Zhao, Dong; Li, Hongyu; Zhen, Zhen

    2014-10-01

    In this paper, we develop an analytical model of an integrated acousto-optical (AO) device with arms modulated by a single surface acoustic wave beam. A comparison between one-arm and two-arm modulation is presented, which shows that two-arm modulation can significantly enhance modulation efficiency by an optimized design. A detailed analysis of the influence of static phase difference on the behavior of the AO devices has been provided, and some interesting results have been obtained. These will be helpful for an optimized design of AO devices for different functionalities.

  8. Improvements on the refresh rate and dynamical properties of a SLM by sequential readout using an acousto-optic modulator

    NASA Astrophysics Data System (ADS)

    Mestre, Michael; Viaris de Lesegno, Bruno; Farcy, René; Pruvost, Laurence; Bourderionnet, Jérôme; Delboulbé, Anne; Loiseaux, Brigitte; Dolfi, Daniel

    2006-08-01

    We demonstrate the use of an acousto-optic modulator to enhance the refresh rate and dynamic properties of a liquid-crystal spatial light modulator (SLM). The useful area of the SLM surface is split in several zones which are addressed separately, and read in a sequence by a steered laser beam. This configuration allows to increase the refresh rate by five orders of magnitude. Furthermore, improvements on the nature of the transition between different holograms are experimentally shown. The advantages of this technique are discussed in the particular context of cold atom manipulation with holographic optical tweezers.

  9. Acousto-optic effect in random media

    NASA Astrophysics Data System (ADS)

    Hoskins, Jeremy G.; Schotland, John C.

    2017-03-01

    We consider the acousto-optic effect in a random medium. We derive the radiative transport equations that describe the propagation of multiply scattered light in a medium whose dielectric permittivity is modulated by an acoustic wave. Using this result, we present an analysis of the sensitivity of an acousto-optic measurement to the presence of a small absorbing inhomogeneity.

  10. A novel acousto-optic modulation-deflection mechanism using refractive index grating as graded index beam router

    NASA Astrophysics Data System (ADS)

    Jangjoo, Alireza; Reza Baezzat, Mohammad; Razavizadeh, Ahmad

    2014-03-01

    A novel acousto-optic modulation mechanism will be addressed in this paper. Focused Gaussian beam passing through acousto-optic media experiences different refractive index regions arising from acoustic waves generated by ultrasonic source. In this way according to the snell's law of refraction the beam propagation path will be altered when these periodic traveling waves reach the incoming radiation where a typical p-n junction photodiode located inside the rising or falling lobe of the undiffracted Gaussian beam senses these small lateral deflections. Due to small variations of the refractive index the magnitude of deflection will be up to tens of micron outside the modulator. Hence, sharp intensity gradient is required for detecting such small beam movements by appropriate lens configuration to focus the Gaussian profile on the detector junction area. In the other words intensity profile of zero order beam oscillates proportional to the time dependent amplitude of the acoustic waves versus previous methods that intensity of diffracted beam changes with applied ultrasonic intensity. The extracted signal properties depend on the beam collimation, quality of beam profile and depth of focus inside the modulator. The first experimental approach was proceeded using a collimated 532 nm diode laser source (TEM00), distilled water as interaction media and 10 MHz transducer as ultrasonic generator where a cylindrical glass column with input-output flat windows was used for liquid support. The present method has advantages over common acoustooptical techniques as low cost, simplicity of operation, direct modulation of the signal and minimum alignment requirement.

  11. 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)

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

    PubMed Central

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

    2013-01-01

    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. PMID:22743445

  13. 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.

  14. LIGHT MODULATION: Quasi-collinear tunable acousto-optic paratellurite crystal filters for wavelength division multiplexing and optical channel selection

    NASA Astrophysics Data System (ADS)

    Molchanov, V. Ya; Voloshinov, V. B.; Makarov, O. Yu

    2009-04-01

    Quasi-collinear acousto-optic interaction is studied in acoustically and optically anisotropic paratellurite crystals. The possible applications of this interaction in acousto-optic tunable filters with a high spectral resolution are discussed. Different modifications of devices are compared and variants of devices intended for processing light beams and selection of light signals in fibreoptic communication systems with wavelength division multiplexing (WDM) at λ simeq 1550 nm are considered.

  15. 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.

  16. Real-Time Display Of 3-D Computed Holograms By Scanning The Image Of An Acousto-Optic Modulator

    NASA Astrophysics Data System (ADS)

    Kollin, Joel S.; Benton, Stephen A.; Jepsen, Mary Lou

    1989-10-01

    The invention of holography has sparked hopes for a three-dimensional electronic imaging systems analogous to television. Unfortunately, the extraordinary spatial detail of ordinary holographic recordings requires unattainable bandwidth and display resolution for three-dimensional moving imagery, effectively preventing their commercial development. However, the essential bandwidth of holographic images can be reduced enough to permit their transmission through fiber optic or coaxial cable, and the required resolution or space-bandwidth product of the display can be obtained by raster scanning the image of a commercially available acousto-optic modulator. No film recording or other photographic intermediate step is necessary as the projected modulator image is viewed directly. The design and construction of a working demonstration of the principles involved is also presented along with a discussion of engineering considerations in the system design. Finally, the theoretical and practical limitations of the system are addressed in the context of extending the system to real-time transmission of moving holograms synthesized from views of real and computer-generated three-dimensional scenes.

  17. Numerical simulation of dual-loss-modulated Q-switched and mode-locked laser with an acousto-optic and Cr4+:YAG saturable absorber.

    PubMed

    Zhao, Shengzhi; Li, Guiqiu; Li, Dechun; Yang, Kejian; Li, Yufei; Li, Ming; Li, Tao; Zhang, Gang; Cheng, Kang

    2010-04-01

    By considering the influence of the turn-off time and the modulation frequency of the acousto-optic (AO) modulator as well as the Gaussian spatial distribution of the photon density, we give a developed rate equation model for a diode-pumped dual-loss-modulated Q-switched and mode-locked (QML) Nd:GdVO(4) laser with AO modulator and Cr(4+):YAG saturable absorber. With this developed model, the dual-loss-modulated QML laser characteristics, such as pulse width and pulse energy, can be numerically simulated, and the theoretical evaluations are in good agreement with the experimental results.

  18. Laser frequency stabilisation by the Pound - Drever - Hall method using an acousto-optic phase modulator operating in the pure Raman - Nath diffraction regime

    SciTech Connect

    Baryshev, Vyacheslav N

    2012-04-30

    Frequency stabilisation of diode laser radiation has been implemented by the Pound - Drever - Hall method using a new acousto-optic phase modulator, operating in the pure Raman - Nath diffraction regime. It is experimentally shown that, as in the case of saturated-absorption spectroscopy in atomic vapour, the spatial divergence of the frequency-modulated output spectrum of this modulator does not interfere with obtaining error signals by means of heterodyne frequency-modulation spectroscopy with a frequency discriminator based on a high-Q Fabry - Perot cavity with finesse of several tens of thousands.

  19. 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)

  20. LIGHT MODULATION: Wide-aperture diffraction of unpolarised radiation in a system of two acousto-optic filters

    NASA Astrophysics Data System (ADS)

    Magdich, L. N.; Yushkov, K. B.; Voloshinov, V. B.

    2009-04-01

    Light diffraction is studied in two tandem acousto-optic cells filtering unpolarised radiation with a wide angular spectrum. It is shown that the side lobes of the ultrasonic radiation pattern of a piezoelectric transducer produce side diffraction intensity maxima at the output of the system consisting of two filters. Diffraction in paratellurite filters is studied experimentally at 1.06 μm.

  1. Long-cavity all-fiber ring laser actively mode locked with an in-fiber bandpass acousto-optic modulator.

    PubMed

    Cuadrado-Laborde, C; Bello-Jiménez, M; Díez, A; Cruz, J L; Andrés, M V

    2014-01-01

    We demonstrate low-frequency active mode locking of an erbium-doped all-fiber ring laser. As the mode locker, we used a new in-fiber bandpass acousto-optic modulator showing 74% modulation depth, 3.7 dB power insertion losses, 4.5 nm of optical bandwidth, and 20 dB of nonresonant light suppression. The laser generates 330 ps mode-locked pulses over a 10 ns pedestal, at a 1.538 MHz frequency, with 130 mW of pump power.

  2. Random depth access full-field heterodyne low-coherence interferometry utilizing acousto-optic modulation and a complementary metaloxide semiconductor camera.

    PubMed

    Egan, Patrick; Connelly, Michael J; Lakestani, Fereydoun; Whelan, Maurice P

    2006-04-01

    With analog scanning, time-domain low-coherence interferometry lacks precise depth information, and optical carrier generation demands a linear scanning speed. Full-field heterodyne low-coherence interferometry that uses a logarithmic complementary metal-oxide semiconductor camera, acousto-optic modulation, and digital depth stepping is reported, with which random regions of interest, lateral and axial, can be accessed. Furthermore, nanometer profilometry is possible through heterodyne phase retrieval of the interference signal. The approach demonstrates inexpensive yet high-precision functional machine vision offering true digital random access in three dimensions.

  3. 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

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

    SciTech Connect

    Lyakh, A. Barron-Jimenez, R.; Dunayevskiy, I.; Go, R.; Patel, C. Kumar N.

    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 than 20 μs.

  5. Narrowing of the linewidth of an optical parametric oscillator by an acousto-optic modulator for the realization of mid-IR noise-immune cavity-enhanced optical heterodyne molecular spectrometry down to 10⁻¹⁰ cm⁻¹ Hz⁻¹/².

    PubMed

    Hausmaninger, Thomas; Silander, Isak; Axner, Ove

    2015-12-28

    The linewidth of a singly resonant optical parametric oscillator (OPO) has been narrowed with respect to an external cavity by the use of an acousto-optic modulator (AOM). This made possible an improvement of the sensitivity of a previously realized OPO-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry instrument for the 3.2 - 3.9 µm mid-infrared region by one order of magnitude. The resulting system shows a detection sensitivity for methane of 2.4 × 10(-10) cm(-1) Hz(-1∕2) and 1.3 × 10(-10) cm(-1) at 20 s, which allows for detection of both the environmentally important (13)CH(4) and CH(3)D isotopologues in atmospheric samples.

  6. High repetition rate laser-induced breakdown spectroscopy using acousto-optically gated detection

    SciTech Connect

    Pořízka, Pavel; Kaiser, Jozef

    2014-07-15

    This contribution introduces a new type of setup for fast sample analysis using laser-induced breakdown spectroscopy (LIBS). The novel design combines a high repetition rate laser (up to 50 kHz) as excitation source and an acousto-optical modulator (AOM) as a fast switch for temporally gating the detection of the emitted light. The plasma radiation is led through the active medium of the AOM where it is diffracted on the transient ultrasonic Bragg grid. The diffracted radiation is detected by a compact Czerny-Turner spectrometer equipped with a CCD line detector. Utilizing the new combination of high repetition rate lasers and AOM gated detection, rapid measurements with total integration times of only 10 ms resulted in a limit of detection (LOD) of 0.13 wt.% for magnesium in aluminum alloys. This short integration time corresponds to 100 analyses/s. Temporal gating of LIP radiation results in improved LODs and consecutively higher sensitivity of the LIBS setup. Therefore, an AOM could be beneficially utilized to temporally detect plasmas induced by high repetition rate lasers. The AOM in combination with miniaturized Czerny-Turner spectrometers equipped with CCD line detectors and small footprint diode pumped solid state lasers results in temporally gateable compact LIBS setups.

  7. Design of acousto-optic chaos based secure free-space optical communication links

    NASA Astrophysics Data System (ADS)

    Ghosh, A. K.; Verma, P.; Cheng, S.; Huck, R. C.; Chatterjee, M. R.; Al-Saedi, M.

    2009-08-01

    We discuss the design of an acousto-optic cell based free space optical communication link where the data beam is made secure through chaos encryption. Using external signal modulation of the diffracted light from a hybrid acousto-optic cell chaos (or directly via incorporation in the sound-cell driver's bias voltage) encryption of data is possible. We have shown numerically that decryption of the encoded data is possible by using an identical acousto-optic system in the receiver.

  8. Acousto-Optical Imaging Spectropolarimeter

    NASA Technical Reports Server (NTRS)

    Saif, Babak; Glenar, David; Zimmerman, Robert; Seery, Bernard

    1992-01-01

    Imaging spectropolarimeter designed around acousto-optical tunable filter (AOTF) takes polarization-specific spectral images of solid surfaces, aerosols, and absorption and emission phenomena in gas phase, at wavelengths from 500 to 1,000 nm. Produces side-by-side spectral images in two mutually perpendicular polarizations, one corresponding to ordinary, other corresponding to extraordinary waves in acousto-optical material. Offers large aperture, high resolving power, and rapid tunability, with no moving parts.

  9. Baseband integrated acousto-optic frequency shifter/modulator module for fiber optic at 1.3 mum.

    PubMed

    Tsai, C S; Cheng, Z Y

    1993-01-01

    A baseband integrated acoustooptic (AO) frequency shifter/modulator module that consists of a pair of titanium-indiffused proton-exchanged (TIPE) waveguide lenses and a pair of cascaded guided-wave AO Bragg cells has been realized in a Y-cut LiNbO(3) waveguide substrate 0.1 cmx1.0 cmx2.0 cm in size. A device module operating at the optical wavelength of 1.3 mum has provided a -3-dB tunable bandwidth of 120 MHz at baseband. The frequency-shifted or -modulated light propagates in a fixed direction, irrespective of the magnitude of frequency shift or modulation, and is focused into a spot (FWHM) of 6.2-mum size on the output edge of the waveguide. Accordingly, this optical frequency shifter/module can be directly interfaced with single-mode optical fibers to facilitate applications in fiber optic systems.

  10. Optimization of doubly Q-switched lasers with both an acousto-optic modulator and a GaAs saturable absorber.

    PubMed

    Li, Dechun; Zhao, Shengzhi; Li, Guiqiu; Yang, Kejian

    2007-08-20

    A doubly Q-switched laser with both an acousto-optic (AO) modulator and a GaAs saturable absorber can obtain a more symmetric and shorter pulse with high pulse peak power, which has been experimentally proved. The key parameters of an optimally coupled doubly Q-switched laser with both an AO modulator and a GaAs saturable absorber are determined, and a group of general curves are generated for what we believe is the first time, when the single-photon absorption (SPA) and two-photon absorption (TPA) processes of GaAs are combined, and the Gaussian spatial distributions of the intracavity photon density and the initial population-inversion density as well as the influence of the AO Q-switch are considered. These key parameters include the optimal normalized coupling parameter, the optimal normalized GaAs saturable absorber parameters, and the normalized parameters of the AO Q-switch, which can maximize the output energy. Meanwhile, the corresponding normalized energy, the normalized peak power, and the normalized pulse width are given. The curves clearly show the dependence of the optimal key parameters on the parameters of the gain medium, the GaAs saturable absorber, the AO Q-switch, and the resonator. Sample calculations for a diode-pumped Nd3+:YVO4 laser with both an AO modulator and a GaAs saturable absorber are presented to demonstrate the use of the curves and the relevant formulas.

  11. 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

  12. 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.

  13. Holographic topography using acousto-optically generated large synthetic wavelengths

    NASA Astrophysics Data System (ADS)

    Abeywickrema, U.; Beamer, D.; Banerjee, P.; Poon, T.-C.

    2016-03-01

    Digital holography uses phase imaging in a variety of techniques to produce a three-dimensional phase resolved image that includes accurate depth information about the object of interest. Multi-wavelength digital holography is an accurate method for measuring the topography of surfaces. Typically, the object phases are reconstructed for two wavelengths separately and the phase corresponding to the synthetic wavelength (obtained from the two wavelengths) is obtained by calculating the phase difference. Then the surface map can be obtained using proper phase-unwrapping techniques. Usually these synthetic wavelengths are on the order of microns which can be used to resolve depths on the order of microns. In this work, two extremely close wavelengths generated by an acousto-optic modulator (AOM) are used to perform two-wavelength digital holography. Since the difference between the two wavelengths is on the order of picometers, a large synthetic wavelength (on the order of centimeters) can be obtained which can be used to determine the topography of macroscopic surface features. Also since the synthetic wavelength is large, an accurate surface map can be obtained without using a phase-unwrapping technique. A 514 nm Argon-ion laser is used as the optical source, and used with an AOM to generate the zeroth-order and frequency-shifted first-order diffracted orders which are used as the two wavelengths. Both beams are aligned through the same spatial filter assembly. Holograms are captured sequentially using a typical Mach-Zehnder interferometric setup by blocking one beam at a time. Limitations of the large synthetic wavelength are also discussed.

  14. Hybrid wide-band, low-phase-noise scheme for Raman lasers in atom interferometry by integrating an acousto-optic modulator and a feedback loop.

    PubMed

    Wang, Kai; Yao, Zhanwei; Li, Runbing; Lu, Sibin; Chen, Xi; Wang, Jin; Zhan, Mingsheng

    2016-02-10

    We report a hybrid scheme for phase-coherent Raman lasers with low phase noise in a wide frequency range. In this scheme, a pair of Raman lasers with a frequency difference of 3.04 GHz is generated by the ±1-order diffracted lights of an acousto-optic modulator (1.52 GHz), where a feedback loop is simultaneously applied for suppressing the phase noise. The beat width of the Raman lasers is narrower than 3 Hz. In the low-frequency range, the phase noise of the Raman lasers is suppressed by 35 dB with the feedback. The phase noise is less than -109  dBc/Hz in the high-frequency range. The sensitivity of an atom gyroscope employing the hybrid Raman lasers can be implicitly improved 10 times. Due to the better high-frequency response, the sensitivity is not limited by the durations of Raman pulses. This work is important for improving the performance of atom-interferometer-based measurements.

  15. 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.

  16. 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).

  17. Physical basis of Acousto-Optical Imaging

    NASA Astrophysics Data System (ADS)

    Jarrett, Christopher W.

    Acousto-Optical Imaging (AOI) is an emerging hybrid multi-modal imaging technique that combines the high spatial resolution of ultrasound with the versatile molecular sensitivity of optical detection to improve upon the limited spatial resolution of purely optical techniques. However, the precise mechanisms that contribute to the contrast in AOI have been relatively little explored, and the influence of several physical factors are not well understood. Kobayashi et al. previously reported observations of modulated fluorescence capable of locating fluorescent regions of interest within turbid media, suggesting the ability to use incoherent light for AOI. This research aimed to develop and extend such an approach for applications in biomedical imaging. We aimed to demonstrate the modulation of incoherent light by ultrasound and investigate what factors affect the magnitude of such effects. We proposed the following specific aims: (1) To design and develop instrumentation to detect and quantify Acousto-Optical interactions; (2) To evaluate the contributions of different mechanisms of ultrasonic modulation of fluorescence and the factors that influence these effects in turbid media like tissues; (3) To test a variety of fluorescent contrast agents to determine if their light output may be directly affected by ultrasonic modulation, which would suggest a novel approach to AOI. This work achieved these aim. We were successful in designing and developing an experimental apparatus capable of detecting and quantifying Acousto-Optical Interactions. We determined this signal scales linearly with squared ultrasound pressure but unlike the interpretation of Kobayashi et al., we found the apparent modulated fluorescence is dominated by acoustic modulation of the excitation light. In addition, we report a novel finding that ultrasound can modulate incoherent light via modulation of tissue absorption and density, incidentally providing a new way to image sound fields. Lastly, we

  18. 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

  19. 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

  20. FPGA-based phase control of acousto-optic modulator Fourier synthesis system through gradient descent phase-locking algorithm.

    PubMed

    Underwood, Kenneth J; Jones, Andrew M; Gopinath, Juliet T

    2015-06-20

    We present a new application of the stochastic parallel gradient descent (SPGD) algorithm to fast active phase control in a Fourier synthesis system. Pulses (4.9 ns) with an 80 MHz repetition rate are generated by feedback from a single phase-sensitive metric. Phase control is applied via fast current modulation of a tapered amplifier using an SPGD algorithm realized on a field-programmable gate array (FPGA). The waveforms are maintained by constant active feedback from the FPGA. We also discuss the extension of this technique to many more semiconductor laser emitters in a diode laser array.

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

    SciTech Connect

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

    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 modulators and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation. (review)

  2. Acousto-Optic Beam Steering Study

    DTIC Science & Technology

    1994-08-01

    8217111 INK $ 1 1 illl iII Ill i, R L-TR-94-121 !1!1Il t 11I1!I!11! ilI, / Final Technical Report August 1994 ACOUSTO - OPTIC BEAM STEERING STUDY Harris...contractual obligations or notices on a specific document require that it be returned. For i ..........I ,, ACOUSTO - OPTIC BEAM STEERING STUDY H. W...4. TITLE AND SUBTITLE 5. FUNDING NUMBERS ACOUSTO - OPTIC BEAM STEERING STUDY C - F30602-91-C-0131 PE - 63215C 6. AUTHOR(S) PR - 1405 TA - 02 H. W

  3. Simple Digital Feed-Forward Circuit to Compensate for AOM Thermal Lensing

    NASA Astrophysics Data System (ADS)

    Hill, Joshua; Aman, James; Killian, Thomas; Neutral Experiment Team

    2016-05-01

    I demonstrate a simple digital feed-forward circuit which, when combined with two-frequency radio frequency (RF) electronics, maintains constant total RF power driving an acousto-optic modulator (AOM). Consistency in total power is desirable to mitigate thermal lensing effects that otherwise displace and misshape the laser beam when the primary frequency drive RF power is changed to, for example, alter the laser power in a diffracted beam. The Arduino-based feed-forward circuit is cost-effective, quick to implement, and easily modified.

  4. Acousto-Optically Addressed Fourier Transform Matched Filters.

    DTIC Science & Technology

    1984-08-01

    ACOUSTO - OPTIC DEFLECTOR .............................. II. THE EXPERIMENT............................................. 2 FV XPERIMENTAl. RESULTS...tcohniqtie1 arc addressed using an acousto - optic beam deflector with good correlation signals resulting. Th is method may be used to address arrays of matched...essentially the standard Vander Lugt method for making matched filters, except for the addition of the acousto - optic deflector between the Fourier

  5. Acousto-optic spectrometer for radio astronomy

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    A prototype acousto-optic spectrometer which uses a discrete bulk acoustic wave Itek Bragg cell, 5 mW Helium Neon laser, and a 1024 element Reticon charge coupled photodiode array is described. The analog signals from the photodiode array are digitized, added, and stored in a very high speed custom built multiplexer board which allows synchronous detection of weak signals to be performed. The experiment is controlled and the data are displayed and stored with an LSI-2 microcomputer system with dual floppy discs. The performance of the prototype acousto-optic spectrometer obtained from initial tests is reported.

  6. 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

  7. Measurement of Isotope Shifts, Hyperfine Splittings and Stark Shift for the Ytterbium (6S)2 SINGLET-S(0) to (6S6P) TRIPLET-P(1) Transition Using AN Acousto-Optically Modulated Laser Beam.

    NASA Astrophysics Data System (ADS)

    Li, Jian

    1995-11-01

    Accurate measurements of isotope shifts, hyperfine splittings and Stark shifts are of interest for studying atomic structure. This thesis reports a new method to precisely measure small frequency intervals. This was done using an acousto-optic modulator to frequency shift part of a laser beam. The frequency shifted and unshifted laser beams were then superimposed and excited an atomic beam. The laser frequency was scanned across the transition while fluorescence produced by the radiative decay of the excited state was detected by a photomultiplier. Each transition generated two peaks in the spectrum separated by the acousto-optic modulation frequency, which permitted the frequency to be calibrated. This method was tested by measuring the isotope shifts and hyperfine splittings of the ytterbium rm (6s)^2 ^1S_0to(6s6p) ^3P_1 transition at 555.6 nm. The shifts (MHz) relative to ^{176} Yb are: ^{173}Yb {it F}=7/2,-1432.1+/-1.2; ^{171}Yb {it F}=1/2, -1176.9+/-1.1; ^{174}Yb, 953.8+/-1.0; ^{172}Yb 1953.9+/-1.6; ^{170}Yb 3240.4+/-2.8; ^{173}Yb {it F}=5/2,3265.8+/-2.8; ^ {168}Yb, 4611.9+/-4.4; ^ {171,173}Yb {it F}=3/2,4760.1 +/-3.7 where the negative sign indicates that the transition occurs at a lower frequency than in ^{176}Yb. The magnetic dipole (a) and electric quadrupole (b) hyperfine coupling constants (MHz) of the (6s6p) ^3P_1 state for ^{171,173}Yb were determined to be a_{171}=3959.1 +/-3.0, a_{173}=-1094.44+/-0.84 and b_{173}=-827.89+/-0.85. These results were in agreement with the most accurate data found in the literature that were obtained by measuring frequency shifts using a Fabry Perot etalon whose length was stabilized with a helium neon laser locked to an iodine line. In contrast, our method uses cheaper and simpler apparatus. Next, the Stark shift of the ytterbium rm (6s)^2 ^1S_0to(6s6p) ^3P_1 transition was measured by passing the atomic beam through a uniform electric field. The Stark shift rate was found to be -15.419+/-0.048 kHz/(kV/cm)^2. No

  8. Optical Oscillation Established Using Acousto-Optic Bragg Angle Defraction In Conjunction With Closed Cavity Feedback

    NASA Astrophysics Data System (ADS)

    Vezzoli, G. C.; Cadwallender, W.; Megargel, L. R.; Mentzer, M. A.; Craley, D. E.

    1987-03-01

    An optical oscillator has been designed, constructed, and operated by using a HeNe laser and acousto-optic modulator in conjunction with two opposed fiber optic feedback circuits. Depending on round-trip feedback time, a low frequency ( 1Hz) sinusoidal oscillator or a high frequency (100KHz) square wave (,..%,1 us rise time) is obtained.

  9. Growth of high quality mercurous halide single crystals by physical vapor transport method for AOM and radiation detection applications

    NASA Astrophysics Data System (ADS)

    Amarasinghe, Priyanthi M.; Kim, Joo-Soo; Chen, Henry; Trivedi, Sudhir; Qadri, Syed B.; Soos, Jolanta; Diestler, Mark; Zhang, Dajie; Gupta, Neelam; Jensen, Janet L.; Jensen, James

    2016-09-01

    Single crystals of mercurous halide were grown by physical vapor transport method (PVT). The orientation and the crystalline quality of the grown crystals were determined using high resolution x-ray diffraction (HRXRD) technique. The full width at half maximum (FWHM) of the grown mercurous bromide crystals was measured to be 0.13 degrees for (004) reflection, which is the best that has been achieved so far for PVT grown mercurous halide single crystals. The extended defects of the crystals were also analyzed using high resolution x-ray diffraction topography. Preliminary studies were carried out to evaluate the performance of the crystals on acousto-optic modulator (AOM) and gamma-ray detector applications. The results indicate the grown mercurous halide crystals are excellent materials for acousto-optic modulator device fabrication. The diffraction efficiencies of the fabricated AOM device with 1152 and 1523 nm wavelength lasers polarizing parallel to the acoustic wave were found to be 35% and 28%, respectively. The results also indicate the grown crystals are a promising material for gamma-ray detector application with a very high energy resolution of 1.86% FWHM.

  10. 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

  11. 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.

  12. Arrangement of an advanced acousto-optical processor for modeling the triple correlations of low-power optical pulse trains

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Hanessian de la Garza, Ana V.; Chavushyan, Vahram; Campos Acosta, Joaquin

    2012-02-01

    Both a high level of developing the spatially spot-like and one-dimensional input devices and the flexibility of a design inherent in two-dimensional optical systems with similar modulating components make it possible to realize various high-bit-rate opto-electronic processors. This is why a one-dimension acousto-optic technique has been involved in data processing and its modeling based on the algorithm of triple product correlations. Practically, triple product correlations originate within an optical scheme including the modulated light source, representing the first input port, and two wideaperture acousto-optical cells forming two other input ports. Due to specifically constructed lens system, initially modulated light beam is crossing sequentially the apertures of acousto-optical cells oriented at right angle to each other. Finally, a CCD-matrix integrates the received optical signal with respect to time and registers the resulting triple product correlations. In a view of arranging similar acousto-optical processor for modeling triple product correlations, we characterize a novel version of the acousto-optical cells exploiting now tellurium-dioxide crystals. Together with this, potential performances of the progressed design for similar processor are estimated as well.

  13. 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

  14. 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

  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. 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.

  17. 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

  18. Photon frequency-mode matching using acousto-optic frequency beam splitters

    SciTech Connect

    Jones, Nick S.; Stace, T. M.

    2006-03-15

    It is a difficult engineering task to create distinct solid state single photon sources which nonetheless emit photons at the same frequency. It is also hard to create entangled photon pairs from quantum dots. In the spirit of quantum engineering we propose a simple optical circuit which can, in the right circumstances, make frequency distinguishable photons frequency indistinguishable. Our circuit can supply a downstream solution to both problems, opening up a large window of allowed frequency mismatches between physical mechanisms. The only components used are spectrum analysers or prisms and an acousto-optic modulator. We also note that an acousto-optic modulator can be used to obtain Hong-Ou-Mandel two photon interference effects from the frequency distinguishable photons generated by distinct sources.

  19. 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

  20. Modeling the noise figure of an acousto-optic receiver

    NASA Astrophysics Data System (ADS)

    Ristic, V. M.; Lee, J. P. Y.

    1996-02-01

    By defining the processing gain of an acousto-optic receiver as the ratio of the signal-to-noise ratio at the output of the detector to the signal-to-noise ratio of the intermediate-frequency input, one can model a noise figure for the acousto-optic receiver. The noise figure has a minimum of 0 dB and depends on the ratio of the noise power (internal to the acousto-optic cell) to the intermediate-frequency input noise power multiplied by the frequency and the spatially dependent exponential factor.

  1. Frequency Resolution of an Acousto-Optical Spectrometer

    DTIC Science & Technology

    1993-08-03

    AD-A267 822 FOREIGN AEROSPACE SCIENCE AND TECHNOLOGY CENTER DTIC S ELECTE AUG 111993 D FREQUENCY RESOLUTION OF AN ACOUSTO - OPTICAL SPECTROMETER by... D ~t• i,5"t~o’• A i +’- 1 Av.:+l +,O ,J Dist Avi! .. DTIC QUALITY I1V’PEMTED 3 FREQUENCY RESOLUTION OF AN ACOUSTO - OPTICAL SPECTROMETER... optical spectrometer (AOS) system as affected by the acousto - optical deflector and the coherent light beam truncation ratio, and examines the response

  2. Acousto-optically tuned isotopic CO{sub 2} lasers for long-range differential absorption LIDAR

    SciTech Connect

    Thompson, D.C.; Busch, G.E.; Hewitt, C.J.; Remelius, D.K.; Shimada, Tsutomu; Strauss, C.E.M.; Wilson, C.W.

    1998-12-01

    The authors are developing 2--100 kHz repetition rate CO{sub 2} lasers with milliJoule pulse energies, rapid acousto-optic tuning and isotopic gas mixes, for Differential Absorption LIDAR (DIAL) applications. The authors explain the tuning method, which uses a pair of acousto-optic modulators and is capable of random access to CO{sub 2} laser lines at rates of 100 kHz or more. The laser system is also described, and they report on performance with both normal and isotopic gas mixes.

  3. Acousto-optic filtering of lidar signals

    NASA Astrophysics Data System (ADS)

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

    1992-07-01

    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.

  4. 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.

  5. Wide-aperture diffraction of unpolarised radiation in a system of two acousto-optic filters

    SciTech Connect

    Magdich, L N; Yushkov, K B; Voloshinov, V B

    2009-04-30

    Light diffraction is studied in two tandem acousto-optic cells filtering unpolarised radiation with a wide angular spectrum. It is shown that the side lobes of the ultrasonic radiation pattern of a piezoelectric transducer produce side diffraction intensity maxima at the output of the system consisting of two filters. Diffraction in paratellurite filters is studied experimentally at 1.06 {mu}m. (light modulation)

  6. Multi-frequency AOM for multi-beam laser scanning exposure system

    NASA Astrophysics Data System (ADS)

    Shinada, Hidetoshi

    2016-10-01

    Digital printing systems recorded on films or computer to plates (CTPs) have been required to improve their productivity and image quality. Under the circumstance, a printing technology of the multi-beam laser scanning for the drum capstan system, which is almost the same as optics configuration as the flat bed system, was developed using a newly developed multi-frequency acousto-optic modulator (AOM) as a key device instead of ultra-fast scanning devices toward a main scan direction. The multi-frequency AOM was developed with phased array-type transducers, achieving a wider bandwidth of over 160 MHz. The design consisted of a simultaneous three beams generation with interlace scan to avoid the beat effect by adjacent Doppler-shifted beams, which consequently attained the fastest recording speed of 5.0 mm/s compared with 2.0-3.0 mm/s of existing systems in those days. Furthermore, a couple of critical parameters of the multi-frequency AOM are studied, for example, a treatment of third-order intermodulation and also beat effect in connection with photosensitive media. As a result, the necessity of interlaces scanning to obtain good image quality without beat effect and also to allow a lower laser power to apply is proposed.

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

    NASA Astrophysics Data System (ADS)

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

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

  8. 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

  9. Acousto-optical properties of metamaterials

    SciTech Connect

    Pustovoit, V I

    2016-02-28

    The possibility of the effective use of metamaterials in acousto-optics is demonstrated. It is shown that photoelastic constants that determine a change in the dielectric constant of a heterogeneous medium under the action of a sound wave can significantly exceed the corresponding constants for conventional crystals. We have analysed the mechanisms of the dielectric constant variation in a heterogeneous medium consisting of nanoparticles in the form of ellipsoids and have found explicitly the values of the photoelastic constants. It is shown that the mechanism of the dielectric constant variation in a longitudinal sound wave is reduced to a change in the local concentration of nanoparticles in the bulk and in a transverse acoustic wave – to a local rotation of space-oriented nanoellipsoids. It is also shown that the use of metamedia with a nonuniform distribution of nanoparticles provides a unique opportunity for designing qualitatively new instruments and devices that cannot be produced on the basis of conventional crystals. It is noted that metamaterials open ample opportunities for creating devices of the IR region of the spectrum due to the absence of restrictions on the size of such media. (metamaterials)

  10. Projecting multichannel acousto-optic cells with low crosstalk

    NASA Astrophysics Data System (ADS)

    Kludzin, Victor V.; Kulakov, Sergei V.; Molotok, Victor V.

    1997-09-01

    An acousto-optic method for spectral processing of rf signals is proposed. This method is based on a multichannel cell with frequency separated channels within a given band. The optimum structure of such a system is a multichannel cell with the slow shear mode in the (110) direction in TeO2 and far- axis anisotropic diffraction. A system with 12 channels covering the frequency band of 84 - 96 MHz with the bandwidth of each channel of approximately 0.5 MHz and frequency separation of approximately 1 MHz is experimentally studied. An optical beam which spreads in the plane orthogonal to that of the acousto-optic interaction must be used in this system. The influence of the transducer electrode shape on the acoustic crosstalk in the adjacent channels is studied. The experimental results are in good agreement with the calculated data. The expansion of acousto-optic processing requires that multichannel acousto-cells be used. Narrow-band acousto-optic interaction regimes can be used for frequency-domain filtering of rf signals in multichannel cells. This scheme can be used for the parallel analysis of an rf signal spectrum. This paper describes the process of the design and manufacturing of a multichannel acousto-optic filter for an rf signal with a narrow bandwidth of each channel and estimates its possible parameters. Each channel of the filter is tuned to its own frequency different from those of the adjacent channels within a given overall bandwidth of the whole device.

  11. 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.

  12. Error Measurements in an Acousto-Optic Tunable Filter Fiber Bragg Grating Sensor System

    DTIC Science & Technology

    1994-05-01

    Acousto - Optic Tunable Filter--Fiber Bragg Grating (AOTF-FBG) system. This analysis was targeted to investigate the measurement error in the AOTF-FBG system...Fiber bragg grating, Wavelength division multiplexing, Acousto - optic tunable filter.

  13. The Role of Adaptive Photorefractive Power Limiting on Acousto-Optic Radio Frequency (RF) Signal Excision

    DTIC Science & Technology

    2001-12-01

    Adaptive RF interference reduction for broadband communication systems continues to be problematic. The acousto - optic RF signal excision system...novel photorefractive optical power limiting device to achieve adaptive notch filtering, and multi- channel acousto - optic deflection to achieve angle...of-arrival signal discrimination at the notch filter. This dissertation describes basic principles of acousto - optic RF signal excision, including

  14. Acousto-optic collinear filter with optoelectronic feedback

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

    A spectral optoelectronic system combining a collinear acousto-optic cell fabricated of calcium molybdate single crystal and a positive electronic feedback is proposed first and examined theoretically and experimentally. The feedback signal is formed at the cell output due to the optical heterodyning effect with the use of an unconventional regime of cell operation. It is shown that the feedback enables controlling spectral characteristics of the acousto-optic cell, resulting in enhancing the spectral resolution and the accuracy of optical wavelength determination. In the experiment, maximal filter passband narrowing was as great as 37 times.

  15. Acousto-optics of liquid crystals: Yesterday, today, and tomorrow

    NASA Astrophysics Data System (ADS)

    Kapustina, O. A.

    2014-09-01

    The most important results of the recent theoretical and experimental studies in the field of acousto-optics of liquid crystals (LCs) in research lines initiated by the pioneering studies of Professor A.P. Kapustin at the Institute of Crystallography of the Russian Academy of Sciences and carried out at the Acoustic Institute of the Russian Academy of Sciences are generalized and analyzed. These lines include the study of the nature of acoustically induced supramolecular structures in nematic liquid crystals (NLCs) and cholesteric liquid crystals (CLCs) and the development of physical bases of practical LC acousto-optics, related to the detection of acoustic signals.

  16. Application of acousto-optic actuator applied in holographic system

    NASA Astrophysics Data System (ADS)

    Ling, FuRi; Wang, Biao

    2002-09-01

    In this paper, we discuss acousto-optical scanning and deflection, and design an acousto-optical actuator for steering the laser beam in the direction of vertical and horizon. In this system a laser whose wavelength is 532 nm is used and is expanded by a cylindrical lens. This horizontal actuator produces the horizontal deflection and the spherical lens following the horizontal actuator rotates the beam to match the aperture of the vertical actuator. The cylindrical lens restores the beam to its original circular cross-section, after which the microscope optics brings it to a focus in the lithium niobate crystal in which we store information.

  17. Acousto-optic diffraction of multicolour Ar-laser radiation in crystalline quartz

    SciTech Connect

    Kotov, V M; Averin, S V; Voronko, A I; Kuznetsov, P I; Tikhomirov, S A; Shkerdin, G N; Bulyuk, A N

    2015-10-31

    We have studied acousto-optic Bragg diffraction of multicolour radiation, generated by an Ar laser in the blue-green region of the spectrum, on an acoustic wave propagating in crystalline quartz. It is shown that crystalline quartz significantly exceeds commonly used paratellurite in terms of phase matching of optical beams with a single acoustic wave. We have performed experiments on pulse modulation of Ar-laser radiation. It is shown that distortions introduced into optical pulses are substantially less when use is made of a quartz crystal rather than paratellurite. (acoustooptics)

  18. Acousto-optic parallel read/write head for optical disk data storage.

    PubMed

    McLeod, Robert R; Walter, Sarah K

    2006-09-20

    Parallel read and write of optical disks has traditionally used a static grating for read or a linear array of independent lasers for read and write. Depending on the implementation, these systems suffer from coherent cross talk, excessive space between spots, and an inability to independently track. We show that a dynamic acousto-optic grating can generate multiple parallel read/write spots on the disk, each of which can be independently modulated and tracked and all of which are incoherent in less that a bit period. The resulting disk pickup can potentially reach gigabit per second transfer rates with only a modest increase in the drive complexity.

  19. Acousto-optic parallel read/write head for optical disk data storage

    NASA Astrophysics Data System (ADS)

    McLeod, Robert R.; Walter, Sarah K.

    2006-09-01

    Parallel read and write of optical disks has traditionally used a static grating for read or a linear array of independent lasers for read and write. Depending on the implementation, these systems suffer from coherent cross talk, excessive space between spots, and an inability to independently track. We show that a dynamic acousto-optic grating can generate multiple parallel read/write spots on the disk, each of which can be independently modulated and tracked and all of which are incoherent in less that a bit period. The resulting disk pickup can potentially reach gigabit per second transfer rates with only a modest increase in the drive complexity.

  20. 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

  1. 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.

  2. Electro-optic and Acousto-optic Laser Beam Scanners

    NASA Astrophysics Data System (ADS)

    Römer, G. R. B. E.; Bechtold, P.

    Optical solid state deflectors rely on the electro-optical or acousto-optic effect. These Electro-Optical Deflectors (EODs) and Acousto-Optical Deflectors (AODs) do not contain moving parts and therefore exhibit high deflection velocities and are free of drawbacks associated with mechanical scanners. A description of the principles of operation of EODs and AODs is presented. In addition, characteristics, properties and the (dis)advantages of EODs and AODs, when compared to mirror based mechanical deflectors, is discussed. Deflection angles, speed and accuracy are discussed in terms of resolvable spots and related quantities. Also, response time, damage threshold, efficiency and the type and magnitude of beam distortions is addressed. Optical deflectors are characterized by high angular deflection velocities, but small deflection angles. Whereas mechanical mechanical scanners are characterized by relatively small deflection velocities, but large deflection angles. Arranging an optical deflector and a mechanical scanner in series allows to take advantage of the best of both worlds.

  3. 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.

  4. Bending effect on fiber acousto-optic mode coupling.

    PubMed

    Zhao, Jianhui; Liu, Xiaoming; Wang, Yan; Luo, Ye

    2005-08-20

    The acousto-optic effect in a bent fiber is studied experimentally and numerically by using the scalar finite-element method. The resulting transmission spectra show that new mode-coupling peaks appear due to the breaking of the mode spatial symmetry. The strength of new peaks increases as the fiber-bending curvature increases with a redshift or blueshift in wavelength, strongly depending on the orientation of fiber bending with respect to the acoustic-wave vibration direction.

  5. High-efficiency acousto-optic coupling in phoxonic resonator based on silicon fishbone nanobeam cavity.

    PubMed

    Chiu, Chien-Chang; Chen, Wei-Min; Sung, Kuen-Wei; Hsiao, Fu-Li

    2017-03-20

    We investigate the acousto-optic coupling rates between different acoustic resonance modes and a specified optical resonance mode in a one-dimensional phoxonic crystal fishbone nanobeam formed by periodically arranging semi-cylinders of air on both sides of a suspended silicon waveguide. The gradually tapered unit cells form optical and acoustic resonators. In acousto-optic coupling rate calculation, the acoustic fields and optical fields are obtained by steady state monochromatic analysis and eigen-mode computation, respectively. Results showed that the acoustic polarizations and symmetries of the acoustic resonance modes are dominant factors in the acousto-optic coupling efficiency, and appropriate selection of these parameters can prevent cancellation of acousto-optic interactions, thereby enhancing acousto-optic coupling rates. This study provides important insights that can be applied to acousto-optic device designs.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

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

    DTIC Science & Technology

    1986-04-29

    AD-AI?3 411 ACOUSTO - OPTIC PROCESSING OF 2-D SIGNALS USING TEMPORAL 1/ AND SPATIAL INTEGR..(U) CRLIFORNIA INST OF TECH PASADENA DEPT OF ELECTRICAL...LECTE 3 FINAL REORT4 Submitted to: Al FORCE OFFICE OF SCIENTIFIC RESEARCH Grant Number AFOSR-82-0128 :A of % ACOUSTO - OPTIC PROCISSING OF 2-D SIGNALS...Psaltis, Applied Optics, Vol. 21, No. 3, 1 February 1982. (3) " Acousto - Optic /CCD Image Processor, Demetri Psaltis, Eung Gi Paek and Santosh Venkatesh

  12. The Study of the Phase Characteristics of Bragg Cells for Acousto-Optic Signal Processing

    DTIC Science & Technology

    1998-01-01

    THE FINAL REPORT ON THE SPECIAL CONTRACT SPC-97-4025 The Study of the Phase Characteristics of Bragg Cells for Acousto - Optic Signal Processing...for Acousto - Optic Signal Processing Unclassified 5a. CONTRACT NUMBER F6170897W0095 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Yurchenko...Characteristics of Bragg Cells for Acousto - Optic Signal Processing 5. FUNDING NUMBERS F6170897W0095 6. AUTHOR(S) Dr. Alexander Yurchenko 7. PERFORMING

  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. 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

  15. 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

  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. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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.

  6. Effect of optoelectronic feedback on the characteristics of acousto-optical collinear filtering

    SciTech Connect

    Balakshy, V I; Kuznetsov, Yu I; Mantsevich, S N

    2016-02-28

    The first results of the theoretical and experimental studies of an acousto-optical system with feedback based on a collinear cell made of a calcium molybdate crystal are presented. It is shown that the positive electronic feedback allows essential sharpening of the instrument function of the acousto-optical collinear filter, thus increasing the precision of measuring the optical radiation wavelength. (acoustooptics)

  7. Research of acousto-optic correlator for new telecommunication receiver system

    NASA Astrophysics Data System (ADS)

    Shao, Dingrong; Li, Shujian; Zhou, Bin

    1994-01-01

    A promising receive system model working in high frequency and wideband, with large processing gain, is researched. As the crux, an acousto-optic correlator is discussed especially. Analyzing the principle of a bulk wave space integrating A-O correlator/convolver, an experimental signal processor with large Gp using a high frequency wideband A-O device is configured. By this system, operation of correlation/convolution with BPSK modulated by Barker code is completed. The result is in accordance with the theoretic calculation. This model works in 175 MHz center frequency, 120 MHz bandwidth, and 29.4 dB processing gain. The method of detecting the first order diffracted light beam is proved theoretically and experimentally to expend dynamic range.

  8. 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.

  9. Acousto-optic Bragg diffraction in a LiNbO3 channel-planar composite waveguide with application to optical computing

    NASA Astrophysics Data System (ADS)

    Tsai, C. S.; Zang, D. Y.; Le, P.

    1985-09-01

    Successful experimentation on acousto-optic Bragg diffraction in a LiNbO3 composite waveguide that consists of an array of parallel but uncoupled channel waveguides directly extended to a single-mode planar waveguide and a titanium-indiffused proton-exchanged (TIPE) microlens array is reported for the first time. A channel-waveguide array, a planar waveguide, a linear TIPE microlens array, a 500-MHz surface acoustic wave transducer, and an integrating lens have all been integrated in a substrate size of 0.2 x 1.0 x 2.0 cm to form an integrated acousto-optic Bragg modulator that should find a variety of applications in optical computing, signal processing, and communications. The resulting modulator module has been utilized to perform matrix-vector multiplication.

  10. Hybrid Q-switched laser with MoS2 saturable absorber and AOM driven sub-nanosecond KTP-OPO.

    PubMed

    Qiao, Junpeng; Zhao, Shengzhi; Yang, Kejian; Zhao, Jia; Li, Guiqiu; Li, Dechun; Li, Tao; Qiao, Wenchao

    2017-02-20

    Two-dimensional (2D) materials, especially transition-metal dichalcogenides, such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2), have attracted great interests due to their exceptional optical properties as saturable absorbers in laser systems. In this work, at first, we presented a diode-pumped passively Q-switched laser with MoS2 saturable absorber (MoS2-SA). At an incident pump power of 6.54 W, a maximum output power of 1.15 W with a minimum pulse duration of 70.6 ns was obtained, which is the shortest pulse duration of diode pumped passively Q-switched laser with MoS2-SA to the best of our knowledge. Then, by using a hybrid Q-switched laser with a MoS2-SA and an acousto-optic modulator (AOM) as pumping fundamental laser, a sub-nanosecond KTiOPO4 (KTP) based intracavity optical parametric oscillation (IOPO) was realized. With an incident pump power of 10.2 W and AOM repetition rate of 10 kHz, the maximum output power of 183 mW with minimum pulse duration of 850 ps was obtained. The experimental results indicate that the IOPO pumped by the hybrid Q-switched laser with AOM and MoS2-SA can generate signal wave with shorter pulse duration than those IOPOs pumped by hybrid Q-switched laser with AOM and Cr4+:YAG or single-walled carbon nanotube saturable absober (SWCNT-SA) or monolayer graphene SA.

  11. 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

  12. 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

  13. Acousto-optic imaging with a smart-pixels sensor

    NASA Astrophysics Data System (ADS)

    Barjean, K.; Contreras, K.; Laudereau, J.-B.; Tinet, E.; Ettori, D.; Ramaz, F.; Tualle, J.-M.

    2015-03-01

    Acousto-optic imaging (AOI) is an emerging technique in the field of biomedical optics which combines the optical contrast allowed by diffuse optical tomography with the resolution of ultrasound (US) imaging. In this work we report the implementation, for that purpose, of a CMOS smart-pixels sensor dedicated to the real-time analysis of speckle patterns. We implemented a highly sensitive lock-in detection in each pixel in order to extract the tagged photons after an appropriate in-pixel post-processing. With this system we can acquire images in scattering samples with a spatial resolution in the 2mm range, with an integration time compatible with the dynamic of living biological tissue.

  14. Acousto-optic/CCD real-time SAR data processor

    NASA Technical Reports Server (NTRS)

    Psaltis, D.

    1983-01-01

    The SAR processor which uses an acousto-optic device as the input electronic-to-optical transducer and a 2-D CCD image sensor, which is operated in the time-delay-and-integrate (TDI) mode is presented. The CCD serves as the optical detector, and it simultaneously operates as an array of optically addressed correlators. The lines of the focused SAR image form continuously (at the radar PRF) at the final row of the CCD. The principles of operation of this processor, its performance characteristics, the state-of-the-art of the devices used and experimental results are outlined. The methods by which this processor can be made flexible so that it can be dynamically adapted to changing SAR geometries is discussed.

  15. Bioimaging system using acousto-optic tunable filter

    NASA Astrophysics Data System (ADS)

    Kasili, Paul M.; Mobley, Joel; Cullum, Brian M.; Vo-Dinh, Tuan

    2000-05-01

    The interaction of light with tissue has ben used to recognize disease since the mid-1800s. The recent developments of light sources, detectors, and fiber optic probes provide opportunities to measure these interactions, which yield information for tissue diagnosis at the biochemical, structural, or physiological level. In this paper, we describe a bioimaging system designed for biomedical applications and show laser-indued fluorescence (LIF) images mammalian brain tissue. The LIF imaging of tissue was carried out in vitro using two laser excitations: 488 nm and 514 nm. Images were recorded through an acousto- optic tunable filter over the range 500 nm-650 nm with a charged coupled device camera. Background subtracted images were generated across the fluorescent wavelength. Subtraction allowed a safe comparison to be made with well- contrasted images. Of the two tested excitation wavelengths, 488 nm excitation gave the more distinctive contrast.

  16. Acousto-optic tunable filter multispectral imaging system

    NASA Technical Reports Server (NTRS)

    Cheng, Li-Jen; Chao, Tien-Hsin; Reyes, George

    1992-01-01

    This paper discusses recent activities of Jet Propulsion Laboratory in the development of a new type of remote sensing multispectral imaging instruments using acousto-optic tunable filter (AOTF) as programmable bandpass filter. This remote sensor provides real-time operation; observational flexibility; measurements of spectral, spatial, and polarization information using a single instrument; and compact, solid state structure without moving parts. Two microcomputer-controlled AOTF imaging spectrometer breadboard systems were designed and built. One operates in the wavelength range of 0.48-0.76 micron and the other in the range of 1.2-2.5 micron. Experiments were performed using these two systems to observe geological and botanical objects in laboratory and outdoor environment. Results have demonstrated the feasibility of using the AOTF multispectral imaging system as a real-time versatile remote sensor with operational flexibility for future Army tactical applications.

  17. Experimental research on the multi-order acousto-optic diffraction based on Raman-Nath diffraction

    NASA Astrophysics Data System (ADS)

    Gu, Huadong; Shao, Zhongxing; Zheng, Chenqi; Yang, Jie; Chen, Ruitao; Gu, Zetong

    2015-03-01

    In this paper, the experimental investigation on the interaction length for getting the optimum diffraction of the multi-order acousto-optic diffraction is presented. Based on these results, the feasibility of acousto-optic Q-switch taking H2O or TeO2 as medium respectively for ultraviolet and visible lasers are discussed. The fact that the optimum interaction length tightly relies on the frequency of the sound and does not relate to the wavelength and power of the light is found in the experiment. The interaction length will become longer as the frequency of the ultrasound becomes higher. The interaction length is about 8mm when the acoustic frequency is at about 9MHz and becomes about 4mm at 6MHz. A Q-switch that works with pure water is designed and a total diffractive efficiency of about 98% was obtained under the condition that the acoustic frequency is 9MHz and the acoustic power is 3.4W. An acousto-optic Q-switch made of TeO2, in terms of Raman-Nath diffraction is designed. With a cooling system on the device, a total diffractive efficiency of about 75% is obtained under the condition that the acoustic frequency is 10MHz and the acoustic power is 10W. The loss by one path of the device is about 5% on the best condition. Then the modulated pulse width is measured as about 200ns on the condition that the acoustic frequency is 11MHz, the acoustic power is 6W and the repetition frequency is 10kHz.

  18. 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.

  19. 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.

  20. Acoustic field structure simulation in quasi-collinear acousto-optic cells with ultrasound beam reflection.

    PubMed

    Mantsevich, S N; Molchanov, V Ya; Yushkov, K B; Khorkin, V S; Kupreychik, M I

    2017-04-02

    Ultrasound wave reflection from one of the crystal faces is the convenient way to arouse the acoustic beam with a desired propagation direction in acousto-optic cells with collinear and quasi-collinear interaction geometries. The reflection process effects on the ultrasound field amplitude and phase structure. The method to simulate the reflected finite ultrasound beam structure in the case of acoustically anisotropic media is presented in this paper. The investigation is carried on the example of two quasi-collinear acousto-optic cells fabricated on the base of tellurium dioxide crystal. The cells have special geometry that allows to obtain extremely long acousto-optic interaction length and to achieve unprecedented spectral resolution. The influence of reflection process in the acousto-optic diffraction characteristics was also examined.

  1. 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

  2. State-of-the art of acousto-optic sensing and imaging of turbid media.

    PubMed

    Resink, Steffen G; Boccara, Albert C; Steenbergen, Wiendelt

    2012-04-01

    Acousto-optic (AO) is an emerging hybrid technique for measuring optical contrast in turbid media using coherent light and ultrasound (US). A turbid object is illuminated with a coherent light source leading to speckle formation in the remitted light. With the use of US, a small volume is selected,which is commonly referred to as the "tagging" volume. This volume acts as a source of modulated light, where modulation might involve phase and intensity change. The tagging volume is created by focusing ultrasound for good lateral resolution; the axial resolution is accomplished by making either the US frequency, amplitude, or phase time-dependent. Typical resolutions are in the order of 1 mm. We will concentrate on the progress in the field since 2003. Different schemes will be discussed to detect the modulated photons based on speckle detection, heterodyne detection, photorefractive crystal (PRC) assisted detection, and spectral hole burning (SHB) as well as Fabry-Perot interferometers. The SHB and Fabry-Perot interferometer techniques are insensitive to speckle decorrelation and therefore suitable for in vivo imaging. However, heterodyne and PRC methods also have potential for in vivo measurements. Besides measuring optical properties such as scattering and absorption, AO can be applied in fluorescence and elastography applications.

  3. CONTROL OF LASER RADIATION PARAMETERS: Tunable acousto-optic filters with the multiple interaction of light and sound

    NASA Astrophysics Data System (ADS)

    Voloshinov, V. B.; Magdich, L. N.; Knyazev, G. A.

    2005-11-01

    Optical multipass schemes of the interaction of light and sound, which are promising for filtration of optical beams based on tunable acousto-optic filters, are studied. The features of operation of acousto-optic filters in the rejection and transmission regimes are considered. It is proved theoretically and confirmed experimentally that the use of multiple interaction improves the spectral and energy parameters of acousto-optic devices. The collinear and transverse geometry of acousto-optic interaction in cells based on a paratellurite crystal is studied in the double-pass, three-pass, and multipass diffraction regimes.

  4. Submillimeter Wave Astronomy Satellite (SWAS) acousto-optical spectrometer

    NASA Astrophysics Data System (ADS)

    Klumb, Markus; Frerick, J.; Tolls, Volker; Schieder, Rudolf; Winnewisser, Gisbert F.

    1994-09-01

    The first fully space qualified acousto-optical spectrometer (AOS) is described. It is built for the Submillimeter Wave Astronomy Satellite (SWAS) to be launched in July 1995. It has a very large bandwidth from 1400 to 2800 MHz covered by 1365 channels. This corresponds to a nearly 1 MHz channel spacing. The design is optimized for very high stability, which is demonstrated by means of Allan variance stability test. The Allan plot minimum time was found well above 800 seconds. The AOS can operate within a temperature range from -5 to +30 degree(s)C (+5 to +25 degree(s)C nominal) and with temperature variations of up to 2 degree(s)C/h. The performance was verified also after environmental testing such as random vibration (10.2 G rms) and thermal cycling of -30 to +50 degree(s)C. The lightweight mechanical design resulted in a total weight of 7.2 kg including electronics. A detailed optical design study was performed in order to achieve diffraction limited channel resolution, high efficiency and low sensitivity to mechanical distortion. The RF input power needed for full scale is 11 mW. The power consumption is 5.4 Watts (including data pre-averaging and DC-DC converter losses). The development has shown that AOSs are well suited for spaceborne applications.

  5. Swept laser source based on acousto-optic tunable filter

    NASA Astrophysics Data System (ADS)

    Chen, Minghui; Li, Hao; Chen, Rong

    2014-12-01

    The design and development of the swept laser for optical coherence tomography is presented. It is manifested by a semiconductor optical amplifier, a fiber coupler, two fiber isolators, a semiconductor optical amplifier (SOA) and an acousto-optic tunable filter (AOTF) for frequency tuning within a unidirectional all-fiber ring cavity. Light output from the coupler is further amplified and spectral shaped by a booster SOA terminated at both ends with two isolators. The total loss in ring cavity is 8.2 dB. The gain SOA provides fiber-to-fiber small signal gain of 22.2 dB with saturation output power of 9.0 dBm. The developed laser source provides up to 100 kHz over a full-width wavelength tuning range of 140 nm at center wavelength of 1308 nm with an average power of 8 mW, yielding an axial resolution of 5.4 μm in air for OCT imaging. Theoretically, the measurement principle and the feasibility of the system are analyzed. Implementing the laser source in swept source based OCT (SS-OCT) system, real-time structural imaging of biological tissue is realized.

  6. Materials for imaging acousto-optic tunable filters

    NASA Astrophysics Data System (ADS)

    Gupta, Neelam

    2014-05-01

    Research and development of robust compact hyperspectral imagers that can acquire both spectral and spatial features from a scene of interest is of utmost importance for standoff detection of targets as well as chemical and biological agents and backgrounds. Hyperspectral imagers can acquire images with a large number of narrow spectral bands and take advantage of the characteristic spectral signatures of different materials making up the scene. At the Army Research Laboratory (ARL), we are developing hyperspectral imagers based on acousto-optic tunable filters (AOTFs) that can provide adaptive no-moving-parts imagers from the ultraviolet (UV) to the long wave infrared (LWIR) to acquire a two-dimensional spectral image and build up a two-dimensional image cube as a function of time instead of using traditional grating or prism based approach that requires relative motion between sensor and scene. Here, we will review the development of different imaging AOTFs operating from the UV to the LWIR based on a variety of birefringent materials and include the spectral imaging carried out with these filters including both with single and double piezoelectric transducers. We will also include the theoretical background needed to carry out the filter design and discuss development of mercurous halide crystals that can be used to develop AOTFs operating over a wide spectral region from the visible to the LWIR.

  7. Acousto-optics studied in polaritonic photonic crystals

    NASA Astrophysics Data System (ADS)

    Singh, Mahi R.; Racknor, C.

    2010-10-01

    We have studied the acousto-optic effect on the photon transmission and the spontaneous emission in polaritonic photonic crystal. We have considered that photonic crystals are fabricated from polaritonic materials such as GaP, MgO, LiNbO3 , and LiTaO3 . A two-level quantum dot is doped in a polaritonic crystal to study the decay rate of the spontaneous emission. The decay rate of quantum dots, band structure, and photon transmission coefficient have been calculated. It is found that band-gap width and the decay rate of quantum dots depends strongly on the high-frequency dielectric constant of the polaritonic crystals while the photonic band edges vary inversely by the ratio of longitudinal- to transverse-optical phonon energies. The spontaneous decay rate of the quantum dot can be controlled by the external strain field. This finding is significant because it is well known that the spontaneous emission is source of undesirable noise in different types of electronic and optical devices. Finally, we have also found the system can be switched from transmitting state to reflecting state by applying an external strain field. These are distinct and interesting results and can be used to fabricate new types of photonic couplers and fibers which in turn can be used to fabricate all photonic switches.

  8. Analysis of quality of images obtained by acousto-optic filtering

    NASA Astrophysics Data System (ADS)

    Bogomolov, Dennis V.; Voloshinov, Vitaly B.

    2005-03-01

    The paper is devoted to the theoretical and experimental investigation of spatial resolution of images obtained during acousto-optic spectral filtration. The consideration was carried out for a wide angle acousto-optic filter designed on the base of paratellurite single crystal. The crystal was cut in the (1 1 0) plane with the direction of acoustic wave propagation at the angle 10 ° relative to the axis [110]. It was found that optical quality of a filtered image is influenced by a spectral bandwidth of a filter. The spectral bandwidth is determined by a length of piezoelectric transducer that generates ultrasonic waves in an acousto-optic cell. The dependence of a number of resolvable spots on the piezotransducer length was examined theoretically. It was shown that a wavelength of the filtered radiation influences the quality of the processed image. Precise and approximate equations have been derived to determine the spectral passband of the acousto-optic filer, the angular field of view of a single pixel, the angular aperture of the device and the number of resolvable spots in a line. Resolution of the images obtained during the acousto-optic filtration was also measured in the experiment.

  9. LD-pumped acousto-optical Q-switched burst-mode Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Pan, Hu; Yan, Renpeng; Li, Xudong; Ma, Yufei; Yu, Xin; Chen, Deying

    2016-04-01

    A high-repetition-rate, high-peak-power burst-mode laser for laser-based measurement applications is presented by using a master oscillator power amplifier structure. An laser diode arrays (LDA) side-pumped Nd:YAG acousto-optical (A-O) Q-switched laser serves as the master oscillator. Under pulsed pumping, pulse trains with 2-25 pulses are obtained when the repetition rate changes from 10 kHz to 100 kHz. The maximum pulse burst energy of 31.2 mJ is achieved in the A-O Q-switched pulse burst laser oscillator at 10 kHz. Two LDA side pumped Nd:YAG modules are employed in the amplification stage. After the amplification, the pulse burst energy at 10 kHz reaches ~170 mJ with a single pulse energy of 85.2 mJ and a pulse width of 14.5 ns, generating a peak power of 6.1 MW. At 100 kHz, the total burst energy reaches 220 mJ with a single pulse energy of 8.8 mJ in the pulse burst laser system.

  10. Theoretical calculation and experimental study of acousto-optically Q-switched CO2 laser.

    PubMed

    Xie, Jijang; Guo, Ruhai; Li, Dianjun; Zhang, Chuansheng; Yang, Guilong; Geng, Yumin

    2010-06-07

    Using resonator inserted with acousto-optically modulator, the experiments of the compacted CO(2) laser were performed with Q-switch. According to various factors that influenced the output of laser, the theoretical calculation of its main parameters was conducted by Q-switched pulsed laser rate equations. Based on the results, the technical route and approach were presented for optimization design of this laser. The measured peak power of this laser device was more than 4000W and pulsed width was 180ns which agreed well with the theoretical calculation. The range of repetition frequency could adjust from 1 Hz to 100 kHz. The theoretical analyzes and experimental results showed that the acoustic traveling time of ultrasonic field could not influence the pulse width of laser so that it did not require inserting optical lens in the cavity to reduce the diameter of beam. The acoustic traveling time only extended the establishingtime of laser pulse. The optimum working frequency of laser is about 1 kHz, which it matched with the radiation life time (1 ms) of CO(2) molecular upper energy level. When the frequency is above 1 kHz, the pulse width of laser increased with the frequency. The full band of wavelength tuning between 9.2 microm and 10.8 microm was obtained by grating selection one by one which the measured spectrum lines were over 30 in the condition of Q-switch.

  11. Applications of acousto-optics in holographic memories

    NASA Astrophysics Data System (ADS)

    Gurevich, Boris S.; Gurevich, Simon B.; Zhumaliev, Kubanychbek M.; Akkoziev, Imil A.; Alymkulov, Salmor A.

    1999-09-01

    Acousto-optic deflectors (AODs) are used for data by-page recording as holograms, and for data extraction from the hologram sampled by the AOD. The possibilities and characteristics of AODs define information capacity of the holographic memory devices as well as architecture and parameters of their separate components. Usually 2 AODs are used for 2-D hologram recording, and 3 AODs -- for volume multiplex recording. The calculations of amount of the recorded holograms which can be provided by different AODs have been carried out in the present work, and the limits of information capacity increasing at expense of optimal using of both AODs and recording media, have been appointed. The specific attention have been paid to the hologram 3-D recording with angular multiplexing where information capacity can be increased by 2 orders. The difficulties to be overcome in order to achieve the biggest information capacity, have been noted. Another subject of study is the problem of the sampled data arbitrary access rate increasing which can be provided by AODs application. It has been noted that minimum access time is limited, and this limitation is connected with the duration of the signal transmission through Bragg cell and with the time of signal transmission and processing in other components of holographic memory. It has been shown that information quality of holographic memory grows along with increasing of the number of used AODs. It has also been noted that if the memory parameters are close to their limits, the cross-talks grow, and the optimum must be found.

  12. 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.

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

    PubMed

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

    2017-03-31

    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.

  14. 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.

  15. Acousto-optical combined frequency splitters and shifters as components of a ring optical gyroscope

    SciTech Connect

    Kotov, V M

    1999-03-31

    An analysis is made of the task of symmetrisation of a Y-type directional coupler and of shifting the frequency of counterpropagating waves in a ring gyroscope by means of the relatively recently discovered new type of acousto-optical diffraction when the incident radiation is diffracted simultaneously into two orders. Anisotropic and isotropic acousto-optical diffraction in a uniaxial crystal is considered and expressions convenient for calculations are derived. Experiments carried out on isotropic diffraction in LiNbO{sub 3} confirm, on the whole, the theoretical predictions. (laser applications and other topics in quantum electronics)

  16. Wide-band acousto-optic deflectors with high efficiency for visible range fringe pattern projector.

    PubMed

    Dupont, S; Kastelik, J C; Causa, F

    2007-10-01

    A laser fringe projection system based on a pair of identical acousto-optic TeO(2) deflectors operated at the same frequency and using tangential phase matching anisotropic interaction is demonstrated, achieving large bandwidth and high efficiency. A 40 MHz bandwidth and an acousto-optic efficiency higher than 60% have been measured at wavelength of 514 nm. The specific pris-matic configuration of the in-house developed deflectors greatly facilitates optical alignment of the instrument. The spatial period of the interference fringes can be dynamically controlled over almost one decade by tuning the frequency of the acoustic carriers.

  17. Invited Article: Acousto-optic finite-difference frequency-domain algorithm for first-principles simulations of on-chip acousto-optic devices

    NASA Astrophysics Data System (ADS)

    Shi, Yu; Cerjan, Alexander; Fan, Shanhui

    2017-02-01

    We introduce a finite-difference frequency-domain algorithm for coupled acousto-optic simulations. First-principles acousto-optic simulation in time domain has been challenging due to the fact that the acoustic and optical frequencies differ by many orders of magnitude. We bypass this difficulty by formulating the interactions between the optical and acoustic waves rigorously as a system of coupled nonlinear equations in frequency domain. This approach is particularly suited for on-chip devices that are based on a variety of acousto-optic interactions such as the stimulated Brillouin scattering. We validate our algorithm by simulating a stimulated Brillouin scattering process in a suspended waveguide structure and find excellent agreement with coupled-mode theory. We further provide an example of a simulation for a compact on-chip resonator device that greatly enhances the effect of stimulated Brillouin scattering. Our algorithm should facilitate the design of nanophotonic on-chip devices for the harnessing of photon-phonon interactions.

  18. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. 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.

  1. Extending single molecule fluorescence observation time by amplitude-modulated excitation

    NASA Astrophysics Data System (ADS)

    Kisley, Lydia; Chang, Wei-Shun; Cooper, David; Mansur, Andrea P.; Landes, Christy F.

    2013-09-01

    We present a hardware-based method that can improve single molecule fluorophore observation time by up to 1500% and super-localization by 47% for the experimental conditions used. The excitation was modulated using an acousto-optic modulator (AOM) synchronized to the data acquisition and inherent data conversion time of the detector. The observation time and precision in super-localization of four commonly used fluorophores were compared under modulated and traditional continuous excitation, including direct total internal reflectance excitation of Alexa 555 and Cy3, non-radiative Förster resonance energy transfer (FRET) excited Cy5, and direct epi-fluorescence wide field excitation of Rhodamine 6G. The proposed amplitude-modulated excitation does not perturb the chemical makeup of the system or sacrifice signal and is compatible with multiple types of fluorophores. Amplitude-modulated excitation has practical applications for any fluorescent study utilizing an instrumental setup with time-delayed detectors.

  2. 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.

  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.

  4. Stable Q-switched and mode-locked Nd:GdVO4/KTP green laser with dual-loss-modulation.

    PubMed

    Zhang, Gang; Zhao, Shengzhi; Li, Guiqiu; Li, Dechun; Yang, Kejian; Cheng, Kang; Zhang, Yan

    2010-08-20

    A diode-pumped dual-loss-modulated Q-switched and mode-locked (QML) Nd:GdVO(4)/KTP green laser with an acousto-optic modulator (AOM) and GaAs saturable absorber is presented. The experimental results show that the stability and the peak power of the dual-loss-modulated QML Nd:GdVO(4)/KTP green laser are significantly improved. The pulse width of the Q-switched pulse envelope in the dual-loss-modulation QML green laser has a compression of 50% compared with that in the singly passively QML green laser with GaAs. By using a hyperbolic secant square function and considering the Gaussian distribution of the intracavity photon density, the coupled equations for diode-pumped dual-loss-modulated QML Nd:GdVO(4) green laser are given, and the numerical solutions of the equations are in good agreement with the experimental results.

  5. Acousto-optical pulsar processor usage for interstellar medium dispersion measurements

    NASA Astrophysics Data System (ADS)

    Esepkina, Nelli A.; Lavrov, Aleksandr P.; Molodyakov, Sergey A.

    2005-02-01

    The acousto-optical processor (AOP) of a new type for the investigation of pulsar radio emission is proposed that provides for the compensation of signal dispersion in a wide frequency bandwidth. The AOP is based on an acousto-optical spectrum analyzer with a CCD photodetector operating in a special pipeline operational mode (shift-and-add mode), which allows spectral components of the input signal to be added with a controlled time delay immediately in the CCD photodetector. The proposed AOP was successfully used on an RT-64 radio telescope (Kalyazin Radio Astronomy Observatory FIAN) for the observation of pulsars at 1.4 GHz band with bandwidth 45 MHz. The method of direct interstellar medium dispersion measurement on two-frequency band observations with application AOP is described. The measurements of DM for pulsar PSR 1937 + 21 are submitted.

  6. Narrow-band acousto-optic tunable filtering in a two-mode fiber.

    PubMed

    Ostling, D; Engan, H E

    1995-06-01

    We demonstrate an optical filter that utilizes acousto-optic coupling between the spatial modes that propagate in a two-mode elliptical-core fiber. The optical bandwidth at 1090 nm is 0.85 nm, which is in agreement with predictions based on measurement of differential group delay between the modes. The filter is slightly polarization dependent, with a 0.28-nm wavelength difference between the passband peaks for the two polarization eigenstates. The optical insertion loss is dominated by 2-4-dB bending loss in nonoptimized mode strippers, and the coupling loss is negligible. Full acousto-optic mode conversion was achieved at an 8-mW electrical input power to the acoustic transducer.

  7. Ultraviolet-visible imaging acousto-optic tunable filters in KDP.

    PubMed

    Voloshinov, Vitaly; Gupta, Neelam

    2004-07-01

    There is a need to develop large-aperture acousto-optic tunable filters (AOTFs) in the UV region for applications in astronomy, environmental sciences, biology, etc. We have developed a high-quality noncollinear AOTF cell that uses a single crystal of KDP that has nearly a four times larger acousto-optic figure of merit, M2, than quartz. The linear and angular apertures of this cell are 1.5 cm x 1.5 cm and 1.2 degrees, respectively. The spectral range is 220-480 nm, with 160-cm(-1) spectral resolution and high transmission in the UV. We present an analysis of the design and describe the characterization results.

  8. Designing an acousto-optical spectrometer for Guillermo Haro Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Arellanes Bernabe, Adan Omar; Chavushyan, Vahram

    2013-09-01

    The Guillermo Haro astrophysical observatory (Mexico) realizes investigations in the visible and near-infrared range . Actually, the classical grating spectrometer with mechanically removable optical filters and diffraction gratings is exploited there. Unfortunately, the regular process of changing the diffraction gratings with different resolutions and recalibrating the spectrometer is inconvenient and wastes expensive time for observations. This is why exploiting an acousto-optical cell as a dynamic dispersive element is practically desirable, because potentially it realizes tuning the spectral resolution and the range of observation electronically and excludes filters. Some aspects of inserting just one dynamic acousto-optical diffraction grating instead of a set of the traditional static diffraction gratings are preliminarily considered.

  9. Wide spectral range imaging acousto-optic turnable filter used in outer space probe

    NASA Astrophysics Data System (ADS)

    Zhang, Zehong; Wang, Liangqiu; He, Xiaoliang; Zhou, Yong

    2014-02-01

    This article introduces a wide spectral range imaging acousto-optic turnable filter made of two transducers. "Mismatch rate" was firstly put forward to represent the degree to which the impedance mismatch and a three stage matching circuit was designed for the filter to improve its spectral range and operating bandwidth. Now the spectral range is from 0.4μm to 1.1μm, the overall operating bandwidth reaches 1.14 octave, the diffraction efficiency over 60%, spectral resolution from 1.3nm to 7.5nm. To get rid of " tin pest", alloy material was used to make bonding layer material instead of pure tin, making the storage temperature of the acousto-optic turnable filter ranges from -65 °C to 85 °C, and the operating temperature from -35 °C to 70 °C.

  10. JPL activities on development of acousto-optic tunable filter imaging spectrometer

    NASA Technical Reports Server (NTRS)

    Cheng, Li-Jen; Chao, Tien-Hsin; Reyes, George

    1992-01-01

    Recent activities of JPL in the development of a new type of imaging spectrometers for earth observation and planetary exploration are reported. This instrument uses the acousto-optic tunable filter (AOTF) as high resolution and fast programmable bandpass filter. AOTF operates in the principle of acousto-optic interaction in an anisotropic medium. This filter can be tuned in sequential, random, and multiwavelength access modes, providing observational flexibility. The diffraction process in the filter generates two diffracted monochromatic beams with polarization orthogonal to each other, creating a unique capability to measure both polarimetric and spectral properties of the incoming light simultaneously with a single instrument. The device gives wide wavelength operations with reasonably large throughput. In addition, it is in a compact solid-state structure without moving parts, providing system reliability. These attractive features give promising opportunities to develop a new generation of airborne/spaceborne and ground, real-time, imaging spectrometer systems for remote sensing applications.

  11. A new method for determining the transfer function of an acousto optical tunable filter.

    PubMed

    Mahieux, A; Wilquet, V; Drummond, R; Belyaev, D; Federova, A; Vandaele, A C

    2009-02-02

    The current study describes the determination of the transfer function of an Acousto Optical Tunable Filter from the in-flight solar observations of the SOIR instrument on board Venus Express. An approach is proposed in order to reconstruct the transfer function profile from the analysis of various solar lines. Moreover this technique allows the determination of the evolution of the transfer function as a function of the AOTF radio frequency.

  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. 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

    2007-11-02

    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

  14. A recirculating delayed self-heterodyne method using a Mach-Zehnder modulator for kHz-linewidth measurement

    NASA Astrophysics Data System (ADS)

    Deng, Shuo; Li, Min; Gao, Hongyun; Dai, Yawen

    2016-09-01

    A laser linewidth measurement method which uses a Mach-Zehnder electro-optic modulator (MZM) is proposed in a loss-compensated recirculating delayed self-heterodyne interferometer (LC-RDSHI). Compared with the traditional acousto-optic modulator (AOM), the electro-optic modulator has the merits of broader bandwidth, lower insertion loss, higher extinction ratio and thus, a wider application. A theoretical analysis shows that the power spectrum curve of the novel measurement system is a Lorentzian line, which fits well with experiment. The linewidth is measured to be 137 ± 7 kHz at a frequency shift of 4 GHz. Measurement of a distributed feedback Bragg (DFB) laser has manifested that the linewidth broadens from 98.5 kHz to 137.4 kHz as the operating temperature changes by 16 °C. This work will allow investigation of narrow linewidth semiconductor and fiber laser stability.

  15. An advanced regime of the anomalous acousto-optical interaction with tangential phase matching in crystalline materials

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Arellanes, Adan O.

    2016-09-01

    Regime of effective non-collinear acousto-optical interaction with tangential phase matching had been identified and previously observed only in two limiting cases: in tellurium dioxide (TeO2) at low acoustic frequencies ( 60 MHz) and in rutile (TiO2) at ultra-high frequencies ( 5 GHz). Both these limits are motivated by optical properties of the chosen materials. Low frequencies in TeO2 admit designing a wide-aperture acousto-optical cell, but limit the frequency bandwidth. While an acousto-optical cell made of TiO2 has very small aperture and exhibits low spectral resolution due to the effect of linear acoustic attenuation. Instead of those limits, we propose an advanced regime of the anomalous acousto-optical interaction with tangential phase matching, which allows us varying the frequency range and optimizing all the performances (for instance, the spectral resolution) of a wide-aperture acousto-optical cell made of the chosen crystal, as the case requires. Recently, we had suggested and successfully tested experimentally the revealed additional degree of freedom, i.e. the action of the tilt angle within the refractive indices ellipsoids to manipulate by the performances of crystalline acousto-optical cells. Now, we consider an opportunity of refining this additional degree of freedom within those ellipsoids of crystalline acousto-optical cell through some declination of the acoustic beam. For our investigations, the lithium niobate (LiNbO3) and rutile (TiO2) crystals of about 5 cm length, operating with the slow-shear acoustic mode along the acoustic axes had been selected. The needed theoretical analysis, numerical estimations, and 3D-vector diagrams have been developed to reveal potential benefits of the proposed technique.

  16. 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.

  17. Acoustic wave velocities in two-dimensional composite structures based on acousto-optical crystals

    NASA Astrophysics Data System (ADS)

    Mal'neva, P. V.; Trushin, A. S.

    2015-04-01

    Sound velocities in two-dimensional composite structures based on isotropic and anisotropic acousto-optical crystals have been determined by numerical simulations. The isotropic materials are represented by fused quartz (SiO2) and flint glass, while anisotropic materials include tetragonal crystals of paratellurite (TeO2) and rutile (TiO2) and a trigonal crystal of tellurium (Te). It is established that the acoustic anisotropy of periodic composite structures strongly depends on both the chemical composition and geometric parameters of components.

  18. 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.

  19. Compact tunable microwave filter using retroreflective acousto-optic filtering and delay controls.

    PubMed

    Riza, Nabeel A; Ghauri, Farzan N

    2007-03-01

    Programmable broadband rf filters are demonstrated using a compact retroreflective optical design with an acousto-optic tunable filter and a chirped fiber Bragg grating. This design enables fast 34 micros domain analog-mode control of rf filter time delays and weights. Two proof-of-concept filters are demonstrated including a two-tap notch filter with >35 dB notch depth and a four-tap bandpass filter. Both filters have 2-8 GHz tunability and a 34 micros reset time.

  20. Acousto-optical interaction in fishbone-like one-dimensional phoxonic crystal nanobeam

    NASA Astrophysics Data System (ADS)

    Hsiao, Fu-Li; Hsieh, Hao-Yu; Hsieh, Cheng-Yi; Chiu, Chien-Chang

    2014-09-01

    We demonstrate the simultaneous existence of slow photonic and phononic modes in a fishbone-like one-dimensional phoxonic crystal nanobeam. The phoxonic crystal nanobeam, which is formed by a suspended fishbone-like silicon waveguide, is not only an optical one-dimensional grating waveguide but also a waveguide with acoustic local resonance. Because of the slow group velocities, the acousto-optical interactions are significantly enhanced. The operating optical wavelength and acoustic frequency can be manipulated individually by varying certain geometric parameters of the nanobeam.

  1. Incoherent acousto-optic image correlator with the kinoform

    NASA Astrophysics Data System (ADS)

    Starikov, Sergey N.; Rodin, Vladislav G.; Solyakin, Ivan V.; Shapkarina, Ekaterina A.; Chervonkin, Alexander P.

    2004-04-01

    Fourier holograms are commonly used for reference images storing in diffraction correlators with spatially coherent or spatially incoherent illumination. Kinoforms can be a real alternative to Fourier holograms in the correlators. The kinoform represents a computer-synthesized optical element which performs only a phase modulation of a light wave. The kinoform restores true intensity of the recorded image and random distribution of phase. Therefore, it can be utilized for storing reference images, first of all, in correlators with spatially incoherent illumination. The absence of carrier frequency reduces demanded number of pixels of the spatial light modulator being used. Since the kinoform provides reconstruction of reference image in zero diffraction order, requirement on monochromaticity of illumination are decreased as well. The diffraction correlator with the kinoform used as spatial frequency filter is considered. The 2-D acoustooptic deflector was employed to form input images in real time by monochromatic spatially incoherent light. The reference images were recorded on the commercially available kinoforms. The input and reference images were of 256×256 pixels and 200×200 pixels respectively. Since input images were consisted of approximately 400 pixels with non-zero brightness, the image update frequency was gained at 200 Hz. The experimental setup and experimental results on images recognition are presented.

  2. Anisotropy of an acousto-optic figure of merit for NaBi(MoO4)2 crystals.

    PubMed

    Mys, Oksana; Krupych, Oleh; Vlokh, Rostyslav

    2016-10-01

    We develop a technique for analyzing the anisotropy of an acousto-optic figure of merit for crystals belonging to tetragonal symmetry groups 4/m, 4, and 4¯. The technique is based on phenomenological relations that describe anisotropies of the effective elasto-optic coefficients and the acoustic wave velocities. Our approach is verified on the example of NaBi(MoO4)2 crystals for all possible types and geometries of acousto-optic interactions. We list and characterize the acousto-optic interaction geometries at which the maximal acousto-optic figures of merit are reached for both isotropic and anisotropic interaction types. Finally, we show that the acousto-optic efficiency of NaBi(MoO4)2 originates mainly from large elasto-optic coefficients.

  3. 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.

  4. Exploring Ramsey-coherent population trapping atomic clock realized with pulsed microwave modulated laser

    SciTech Connect

    Yang, Jing; Yun, Peter; Tian, Yuan; Tan, Bozhong; Gu, Sihong

    2014-03-07

    A scheme for a Ramsey-coherent population trapping (CPT) atomic clock that eliminates the acousto-optic modulator (AOM) is proposed and experimentally studied. Driven by a periodically microwave modulated current, the vertical-cavity surface-emitting laser emits a continuous beam that switches between monochromatic and multichromatic modes. Ramsey-CPT interference has been studied with this mode-switching beam. In eliminating the AOM, which is used to generate pulsed laser in conventional Ramsey-CPT atomic clock, the physics package of the proposed scheme is virtually the same as that of a conventional compact CPT atomic clock, although the resource budget for the electronics will slightly increase as a microwave switch should be added. By evaluating and comparing experimentally recorded signals from the two Ramsey-CPT schemes, the short-term frequency stability of the proposed scheme was found to be 46% better than the scheme with AOM. The experimental results suggest that the implementation of a compact Ramsey-CPT atomic clock promises better frequency stability.

  5. AIMS: Acousto-optic imaging spectrometer for spectral mapping of solid surfaces

    NASA Astrophysics Data System (ADS)

    Glenar, David A.; Blaney, Diana L.; Hillman, John J.

    2003-01-01

    A compact, two-channel acousto-optic tunable filter (AOTF) camera is being built at GSFC as a candidate payload instrument for future Mars landers or small-body rendezvous missions. This effort is supported by the NASA Mars Instrument Development Program (MIDP), Office of Space Science Advanced Technologies and Mission Studies. Acousto-optic Imaging Spectrometer (AIMS) is electronically programmable and provides arbitrary spatial and spectral selection from 0.48 to 2.4 μm. The geometric throughput of AOTF's are well matched to the requirements for lander mounted cameras since (I) they can be made very compact, (II) "slow" (f/14-f/18) optics required for large depth-of-field fall well within the angular aperture limit of AOTF's, and (III) they operate at low ambient temperatures. A breadboard of the AIMS short-wavelength channel is now being used for spectral imaging of high-interest Mars analog materials (iron oxides, carbonates, sulfates and sedimentary basalts) as part of the initial instrument validation exercises.

  6. Designing the acousto-optical cell for optical spectrometer incorporated into the Guillermo Haro Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Arellanes Bernabe, Adan Omar; Chavushyan, Vahram

    2013-09-01

    Optical spectrometer of the Guillermo Haro astrophysical observatory (Mexico) exploits mechanically removable traditional static diffraction gratings as dispersive elements. There is a set of the static gratings with the slit-density 50 - 600 lines/mm and optical apertures 9 cm x 9 cm that provide the first order spectral resolution from 9.6 to 0.8 A/pixel, respectively, in the range 400 - 1000 nm. However, the needed mechanical manipulations, namely, replacing the static diffraction gratings with various resolutions and following recalibration of spectrometer within studying even the same object are inconvenient and lead to losing rather expensive observation time. We suggest exploiting an acousto-optical cell, i.e. the dynamic diffraction grating tunable electronically, as dispersive element in that spectrometer. Involving the acousto-optical technique, which can potentially provide electronic control over the spectral resolution and the range of observations, leads to possible eliminating the above-mentioned demerits and to improving the efficiency of analysis.

  7. 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.

  8. Contrast enhancement in microscopy of human thyroid tumors by means of acousto-optic adaptive spatial filtering

    NASA Astrophysics Data System (ADS)

    Yushkov, Konstantin B.; Molchanov, Vladimir Y.; Belousov, Pavel V.; Abrosimov, Aleksander Y.

    2016-01-01

    We report a method for edge enhancement in the images of transparent samples using analog image processing in coherent light. The experimental technique is based on adaptive spatial filtering with an acousto-optic tunable filter in a telecentric optical system. We demonstrate processing of microscopic images of unstained and stained histological sections of human thyroid tumor with improved contrast.

  9. Quasi-4D laser diagnostics using an acousto-optic deflector scanning system

    NASA Astrophysics Data System (ADS)

    Li, Tao; Pareja, Jhon; Becker, Lukas; Heddrich, Wolfgang; Dreizler, Andreas; Böhm, Benjamin

    2017-03-01

    In this paper, a novel scanning system for laser diagnostics was developed and characterized. The system is based on the acousto-optic deflection of a high-speed pulsed laser. Results showed that quasi-volumetric laser illumination with high precision and accuracy can be achieved with a simplified and flexible optical setup. The feasibility of the method for performing high-speed quasi-4D laser diagnostics was demonstrated by the tomographic visualization of a lifted turbulent jet flame using Mie-scattering and multi-plane particle image velocimetry measurements of a turbulent non-reactive mixing case. Three-dimensional flame and flow structures can be detected and tracked with this new scanning system.

  10. Efficient double-filtering with a single acousto-optic tunable filter.

    PubMed

    You, Jang-Woo; Ahn, Jeongho; Kim, Soohyun; Kim, Daesuk

    2008-12-22

    We describe an efficient double-filtering method that uses a single acousto-optic tunable filter (AOTF) to improve the spectral resolution and intrinsic sidelobes for the spectral domain analysis systems. Double filtering with a single AOTF is realized by applying a unique feedback scheme based on the fact that incident light can be diffracted into two orthogonally polarized beams of light by an AOTF. Our theoretical explanation attempts to address and satisfy the main prerequisite for the proposed idea. The experimental results confirm that the proposed method achieves a 20% to 30% improvement in spectral resolution and 10 dB suppression of sidelobes with minimized light loss for the extraordinary incident light. We believe that the results of using an AOTF are comparable to the results achieved with two AOTFs in tandem.

  11. Spatial and temporal thermal analysis of acousto-optic deflectors using finite element analysis model.

    PubMed

    Jiang, Runhua; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun; Huang, Zhifeng; Zhou, Huaichun

    2012-07-01

    Thermal effects greatly influence the optical properties of the acousto-optic deflectors (AODs). Thermal analysis plays an important role in modern AOD design. However, the lack of an effective method of analysis limits the prediction in the thermal performance. In this paper, we propose a finite element analysis model to analyze the thermal effects of a TeO(2)-based AOD. Both transducer heating and acoustic absorption are considered as thermal sources. The anisotropy of sound propagation is taken into account for determining the acoustic absorption. Based on this model, a transient thermal analysis is employed using ANSYS software. The spatial temperature distributions in the crystal and the temperature changes over time are acquired. The simulation results are validated by experimental results. The effect of heat source and heat convection on temperature distribution is discussed. This numerical model and analytical method of thermal analysis would be helpful in the thermal design and practical applications of AODs.

  12. 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.

  13. Acousto-optic liquid-crystal analog beam former for phased-array antennas.

    PubMed

    Riza, N A

    1994-06-10

    A compact phased-array antenna acousto-optic beam former with element-level analog phase (0-2π) and amplitude control using nematic-liquid-crystal display-type technology is experimentally demonstrated. Measurements indicate > 6-bit phase control and 52.6 dB of amplitude-attenuation control. High-quality error calibration and antenna sidelobe-level control is possible with this low-control-power analog beam former. Optical system options using rf Bragg cells or wideband Bragg cells are discussed, with the rf design being the current preferred approach. Transmit-receive beam forming based on frequency upconversion-downconversion by electronic mixing is introduced for the rf Bragg-cell beam former, and comparisons with digital beam forming are highlighted. A millimeter-wave signal generation and control optical architecture is described.

  14. 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.

  15. Acousto-optic control of the LPG spectrum for sensing applications

    NASA Astrophysics Data System (ADS)

    Oliveira, Roberson A.; Possetti, Gustavo R. C.; Marques, Carlos A. F.; Neves, Paulo T., Jr.; Bavastri, Carlos A.; Kamikawachi, Ricardo C.; Fabris, José L.; Muller, Marcia; Nogueira, Rogério N.; Canning, John; Pohl, Alexandre A. P.

    2011-05-01

    Experimental and numerical demonstration of the acousto-optic effect applied in long period grating by means of flexural waves is presented. The interaction between acoustic and optical waves is modeled with help of the method of assumed modes, which delivers the strain field inside the grating and the transfer matrix method, which, given the strain field as input, calculate the resultant grating spectrum. The experimental and theoretical results are found to be in good agreement. The main effect of the bends in the grating is the break of degeneracy of the circular cladding modes, leading the attenuation band to be changed. Among all the applications of this methodology, it is important to mention the possibility of use as a tunable filter, laser cavity gain controller, switching device and transducer in sensing systems.

  16. Performance of an acousto-optic Bragg cell under ion microbeam irradiation

    SciTech Connect

    Paxton, A.H.; Schone, H.; Taylor, E.W.; McKinney, S.; Doyle, B.L.

    1997-08-01

    An acousto optic (AO) deflector composed of PbMoO{sub 4} was exposed to 4 MeV protons while operating under Bragg angle conditions. An ion beam in air of 1 mm width was directed normal to the crystal face and laser beam. Between exposures, the approximately 13 mm x 8.5 mm AO deflector was mechanically translated in two dimensions in front of the fixed ion beam. The AO diffraction efficiency was mapped and was observed to change as a function of ion beam location and dose rate. These effects are attributed to the induced change in the temperature distribution of the crystal, which changed the sonic velocity and refractive index. Similar effects were observed when the ion beam was directed at the acoustic transducer.

  17. Optical Multiplications With Single Element 2-D Acousto-Optic Laser Beam Deflector

    NASA Astrophysics Data System (ADS)

    Soos, Jolanta I.; Leepa, Douglas C.; Rosemeier, Ronald G.

    1989-05-01

    With the current need for developing very fast computers in comparison to conventional digital chip based systems, the future for optical based signal processing is very bright. Attention has turned to a different application of optics utilizing mathematical operations, in which case operations are numerical, sometimes discrete, and often algebraic in nature. Interest has been so vigorous that many view it as a small revolution in optics, whereby optical signal processing is beginning to encompass what is frequently described as optical computing. The term is fully intended to imply a close comparison with the operations performed by scientific digital canputers. This paper will describe the applications of single element 2-D acousto-optic deflectors for optical multiplication systems.

  18. Matrix operations utilizing multichannel two-dimensional acousto-optic deflector

    NASA Astrophysics Data System (ADS)

    Barocsi, Attila; Jakab, Laszlo; Richter, Peter I.

    1994-01-01

    A linear scanning light deflector, or Bragg-cell, is a widely utilized acousto-optic (AO) signal processing device. Its application is, however, limited due to its line scanning property. To overcome this deficiency an area (or matrix) scanning deflector can be built by consecutively placing two, orthogonally positioned, linear deflectors. A more sophisticated method, however, is the realization of a `monolithic' area scanning device, or 2-D (XY-) deflector, that contains a single Bragg cell. If each dimension of the cell has several input channels the element can serve as a special optical processor in various applications. In this work a multichannel XY-deflector is examined with special regard to its utilization as a fast optical crossbar switch and matrix processor. An experimental set-up with a 2 * 2 channel cell is also demonstrated.

  19. Spatial mapping of transient atomic concentrations using acousto-optic deflection

    SciTech Connect

    Huie, C.W.; Yeung, E.S.

    1986-08-01

    We report a new imaging system for obtaining spatially and temporally resolved atomic absorption profiles for transient events. This is based on an acousto-optic beam deflector that scans the probe laser beam in one dimension repeatedly across the spatial region of interest. Scan rates of 10 ..mu..s durations essentially freeze the absorbing species in time to allow a spatial resolution of 0.06 cm over a 1.2 cm length. With the use of 2K of buffer memory and a digitization interval of 200 nm (12 bits), the time evolution can be followed up to a total of 400 ..mu..s. The capabilities are demonstrated in the study of atom formation in a laser generated plume for a sodium tungstate surface.

  20. Hyperspectral imager, from ultraviolet to visible, with a KDP acousto-optic tunable filter.

    PubMed

    Gupta, Neelam; Voloshinov, Vitaly

    2004-05-01

    Hyperspectral imaging in the ultraviolet to visible spectral region has applications in astronomy, biology, chemistry, medical sciences, etc. A novel electronically tunable, random-wavelength access, compact, no-moving-parts, vibration-insensitive, computer-controlled hyperspectral imager operating from 220 to 480 nm with a spectral resolution of 160 cm(-1), e.g., 2 nm at 350 nm, has been developed by use of a KDP acousto-optic tunable filter (AOTF) with an enhanced CCD camera and a pair of crossed calcite Glan-Taylor polarizing prisms. The linear and angular apertures of the AOTF are 1.5 x 1.5 cm2 and 1.2 degrees, respectively. Imager setup and spectral imaging results as well as analyses and discussion of various factors affecting image quality are presented.

  1. Acousto-optical post-processor time-integrating correlator calibration updates

    NASA Astrophysics Data System (ADS)

    Baker, P.

    1992-02-01

    The acousto-optical signal processing facility and time integrating correlator system has been updated to allow proper handling of multiple peaks and to increase the readout rate. These modifications are described. In the supervisor task, a phase shift dialog box has been added to the phase shift menu items. This dialog box allows the operator to limit the area examined while searching for peaks or to specify the peak location directly. An amplitude offset calibration dialog box has been added to the amplitude offset menu item. This dialog box allows the operator to limit the area examined during the amplitude offset calibration, which is designed to perform calculations on a portion of the correlogram that does not contain a peak. In addition, the interface between the photodetector and personal computer has been modified to double the maximum pixel clock rate to 10 MHz.

  2. 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

  3. Prolonged acousto-optic interaction with Lamb waves in crystalline plates

    PubMed

    Parygin; Vershoubskiy; Mozhaev; Weihnacht

    2000-03-01

    The propagation and acousto-optic interaction of Lamb modes in an anisotropic plate of tellurium dioxide (TeO2) are studied numerically and analytically. In the case of a Y-cut X-propagating TeO2 plate, the very high elastic anisotropy of the crystal greatly modifies the dispersion curves, giving rise to their multiple oscillations. The existence ranges of backward Lamb modes increase with the mode order contrary to the case of isotropic plates. The quasi-collinear light scattering by Lamb waves is considered. Owing to the structure of Lamb wave field, a simultaneous light diffraction at two different optical frequencies can take place while Lamb waves are excited only at the single frequency. It is demonstrated with the Z-cut (110)-propagating plate that a small change in the acoustic frequency can result in a significant shift in the frequency of the scattered light.

  4. 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.

  5. Acousto-optical pulsar processor frequency scale calibration for increase accuracy measurement of time of arrival radioemission impulses

    NASA Astrophysics Data System (ADS)

    Esepkina, Nelli A.; Lavrov, Aleksandr P.; Molodyakov, Sergey A.

    2006-04-01

    The acousto-optical processor (AOP) is based on an acousto-optical spectrum analyzer with a CCD photodetector operating in special pipeline mode (shift-and-add mode), which allows spectral components of the input signal to be added with controlled time delay immediately in the CCD photodetector. The proposed AOP was successfully used on radiotelescope RT-64 (Kalyazin Radio Astronomy Observatory FIAN) for the observation of pulsars at 1 .4 GHz in 45 MHz bandwidth. The AOP frequency scale calibration allows increasing accuracy of measurement of time of arrival radioemission pulses. Experimental results on investigation of AOP work on RT-64 and radioemission pulses profiles for pulsar PSR 1937+21 are submitted.

  6. Algorithm of Shaping Multiple-beam Braggs Acousto-optic Diffraction Laser Field Into 1D and 2D Patterns

    NASA Astrophysics Data System (ADS)

    Zakharchenko, S.; Baturin, A.

    2015-09-01

    Algorithm of solving a direct problem of acousto-optic interaction between laser emission and acoustic signal consisting of a set of equidistant frequency components is proposed. An infinite system of coupled wave differential equations is reduced to eigenvalue problem. The contribution of the higher rediffraction orders is analyzed separately. Inverse problem of finding an optimal set of equidistant frequency components of a driving acoustic signal to form the objective diffraction pattern is also considered and a few optimization approaches are analyzed. A naïve heuristic method of splitting 2D pattern into subframes, each suitable for simultaneous projection by two acousto-optical deflectors driven by multifrequency composite signal, is developed.

  7. Experimental analysis of distributed pump absorption and refractive index changes in Yb-doped fibers using acousto-optic interaction.

    PubMed

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

    2015-03-01

    In-fiber acousto-optic interaction is used to characterize the refractive index changes at the C band in a single-mode ytterbium-doped optical fiber under 980 nm pumping. The transmission notch created by the acoustic-induced coupling between the core mode and a cladding mode shifts to longer wavelengths when the pump is delivered to the fiber. The electronic contribution to the refractive index change is quantified from the wavelength shift. Using a time-resolved acousto-optic method, we investigate the distribution of pump absorption, and the resulting refractive index change profile, along sections of ytterbium-doped fiber exceeding 1 m long under different pump power levels.

  8. An acousto-optical method for registration of erythrocytes' agglutination reaction—sera color influence on the resolving power

    NASA Astrophysics Data System (ADS)

    Doubrovski, V. A.; Medvedeva, M. F.; Torbin, S. O.

    2016-01-01

    The absorption spectra of agglutinating sera were used to determine blood groups. It was shown experimentally that the sera color significantly affects the resolving power of the acousto-optical method of blood typing. In order to increase the resolving power of the method and produce an invariance of the method for sera color, we suggested introducing a probing light beam individually for different sera. The proposed technique not only improves the resolving power of the method, but also reduces the risk of false interpretation of the experimental results and, hence, error in determining the blood group of the sample. The latter is especially important for the typing of blood samples with weak agglutination of erythrocytes. This study can be used in the development of an instrument for instrumental human blood group typing based on the acousto-optical method.

  9. 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.

  10. Calomel-made crystalline acousto-optical cell designed for an advanced regime of noncollinear two-phonon light scattering

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Alexandre S.; Arellanes, Adan Omar

    2016-03-01

    We study the potentials of a wide-aperture crystalline calomel-made acousto-optical cell. Characterizing this cell is nontrivial due to the chosen regime based on an advanced noncollinear two-phonon light scattering. Recently revealed important features of this phenomenon are essentially exploited in the cell and are investigated in more detail. These features can be observed more easily and simply in tetragonal crystals, e.g., calomel, exhibiting specific acousto-optical nonlinearity caused by the acoustic waves of finite amplitude. This parametric nonlinearity manifests itself at low acoustic powers in calomel possessing linear acoustic attenuation. The formerly identified additional degree of freedom, unique to this regime, is exploited for designing the cell with an eye to doubling the resolution due to two-phonon processes. We clarify the role of varying the central acoustic frequency and acoustic attenuation using that degree of freedom. Then the efficiency of calomel is exploited to expand the cell's bandwidth with a cost of its efficiency. Proof-of-principle experiments confirm the developed approaches and illustrate their applicability to innovative techniques of optical spectrum analysis with the improved resolution. The achieved spectral resolution of 0.205 Å at 405 nm and the resolving power 19,800 are the best for acousto-optical spectrometers dedicated to space or airborne operations to date as far as we know.

  11. 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

  12. Single Element 2-DIMENSIONAL Acousto-Optic Deflectors Design, Fabrication and Implementation for Digital Optical Computing

    NASA Astrophysics Data System (ADS)

    Rosemeier, Jolanta Iwona

    1992-09-01

    With the need to develop very fast computers compared to the conventional digital chip based systems, the future is very bright for optical based signal processing. Attention has turned to a different application of optics utilizing mathematical operations, in which case operations are numerical, sometimes discrete, and often algebraic in nature. Interest has been so vigorous that many view it as a small revolution in optics whereby optical signal processing is beginning to encompass what many frequently describe as optical computing. The term is fully intended to imply close comparison with the operations performed by scientific digital computers. Most present computer intensive problem solving processors rely on a common set of linear equations found in numerical matrix algebra. Recently, considerable research focused on the use of systolic array, which can operate at high speeds with great efficiency. This approach addresses the acousto-optic digital and analog arrays utilizing three dimensional optical interconnect technology. In part I of this dissertation the first single element 2-dimensional (2-D) acousto-optic deflector was designed, fabricated and incorporated into an optical 3 x 3 vector-vector or matrix-matrix multiplier system. This single element deflector is used as a outer-product device. The input vectors are addressed by electronic means and the outer product matrix is displayed as a 2-D array of optical (laser) pixels. In part II of this work a multichannel single element 2-D deflector was designed, fabricated and implemented into a Programmable Logic Array (PLA) optical computing system. This system can be used for: word equality detection, free space optical interconnections, half adder optical system implementation. The PLA system described in this dissertation has capability of word equality detection. The 2-D multichannel deflector that was designed and fabricated is capable of comparing 16 x 16 words every 316 nanoseconds. Each word is 8

  13. Time Domain Spectral Hole-Burning Storage

    DTIC Science & Technology

    1994-05-02

    hyperfine transition. Since the laser frequency was shifted by a menue of acousto - optic moodulators, exact and repeatable offsets of the laser... acousto - optic modulators (AOM) to remove the fluctuations. The long tem dr can be removed by dchnin the law cavity length with ether pazo controlled...The control system u electro- optic modulator El and acousto - optic modulator Al, along with the lase tweete and Vlvo plate to remove the phase and

  14. 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.

  15. Acousto-optic tunable filter for dispersion characterization of time-domain optical coherence tomography systems.

    PubMed

    Chin, Catherine; Toadere, Florin; Feuchter, Thomas; Leick, Lasse; Moselund, Peter; Bradu, Adrian; Podoleanu, Adrian

    2016-07-20

    A broadband supercontinuum light source with an acousto-optic tunable filter (AOTF) are used to characterize dispersion in two time-domain OCT systems, at 850 and 1300 nm. The filter is designed to sweep across two spectral ranges, which are restricted here from 800 to 900 nm and from 1200 to 1500 nm, respectively. Dispersion compensation for 850 nm was achieved with a spectral delay line. Dispersion compensation for 1300 nm was achieved using BK 7 rod glasses in the reference arm. The AOTF allows evaluation of dispersion in under as well as overcompensated systems. The AOTF method is based on wavelength dependence of the optical path difference corresponding to the maximum strength of the interference signal recorded using a mirror as object. Comparison is made between the AOTF method and the more usual method based on measurement of the full width at half-maximum of the autocorrelation peak. This comparison shows that the AOTF method is more accurate in terms of evaluation of the dispersion left uncompensated after each adjustment. The AOTF method additionally provides information on the direction of dispersion compensation.

  16. A Lyman-alpha tunable acousto-optic filter for detecting superthermal flare protons

    NASA Technical Reports Server (NTRS)

    Mickey, Donald L.

    1994-01-01

    The goal of this project was to develop and characterize a narrow-band, tunable filter for use near the Lyman-alpha line of hydrogen at 121.6 nm. Such a filter could form the critical component of an instrument to observe asymmetries in the solar Lyman-alpha line, caused by energetic protons accelerated during the impulsive phase of solar flares. Characteristic charge-exchange nonthermal emission at Lyman alpha should be produced when sub-MeV protons are injected into the chromosphere, but no instrument suitable for their detection has been developed. Such an instrument would require a narrow-band (less than 0.01 nm) tunable filter with aperture and throughput consistent with imaging a solar active region at 0.1 second intervals. The development of acousto-optic tunable filters (AOTF) suitable for use as compact, simple tunable filters for astronomical work suggested an investigation into the use of an AOTF at Lyman-alpha.

  17. An acousto-optic tunable filter enhanced CO{sub 2} lidar atmospheric monitor

    SciTech Connect

    Taylor, L.H.; Suhre, D.R.; Mani, S.S.

    1996-12-31

    The atmospheric monitor conceptual design is based on a pulsed CO{sub 2} laser. The narrow laser lines provide high spectral selectivity in the 9-11 {mu}m region, within the 8-14 {mu}m ``fingerprint`` region where most large molecules have unique spectral absorption signatures. Laser power has been chosen so that topological objects, e.g., trees or buildings, as far as 4 km can be used as backreflectors, but the laser intensity is sufficiently low that the laser beam is eye-safe. Time-of-flight measurements give the distance to the topological reflector. The lidar system is augmented with an acousto-optic tunable filter (AOTF) which measures the thermal emission spectra from 3 to 14 {mu}m with a 3 cm{sup -1} passband. Sensitivity to narrow emission lines is enhanced by derivative spectroscopy in which the passband of the AOTF is dithered via the rf drive. Path-averaged concentrations are determined from the emission intensity and laser- determined range.

  18. Configurable-bandwidth imaging spectrometer based on an acousto-optic tunable filter

    NASA Astrophysics Data System (ADS)

    Vila-Francés, Joan; Calpe-Maravilla, Javier; Muñoz-Mari, Jordi; Gómez-Chova, Luis; Amorós-López, Julia; Ribes-Gómez, Emilio; Durán-Bosch, Vicente

    2006-07-01

    This article presents a new imaging spectrometer called autonomous tunable filtering system. The instrument acquires sequential images at different spectral wavelengths in the visible and near infrared range of the electromagnetic spectrum. The spectral selection is performed by an acousto-optic tunable filter (AOTF), which is driven by a custom radio-frequency (rf) generator based on a direct digital synthesizer (DDS). The DDS allows a high flexibility in terms of acquisition speed and bandwidth selection. The rf power is dynamically controlled to drive the AOTF with the optimum value for each wavelength. The images are formed through a carefully designed optical layout and acquired with a high performance digital camera. The application software controls the instrument and acquires the raw spectral images from the camera. This software optionally corrects the image for the AOTF nonidealities, such as diffraction efficiency variations, spatial nonuniformity, and chromatic aberration, and generates a single multiband image file. Moreover, the software can calculate the reflectance or transmittance of the acquired images. The instrument has been calibrated to give precise and repetitive measurements and has been validated against a high performance point spectrometer. As a case example, the instrument has been successfully used for the mapping of chlorophyll content of plant leaves from their multispectral reflectance images.

  19. Tunable transportable spectroradiometer based on an acousto-optical tunable filter: Development and optical performance

    NASA Astrophysics Data System (ADS)

    Kozlova, O.; Sadouni, A.; Truong, D.; Briaudeau, S.; Himbert, M.

    2016-12-01

    We describe a high-performance, transportable, versatile spectroradiometer based on an acousto-optical tunable filter (AOTF). The instrument was developed for temperature metrology, namely, to determine the thermodynamic temperature of black bodies above the Ag freezing point (961.78 °C). Its main design feature is the attenuation of the diffraction side lobes (and, thus, out-of-band stray light) thanks to the use of a double-pass configuration. The radiofrequency tuning of the AOTF allows continuous, fine, and rapid wavelength control over a wide spectral range (650 nm-1000 nm). The instrument tunability can be easily calibrated with an Ar spectral lamp with reproducibility within 10 pm over one week. The instrument was characterised in terms of relative signal stability (few 10-4) and wavelength stability (1 pm) over several hours. The spectral responsivity of the instrument was calibrated with two complementary methods: tuning of the wavelength of the optical source or tuning the radiofrequency of the AOTF. Besides the application for thermodynamic temperature determination at the lowest uncertainty level, this instrument can also be used for multispectral non-contact thermometry of processed materials of non-grey and non-unitary emissivity (in the glass or metallurgical industries).

  20. 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.

  1. The effect of scattering-medium parameters on signal magnitude under acousto-optic tomography

    NASA Astrophysics Data System (ADS)

    Zyuryukina, O. V.; Volkova, E. K.; Perchenko, M. I.; Solov'ev, A. P.

    2014-04-01

    We have experimentally studied the influence of scattering anisotropy parameter g of a medium on the magnitude of signal S (visualization parameter) at an ultrasonic frequency that is registered upon acoustooptic tomography. Aqueous solutions of mixtures of cream and skimmed milk with different ratios between them were used as scattering media. The optical properties of media (absorption coefficient μa and reduced scattering coefficient μ' S ) have been measured on a spectrophotometer (Perkin-Elmer Lambda 950 UV-VIS-NIR) using the inverse adding-doubling technique. As a result of the investigation, we have found that there is a certain correlation between the value of the scattering anisotropy parameter g of aqueous solutions of investigated mixtures and the percentage of the mixture in the aqueous solution, which ensures the required small value of extinction coefficient μ of the scattering medium. An increase in signal S has been revealed with increasing anisotropy parameter g of the medium at a invariable value of extinction coefficient μ. We have concluded that, to solve an inverse problem on the acousto-optic tomography, it is necessary to take into account possible changes in the g factor in scattering media, including biological ones.

  2. 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).

  3. Analysis of the dispersion compensation of acousto-optic deflectors used for multiphoton imaging.

    PubMed

    Zeng, Shaoqun; Lv, Xiaohua; Bi, Kun; Zhan, Cheng; Li, Derong; Chen, Wei R; Xiong, Wenhui; Jacques, Steven L; Luo, Qingming

    2007-01-01

    The acousto-optic deflector (AOD) is highly preferred in laser scanning microscopy for its fast scanning ability and random-addressing capability. However, its application in two-photon microscopy is frustrated by the dispersion of the AOD, which results in beam distortion and pulse lengthening. We report the analysis of simultaneous compensation for the angular dispersion and temporal dispersion of the AOD by merely introducing a single dispersive element such as a prism or a grating. Besides serving as a scanner, the AOD is also a part of the compressor pair by integrating the dispersive nature of the AO interaction. This compensation principle is effective for both one-dimensional (1-D) AOD and two-dimensional (2-D) AOD scanning. Switching from a 1-D to a 2-D system requires proper optical alignment with the compensation element, but does not involve any new components. Analytical expressions are given to illustrate the working principle and to help with understanding the design of the system. Fluorescence images of beads and cells are shown to demonstrate the performance of two-photon microscopy when applying this compensated 2-D AOD as scanner.

  4. A RAPIDLY-TUNABLE ACOUSTO-OPTIC SPECTROMETER FOR A SPACE ENVIRONMENT

    SciTech Connect

    D. THOMPSON; C. HEWITT; C. WILSON

    2000-08-01

    As a complement to our work developing rapidly-tunable ({approximately}10-100 kHz) CO{sub 2} lasers for differential absorption lidar (DIAL) applications,l we have developed a rapidly-tunable spectrometer. A rapid spectral diagnostic is critical for a high speed DIAL system, since analysis of the return signals depends on knowing the spectral purity of the transmitted beam. The spectrometer developed for our lidar system is based on a double-passed large- (75 mm) aperture acousto-optic deflector, a grating, and a fast single-element room temperature mercury-cadmium-telluride detector. The spectrometer has a resolution of {approximately}0.5 cm{sup {minus}1}, a tuning range of 9.0-11.4 pm, a random-access tuning speed of greater than 80 kHz and a S/N ratio of greater than 100:1. We describe the design and performance of this device, as well as of future devices featuring improved resolution, higher speed and easier and more robust alignment. We will also briefly discuss the applications and limitations of the technique in a space environment.

  5. Tunable acousto-optic spectral imager for atmospheric composition measurements in the visible spectral domain.

    PubMed

    Dekemper, Emmanuel; Loodts, Nicolas; Van Opstal, Bert; Maes, Jeroen; Vanhellemont, Filip; Mateshvili, Nina; Franssens, Ghislain; Pieroux, Didier; Bingen, Christine; Robert, Charles; De Vos, Lieve; Aballea, Ludovic; Fussen, Didier

    2012-09-01

    We describe a new spectral imaging instrument using a TeO(2) acousto-optical tunable filter (AOTF) operating in the visible domain (450-900 nm). It allows for fast (~1 second), monochromatic (FWHM ranges from 0.6 nm at 450 nm to 3.5 nm at 800 nm) picture acquisition with good spatial resolution. This instrument was designed as a breadboard of the visible channel of a new satellite-borne atmospheric limb spectral imager, named the Atmospheric Limb Tracker for the Investigation of the Upcoming Stratosphere (ALTIUS), that is currently being developed. We tested its remote sensing capabilities by observing the dense, turbulent plume exhausted by a waste incinerator stack at two wavelengths sensitive to NO(2). An average value of 6.0±0.4×10(17) molecules cm(-2) has been obtained for the NO(2) slant column density within the plume, close to the stack outlet. Although this result was obtained with a rather low accuracy, it demonstrates the potential of spectral imaging by using AOTFs in remote sensing.

  6. Dual-loss-modulated Q-switched mode-locked laser intracavity pumped temperature-tuned subnanosecond KTiOPO4 optical parametric oscillator.

    PubMed

    Chu, Hongwei; Zhao, Jia; Yang, Kejian; Zhao, Shengzhi; Li, Dechun; Li, Tao; Li, Guiqiu; Qiao, Wenchao

    2015-12-10

    Using an acousto-optic modulator (AOM) and Cr4+:YAG as the dual-loss modulation, an intracavity KTiOPO4 optical parametric oscillator (OPO) pumped by a simultaneously Q-switched and mode-locked (QML) YVO4/Nd:YVO4 laser was realized. The shortest mode-locking pulse duration of the signal wave at 1573 nm was directly measured as 450 ps at an AOM frequency of 2 kHz and a diode pump power of 10.5 W, corresponding to a peak power of 35.5 kW. The temperature tuning of the output signal wavelength was realized in the range from 1571.99 to 1572.61 nm with a blueshift ratio of 0.027  nm/°C. A set of coupled rate equations for the dual-loss-modulated QML laser pumping intracavity OPO was built for the first time to our knowledge. The numerical solutions were fitted with the experimental results.

  7. Acousto-optic, point receiver hydrophone probe for operation up to 100 MHz.

    PubMed

    Lewin, P A; Mu, C; Umchid, S; Daryoush, A; El-Sherif, M

    2005-12-01

    This work describes the results of initial evaluation of a wideband acousto-optic hydrophone probe designed to operate as point receiver in the frequency range up to 100 MHz. The hydrophone was implemented as a tapered fiber optic (FO) probe sensor with a tip diameter of approximately 7 microm. Such small physical dimensions of the sensor eliminate the need for spatial averaging corrections so that true pressure-time (p-t) waveforms can be faithfully recorded. The theoretical considerations that predicted the FO probe sensitivity to be equal to 4.3 mV/MPa are presented along with a brief description of the manufacturing process. The calibration results that verified the theoretically predicted sensitivity are also presented along with a brief description of the improvements being currently implemented to increase this sensitivity level by approximately 20 dB. The results of preliminary measurements indicate that the fiber optic probes will exhibit a uniform frequency response and a zero phase shift in the frequency range considered. These features might be very useful in rapid complex calibration i.e. determining both magnitude and phase response of other hydrophones by the substitution method. Also, because of their robust design and linearity, these fiber optic hydrophones could also meet the challenges posed by high intensity focused ultrasound (HIFU) and other therapeutic applications. Overall, the outcome of this work shows that when fully developed, the FO probes will be well suited for high frequency measurements of ultrasound fields and will be able to complement the data collected by the current finite aperture piezoelectric PVDF hydrophones.

  8. Wavelength-swept fiber laser based on acousto-optic tuning method

    NASA Astrophysics Data System (ADS)

    Chen, Ming-hui; Fan, Yun-ping; Zhang, Hao; Tao, Jian-feng; Zheng, Gang

    2016-10-01

    In this study, we have demonstrated a wavelength-swept fiber laser based on an acousto-optic tunable filter(AOTF) as a selective element and a semiconductor optical amplifier(SOA) as a gain medium in an internal fiber ring cavity. The light deriving from one port of the SOA goes through an optical isolator, the AOTF, a fiber coupler and a polarized controller successively, then it goes back to the other port of the SOA to form a ring cavity. The laser output is from another port of the fiber coupler. The laser made by this method is mainly used for swept-source optical coherence tomography(SS-OCT). The application of the SOA provides a sufficiently broad range and can ensure an increased axial resolution of SS-OCT. AOTF offers a wide tuning range, high switching speed and stable operation against vibration for the non-mechanical structure. The proposed wavelength-swept fiber laser ensures a high axial resolution of tomographic images and has a stable laser output. We have discussed the influence of the SOA injection current to the tuning range of the laser. In the SOA injection current of 280 mA, a continuous wavelength tuning range from 1295 to 1370 nm centered at a wavelength of 1330nm is obtained at the sweep rate of 1.06 kHz, and the power of the swept source was 1.14 mW. In addition, for quantitative characterization of the wavelength-swept performance with a AOTF, we have theoretically and experimentally analyzed the influence of the following controllable parameters: injection current, output power and sweeping frequency.

  9. Acousto-optical deflection-based laser beam scanning for fluorescence detection on multichannel electrophoretic microchips.

    PubMed

    Huang, Z; Munro, N; Hühmer, A F; Landers, J P

    1999-12-01

    Laser beam scanning driven by an acousto-optical deflector (AOD) is presented for multimicrochannel laser-induced fluorescence (LIF) detection during microchip-based electrophoresis. While fast laser beam scanning for LIF detection on capillary or microchannel arrays can been achieved with galvanometric scanning or a translating stage, it can also be accomplished by using acoustic waves to deflect the laser beam in a manner that is dependent on the acoustic frequency. AOD scanning differs from other approaches in that no moving parts are required, and the scan frequency is faster than conventional approaches. Using a digital/analog (D/A) converter to provide addressing voltages to a voltage/frequency converter, rapidly changing the frequency input to the AOD allows the laser beam to be addressed accurately on a microchip. With the ability to change the frequency on the nanosecond time scale, scanning rates as high as 30 Hz for Windows-based LabView programming are possible, with much faster scan rates achievable if a microprocessor-embedded system is utilized. In addition to spatial control, temporal control is easily attainable via raster scanning or random addressing, allowing for the scanning process to be self-aligning. Since the D/A output voltages drive the scanning of the laser beam over all channels, the software can define addressing voltages corresponding to the microchannel centers and, subsequently, fluorescence data can be collected from only those locations. This method allows for flexible, high-speed, self-align scanning for fluorescence detection in capillary or microchip electrophoresis and has the potential to be applied to a number of applications.

  10. Development of fast two-dimensional standing wave microscopy using acousto-optic deflectors

    NASA Astrophysics Data System (ADS)

    Gliko, Olga; Reddy, Duemani G.; Brownell, William E.; Saggau, Peter

    2008-02-01

    A novel scheme for two-dimensional (2D) standing wave fluorescence microscopy (SWFM) using acousto-optic deflectors (AODs) is proposed. Two laser beams were coupled into an inverted microscope and focused at the back focal plane of the objective lens. The position of each of two beams at the back focal plane was controlled by a pair of AODs. This resulted in two collimated beams that interfered in the focal plane, creating a lateral periodic excitation pattern with variable spacing and orientation. The phase of the standing wave pattern was controlled by phase delay between two RF sinusoidal signals driving the AODs. Nine SW patterns of three different orientations about the optical axis and three different phases were generated. The excitation of the specimen using these patterns will result in a SWFM image with enhanced 2D lateral resolution with a nearly isotropic effective point-spread function. Rotation of the SW pattern relative to specimen and varying the SW phase do not involve any mechanical movements and are only limited by the time required for the acoustic wave to fill the aperture of AOD. The resulting total acquisition time can be as short as 100 µs and is only further limited by speed and sensitivity of the employed CCD camera. Therefore, this 2D SWFM can provide a real time imaging of subresolution processes such as docking and fusion of synaptic vesicles. In addition, the combination of 2D SWFM with variable angle total internal reflection (TIR) can extend this scheme to fast microscopy with enhanced three-dimensional (3D) resolution.

  11. 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.

  12. Secure transmission of static and dynamic images via chaotic encryption in acousto-optic hybrid feedback with profiled light beams

    NASA Astrophysics Data System (ADS)

    Chatterjee, Monish R.; Almehmadi, Fares S.

    2015-01-01

    Secure information encryption via acousto-optic (AO) chaos with profiled optical beams indicates substantially better performance in terms of system robustness. This paper examines encryption of static and time-varying (video) images onto AO chaotic carriers using Gaussian-profile beams with diffracted data numerically generated using transfer functions. The use of profiled beams leads to considerable improvement in the encrypted signal. While static image encryption exhibits parameter tolerances within about +/-10% for uniform optical beams, profiled beams reduce the tolerance to less than 1%, thereby vastly improving both the overall security of the transmitted information as well as the quality of the image retrieval.

  13. Experimental study of the use of multiband acousto-optic filters for spectral encoding / decoding the optical signals

    NASA Astrophysics Data System (ADS)

    Proklov, V. V.; Byshevski-Konopko, O. A.; Filatov, A. L.; Lugovskoi, A. V.; Pisarevsky, Yu V.

    2016-08-01

    A prototype of the acousto-optic (AO) decoder of optical signals is created on the base of the multiband AO filter. The joint work of the decoder with the developed previously AO coder has been verified experimentally. The main qualitative and quantitate characteristics of the spectral coding and decoding by Walsh sequences of the industrial LED radiation in the near infrared range are investigated. It is shown, that in the proposed data transmission system realization Signal-to-Interference Ratio (SIR) is not less than 13 dB.

  14. Kilohertz generation of high contrast polarization states for visible femtosecond pulses via phase-locked acousto-optic pulse shapers

    SciTech Connect

    Seiler, Hélène; Walsh, Brenna; Palato, Samuel; Kambhampati, Patanjali; Thai, Alexandre; Forget, Nicolas; Crozatier, Vincent

    2015-09-14

    We present a detailed analysis of a setup capable of arbitrary amplitude, phase, and polarization shaping of broadband visible femtosecond pulses at 1 kHz via a pair of actively phase stabilized acousto-optic programmable dispersive filters arranged in a Mach-Zehnder interferometer geometry. The setup features phase stability values around λ/225 at 580 nm as well as degrees of polarization of at least 0.9 for any polarization state. Both numbers are important metrics to evaluate a setup's potential for applications based on polarization-shaped femtosecond pulses, such as fully coherent multi-dimensional electronic spectroscopy.

  15. Hyperspectral imaging performance based on two TeO2 acousto-optic tunable filters.

    PubMed

    Wang, Pengchong; Zhang, Zhonghua

    2017-02-20

    The performance parameters of an acousto-optic tunable filter (AOTF) were reasonably optimized based on the previous research, according to which two AOTFs that could be applied to hyperspectral imaging were produced. Through testing, the basic tuning relationship of the two AOTFs was basically in line with the principle. Then, a hyperspectral imaging system was built based on the two AOTFs, and a long-range perspective target imaging experiment was carried out in the entire white light region. Finally, the proposed double-filtering method was applied to the hyperspectral imaging for the first time, and the imaging result was analyzed in detail.

  16. Optimization of the input losses in fiber-optic communications with an acousto-optic all-optical switch.

    PubMed

    Danilyan, A V; Shulgin, V A; Chernov, V E

    2006-06-20

    We study optical losses in the single-mode fiber system with an all-optical switch based on the anisotropic acousto-optic (AO) TeO(2) 2D deflector. It is shown, theoretically and experimentally, that the mismatch of the output-fiber mode profile and the switched optical beam shape depends significantly on the monochromaticity of the light beam and is determined by the frequency dispersion of the laser beam diffracted on a Bragg AO cell. A quantitative analysis of the dependence of the input optical losses on the spectral width of the light beam is presented.

  17. Applications of Optical Coherent Transient Technology to Pulse Shaping, Spectral Filtering, Arbitrary Waveform Generation and RF Beamforming

    DTIC Science & Technology

    2006-04-15

    optical pulses: (1) using acousto - optic modulators (AOMs) driven with a chirped RF source, ( 2 ) using EOPMs driven with a chirped RF source, (3) utilizing a...holograms (SSH) have the potential to duplicate the functional operation of acousto - optic (AO) deflectors , but with bandwidths (BW) in excess of 10 GHz... acousto - optic deflector to create a scanned optical signal that was recorded in an OCT crystal. The scanner functionality of the AOD was thus

  18. Global maxima for the acousto-optic effect in SrB4O7 crystals.

    PubMed

    Oleh, Buryy; Nazariy, Andrushchak; Andriy, Ratych; Natalia, Demyanyshyn; Bohdan, Mytsyk; Anatoliy, Andrushchak

    2017-03-01

    For the first time, the global maxima of the acousto-optic interaction are theoretically determined for biaxial SrB4O7 crystals by the extreme surfaces method. As it is shown, the highest value of the acousto-optic figure-of-merit M2 is equal to 6.3×10-16  s3/kg and achieved in the case of the isotropic diffraction of the electromagnetic wave propagating in the [010] direction on the fast quasi-transversal acoustic wave.

  19. UV laser with an acousto-optic intra-cavity control for GaN-sapphire cut

    NASA Astrophysics Data System (ADS)

    Gradoboev, Yury G.; Kazaryan, Mishik A.; Mokrushin, Yury M.; Shakin, Oleg V.

    2012-09-01

    A copper vapor laser is proposed as the basic component of the installation for processing of sapphire substrates with a GaN-coating. Laser radiation is transformed to UV range by optical frequency doubling. Powerful UV lasers are prospective tools for crystal cutting, photolithography and recording of the fiber Bragg gratings. The proposed approach is more promising in comparison with the use of excimer radiation because of instabilities of excimer laser generation and low coherence of its radiation, which makes difficult precise focusing and using interference pattern of UV radiation for exposing materials. UV laser based on second harmonic radiation of copper vapors laser has been designed. The UV laser system of high operation stability has been developed with output power 1 W at wavelengths 255.5 nm, 271.1 nm, 289.1 nm and coherence length radiation about 4 cm. The original intra-cavity acousto-optic control of output radiation is developed. It is allows adjusting frequency and on-off time ratio of output laser pulses with high accuracy. The stable heat regime was achieved for an active element of copper vapor laser̤ The laser system allows to select an optimum mode of ultra-violet radiation exposition for production of different optical elements. Intra-cavity acousto-optic cell was used for controlling of single pulse amplitude and number of pulses without any power supply tuning providing the stable operation of the laser system.

  20. Self-tuning acousto-optic deflectors with acoustic line made of NaBi(MoO4)2 crystal

    NASA Astrophysics Data System (ADS)

    Khansuvarov, Ruslan A.; Shakin, Oleg V.; Vaganov, Mikhail A.; Zhdanov, Arseniy Y.

    2014-09-01

    The idea of acousto-optic self-tuning deflector, which automatically returns the position of the acoustic line, corresponding to the mode of Bragg diffraction feedback implementation is proposed. Features of sodium bismuthate's double molybdate grown by new technology - low gradient Czochralski process are illustrated.

  1. On the possibility of developing incoherent fibre-optic data transmission systems based on signal spectral coding with matched acousto-optical filters

    SciTech Connect

    Proklov, Valerii V; Byshevski-Konopko, O A; Grigorievski, V I

    2013-06-30

    The scheme is suggested for developing the optical communication line based on the principle of code division of multiple access with matched acousto-optical filters and a 16-bit long Walsh sequence. Results of modelling show that such a line can operate if adjacent spectral lines are separated by at least double the Rayleigh criterion. (optical information transmission)

  2. 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.

  3. Integrated acousto-optic polarization converter in a ZX-cut LiNbO(3) waveguide superlattice.

    PubMed

    Yudistira, D; Janner, D; Benchabane, S; Pruneri, V

    2009-10-15

    We report an integrated acousto-optic polarization converter exploiting a novel surface acoustic superlattice (S-ASL) transducer. The S-ASL transducer is made of a ZX-cut periodically poled lithium niobate (PPLN) crystal with uniform coplanar electrodes for surface acoustic wave (SAW) generation. For a PPLN period of 20 microm the SAW is excited at an rf of about 190 MHz, while the phase matching occurs at an optical wavelength of around 1456 nm. The measured mode conversion efficiency of 90% at an input rf power of 1 W and the 3 dB optical bandwidth of 2.5 nm confirm the confinement of the SAW between the electrode gap and the constructive interaction along the whole 10 mm electrode length.

  4. 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.

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

    PubMed

    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.

  6. 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

  7. Femtosecond terahertz time-domain spectroscopy at 36 kHz scan rate using an acousto-optic delay

    NASA Astrophysics Data System (ADS)

    Urbanek, B.; Möller, M.; Eisele, M.; Baierl, S.; Kaplan, D.; Lange, C.; Huber, R.

    2016-03-01

    We present a rapid-scan, time-domain terahertz spectrometer employing femtosecond Er:fiber technology and an acousto-optic delay with attosecond precision, enabling scanning of terahertz transients over a 12.4-ps time window at a waveform refresh rate of 36 kHz, and a signal-to-noise ratio of 1.7 × 105 / √{ H z } . Our approach enables real-time monitoring of dynamic THz processes at unprecedented speeds, which we demonstrate through rapid 2D thickness mapping of a spinning teflon disc at a precision of 10 nm/ √{ H z } . The compact, all-optical design ensures alignment-free operation even in harsh environments.

  8. Acousto-optical deflection-based whole channel scanning for microchip isoelectric focusing with laser-induced fluorescence detection.

    PubMed

    Sanders, J C; Huang, Z; Landers, J P

    2001-12-01

    This paper describes the development of a technique amenable to the separation of proteins on a microchip by isoelectric focusing (IEF) with entire channel scanning laser-induced fluorescence detection using acousto-optical deflection (AOD). The ability to use AOD to scan the portions of or the entire length of an IEF separation channel allows for high-speed analysis since the mobilization step is circumvented with this technique. Employing no moving parts eliminates mechanical noise and, not only is there no loss of resolution, AOD scanning can potentially increase resolution. The ability of AOD to provide ultra-fast scanning rates (kHz timescale) allows for real-time imaging of the focusing process. This is demonstrated with the separation of naturally fluorescent proteins using entire channel (total scanning range of 2.4 cm) AOD-mediated scanning laser-induced fluorescence detection.

  9. 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.

  10. Frequency response of a TeO{sub 2} slow shear wave acousto-optic cell exposed to radiation

    SciTech Connect

    Erteza, I.A.; Craft, D.C.; Stalker, K.T.; Taylor, E.W.; Kelley, M.A.; Sanchez, A.D.; Chapman, S.P.; Craig, D.M.; Kinsley, E.

    1994-12-31

    Radiation testing of photonic components is not new, however component level testing to date has not completely addressed quantities which are important to system behavior. One characteristic that is of particular importance for optical processing systems is the frequency response. In this paper, the authors present the results of the analysis of data from an experiment designed to provide a preliminary understanding of the effects of radiation on the frequency response of acousto-optic devices. The goal is to present possible physical mechanisms responsible for the radiation effects and to discuss the effects on signal processing functionality. The experiment discussed in this paper was designed by Sandia National Laboratories (SNL) and performed by SNL and Phillips Laboratory (PL) personnel at White Sands Missile Range (WSMR). In the experiment, a TeO{sub 2} slow shear-wave acousto-optic cell was exposed to radiation from the WSMR linear accelerator. The TeO{sub 2} cell was placed in an experimental configuration which allowed swept frequency diffracted power measurements to be taken during radiation exposure and recovery. A series of exposures was performed. Each exposure consisted of between 1 to 800, 1 {mu}sec radiation pulses (yielding exposures of 2.25 kRad(Si) to 913 kRad(Si)), followed by recovery time. At low total and cumulative doses, the bandshape of the frequency response (i.e. diffracted power vs. frequency) remained almost identical during and after radiation. At the higher exposures, however, the amplitude and width of the frequency response changed as the radiation continued, but returned to the original shape slowly after the radiation stopped and recovery proceeded. It is interesting to note that the location of the Bragg degeneracy does not change significantly with radiation. In this paper, the authors discuss these effects, and they discuss the effect on the signal processing functionality.

  11. 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.

  12. Acousto-optic multiphoton laser scanning microscopy and multiphoton photon counting spectroscopy: Applications and implications for optical neurobiology

    NASA Astrophysics Data System (ADS)

    Iyer, Vijay

    Multiphoton excitation of molecular probes has become an important tool in experimental neurobiology owing to the intrinsic optical sectioning and low light scattering it affords. Using molecular functional indicators, multiphoton excitation allows physiological signals within single neurons to be observed from within living brain tissue. Ideally, it would be possible to record from multiple sites located throughout the elaborately branching dendritic arbors, in order to study the correlations of structure and function both within and across experiments. However, existing multiphoton microscope systems based on scanning mirrors do not allow optical recordings to be obtained from more than a handful of sites simultaneously at the high rates required to capture the fast physiological signals of interest (>100Hz for Ca2+ signals, >1kHz for membrane potential transients). In order to overcome this limitation, two-dimensional acousto-optic deflection was employed, to allow an ultrafast laser beam suited for multiphoton excitation to be rapidly repositioned with low latency (˜15mus). This supports a random-access scanning mode in which the beam can repeatedly visit a succession of user-selected sites of interest within the microscope's field-of-view at high rates, with minimal sacrifice of pixel dwell time. This technique of acousto-optic multiphoton laser scanning microscope (AO-MPLSM) was demonstrated to allow the spatial profile of signals arising in response to physiological stimulation to be rapidly mapped. Means to compensate or avoid problems of dispersion which have hampered AO-MPLSM in the past are presented, with the latter being implemented. Separately, the combination of photon counting detection with multiphoton excitation, termed generally multiphoton photon counting spectroscopy (MP-PCS), was also considered, with particular emphasis on the technique of fluorescence correlation spectroscopy (FCS). MP-PCS was shown to allow information about molecular

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

    PubMed

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-06-01

    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. 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.

  14. Wet/dry film thickness measurement of paint by absorption spectroscopy with acousto-optic tunable filter spectrometer

    NASA Astrophysics Data System (ADS)

    Sinha, Pranay G.; Xiong, Xiangchun; Jin, Feng; Trivedi, Sudhir; Prasad, Narashima S.

    2005-08-01

    Controlling/monitoring the thickness of applied paint in real time is important to many situations including painting ship and submarine hulls in dry docks for maintaining health of ships and submarines against the harshness of the sea, in automobile and aerospace industries, and in a variety of other industries as a control sensor that plays significant role in product quality, process control, and cost control. Insufficient thickness results to inadequate protection while overspray leads to waste and pollution of the environment. A rugged instrumentation for the real time non-contact accurate measurement of wet and dry paint film thickness measurement will be immensely valuable. As paint is applied with several layers of the same or different type, thickness of each newly sprayed wet layer is of most interest, but measurement on dry paint is also useful. In this study, we use acousto-optic tunable filter-based near infrared spectrometer to obtain the absorption spectrum of layers of paint sprayed on sand blasted steel surface and thus measure the thickness of coating under both wet and dry situations. NIR spectra are obtained from 1100 to 2300 nm on four sample of different thickness of paint up to 127 micron. Partial least squares model built with the spectra shows good correlation with standard error of prediction within ~ 0.7 micron. Results indicate that the spectra also respond to the amount of organic solvent in the wet paint and can be used to monitor the degree of dryness of the paint in real time.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    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.

  16. Novel time-of-flight fiber dispersion measurement technique using supercontinuum light sources and acousto-optical tunable filters.

    PubMed

    Blume, Niels Göran; Wagner, Steven

    2015-07-20

    Long-distance fiber links require precise knowledge of fiber dispersion characteristics. Similar dispersion characteristics are necessary for supercontinuum broadband laser absorption spectroscopy (SCLAS) to allow proper data evaluation and species concentration determination, as well as numerous other applications. In this work, a time-of-flight approach to measuring the dispersion characteristic of fibers with supercontinuum laser light sources (SCLs) and acousto-optical tunable filters (AOTFs) is presented. Broadband emission of the SCL is filtered with a narrowband AOTF and dispersed in time by the fiber under test. By using the wavelength-specific delay, the dispersion characteristic can be calculated. The technique is especially suited for longer fibers and was verified against a state-of-the-art phase-shift-based dispersion measurement system. Advantages of the new approach include solely utilizing SCLAS system components, as well as a high level of automation and wide spectral coverage, ranging from 1100 to 1700 nm in a single measurement setup.

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

    PubMed

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

    2017-01-05

    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.

  18. Application of the acousto-optic effect to pressure measurements in ultrasound fields in water using a laser vibrometer

    NASA Astrophysics Data System (ADS)

    Buick, J. M.; Cosgrove, J. A.; Douissard, P.-A.; Greated, C. A.; Gilabert, B.

    2004-10-01

    A non-intrusive measuring technique, applied to sensing and measuring acoustic waves at ultrasonic frequencies is considered. The method is optically based and so does not interfere with the ultrasound field. The measurement procedure relies on the acousto-optic effect, that is the change in refractive index which occurs with changing pressure in the ultrasound field. This change in refractive index is detected through the change in the path length of a laser beam propagating through the region of interest. Typically these changes are small corresponding to a physical change of the order of 10-6 m. Fourier analysis is used to separate the component of the signal corresponding to the pressure variation from background noise and vibrations which can be dominant. Application of the technique is illustrated for an underwater ultrasound transducer. Measurements are made using the optical technique and compared to measurements taken with a hydrophone. The effectiveness of the optical measuring technique is discussed. It is shown that the laser vibrometer produces a good estimation of the mean beam pressure provided an estimation of the beam width is available, a restriction which is often satisfied; and the acoustic field can be assumed to be approximately constant across the beam.

  19. 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

  20. Research Cooperation between Catholic Universityof Leuven Campus Kortrijk and University of Gdansk in Acousto-optics - A Historical Recollection1

    NASA Astrophysics Data System (ADS)

    Śliwiński, A.

    A short review of results achieved during many years of cooperation between the Belgian group of KULAK and the Polish group of Gdansk University (UG) is presented as a tribute to Oswald Leroy for his significant contribution. The scientific research in examination of ultrasonic light interaction phenomena was the area of this fruitful joint collaboration since 1971. Oswald Leroy's crucial role in the cooperation is emphasized and some historical events are recalled. His original theoretical papers predicted new theoretical phenomena which were successfully experimentally verified in the A. O. laboratory at the University of Gdansk. Later on, they have become inspiration for further fundamental search in acousto-optics. Members of Gdansk AO group many times visited Kortrijk to work together on ULD phenomena or attending seminars and symposia organized in Belgium and the Belgian group took part in the international Spring Schools and Applications systematically organized by Gdansk University as the triennial meetings since 1980. Leroy's contribution to the mutual co-operation has been recognized as so important and significant that in 1991 he was honored with the Doctorate Honoris Causa of the University of Gdansk.

  1. Acousto-optic mode coupling excited by flexural waves in simplified hollow-core photonic crystal fibers

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Qiu, Minghui; Wu, Zhifang; Dong, Hongguang; Liu, Bo; Miao, Yinping

    2013-05-01

    We have demonstrated the formation of an acoustic grating in a simplified hollow-core photonic crystal fiber, which consists of a hollow hexagonal core and six crown-like air holes, by applying flexural acoustic waves along the fiber axis. The dependence of the resonance wavelength on the applied acoustic frequency has been acquired on the basis of the theoretical calculation of the phase matching curve; it is in good agreement with our experimental observation of the transmission spectral evolution as the applied acoustic frequency varies. Experimental results show that the acoustic grating resonance peak possesses acoustic frequency and strain dependences of 728 nm MHz-1 and -6.98 pm μɛ-1, respectively, based on which high-performance acousto-optic tunable filters and fiber-optic strain sensors with high sensitivity could be achieved. And furthermore, the research work presented in this paper indicates that microbending rather than physical deformation is the main physical mechanism that leads to the formation of equivalent long-period gratings, which would be of significance for developing related grating devices based on simplified hollow-core photonic crystal fibers.

  2. Narrow linewidth broadband tunable semiconductor laser at 840 nm with dual acousto-optic tunable configuration for OCT applications

    NASA Astrophysics Data System (ADS)

    Chamorovskiy, Alexander; Shramenko, Mikhail V.; Lobintsov, Andrei A.; Yakubovich, Sergei D.

    2016-03-01

    We demonstrate a tunable narrow linewidth semiconductor laser for the 840 nm spectral range. The laser has a linear cavity comprised of polarization maintaining (PM) fiber. A broadband semiconductor optical amplifier (SOA) in in-line fiber-coupled configuration acts as a gain element. It is based on InGaAs quantum-well (QW) active layer. SOA allows for tuning bandwidth exceeding 25 nm around 840 nm. Small-signal fiber-to-fiber gain of SOA is around 30 dB. A pair of acousto-optic tunable filters (AOTF) with a quasi-collinear interaction of optical and acoustic waves are utilized as spectrally selective elements. AOTF technology benefits in continuous tuning, broadband operation, excellent reproducibility and stability of the signal, as well as a high accuracy of wavelength selectivity due to the absence of mechanically moving components. A single AOTF configuration has typical linewidth in 0.05-0.15 nm range due to a frequency shift obtained during each roundtrip. A sequential AOTF arrangement enables instantaneous linewidth generation of <0.01 nm by compensating for this shift. Linewidth as narrow as 0.0036 nm is observed at 846 nm wavelength using a scanning Fabry-Perot interferometer with 50 MHz spectral resolution. Output power is in the range of 1 mW. While the majority of commercial tunable sources operate in 1060-1550 nm spectral ranges, the 840 nm spectral range is beneficial for optical coherence tomography (OCT). The developed narrow linewidth laser can be relevant for OCT with extended imaging depth, as well as spectroscopy, non-destructive testing and other applications.

  3. Time-resolved acousto-optic interaction in single-mode optical fibers: characterization of axial nonuniformities at the nanometer scale.

    PubMed

    Alcusa-Sáez, E P; Díez, A; González-Herráez, M; Andrés, M V

    2014-03-15

    We report on a time-resolved acousto-optic interaction technique for the detection of axial nonuniformities in single-mode fibers. It is based on the propagation of short packets of flexural acoustic waves. Small axial nonuniformities (of the order of nanometers) are detected by measuring the transmittance of the fundamental mode as a function of time. It is shown that the technique allows the detection of axial nonuniformities along sections of single-mode fiber exceeding 1 m long with spatial resolution of the order of a few centimeters.

  4. Efficient diode end-pumped acousto-optically Q-switched Nd:YAG/BaTeMo2O9 Raman laser.

    PubMed

    Bai, Fen; Wang, Qingpu; Jiao, Zhiyong; Xu, Xianfeng; Zhang, Hui; Tao, Xutang

    2016-11-10

    BaTeMo2O9 (BTM) is employed to achieve efficient stimulated Raman scattering conversion in a diode end-pumped acousto-optically Q-switched Nd:YAG laser. With an incident diode power of 8.6 W, 732 mW of 1179 nm first-Stokes average output power was generated at a pulse repetition rate of 10 kHz, corresponding to a diode-to-Raman conversion efficiency of 8.5%.

  5. LD end-pumped acousto-optic Q-switched 1319 nm/1338 nm dual-wavelength Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Wu, C. T.; Yu, M.; Wang, C.; Yu, K.; Yu, Y. J.; Chen, X. Y.; Jin, G. Y.

    2016-10-01

    Laser characteristics of acousto-optic Q-switched operation of 1319 nm/1338 nm dual-wavelength composite Nd:YAG laser were studied. Maximum output power of 5.77 W was achieved in CW operation. Under Q-switched operation, the maximum peak power of 3.96 kW and minimum pulse width of 65.6 ns was obtained at repetition frequency of 20 kHz with the duty ratio of 96%. The influence of the duration of the ultrasonic field acted on the Q-switch to the output characteristics of dual-wavelength composite Nd:YAG laser had been reported first time.

  6. Combination of a 2-D acousto-optic deflector with laser amplifier for efficient scanning of a Q-switched ND:YAG laser

    NASA Astrophysics Data System (ADS)

    Maák, P.; Jakab, L.; Richter, P. I.; Brignon, A.; Huignard, J.-P.

    2000-03-01

    A two-dimensional acousto-optic deflector has been combined with a large angular acceptance, laser diode-pumped Nd:YAG optical amplifier in order to obtain a scanning system with high angular resolution and with high and uniform optical transmission. Experiments have been carried out in order to optimize the set-up for intensity distribution and optical losses. The combination of newly developed nonlinear and active optical elements provides a relatively uniform intensity distribution over the scanned region corresponding to 300×300 discrete points in the back focal plane of a Fourier lens, at laser pulse energy levels of 1-5 mJ.

  7. A new high efficiency InP acousto-optic device for IR wavelengths

    NASA Astrophysics Data System (ADS)

    Soos, Jolanta I.; Rosemeier, Ronald G.; Rosenbaum, Joel

    1990-09-01

    InP acoustooptic Bragg cells which are IR-transparent in the 1-10 micron bandpass have a center frequency in the 200-600 MHz range, and a diffraction efficiency of 40-60 percent, on the basis of 1-W RF driving power. These devices are anticipated to be ideal in such applications as fiber-optic modulators, IR scanners, deflectors, and HF mode-lockers. In the course of fabrication, the photoelastic constant p44 has been defined; using other crystallographic configurations, such photoelastic constants as p11 and p12 are expected to emerge.

  8. Millimeter-resolution acousto-optic quantitative imaging in a tissue model system

    NASA Astrophysics Data System (ADS)

    Bratchenia, Aliaksandr; Molenaar, Robert; van Leewen, Ton; Kooyman, Rob P. H.

    2009-05-01

    We have investigated the application of ultrasound modulated coherent light for quantitative determination of the ratio of dye concentrations and total concentration of absorbers in a blood vessel-mimicking sample. A 3-mm-diam tube containing the mixture of dyes inside an Intralipid-based gel with optical properties similar to tissue was interrogated by two different laser wavelengths in combination with intense microsecond ultrasound bursts. The use of calibration curves allowed us to extract quantitative information on the ratio of dye concentrations with the accuracy of better than 15%, as well as on the total concentration. Furthermore, we demonstrated the feasibility to obtain a quantitative 3-D map of the absorbing structure with a spatial resolution of better than 3 mm. These findings give an outlook to apply this technique for noninvasive 3-D mapping of oxygen saturation and total concentration of hemoglobin in tissue.

  9. 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

  10. Applications of Optical Coherent Transient Technology to Pulse Shaping, Spectral Filtering Arbitrary Waveform Generation and RF Beamforming

    DTIC Science & Technology

    2006-04-14

    for creating fast (~MHz/µs) linear frequency chirped optical pulses: (1) using acousto - optic modulators (AOMs) driven with a chirped RF source, ( 2 ...the cavity. The frequencies allowed in a Fabry–Perot cavity are: where =1,2,... and optical path length of cavity 2 qcv q d d = = (29) The...the functional operation of acousto - optic (AO) deflectors , but with bandwidths (BW) in excess of 10 GHz and Time-Bandwidth Prod- ucts (TB) over 103 by

  11. Numerical Analysis of the Crosstalk on an Integrated Acousto-Optic Tunable Filter (AOTF) for Network Applications

    NASA Astrophysics Data System (ADS)

    Sobrinho, C. S.; de Oliveira, M. V. N.; Silva, M. G. Da; Lima, J. L. S.; de Almeida, E. F.; Sombra, A. S. B.

    In this article, we did a study of the crosstalk level (Xtalk) and extinction ratio (Xratio) of an acousto-optic tunable filter (AOTF) operating with ultra-short light pulses (2 ps). It is clear that the transmission bandwidth decreases as the length of the device increases. The compression factor was studied for the switched pulse in an AOTF without loss considering five nonlinearity profiles. One can observe that there is always an optimum value for β (final value of the nonlinearity) that one can obtain a switched pulse with the same time duration of the input pulse. The study of the crosstalk level, of this device, considering the optimum values of β obtained from the compression studies, as a function of the pump power (P0) was done. For the soliton profile at 1 W of pump power one can notice that the Gaussian profile presents the lower Xtalk value (-13 dB), and the constant profile presents the worst value (-9.8 dB). However, if one is looking for a specific Xtalk value, one can conclude that with the constant profile one can obtain this value with a lower power. For the quasi-soliton profile of the same device, with low pump power (1 W), one can notice again that the Gaussian profile presents the lower Xtalk value (-13 dB) and the constant profile presents the worst value (-9.87 dB). This fact can be explained because, with pump power at 1 W, soliton and quasi-soliton profiles lead equivalent input pulses and under the same conditions produce equal results. The Xtalk level, considering all the profiles as a function of the β value, was studied. For all the profiles one has a strong increase of the Xtalk level with the increase of the final β value of the nonlinearity profile. Comparing all the profiles one can conclude that the Gaussian profile presents the lower Xtalk value in the range of β values in use. At the same time the value of the Xtalk for this profile does not change much with the change in the β value, presenting values in interval (-13 d

  12. Compact interrogator for fiber optic Bragg sensors based on an acousto-optic filter formed by photonic crystal rows of air holes.

    PubMed

    Tsarev, Andrei V; De Leonardis, Francesco; Passaro, Vittorio M N

    2011-10-01

    Fiber optic sensors are typically used with expensive tunable lasers or optical spectrum analyzers for wavelength interrogation. We propose to replace the tunable laser by a broadband optical source incorporated with a novel thin linewidth acousto-optic tunable filter. It utilizes optical beam expanders constituted by photonic crystal rows of air holes in LiNbO(3) waveguide. A new design is numerically studied for a short structure (with 32 photonic crystal rows) by a two-dimensional finite-difference time-domain method. Extrapolation of these results to larger structure sizes (about 1 cm) demonstrates the possibility to develop compact interrogators with 0.4 pm wavelength resolution and 40 nm tunable range around 1550 nm.

  13. Two wavelength operation of an acousto-optically tuned quantum cascade laser and direct measurements of quantum cascade laser level lifetimes

    NASA Astrophysics Data System (ADS)

    Patel, C. Kumar N.; Barron-Jimenez, Rodolfo; Dunayevskiy, Ilya; Tsvid, Gene; Lyakh, Arkadiy

    2017-01-01

    We report simultaneous two wavelength operation of an acousto-optically tuned quantum cascade laser (QCL). The two wavelengths can be independently tuned as well as independently switched, retaining the submicrosecond switching capability. In addition, we have used the two wavelength operation as a tool for the direct measure of the lifetimes of the lasing states in a practical QCL. The lifetime measurements in an operational QCL are facilitated by our ability to vary the frequency separation between two simultaneously lasing wavelengths. The measured lifetime is 0.6 ps ± 0.2 ps for our quantum cascade laser. The two wavelength operation of QCLs paves the way for time resolved pump/probe studies of infrared phenomena and provides direct insight into the effectiveness of various QCL structure designs.

  14. 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.

  15. Analysis of the frequency response of a TeO{sub 2} slow shear wave acousto-optic cell exposed to radiation

    SciTech Connect

    Erteza, I.A.

    1995-04-01

    Radiation testing of photonic components is not new, however component level testing to date has not completely addressed quantities which are important to system behavior. One characteristic that is of particular importance for optical processing systems is the frequency response. In this report, we present the analysis of data from an experiment designed to provide a preliminary understanding of the effects of radiation on the frequency response of acousto-optic devices. The goal of the analysis is to describe possible physical mechanisms responsible for the radiation effects and to discuss the effects on signal processing functionality. The experiment discussed in this report was designed by Sandia National Laboratories and performed by Sandia and Phillips Laboratory personnel at White Sands Missile Range (WSMR). In the experiment, a TeO{sub 2} slow shear wave acousto-optic cell was exposed to radiation from the WSMR linear accelerator. The TeO{sub 2} cell was placed in an experimental configuration which allowed swept frequency diffracted power measurements to be taken during radiation exposure and recovery. A series of exposures was performed. Each exposure consisted of between 1 to 800, 1{mu}sec radiation pulses (yielding exposures of 2.25 kRad(Si) to 913 kRad(Si)), followed by recovery time. At low total and cumulative doses, the bandshape of the frequency response (i.e. diffracted power vs. frequency) remained almost identical during and after radiation. At the higher exposures, however, the amplitude and width of the frequency response changed as the radiation continued, but returned to the original shape slowly after the radiation stopped and recovery proceeded. It is interesting to note that the location of the Bragg degeneracy does not change significantly with radiation. In this report, we discuss these effects from the perspective of anisotropic Bragg diffraction and momentum mismatch, and we discuss the effect on the signal processing functionality.

  16. Doppler-free, multiwavelength acousto-optic deflector for two-photon addressing arrays of Rb atoms in a quantum information processor

    NASA Astrophysics Data System (ADS)

    Kim, Sangtaek; McLeod, Robert R.; Saffman, M.; Wagner, Kelvin H.

    2008-04-01

    We demonstrate a dual wavelength acousto-optic deflector (AOD) designed to deflect two wavelengths to the same angles by driving with two RF frequencies. The AOD is designed as a beam scanner to address two-photon transitions in a two-dimensional array of trapped neutral Rb87 atoms in a quantum computer. Momentum space is used to design AODs that have the same diffraction angles for two wavelengths (780 and 480 nm) and have nonoverlapping Bragg-matched frequency response at these wavelengths, so that there will be no cross talk when proportional frequencies are applied to diffract the two wavelengths. The appropriate crystal orientation, crystal shape, transducer size, and transducer height are determined for an AOD made with a tellurium dioxide crystal (TeO2). The designed and fabricated AOD has more than 100 resolvable spots, widely separated band shapes for the two wavelengths within an overall octave bandwidth, spatially overlapping diffraction angles for both wavelengths (780 and 480 nm), and a 4 μs or less access time. Cascaded AODs in which the first device upshifts and the second downshifts allow Doppler-free scanning as required for addressing the narrow atomic resonance without detuning. We experimentally show the diffraction-limited Doppler-free scanning performance and spatial resolution of the designed AOD.

  17. Quantitative analysis of anaerobic oxidation of methane (AOM) in marine sediments: A modeling perspective

    NASA Astrophysics Data System (ADS)

    Regnier, P.; Dale, A. W.; Arndt, S.; LaRowe, D. E.; Mogollón, J.; Van Cappellen, P.

    2011-05-01

    Recent developments in the quantitative modeling of methane dynamics and anaerobic oxidation of methane (AOM) in marine sediments are critically reviewed. The first part of the review begins with a comparison of alternative kinetic models for AOM. The roles of bioenergetic limitations, intermediate compounds and biomass growth are highlighted. Next, the key transport mechanisms in multi-phase sedimentary environments affecting AOM and methane fluxes are briefly treated, while attention is also given to additional controls on methane and sulfate turnover, including organic matter mineralization, sulfur cycling and methane phase transitions. In the second part of the review, the structure, forcing functions and parameterization of published models of AOM in sediments are analyzed. The six-orders-of-magnitude range in rate constants reported for the widely used bimolecular rate law for AOM emphasizes the limited transferability of this simple kinetic model and, hence, the need for more comprehensive descriptions of the AOM reaction system. The derivation and implementation of more complete reaction models, however, are limited by the availability of observational data. In this context, we attempt to rank the relative benefits of potential experimental measurements that should help to better constrain AOM models. The last part of the review presents a compilation of reported depth-integrated AOM rates (ΣAOM). These rates reveal the extreme variability of ΣAOM in marine sediments. The model results are further used to derive quantitative relationships between ΣAOM and the magnitude of externally impressed fluid flow, as well as between ΣAOM and the depth of the sulfate-methane transition zone (SMTZ). This review contributes to an improved understanding of the global significance of the AOM process, and helps identify outstanding questions and future directions in the modeling of methane cycling and AOM in marine sediments.

  18. A Full-Color, High-Resolution Laser Projector for a Flight Simulator Visual Display

    DTIC Science & Technology

    1993-08-01

    Acousto - optic deflectors work in a similar manner as the acousto - optic modulator. The difference is...that acousto - optic deflectors vary acoustic drive frequency to deflect the beam where the acousto - optic modulator varies acoustic drive amplitude to... acousto - optic modulators, deflectors , and high-speed polygon mirror scanners, cost-effective laser projection can be attained. These new

  19. Modeling of power spectral density of modified von Karman atmospheric phase turbulence and acousto-optic chaos using scattered intensity profiles over discrete time intervals

    NASA Astrophysics Data System (ADS)

    Chatterjee, Monish R.; Mohamed, Fathi H. A.

    2014-10-01

    In recent research, propagation of plane electromagnetic (EM) waves through a turbulent medium with modified von Karman phase characteristics was modeled and numerically simulated using transverse planar apertures representing narrow phase turbulence along the propagation path. The case for extended turbulence was also studied by repeating the planar phase screens multiple times over the propagation path and incorporating diffractive effects via a split-step algorithm. The goal of the research reported here is to examine two random phenomena: (a) atmospheric turbulence due to von Karman-type phase fluctuations, and (b) chaos generated in an acousto-optic (A-O) Bragg cell under hybrid feedback. The latter problem has been thoroughly examined for its nonlinear dynamics and applications in secure communications. However, the statistical characteristics (such as the power spectral density (PSD)) of the chaos have not been estimated in recent work. To that end, treating the chaos phenomena as a random process, the time waveforms of the chaos intensity and their spectra are numerically evaluated over a (large) number of time iterations. These spectra are then averaged to derive the equivalent PSD of the A-O chaos. For the turbulence problem, an optical beam passing through an input pinhole is propagated through a random phase screen (placed at different locations) to a desired distance (typically near-field) under different levels of turbulence strength. The resulting spatial intensity profile is then averaged and the process repeated over a (large) number of pre-specified time intervals. From this data, once again, the turbulence PSD is calculated via the Fourier spectra of the average intensity snapshots. The results for the two systems are compared.

  20. 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

    SciTech Connect

    Rosenfield, J.R.; La Riviere, P.J.; Sandhu, J.S.

    2014-06-15

    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 by 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 the

  1. Mucin-depleted foci (MDF) in the colon of rats treated with azoxymethane (AOM) are useful biomarkers for colon carcinogenesis.

    PubMed

    Femia, Angelo Pietro; Dolara, Piero; Caderni, Giovanna

    2004-02-01

    Crypt foci with absent or scant mucous production (mucin-depleted foci, MDF) were recently described by our group in the colon of azoxymethane (AOM)-treated rats. Since MDF are dysplastic and easy to quantify, we think that MDF are pre-neoplastic lesions that could be used as biomarkers for carcinogenesis. To test this hypothesis, we studied MDF in azoxymethane (AOM)-initiated rats treated with cholic acid (CHA), a promoter of colon carcinogenesis or with piroxicam (PXC), a colon cancer-inhibiting drug. Aberrant crypt foci (ACF) were determined as well. F344 male rats were treated with AOM (15 mg/kg x 2, s.c.) and then divided into: controls, which were fed AIN76 diet; CHA group, which was fed AIN76 diet containing CHA 0.5% w/w; PXC group, which was fed AIN76 diet containing PXC 0.02% w/w. Ten weeks after the first dose of AOM, the total number of MDF was significantly increased in rats treated with CHA (P<0.05) and drastically reduced (P<0.01) in rats treated with PXC (MDF/colon were 6.10 +/- 1.26, 10.59 +/- 1.96 and 1.31 +/- 0.21 in controls, CHA and PXC groups, respectively, means +/- SE). The multiplicity of MDF was also increased in CHA-treated rats. On the contrary, ACF multiplicity was significantly decreased by CHA. In PXC-treated rats there were fewer ACF with lower multiplicity. The effect of PXC was also investigated 15 weeks after the first AOM dose and the results showed that the total number of MDF in the PXC group was significantly lower than in controls. The number of 'large' MDF, formed by 12 or more crypts, was also reduced (P<0.01) by PXC ('large' MDF were 1.7 +/- 0.5 and 0.4 +/- 0.2 in control and PXC groups, respectively). Since CHA promotes and PXC reduces colon cancer, MDF are correlated with carcinogenesis and can be proposed as endpoints to study the modulation of colon carcinogenesis in short-term experiments.

  2. Specific directions of ultrasound propagation in double potassium tungstates for light modulation.

    PubMed

    Mazur, M M; Mazur, L I; Pozhar, V E

    2017-01-01

    Acousto-optical characteristics of double potassium tungstates are analyzed and specific directions for light modulation are found. First, an important subgroup of elasto-optic coefficients of KYb(WO4)2 and KLu(WO4)2 crystals are calculated with use of experimental data. It is revealed that with proper choice of ultrasound direction the acousto-optical figure-of-merit approximately 2 times exceeds the maximum value detected in previous experiments. Another unique direction is determined, which permits modulation of randomly polarized light. The elasto-optic characteristics of KYb(WO4)2 and KLu(WO4)2 crystals are compared to those of previously investigated materials of the same crystal group: KY(WO4)2, KGd(WO4)2.

  3. Continuous wave operation of quantum cascade lasers with frequency-shifted feedback

    SciTech Connect

    Lyakh, A.; Barron-Jimenez, R.; Dunayevskiy, I.; Go, R.; Tsvid, G.; Patel, C. Kumar N.

    2016-01-15

    Operation of continuous wave quantum cascade lasers with a frequency-shifted feedback provided by an acousto-optic modulator is reported. Measured linewidth of 1.7 cm{sup −1} for these devices, under CW operating conditions, was in a good agreement with predictions of a model based on frequency-shifted feedback seeded by spontaneous emission. Linewidth broadening was observed for short sweep times, consistent with sound wave grating period variation across the illuminated area on the acousto-optic modulator. Standoff detection capability of the AOM-based QCL setup was demonstrated for several solid materials.

  4. 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.

  5. Compact high-resolution spaceborne echelle grating spectrometer with acousto-optical tunable filter based order sorting for the infrared domain from 2.2 to 4.3 microm.

    PubMed

    Nevejans, Dennis; Neefs, Eddy; Van Ransbeeck, Emiel; Berkenbosch, Sophie; Clairquin, Roland; De Vos, Lieve; Moelans, Wouter; Glorieux, Stijn; Baeke, Ann; Korablev, Oleg; Vinogradov, Imant; Kalinnikov, Yuri; Bach, Benny; Dubois, Jean-Pierre; Villard, Eric

    2006-07-20

    A new compact spaceborne high-resolution spectrometer developed for the European Space Agency's Venus Express spacecraft is described. It operates in the IR wavelength range of 2.2 to 4.3 microm and measures absorption spectra of minor constituents in the Venusian atmosphere. It uses a novel echelle grating with a groove density of 4 lines/mm in a Littrow configuration in combination with an IR acousto-optic tunable filter for order sorting and an actively cooled HgCdTe focal plane array of 256 by 320 pixels. It is designed to obtain an instrument line profile of 0.2 cm(-1). First results on optical and spectral properties are reported.

  6. Effect of algogenic organic matter (AOM) and sodium chloride on Nannochloropsis salina flocculation efficiency.

    PubMed

    Garzon-Sanabria, Andrea J; Ramirez-Caballero, Silvia S; Moss, Francesca E P; Nikolov, Zivko L

    2013-09-01

    This study evaluates the effect of polymer molecular weight and charge density, algogenic organic matter (AOM), and salt concentration on harvesting efficiency of marine microalgae. Aluminum chloride (AlCl3), chitosan, and five synthetic cationic polymers of different molecular weights and charge density levels were used as flocculation agents. Polymer flocculation of marine microalgae was most efficient when using the highest charge density polymer (FO4990). The flocculant dosage irrespectively of the agent chemistry and charge density was affected by the amount of AOM secreted into the culture media. The presence of AOM increased the amount of required flocculant 7-fold when using synthetic cationic polymers; 10-fold with chitosan; and ~3-fold with AlCl3. Salt concentration of 5 or 35 g/L NaCl alone did not significantly affect removal efficiency, indicating that AOM were the main cause for the increased flocculant dosage requirement. The synthetic cationic polymer (FO4990) was the least expensive flocculation agent.

  7. Widefield heterodyne interferometry using a custom CMOS modulated light camera.

    PubMed

    Patel, Rikesh; Achamfuo-Yeboah, Samuel; Light, Roger; Clark, Matt

    2011-11-21

    In this paper a method of taking widefield heterodyne interferograms using a prototype modulated light camera is described. This custom CMOS modulated light camera (MLC) uses analogue quadrature demodulation at each pixel to output the phase and amplitude of the modulated light as DC voltages. The heterodyne interference fringe patterns are generated using an acousto-optical frequency shifter (AOFS) in an arm of a Mach-Zehnder interferometer. Widefield images of fringe patterns acquired using the prototype MLC are presented. The phase can be measured to an accuracy of ±6.6°. The added value of this method to acquire widefield images are discussed along with the advantages.

  8. Broadband optical modulators based on graphene supercapacitors.

    PubMed

    Polat, Emre O; Kocabas, Coskun

    2013-01-01

    Optical modulators are commonly used in communication and information technology to control intensity, phase, or polarization of light. Electro-optic, electroabsorption, and acousto-optic modulators based on semiconductors and compound semiconductors have been used to control the intensity of light. Because of gate tunable optical properties, graphene introduces new potentials for optical modulators. The operation wavelength of graphene-based modulators, however, is limited to infrared wavelengths due to inefficient gating schemes. Here, we report a broadband optical modulator based on graphene supercapacitors formed by graphene electrodes and electrolyte medium. The transparent supercapacitor structure allows us to modulate optical transmission over a broad range of wavelengths from 450 nm to 2 μm under ambient conditions. We also provide various device geometries including multilayer graphene electrodes and reflection type device geometries that provide modulation of 35%. The graphene supercapacitor structure together with the high-modulation efficiency can enable various active devices ranging from plasmonics to optoelectronics.

  9. Simulation of the advective methane transport and AOM in Shenhu area, the Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Liu, L.; Wu, N.

    2012-04-01

    Anaerobic Oxidation of Methane (AOM) occurs in the transition zone between the presence of sulfate and methane. This reaction is an important process for methane and the global carbon cycle. Methane gas hydrates bearing sediments were recovered in Shenhu Area, the Northern South China Sea, and methane advective transport was detected in this area as well. A one dimension numerical simulation tool was implemented to study the AOM process combined with the advective methane transport in Shenhu Area according to the local drilling data and geochemical information. The modeled results suggest that local methane flux will be consumed in the sediment column via dissolution, sorption and AOM reaction. A portion of methane will enter water column and possibly atmosphere if the methane flux was one order of magnitude higher than current level. Furthermore, the calculated rates of AOM in Shenhu area range similar to that of gas hydrate mounds in Mexico Golf. However, AOM is ability to consume more methane than that in Golf of Mexico due to the lower permeable sediment associated with a deeper sulfate methane transition layer.

  10. A process to control light in a micro resonator through a coupling modulation by surface acoustic waves

    PubMed Central

    Fan, Guofang; Li, Yuan; Hu, Chunguang; Lei, Lihua; Guo, Yanchuan

    2016-01-01

    A novel process to control light through the coupling modulation by surface acoustic wave (SAW) is presented in an optical micro resonator. An optical waveguide modulator of a racetrack resonator on silicon-on-insulator (SOI) technology is took as an example to explore the mechanism. A finite-difference time-domain (FDTD) is developed to simulate the acousto-optical (AO) modulator using the mechanism. An analytical method is presented to verify our proposal. The results show that the process can work well as an optical modulator by SAW. PMID:27485470

  11. A process to control light in a micro resonator through a coupling modulation by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Fan, Guofang; Li, Yuan; Hu, Chunguang; Lei, Lihua; Guo, Yanchuan

    2016-08-01

    A novel process to control light through the coupling modulation by surface acoustic wave (SAW) is presented in an optical micro resonator. An optical waveguide modulator of a racetrack resonator on silicon-on-insulator (SOI) technology is took as an example to explore the mechanism. A finite-difference time-domain (FDTD) is developed to simulate the acousto-optical (AO) modulator using the mechanism. An analytical method is presented to verify our proposal. The results show that the process can work well as an optical modulator by SAW.

  12. High-power PPMgLN-based optical parametric oscillator pumped by a linearly polarized, semi-fiber-coupled acousto-optic Q-switched fiber master oscillator power amplifier.

    PubMed

    Chen, Tao; Jiang, Peipei; Yang, Dingzhong; Hu, Chengzhi; Wu, Bo; Shen, Yonghang

    2013-09-01

    We have experimentally demonstrated a periodically poled magnesium-oxide-doped lithium niobate (PPMgLN)-based, fiber-laser-pumped optical parametric oscillator (OPO) generating idler wavelength of 3.82 μm. The pump fiber laser was constructed with a linearly polarized, semi-fiber-coupled acousto-optic Q-switched fiber oscillator and a polarization-maintaining fiber amplifier with pulse duration of 190 ns at the highest output power. The OPO was specifically configured in single-pass, singly resonant linear cavity structure to avoid the damage risk of the pump fiber laser, which is always a serious issue in the fiber-laser-pumped, double-pass, singly oscillating structured OPOs. Under the highest pump power of 25 W, an idler average output power of 3.27 W with one-hour peak-to-peak instability of 5.2% was obtained. The measured M2 factors were 1.98 and 1.44 for horizontal and vertical axis, respectively. The high power stability and good beam quality demonstrated the suitability of such technology for practical application.

  13. Characterizing algogenic organic matter (AOM) and evaluating associated NF membrane fouling.

    PubMed

    Her, Namguk; Amy, Gary; Park, Hyoung-Ryun; Song, Myoungsuk

    2004-03-01

    Occasional algal blooms, comprised of blue-green algae and/or green algae, cause significant challenges in drinking water treatment due to the release of algogenic organic matter (AOM) into water extracellularly and, upon cell lysis, intracellularly. AOM has been extracted from blue-green algae (cyanobacteria) by various means and analyzed by UV absorbance scanning, HPSEC-UV-fluorescence-DOC, UV absorbance ratio index (URI), FTIR, and fluorescence excitation emission matrix (EEM). AOM extracted in water as a solvent exhibited a high hydrophilic fraction (57.3%) with a low SUVA (1.0 L/m-mg). The molecular weight (MW) distribution showed a significant heterogeneity (high value of polydispersivity) and high protein content (as indicated by specific fluorescence). Significant amounts of proteinaceous components such as mycosporine-like amino acids (MAAs, UV-screening components) and phycobilins (light-harvesting pigment) were detected by UV/visible absorption. The presence of proteins was confirmed by FTIR (at 1661 and 1552 cm(-1)), EEM spectra (EX:278-282 nm and EM:304-353 nm), and high URI values (3.1-6.0). A bench-scale cross-flow unit, employing a flat-sheet membrane specimen, was used to examine nanofiltration (NF) membrane fouling and removal of natural organic matter (NOM) derived from different blends of Suwannee River humic acid (SRHA) and AOM: SRHA 10 mgC/L, AOM 3mg C/L + SRHA 7 mgC/L, AOM 7 mgC/L + SRHA 3 mgC/L, and AOM 10 mgC/L. The study focused mainly on the effects of two different sources of organic matter on NF (NF 200) membrane fouling under otherwise similar conditions. Flux decline and organic matter rejection as a function of delivered DOC (cumulative mass of feed DOC per unit area) showed significantly different results depending on the organic matter composition of samples even though the test conditions were the same (organic matter concentration, pH, temperature, inorganic salt composition and concentration, and recovery). A higher flux decline

  14. Modeling Colitis-Associated Cancer with Azoxymethane (AOM) and Dextran Sulfate Sodium (DSS)

    PubMed Central

    Thaker, Ameet I.; Shaker, Anisa; Rao, M. Suprada; Ciorba, Matthew A.

    2012-01-01

    Individuals with inflammatory bowel disease (IBD), such as Crohn's disease (CD) or ulcerative colitis (UC) are at increased risk of developing colorectal cancer (CRC) over healthy individuals. This risk is proportional to the duration and extent of disease, with a cumulative incidence as high as 30% in individuals with longstanding UC with widespread colonic involvement.1 Colonic dysplasia in IBD and colitis associated cancer (CAC) are believed to develop as a result of repeated cycles of epithelial cell injury and repair while these cells are bathed in a chronic inflammatory cytokine milieu.2 While spontaneous and colitis-associated cancers share the quality of being adenocarcinomas, the sequence of underlying molecular events is believed to be different.3 This distinction argues the need for specific animal models of CAC. Several mouse models currently exist for the study of CAC. Dextran sulfate sodium (DSS), an agent with direct toxic effects on the colonic epithelium, can be administered in drinking water to mice in multiple cycles to create a chronic inflammatory state. With sufficient duration, some of these mice will develop tumors.4 Tumor development is hastened in this model if administered in a pro-carcinogenic setting. These include mice with genetic mutations in tumorigenesis pathways (APC, p53, Msh2), as well as mice pre-treated with genotoxic agents (azoxymethane [AOM], 1,2-dimethylhydrazine [DMH]).5 The combination of DSS with AOM as a model for colitis associated cancer has gained popularity for its reproducibility, potency, low price, and ease of use. Though they have a shared mechanism, AOM has been found to be more potent and stable in solution than DMH. While tumor development in other models generally requires several months, mice injected with AOM and subsequently treated with DSS develop adequate tumors in as little as 7-10 weeks.6, 7 Finally, AOM and DSS can be administered to mice of any genetic background (knock out, transgenic, etc

  15. Flavonoids Extracted from Licorice Prevents Colitis-Associated Carcinogenesis in AOM/DSS Mouse Model

    PubMed Central

    Huo, Xiaowei; Liu, Dongyu; Gao, Li; Li, Liyong; Cao, Li

    2016-01-01

    Inflammatory bowel disease (IBD) is generally considered as a major risk factor in the progression of colitis-associated carcinogenesis (CAC). Thus, it is well accepted that ameliorating inflammation creates a potential to achieve an inhibitory effect on CAC. Licorice flavonoids (LFs) possess strong anti-inflammatory activity, making it possible to investigate its pharmacologic role in suppressing CAC. The purpose of the present study was to evaluate the anti-tumor potential of LFs, and further explore the underlying mechanisms. Firstly, an azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced mouse model was established and administered with or without LFs for 10 weeks, and then the severity of CAC was examined macroscopically and histologically. Subsequently, the effects of LFs on expression of proteins associated with apoptosis and proliferation, levels of inflammatory cytokine, expression of phosphorylated-Janus kinases 2 (p-Jak2) and phosphorylated-signal transducer and activator of transcription 3 (p-Stat3), and activation of nuclear factor-κB (NFκB) and P53 were assessed. We found that LFs could significantly reduce tumorigenesis induced by AOM/DSS. Further study revealed that LFs treatment substantially reduced activation of NFκB and P53, and subsequently suppressed production of inflammatory cytokines and phosphorylation of Jak2 and Stat3 in AOM/DSS-induced mice. Taken together, LFs treatment alleviated AOM/DSS induced CAC via P53 and NFκB/IL-6/Jak2/Stat3 pathways, highlighting the potential of LFs in preventing CAC. PMID:27563884

  16. High power CO2 laser development with AOM integration for ultra high-speed pulses

    NASA Astrophysics Data System (ADS)

    Bohrer, Markus; Vaupel, Matthias; Nirnberger, Robert; Weinberger, Bernhard; Jamalieh, Murad

    2017-01-01

    There is a 500 billion USD world market for packaging expected to grow to a trillion in 2030. Austria plays an important role world wide for high speed laser engraving applications — especially when it comes to high end solutions. Such high end solutions are fundamental for the production of print forms for the packaging and decorating industry (e. g. cans). They are additionally used for security applications (e. g. for printing banknotes), for the textile printing industry and for creating embossing forms (e. g. for the production of dashboards in the automotive industry). High speed, high precision laser engraving needs laser resonators with very stable laser beams (400 - 800W) especially in combination with AOMs. Based upon a unique carbon fiber structure - stable within the sub-micrometer range - a new resonator has been developed, accompanied by most recent thermo-mechanical FEM calculations. The resulting beam is evaluated on an automated optical bench using hexapods, allowing to optimize the complete beam path with collimators and AOM. The major steps related to laser engraving of dry offset printing plates during the full workflow from the artists design to the printed result on an aluminum can is presented in this paper as well as laser characteristics, AOM integration and correlative CLSM and SEM investigation of the results.

  17. Continuous-wave phase-matched molecular optical modulator.

    PubMed

    Zaitsu, Shin-ichi; Izaki, Hirotomo; Tsuchiya, Takao; Imasaka, Totaro

    2016-02-18

    In optical modulation, the highest available modulation rate is basically limited to the GHz frequency range at best. This is because optical modulation is often performed using electro-optic or acousto-optic effects that require application of an external signal to solid-state nonlinear optical materials. Here we describe optical modulation of continuous-wave radiation at frequencies exceeding 10 THz based on ultrafast variation of molecule polarizability arising from coherent molecular motion. The optical modulation efficiency is extensively enhanced by fulfilling phase-matching conditions with the help of dispersion control of the optical cavity, generating sidebands with a highest ratio of 7.3 × 10(-3). These results will pave the way for development of versatile optical modulation-based techniques in a wide range of research fields in optical sciences, such as mode-locked lasers operating in the THz range.

  18. Evidence on Anaerobic Methane Oxidation (AOM) in a boreal cultivated peatland with natural and added electron acceptors

    NASA Astrophysics Data System (ADS)

    Dorodnikov, Maxim; Silvennoinen, Hanna; Martikainen, Pertti; Dörsch, Peter

    2015-04-01

    Anaerobic oxidation of methane (AOM) is a process of methane (CH4) consumption under anoxic conditions driven by microorganisms, which oxidize CH4 with various alternate electron acceptors (AEA): sulfate, nitrate, nitrite, metals-(Fe, Mn, Cu), organic compounds. AOM is common in marine ecosystems, where microbial sulfate reduction (SR) consumes most of the CH4 produced in sediments. Despite the global significance of AOM, the exact mechanisms and relevance of the process in terrestrial ecosystems are almost unknown. In the current study the occurrence of AOM was tested for two organic soil horizons (30 and 40 cm depth) and one mineral sub-soil (sand, 50 cm depth) of a cultivated boreal peatland (Linnansuo, Eastern Finland, energy crop Phalaris arundinacea - reed canarygrass) under controlled conditions with the addition of 13C-labeled CH4 and two common AEAs - SO4-2 and Fe+3. Concentrations of CH4, CO2 and O2 were continuously measured during 10 days of incubation and CO2 was sampled periodically under anaerobic conditions for stable 13C analysis. Oxygen dynamics revealed negligible O2 contamination during incubation and its trace amounts (0.05-0.8% from the atmospheric) were accounted in the net CH4 uptake. Application of 13C-enriched CH4 (4.9 atom%) allowed to track the label in CO2 as the end-product of AOM. The highest 13CO2 enrichment (up to 60‰) was observed in mineral sub-soil, however AOM was quantitatively more pronounced in the upper 30 cm horizon (2.1 vs. 0.2 μg CO2 g soil DW-1 in the 50 cm sub-soil). The highest AOM rate of 8.9 ng CO2 g soil DW-1 h-1 was estimated for the control treatment where no AEAs were added indicating sufficient amount of naturally available AEAs, likely organic compounds. This rate was 50 times more intensive (on the C basis) than the CH4 production potential of the same soil. In contrast, external AEAs decreased AOM rates but added Fe+3 stimulated decomposition of native SOM (as seen from the most depleted 13CO2 signatures

  19. Quantum interference of biphotons with a Doppler frequency shift

    NASA Astrophysics Data System (ADS)

    Lariontsev, E. G.

    2016-08-01

    We report a theoretical study of transformation of a biphoton state of light under Bragg diffraction on a travelling sound wave in an acousto-optic modulator (AOM). It is shown that the diffraction of AOM biphotons emitted during the collinear parametric scattering of light leads to a shift of the carrier frequency of a biphoton wave packet, which exceeds twice the Doppler frequency shift for the classical field. A method is proposed for measuring the Doppler frequency shift of a biphoton, which is based on interference between independent biphotons.

  20. Depth selective acousto-optic flow measurement

    PubMed Central

    Tsalach, Adi; Schiffer, Zeev; Ratner, Eliahu; Breskin, Ilan; Zeitak, Reuven; Shechter, Revital; Balberg, Michal

    2015-01-01

    Optical based methods for non-invasive measurement of regional blood flow tend to incorrectly assess cerebral blood flow, due to contribution of extra-cerebral tissues to the obtained signal. We demonstrate that spectral analysis of phase-coded light signals, tagged by specific ultrasound patterns, enables differentiation of flow patterns at different depths. Validation of the model is conducted by Monte Carlo simulation. In-vitro experiments demonstrate good agreement with the simulations' results and provide a solid validation to depth discrimination ability. These results suggest that signal contamination originating from extra-cerebral tissue may be eliminated using spectral analysis of ultrasonically tagged light. PMID:26713201

  1. Multiple acousto-optic q-switch

    DOEpatents

    Deason, Vance A.

    1993-01-01

    An improved dynamic moire interferometer comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event.

  2. Multiple acousto-optic q-switch

    DOEpatents

    Deason, Vance A.

    1993-12-07

    An improved dynamic moire interferometer comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event.

  3. Acousto-optic tunable filter imaging spectrometers

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Yu, Jeffrey; Reyes, George; Rider, David; Cheng, Li-Jen

    1991-01-01

    A remote sensing multispectral imaging instrument is being developed that uses a high resolution, fast programmable acoustooptic tunable filter (AOTF) as the spectral bandpass filter. A compact and fully computer controllable AOTF-based imaging spectrometer that operates in the visible wavelength range (0.5-0.8 microns) has been built and tested with success. A second imaging spectrometer operating in the near-infrared wavelength range (1.2-2.4 microns) is also under experimental investigation. The design criteria meeting various system issues, such as imaging quality, spectral response, and field of view (FOV), are discussed. An experiment using this AOTF imaging spectrometer breadboard is described.

  4. Dietary cholesterol promotes AOM-induced colorectal cancer through activating the NLRP3 inflammasome.

    PubMed

    Du, Qianming; Wang, Qing; Fan, Huimin; Wang, Jianing; Liu, Xiuting; Wang, Hong; Wang, Yajing; Hu, Rong

    2016-04-01

    Prolonged ingestion of a cholesterol-enriched diet induces chronic, auto-inflammatory responses resulting in significant health problems including colorectal cancer. Inflammasomes are thought to mediate intestinal homeostasis, and their dysregulation contributes to inflammatory bowel diseases and colitis-associated cancer (CAC). However, in vitro and in vivo information regarding the inflammation-inducing and tumor-promoting effect of cholesterol is lacking. Here we show that the cholesterol promoted colon carcinogenesis in azoxymethane (AOM)-treated mice through activating the NLRP3 inflammasome. High cholesterol diet (HCD) significantly increased inflammatory responses and tumor burden. Cholesterol crystals, detected in the colon of mice fed with HCD, also promoted NLRP3 inflammasome activation in macrophages, as indicated by elevated expression of cleaved caspase-1, formation of NLRP3-ASC-caspase-1 complex assembly, and higher IL-1β secretion. Importantly, cholesterol was found to inhibit the activity of AMPKα in macrophages, leading to a significant production of mitochondrial ROS, which in turn activated the NLRP3 inflammasome. Moreover, crystal uptake and cathepsin B accounted for cholesterol crystal-induced inactivation of AMPKα. Finally, HCD-induced increase in IL-1β secretion, macrophage infiltration and tumor burden was diminished by the deletion of NLRP3 in AOM-treated mice. Taken together, our findings demonstrate that the pro-inflammatory and cancer-promoting effects of HCD are mediated by the activation of NLRP3 inflammasome. Our study extended our knowledge on how dietary choices can influence processes involved in chronic inflammatory disorders and colorectal cancer.

  5. Space product development experiment module utilizing the ISS

    NASA Astrophysics Data System (ADS)

    Watson, Christine; Lundquist, Charles; Wessling, Francis; Smith, James; Naumann, Robert

    1999-01-01

    Furnace facilities for materials processing on the International Space Station (ISS) will include the Space Product Development Experiment Module (SPDEM) which includes a transparent Furnace module and an opaque Furnace Module. The SPDEM is scheduled currently for UF-3 aboard the Materials Science Research Rack(MSRR). Various commercial interests can be satisfied sequentially by scheduled employment of the SPDEM. The CMDS will be the facility manager through whom arrangements can be made for SPDEM access. The ISS should provide long growth periods which are needed to grow large single crystals in microgravity. A typical area of commercial interest is acousto-optic filters (AOTF) based on mercurous halide research which would continue on the ISS, research begun on the STS-77 mission. Another area of commercial interest planned for implementation on ISS is liquid metal sintering of composites to further improve techniques for making better quality materials.

  6. The AOM/DSS murine model for the study of colon carcinogenesis: From pathways to diagnosis and therapy studies

    PubMed Central

    Robertis, Mariangela De; Massi, Emanuela; Poeta, Maria Luana; Carotti, Simone; Morini, Sergio; Cecchetelli, Loredana; Signori, Emanuela; Fazio, Vito Michele

    2011-01-01

    Colorectal cancer (CRC) is a major health problem in industrialized countries. Although inflammation-linked carcinogenesis is a well accepted concept and is often observed within the gastrointestinal tract, the underlying mechanisms remain to be elucidated. Inflammation can indeed provide initiating and promoting stimuli and mediators, generating a tumour-prone microenvironment. Many murine models of sporadic and inflammation-related colon carcinogenesis have been developed in the last decade, including chemically induced CRC models, genetically engineered mouse models, and xenoplants. Among the chemically induced CRC models, the combination of a single hit of azoxymethane (AOM) with 1 week exposure to the inflammatory agent dextran sodium sulphate (DSS) in rodents has proven to dramatically shorten the latency time for induction of CRC and to rapidly recapitulate the aberrant crypt foci–adenoma–carcinoma sequence that occurs in human CRC. Because of its high reproducibility and potency, as well as the simple and affordable mode of application, the AOM/DSS has become an outstanding model for studying colon carcinogenesis and a powerful platform for chemopreventive intervention studies. In this article we highlight the histopathological and molecular features and describe the principal genetic and epigenetic alterations and inflammatory pathways involved in carcinogenesis in AOM/DSS–treated mice; we also present a general overview of recent experimental applications and preclinical testing of novel therapeutics in the AOM/DSS model. PMID:21483655

  7. Wideband laser locking to an atomic reference with modulation transfer spectroscopy.

    PubMed

    Negnevitsky, V; Turner, L D

    2013-02-11

    We demonstrate that conventional modulated spectroscopy apparatus, used for laser frequency stabilization in many atomic physics laboratories, can be enhanced to provide a wideband lock delivering deep suppression of frequency noise across the acoustic range. Using an acousto-optic modulator driven with an agile oscillator, we show that wideband frequency modulation of the pump laser in modulation transfer spectroscopy produces the unique single lock-point spectrum previously demonstrated with electro-optic phase modulation. We achieve a laser lock with 100 kHz feedback bandwidth, limited by our laser control electronics. This bandwidth is sufficient to reduce frequency noise by 30 dB across the acoustic range and narrows the imputed linewidth by a factor of five.

  8. Fourier domain low coherence interferometry for detection of early colorectal cancer development in the AOM rat model

    NASA Astrophysics Data System (ADS)

    Robles, Francisco E.; Zhu, Yizheng; Lee, Jin; Sharma, Sheela; Wax, Adam

    2011-03-01

    We present Fourier domain low coherence interferometry (fLCI) applied to the detection of preneoplastic changes in the colon using the ex-vivo azoxymethane (AOM) rat carcinogenesis model. fLCI measures depth resolved spectral oscillations, also known as local oscillations, resulting from coherent fields induced by the scattering of cell nuclei. The depth resolution of fLCI permits nuclear morphology measurements within thick tissues, making the technique sensitive to the earliest stages of precancerous development. To achieve depth resolved spectroscopic analysis, we use the dual window method, which obtains simultaneously high spectral and depth resolution and yields access to the local oscillations. The results show highly statistically significant differences between the AOM-treated and control group samples. Further, the results suggest that fLCI may be used to detect the field effect of carcinogenesis, in addition to identifying specific areas where more advanced neoplastic development has occurred.

  9. Weight loss following diet-induced obesity does not alter colon tumorigenesis in the AOM mouse model.

    PubMed

    Velázquez, Kandy T; Enos, Reilly T; Carson, Meredith S; Cranford, Taryn L; Bader, Jackie E; Chatzistamou, Ioulia; Singh, Udai P; Nagarkatti, Prakash S; Nagarkatti, Mitzi; Davis, J Mark; Carson, James A; Murphy, E Angela

    2016-10-01

    Obesity presents a significant public health concern given its association with increased cancer incidence, unfavorable prognosis, and metastasis. However, there is very little literature on the effects of weight loss, following obesity, on risk for colon cancer or liver cancer. Therefore, we sought to study whether intentional weight loss through diet manipulation was capable of mitigating colon and liver cancer in mice. We fed mice with a high-fat diet (HFD) comprised of 47% carbohydrates, 40% fat, and 13% protein for 20 wk to mimic human obesity. Subsequently, azoxymethane (AOM) was used to promote colon and liver carcinogenesis. A subset of obese mice was then switched to a low-fat diet (LFD) containing 67.5% carbohydrate, 12.2% fat, and 20% protein to promote intentional weight loss. Body weight loss and excess fat reduction did not protect mice from colon cancer progression and liver dysplastic lesion in the AOM-chemical-cancer model even though these mice had improved blood glucose and leptin levels. Intentional weight loss in AOM-treated mice actually produced histological changes that resemble dysplastic alterations in the liver and presented a higher percentage of F4/80(+)CD206(+) macrophages and activated T cells (CD4(+)CD69(+)) in the spleen and lymph nodes, respectively. In addition, the liver of AOM-treated mice exposed to a HFD during the entire period of the experiment exhibited a marked increase in proliferation and pNF-κB activation. Altogether, these data suggest that intentional weight loss following chemical-induced carcinogenesis does not affect colon tumorigenesis but may in fact negatively impact liver repair mechanisms.

  10. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.

    1998-01-01

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

  11. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.

    1998-09-29

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

  12. Novel intercore-cladding lithium niobate thin film coated MOEMS fiber sensor/modulator

    NASA Technical Reports Server (NTRS)

    Jamlson, Tracee L.; Konreich, Phillip; Yu, Chung

    2005-01-01

    A MOEMS fiber modulator/sensor is fabricated by depositing a lithium niobate sol-gel thin film between the core and cladding of a fiber preform. The preform is then drawn into 125-micron fibers. Such a MOEMS modulator design is expected to enhance existing lithium niobate undersea acousto-optic sound wave detectors. In our proposed version, the lithium niobate thin film alters the ordinary silica core/cladding boundary conditions such that, when a stress or strain is applied to the fiber, the core light confinement factor changes, leading to modulation of fiber light transmission. Test results of the lithium niobate embedded fiber with a 1550-nm, 4-mW laser source revealed a reduction in light transmission with applied tension. As a comparison, using the same laser source, an ordinary silica core/cladding fiber did not exhibit any reduction in transmitted light when the same strain was applied. Further experimental work and theoretical analysis is ongoing.

  13. The Development and Implementation of an Optical Communications Laboratory.

    DTIC Science & Technology

    1984-12-01

    102 VII- 2 . Acousto - Optic Interaction in the Bragg Regime ...... ................ 104 VII-3. Bragg Diffraction Sound Cell Used as Spectrum Analyzer...I. Bragg Cell with Plane Wave Illumination . . 124 VIII- 2 . Bragg Diffraction of an Acousto - Optic Cell . 127 VIII-3. Illustration of an Acousto - Optic ...Diffraction with lenses. 2 3. Imaging and Spatial Filtering. 4. Measurement of the Bragg Angle of an Acousto - Optic Modulator (Bragg Cell). 5. Beam

  14. Ultrafast pulse shaping: amplification and characterization.

    PubMed

    Fetterman, M; Goswami, D; Keusters, D; Yang, W; Rhee, J K; Warren, W

    1998-11-09

    We demonstrate high-resolution amplified pulse shaping using an acousto-optic modulator (AOM) at a center-wavelength of 795nm. The output pulses have energy of 200mJ/pulse and a transform-limited pulsewidth of 150fs. A spectral modulation of over 40 features is achieved in a single pulse. We characterize the pulses using the STRUT (Spectrally and Temporally Resolved Upconversion Technique). Using predistortion techniques, we demonstrate that the pulses can be shaped in amplitude and phase. We create a complex pulse shape with hyperbolic secant amplitude and hyperbolic tangent frequency sweep, which is useful for applications in adiabatic rapid passage experiments.

  15. Ultrafast pulse shaping: amplification and characterization

    NASA Astrophysics Data System (ADS)

    Fetterman, Matthew R.; Goswami, Debabrata; Keusters, Dorine; Yang, Weiguo; Rhee, June-Koo; Warren, Warren S.

    1998-11-01

    We demonstrate high-resolution amplified pulse shaping using an acousto-optic modulator (AOM) at a center-wavelength of 795nm. The output pulses have energy of 200mJ/pulse and a transform-limited pulsewidth of 150fs. A spectral modulation of over 40 features is achieved in a single pulse. We characterize the pulses using the STRUT (Spectrally and Temporally Resolved Upconversion Technique). Using predistortion techniques, we demonstrate that the pulses can be shaped in amplitude and phase. We create a complex pulse shape with hyperbolic secant amplitude and hyperbolic tangent frequency sweep, which is useful for applications in adiabatic rapid passage experiments.

  16. Research on free-space optical communication based on time-division multiplexing

    NASA Astrophysics Data System (ADS)

    Wang, Dan; Zhou, Wenchao; Li, Zhen; Chen, Zhenqiang; Yin, Hao; Zhu, Siqi; Li, Anming

    2016-10-01

    This paper aims at designing and demonstrating a video and audio signals synchronous wireless transmission of free-space optical communication (FSO) system. Video and audio signals were modulated by the acousto-optical modulator (AOM). With the help of a designed circuit and programmable microcontroller, the system based on time division multiplexing (TDM) achieves the functions of signal de-multiplexing and wireless transmitting. Proved by experiments, the system meets the actual requirements with advantages of flexibility, practicality and low cost. And it provides an efficient scheme of synchronous wireless transmission of video and audio signals for monitoring system and TV access network.

  17. 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…

  18. Dinitrogen and Cyanide Fixation by Methane Seep Microorganisms Revealed by FISH- SIMS And Implications for AOM Productivity and Nitrogenase Evolution

    NASA Astrophysics Data System (ADS)

    Dekas, A.; Orphan, V.

    2008-12-01

    The anaerobic oxidation of methane (AOM), mediated by methane oxidizing archaea (ANME) and sulfate reducing bacterial symbionts (SRB), minimizes the flux of methane from marine sediment to the overlying water column. Understanding the factors determining AOM productivity, and particularly the rates of methane catabolism and anabolism, is of interest to both modern and ancient investigations of climate and bulk carbon isotopic change. It has been hypothesized that nitrogen availability in methane seeps is temporally variable, and that the seep biomass may be at least partially nitrogen limited. The recent finding of nif genes, those necessary for the production of nitrogenase, in enrichments of ANME and SRB consortia suggested that the organisms mediating AOM have the potential to fix dinitrogen. In the present study we incubated methane seep sediment with nitrogen-deplete artificial marine media and a headspace of methane (CH4) and either 15N-labeled dinitrogen (15N2), cyanide (C15N-), or ammonia (15NH3) in order to (1) test the ability of these currently unculturable microorganisms to fix nitrogen and other triple bonded substrates, (2) investigate which AOM partner was responsible for the fixation, (3) compare growth rates on different nitrogen sources, and (4) characterize the phylogeny of these methane seep-associated nitrogenases. Fluorescence in situ hybridization coupled to nano-scale Secondary Ion Mass Spectroscopy imaging (FISH-SIMS) revealed incorporation of 15N into ANME and SRB biomass of up to 0.06 15N fractional abundance in the 15N2 incubation, and up to 0.02 in the C15N- incubation, after 6 and 4 months, respectively. This represents a nearly ten-fold enrichment of 15N compared to the measured natural 15N fractional abundance (0.0036). The NanoSIMS ion images of ANME/SRB aggregates from 15N2 incubations show evidence for 15N enrichment in both partners with the highest incorporation of 15N within the methanotrophic ANME cells. Cyanide incubations

  19. Lidar-radar velocimetry using a pulse-to-pulse coherent rf-modulated Q-switched laser.

    PubMed

    Vallet, M; Barreaux, J; Romanelli, M; Pillet, G; Thévenin, J; Wang, L; Brunel, M

    2013-08-01

    An rf-modulated pulse train from a passively Q-switched Nd:YAG laser has been generated using an extra-cavity acousto-optic modulator. The rf modulation reproduces the spectral quality of the local oscillator. It leads to a high pulse-to-pulse phase coherence, i.e., phase memory, over thousands of pulses. The potentialities of this transmitter for lidar-radar are demonstrated by performing Doppler velocimetry on indoor moving targets. The experimental results are in good agreement with a model based on elementary signal processing theory. In particular, we show experimentally and theoretically that lidar-radar is a promising technique that allows discrimination between translation and rotation movements. Being independent of the laser internal dynamics, this scheme can be applied to any Q-switched laser.

  20. Nonmechanical axial scanning laser Doppler velocimeter with directional discrimination.

    PubMed

    Maru, Koichi; Hata, Takahiro

    2012-07-10

    An axial scanning laser Doppler velocimeter (LDV) with directional discrimination not requiring any moving mechanism in its probe is proposed. The proposed LDV utilizes frequency shift induced by acousto-optic modulators (AOMs) for discriminating the direction of velocity. The measurement position is axially scanned by changing the wavelength of the light input to the probe. The experimental result reveals that both the axial scan and the directional discrimination can be realized by using the proposed method without any moving element in the probe.

  1. Automated laser guidance of neuronal growth cones using a spatial light modulator.

    PubMed

    Carnegie, David J; Cizmár, Tomás; Baumgartl, Jörg; Gunn-Moore, Frank J; Dholakia, Kishan

    2009-11-01

    The growth cone of a developing neuron can be guided using a focused infra-red (IR) laser beam [1]. In previous setups this process has required a significant amount of user intervention to adjust continuously the laser beam to guide the growing neuron. Previously, a system using an acousto-optical deflector (AOD) has been developed to steer the beam [2]. However, to enhance the controllability of this system, here we demonstrate the use of a computer controlled spatial light modulator (SLM) to steer and manipulate the shape of a laser beam for use in guided neuronal growth. This new experimental setup paves the way to enable a comprehensive investigation into beam shaping effects on neuronal growth and we show neuronal growth initiated by a Bessel light mode. This is a robust platform to explore the biochemistry of this novel phenomenon.

  2. Anti-inflammatory effects of betaine on AOM/DSS‑induced colon tumorigenesis in ICR male mice.

    PubMed

    Kim, Dong Hwan; Sung, Bokyung; Kang, Yong Jung; Jang, Jung Yoon; Hwang, Seong Yeon; Lee, Yujin; Kim, Minjung; Im, Eunok; Yoon, Jeong-Hyun; Kim, Cheol Min; Chung, Hae Young; Kim, Nam Deuk

    2014-09-01

    Betaine is an important human nutrient obtained from various foods and studies in animals and humans have provided results suggesting their pathogenesis of various chronic diseases and points to a role in risk assessment and disease prevention. However, the molecular mechanisms of its activity remain poorly understood and warrant further investigation. This study was performed to investigate the anti-inflammation and tumor preventing capacity of betaine on colitis-associated cancer in mice. In in vivo experiments, we induced colon tumors in mice by azoxymethane (AOM) and dextran sulfate sodium (DSS) and evaluated the effects of betaine on tumor growth. Administration with betaine significantly decreased the incidence of tumor formation with downregulation of inflammation. Treatment with betaine inhibited ROS generation and GSSG concentration in colonic mucosa. Based on the qPCR data, administration of betaine inhibited inflammatory cytokines such TNF-α, IL-6, iNOS and COX-2. In in vitro experiments, LPS-induced NF-κB and inflammatory-related cytokines were inhibited by betaine treatment in RAW 264.7 murine macrophage cells. Our findings suggest that betaine is one of the candidates for the prevention of inflammation-associated colon carcinogenesis.

  3. Integrated acoustooptic device modules for optical information processing

    NASA Astrophysics Data System (ADS)

    Tsai, Chen S.

    1988-07-01

    The objectives of this program year are focused on design, fabrication, and testing of wideband guided wave AO Bragg diffraction from surface acoustic waves in Gallium arsenide optical waveguides and conception/realization of multichannel integrated acousto-optics and electrooptics Bragg modulator modules in TIPE microlenses-based lithium niobates and GaAs channel-planar composite waveguides with applications to signal processing and computing. Wideband GaAs waveguide AO Bragg cells that operate in the acoustic frequency range from 300 to 1200 MHz have been realized. This represents realization of GHz GaAs waveguide AO Bragg cells shows that monolithically integrated optic signal processors such as radiofrequency spectrum analyzers may be fabricated in a common GaAs chip. Multichannel single-mode electrooptic cutoff modulator arrays and Bragg diffraction modulator arrays have been successfully realized in GaAs. One of the vital and remaining components toward monolithic (total) integration in GaAs is the waveguide microlens and linear lens array. Fabrication of negative index-change planar waveguide microlenses in both LiNbO3 and GaAs using ion milling. The waveguide lenses that have been fabricated and tested include single lenses and lens arrays of analog Fresnel, chirp grating, and hybrid analog Fresnel chirp grating types. We have obtained near diffraction-limited spot sizes and good efficiencies in such preliminary components.

  4. Method for independent and continuous tuning of N lasers phase-locked to the same frequency comb.

    PubMed

    Gunton, Will; Semczuk, Mariusz; Madison, Kirk W

    2015-09-15

    We present a method of phase locking any number of continuous-wave lasers to an optical frequency comb (OFC) that enables independent frequency positioning and control of each laser while still maintaining lock to the OFC. The scheme employs an acousto-optic modulator (AOM) in a double-pass configuration added to each laser before its light is compared by optical heterodyne with the comb. The only requirement is that the tuning bandwidth of the double-pass AOM setup be larger than half the OFC repetition rate. We demonstrate this scheme and achieve an arbitrary frequency tuning precision, a tuning rate of 200 MHz/s, and a readout precision at the 1 kHz level.

  5. Investigation of the low-level modulated light action

    NASA Astrophysics Data System (ADS)

    Antonov, Sergei N.; Sotnikov, V. N.; Koreneva, L. G.

    1994-07-01

    Now there exists no clear complete knowledge about mechanisms and pathways by which low level laser bioactivation works. Modulated laser light action has been investigated two new ways: dynamical infrared thermography and computing image of living brain. These ways permit observation in real time laser action on peripheral blood flow, reflex reactions to functional probes, thermoregulation mechanisms as well as brain electrical activity changes of humans. We have designed a universal apparatus which produced all regimes of the output laser light. It has a built-in He-Ne laser with an acousto-optic modulator and an infrared GaAs laser. The device provided spatial combination of both the light beams and permitted us to irradiate an object both separately and simultaneously. This research shows that the most effective frequencies range from several to dozens of hertz. The duty factor and frequency scanning are also important. On the basis of these results in Russian clinics new treatment methods using modulated light are applied in practical neurology, gynecology, etc.

  6. Acousto-Optic Fourier Transform Devices for Surveillance Signal Processing.

    DTIC Science & Technology

    1983-06-30

    diffracted light beams. This scheme is illustrated in Fig. 11, and is essentially a Twyman -Green interferometer . This scheme has not been implemented...1, uses a two-mirror interferometer scheme whereby an imaged scene contains a fringe pattern determined by the mirror separation. An array of...obtained from the individual detectors behind the reticle if there is movement in the field, since in that case the interferometer fringes move across

  7. Three-dimensional acousto-optic spectrum analysis

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Metscher, Brian; Lesh, James R.

    1990-01-01

    A three-dimensional acoustooptic spectrum analyzer with subhertz resolution is demonstrated experimentally. The first and second dimensions are the two spatial dimensions of the output detector array, and the third dimension is time as sampled by the detector array frame rate. A superfine resolution of 0.12 Hz has been achieved.

  8. Acousto-optic processor for autonomous SAR guidance

    NASA Astrophysics Data System (ADS)

    Pape, Dennis R.

    1990-09-01

    This paper describes an acoustooptic signal processor designed to produce real-time spotlight mode synthetic aperture radar (SAR) images for autonomous missile guidance. The processor is designed to maintain a range and azimuth resolution of 2 m. High-quality image formation results from electronic motion compensation applied to each received pulse. The processor controls range sidelobes through a weighting function applied during the correlation process, while azimuth sidelobes are controlled either by weighting or by increasing the corehent integration time.

  9. System Sensitivity Analysis Acousto-Optic Spectrum Analysis Receiver.

    DTIC Science & Technology

    1980-02-01

    facteurs determinants dont il est tenu compte sont notamment le produit temps-largeur de bande et la dur~e d’integration du r ~ seau photod~tecteur. Des...92.0 26 96.0 28 100.5 30 104.0 32 110.0 33 0 w 0 (A W) 9V.LIO UNCLASSIFIED Security Cia.,ficaton OOCUMENT CONTROL DATA - R & D ( :e.rv cla s hmi l...itself is unclassified) represented as ITS), (SI. 1C0, ( R ), or (U). la TOTAL NUMBER OF PAGES’ The total page count should follow otrmal pagination

  10. Infrared fiber coupled acousto-optic tunable filter spectrometer

    NASA Technical Reports Server (NTRS)

    Levin, K. H.; Kindler, E.; Ko, T.; Lee, F.; Tran, D. C.; Tapphorn, R. M.

    1990-01-01

    A spectrometer design is introduced which combines an acoustooptic tunable filter (AOTF) and IR-transmitting flouride-glass fibers. The AOTF crystal is fabricated from TeO2 and permits random access to any wavelength in less than 50 microseconds, and the resulting spectrometer is tested for the remote analysis of gases and hydrocarbons. The AOTF spectrometer, when operated with a high-speed frequency synthesizer and optimized algorithms, permits accurate high-speed spectroscopy in the mid-IR spectral region.

  11. [Research on methane concentration monitoring system based on electro-optical modulation interference].

    PubMed

    Yan, Jie; Meng, Peng-Hua

    2013-08-01

    Gas monitoring for methane concentration has been applied in many areas, while the vast majority of methods were based on the chemical reaction. There is a low security and poor stability shortcomings. In contrast, it is of high stability and strong anti-interference ability to monitor methane concentration using optical interferometry for quantitative analysis. As the system static interference limits the spectrcum resolution, we designed the electro-optical modulation interference system to further improve the detection accuracy for methane concentration. In the interferometer system, a variable refractive index crystal LiNbO3 was used for electro-optical modulation, and the static optical path length scan range was increased to improve the spectrum resolution. Both sides of the crystal were loaded with opposite phase modulated signal, so that it does not change the improved spectrum resolution interferometer size. By derivation of refractive index modulation as a function of optical path difference, the simulation found that the resolution was increased by nearly an order of magnitude than interference system spectrum resolution of the same size. The experiments used the SGT-3-type acousto-optical modulator and the 1 650 nm infrared lasers to detect different concentrations of methane gas. The experimental results show that the method is better than the traditional pyroelectric method in terms of accuracy and stability, and more suitable for application in the mine complex environment.

  12. 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.

  13. A phase-locked laser system based on double direct modulation technique for atom interferometry

    NASA Astrophysics Data System (ADS)

    Li, Wei; Pan, Xiong; Song, Ningfang; Xu, Xiaobin; Lu, Xiangxiang

    2017-02-01

    We demonstrate a laser system based on phase modulation technology and phase feedback control. The two laser beams with frequency difference of 6.835 GHz are modulated using electro-optic and acousto-optic modulators, respectively. Parasitic frequency components produced by the electro-optic modulator are filtered using a Fabry-Perot Etalon. A straightforward phase feedback system restrains the phase noise induced by environmental perturbations. The phase noise of the laser system stays below -125 rad2/Hz at frequency offset higher than 500 kHz. Overall phase noise of the laser system is evaluated by calculating the contribution of the phase noise to the sensitivity limit of a gravimeter. The results reveal that the sensitivity limited by the phase noise of our laser system is lower than that of a state-of-the-art optical phase-lock loop scheme when a gravimeter operates at short pulse duration, which makes the laser system a promising option for our future application of atom interferometer.

  14. Co-integration of a smart CMOS image sensor and a spatial light modulator for real-time optical phase modulation

    NASA Astrophysics Data System (ADS)

    Laforest, Timothé; Verdant, Arnaud; Dupret, Antoine; Gigan, Sylvain; Ramaz, François; Tessier, Gilles

    2014-03-01

    We present a CMOS light detector-actuator array, in which every pixel combines a spatial light modulator and a photodiode. It will be used in medical imaging based on acousto-optical coherence tomography with a digital holographic detection scheme. Our architecture is able to measure an interference pattern between a scattered beam transmitted through a scattering media and a reference beam. The array of 16 μm pixels pitch has a frame rate of several kfps, which makes this sensor compliant with the correlation time of light in biological tissues. In-pixel analog processing of the interference pattern allows controlling the polarization of a stacked light modulator and thus, to control the phase of the reflected beam. This reflected beam can then be focused on a region of interest, i.e. for therapy. The stacking of a photosensitive element with a spatial light modulator on the same chip brings a significant robustness over the state of the art such as perfect optical matching and reduced delay in controlling light.

  15. Tailoring ultrasonic beams with optoacoustic holography

    NASA Astrophysics Data System (ADS)

    Meyer, Alex; Gspan, Stefan J.; Bernet, Stefan; Ritsch-Marte, Monika

    2003-06-01

    A combination of laser-induced ultrasound generation and ultrasonic holography for spatial control of the generated ultrasonic pulse is presented. Ultrasound is produced by absorption of laser pulses at an absorbing layer in a water tank via the optoacoustic effect. In order to produce a defined ultrasonic frequency in the MHz range, the laser pulses are harmonically time-modulated using an acousto-optic modulator (AOM). Additionally, the laser intensity is spatially controlled. This is realized with a high resolution liquid crystal spatial light modulator (LCD). A computer generated pattern is displayed at the LCD and projected by the expanded laser beam to an absorptive layer in the water tank. As a result, the emitted ultrasonic wave emerges in a predetermined way, which is an acoustical analogue to the effect of a "diffractive optical element" in laser optics. The flexible method of optical ultrasound generation and diffractive steering promises new applications in medical and technical ultrasound diagnostics.

  16. Linearly polarized, dual wavelength frequency-modulated continuous-wave fiber laser for simultaneous coherent distance and speed measurements

    NASA Astrophysics Data System (ADS)

    Chen, Tao; Wu, Jun; Xu, Weiming; He, Zhiping; Qian, Liqun; Shu, Rong

    2016-07-01

    We have experimentally demonstrated a high power linearly polarized, dual wavelength frequency-modulated continuous-wave (FMCW) fiber laser with master-oscillator power-amplifier (MOPA) configuration, which is specially designed for simultaneous coherent distance and speed measurements. Two single longitudinal mode laser diodes working at 1550.12 and 1554.13 nm are employed as the seeds of the fiber MOPA. The wavelengths of the seeds are externally modulated by two acousto-optic frequency shifters (AOFSes) with a symmetrical sawtooth wave from 330-460 MHz in the frequency domain. The modulation periodicities for the two seeds are 26 and 26.3 μs, respectively, by which the distance ambiguity can be eliminated and therefore the detection range can be extended to a great extent. The seeds are then amplified independently to reduce their power differences during frequency modulation. After being coupled and boosted with three successive fiber amplifiers, an output power of 12.1 W is recorded from the FMCW laser with a power instability   <0.14% over 1.5 h. The measured PER and full divergence angle of the laser are  >18 dB and  <25 μrad, respectively, indicating its excellent performance for field measurements.

  17. Self-heterodyne interference spectroscopy using a comb generated by pseudo-random modulation.

    PubMed

    Hébert, Nicolas Bourbeau; Michaud-Belleau, Vincent; Anstie, James D; Deschênes, Jean-Daniel; Luiten, Andre N; Genest, Jérôme

    2015-10-19

    We present an original instrument designed to accomplish high-speed spectroscopy of individual optical lines based on a frequency comb generated by pseudo-random phase modulation of a continuous-wave (CW) laser. This approach delivers efficient usage of the laser power as well as independent control over the spectral point spacing, bandwidth and central wavelength of the comb. The comb is mixed with a local oscillator generated from the same CW laser frequency-shifted by an acousto-optic modulator, enabling a self-heterodyne detection scheme. The current configuration offers a calibrated spectrum every 1.12 µs. We demonstrate the capabilities of the spectrometer by producing averaged, as well as time-resolved, spectra of the D1 transition of cesium with a 9.8-MHz point spacing, a 50-kHz resolution and a span of more than 3 GHz. The spectra obtained after 1 ms of averaging are fitted with complex Voigt profiles that return parameters in good agreement with expected values.

  18. Laser Metrology for an Optical-Path-Length Modulator

    NASA Technical Reports Server (NTRS)

    Gursel, Yekta

    2005-01-01

    Laser gauges have been developed to satisfy requirements specific to monitoring the amplitude of the motion of an optical-path-length modulator that is part of an astronomical interferometer. The modulator includes a corner-cube retroreflector driven by an electromagnetic actuator. During operation of the astronomical interferometer, the electromagnet is excited to produce linear reciprocating motion of the corner-cube retroreflector at an amplitude of 2 to 4 mm at a frequency of 250, 750, or 1,250 Hz. Attached to the corner-cube retroreflector is a small pick-off mirror. To suppress vibrations, a counterweight having a mass equal to that of the corner-cube retroreflector and pick-off mirror is mounted on another electromagnetic actuator that is excited in opposite phase. Each gauge is required to measure the amplitude of the motion of the pick-off mirror, assuming that the motions of the pick-off mirror and the corner-cube retroreflector are identical, so as to measure the amplitude of motion of the corner- cube retroreflector to within an error of the order of picometers at each excitation frequency. Each gauge is a polarization-insensitive heterodyne interferometer that includes matched collimators, beam separators, and photodiodes (see figure). The light needed for operation of the gauge comprises two pairs of laser beams, the beams in each pair being separated by a beat frequency of 80 kHz. The laser beams are generated by an apparatus, denoted the heterodyne plate, that includes stabilized helium-neon lasers, acousto-optical modulators, and associated optical and electronic subsystems. The laser beams are coupled from the heterodyne plate to the collimators via optical fibers.

  19. Investigation of a 10 MHz, non-steady state cavity for pulse energy enhancement of ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Breitkopf, Sven; Wunderlich, Stefano; Eidam, Tino; Shestaev, Evgeny; Gottschall, Thomas; Carstens, Henning; Holzberger, Simon; Pupeza, Ioachim; Limpert, Jens; Tünnermann, Andreas

    2016-03-01

    Here, we present a passive 30-m long enhancement cavity that supports a steady-state enhancement of 198, which is the highest enhancement that has ever been reached in such a long cavity. Furthermore, we demonstrate the extraction of a short burst with a total energy of 53.6 μJ employing an acousto-optic modulator (AOM) as a switching device. The cavity was seeded with pulses of 1.49 μJ energy at 10 MHz repetition rate. The individual output coupled pulses showed an energy enhancement of up to 8.5 while the whole burst contained the entire energy of 36 input pulses. In the last section theoretical considerations for the single pulse extraction are presented and briefly discussed.

  20. Fiber laser-microscope system for femtosecond photodisruption of biological samples

    PubMed Central

    Yavaş, Seydi; Erdogan, Mutlu; Gürel, Kutan; Ilday, F. Ömer; Eldeniz, Y. Burak; Tazebay, Uygar H.

    2012-01-01

    We report on the development of a ultrafast fiber laser-microscope system for femtosecond photodisruption of biological targets. A mode-locked Yb-fiber laser oscillator generates few-nJ pulses at 32.7 MHz repetition rate, amplified up to ∼125 nJ at 1030 nm. Following dechirping in a grating compressor, ∼240 fs-long pulses are delivered to the sample through a diffraction-limited microscope, which allows real-time imaging and control. The laser can generate arbitrary pulse patterns, formed by two acousto-optic modulators (AOM) controlled by a custom-developed field-programmable gate array (FPGA) controller. This capability opens the route to fine optimization of the ablation processes and management of thermal effects. Sample position, exposure time and imaging are all computerized. The capability of the system to perform femtosecond photodisruption is demonstrated through experiments on tissue and individual cells. PMID:22435105

  1. Unpolished Thai rice prevents ACF formation and dysplastic progression in AOM-induced rats and induces apoptosis through redox alteration in CaCo-2 cells.

    PubMed

    Tammasakchai, Achiraya; Chaiyasut, Chaiyavat; Riengrojpitak, Suda; Suwannalert, Prasit

    2015-01-01

    Oxidative stress is associated with colon carcinogenesis including aberrant crypt foci (ACF) formation and it plays an important role in pathophysiological changes in cancer cells. The aims of this study were to investigate the effects of dietary unpolished Thai rice (UTR) on ACF formation and dysplastic progression in azoxymethane (AOM)-treated rats. Anti-cancer efficacy of UTR regarding apoptotic induction and oxidative redox status in human colon cancer (CaCo-2) cells was also investigated. Rats given 20% and 70% of UTR in the diet showed significantly and dose-dependently decreased total number of ACF. UTR treatment also was strongly associated with the low percentage of dysplastic progression and mucin depletion. In addition, we found that UTR significantly induced cancer cell apoptosis, increased cellular oxidants, and decreased the level of GSH/GSSG ratio in CaCo-2 cells. Our study suggests that UTR supplementation may be a useful strategy for CRC prevention with the inhibition of precancerous progression, with induction of cancer cell apoptosis through redox alteration.

  2. Ultrasound modulated light blood flow measurement using intensity autocorrelation function: a Monte-Carlo simulation

    NASA Astrophysics Data System (ADS)

    Tsalach, A.; Metzger, Y.; Breskin, I.; Zeitak, R.; Shechter, R.

    2014-03-01

    Development of techniques for continuous measurement of regional blood flow, and in particular cerebral blood flow (CBF), is essential for monitoring critical care patients. 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 133 Xe SPECT1 and laser Doppler2. Coherent light is introduced into the tissue concurrently with an Ultrasound (US) field. Displacement of scattering centers within the sampled volume induced by Brownian motion, blood flow and the US field affects the photons' temporal correlation. Hence, the temporal fluctuations of the obtained speckle pattern provide dynamic information about the blood flow. We developed a comprehensive simulation, combining the effects of Brownian motion, US and flow on the obtained speckle pattern. Photons trajectories within the tissue are generated using a Monte-Carlo based model. Then, the temporal changes in the optical path due to displacement of scattering centers are determined, and the corresponding interference pattern over time is derived. Finally, the light intensity autocorrelation function of a single speckle is calculated, from which the tissue decorrelation time is determined. The simulation's results are compared with in-vitro experiments, using a digital correlator, demonstrating decorrelation time prediction within the 95% confidence interval. This model may assist in the development of optical based methods for blood flow measurements and particularly, in methods using the acousto-optic effect.

  3. Nonlinear dynamics modulation in a neon glow discharge plasma

    NASA Astrophysics Data System (ADS)

    Miller, Paul M.

    In dynamics modulation, two modes in a driven neon glow discharge alternate as the dominant mode as their response to the driving force alternates between spatiotemporal and temporal periodic pulling. This phenomenon was first noted by Koepke, Weltmann, and Selcher (Bull. Am. Phys. Soc. 40, 1716 (1995)), who saw two limited but representative cases and proposed a mechanism (Phys. Rev. E 62, 2773 (2000)) by which it occurs. The intent of this dissertation is to document experimentally and test the dynamics modulation mechanism they proposed. Using a new extension of a previous mathematical treatment of periodic pulling, the resulting experimental data are used to verify the predicted mechanism. A numerical model is also presented that reproduces the signature of dynamics modulation and further supports the validity of the mechanism. For two pairs of mode frequencies, three complete data series as driving frequency is increased are presented. Each of these data series shows the progression of the system from pure spatiotemporal behavior, through dynamics modulation, and ending at entrainment in the upper mode. Ionization wave modes are examined using time series recorded using a photodiode with a narrow band filter that selectively passes the primary neon spectral line at 640 nm. The system was periodically driven using a narrow-band ring dye laser tuned to a wavelength near the metastable neon transition at 588.35 nm. The amplitude of the driving force was decreased (increased) by tuning the laser away from (nearer to) the center of the neon line, while the driving frequency was controlled by an acousto-optic modulator chopping the laser beam at the desired frequency. Arnol'd tongue boundaries identifying the edges of frequency entrainment regions in the driving amplitude-driving frequency plane were established for four different discharge currents. The (upward) dynamics modulation behavior seen by Koepke, Weltmann, and Selcher was reproduced and additional data

  4. Theoretical, Experimental and Numerical Studies on Hybrid Acoustooptic Bistable Devices

    DTIC Science & Technology

    1991-06-01

    refraction-index variation Ano(p,t) in the acousto - optic cell. Since S(P-,t) = fvn 2 (p’t) = (v[no+ A no(P,)] _ no[1 + 2Ano(P,t)/no], (6.1-47) where n0... acousto - optic modulator is operated in the Bragg region. b) Light beam deflector /spectrum analyzer In contrast to intensity modulation where the amplitude...beam deflector , where the acousto - optic modulator is operated in the Bragg region. The angle between the 1st-diffracted beam and the 0-th diffracted

  5. Time Integrating Optical Signal Processing

    DTIC Science & Technology

    1981-07-01

    diode source modulation, and (b) acousto - lit X)= l,(t)l(t - x / v). ( 2 ) optic deflector modulation for SSS example. F,,r double sideband modulation 1... 2 -1 2.1.2 Acousto - Optic Time-Integrating Correlator . ...... .. 2 -3 2.1.3 Noncoherent Space Integrating Correlator ......... . . 2 -6 2.1.4...device limitation. Acousto - optic devices ] are available with time-bandwidth product much greater than the number of resolvable image samples. 1- 2 I i

  6. Double-resonance spectroscopy in Rubidium vapour-cells for high performance and miniature atomic clocks

    NASA Astrophysics Data System (ADS)

    Gharavipour, M.; Affolderbach, C.; Kang, S.; Mileti, G.

    2017-01-01

    We report our studies on using microwave-optical double-resonance (DR) spectroscopy for a high-performance Rb vapour-cell atomic clock in view of future industrial applications. The clock physics package is very compact with a total volume of only 0.8 dm3. It contains a recently in-house developed magnetron-type cavity and a Rb vapour cell. A homed-made frequency-stabilized laser system with an integrated acousto-optical-modulator (AOM) – for switching and controlling the light output power– is used as an optical source in a laser head (LH). The LH has the overall volume of 2.5 dm3 including the laser diode, optical elements, AOM and electronics. In our Rb atomic clock two schemes of continuous-wave DR and Ramsey-DR schemes are used, where the latter one strongly reduces the light-shift effect by separation of the interaction of light and microwave. Applications of the DR clock approach to more radically miniaturized atomic clocks are discussed.

  7. Q-switching an all-fiber laser using acousto-optic null coupler

    NASA Astrophysics Data System (ADS)

    Berg, Yuval; Goldring, Sharone; Pearl, Shaul; Arie, Ady

    2013-05-01

    A new method for Q-switching an all-fiber laser is presented. It is based on induced acoustic long period grating operating on a null coupler, which acts as acoustically controlled tunable output coupler. Q-switching is achieved by switching on and off the acoustic wave in a burst mode, thereby generating laser pulses that are ~400 times shorter than the acoustically controlled coupler's rise time. Output pulse energy of 22 μJ and temporal width of ~100 ns were measured at a wavelength of 1.54 μm.

  8. TeO2 and Te acousto-optic spectrometer imaging system

    NASA Astrophysics Data System (ADS)

    Souilhac, Dominique J.; Billerey, Dominique

    1994-12-01

    An improved TeO2 and Te infrared acoustooptic tuneable spectrometer has been analysed, using infrared fibres, a high speed frequency synthesiser and optimised algorithms. A comparison is made with the next best AOTF infrared materials, Tl3AsSe3, HgCl2 and PbBr2. A design study of the TeO2 and Te AO imaging spectrometer is also presented, operating in the two thermal bands, 1-5micrometers and 6-12micrometers , using an interchangeable fore-optics and a multiplexed electronically scanned infrared array cooled at 77 degrees K. Some initial experimental results indicate that these systems can perform well, an increase in the dynamic range in the 8-12 micrometers and is obtained compared to the 3-5*m band. It can be very useful in chemical process control, medical diagnostics, aerospace and earth remote sensing. Based on recent imaging spectrometer development, a design study of the TeO2 AO imaging spectrometer in the 0.4-1 micrometers band, for simultaneous spectroscopy at every pixel, is presented, using a CCD camera and fast data processing technology.

  9. Acousto-optic back-projection: Physical-model-based sound field reconstruction from optical projections

    NASA Astrophysics Data System (ADS)

    Yatabe, Kohei; Ishikawa, Kenji; Oikawa, Yasuhiro

    2017-04-01

    As an alternative to microphones, optical techniques have been studied for measuring a sound field. They enable contactless and non-invasive acoustical observation by detecting density variation of medium caused by sound. Although they have important advantages comparing to microphones, they also have some disadvantages. Since sound affects light at every points on the optical path, the optical methods observe an acoustical quantity as spatial integration. Therefore, point-wise information of a sound field cannot be obtained directly. Ordinarily, the computed tomography (CT) method has been applied for reconstructing a sound field from optically measured data. However, the observation process of the optical methods have not been considered explicitly, which limits the accuracy of the reconstruction. In this paper, a physical-model-based sound field reconstruction method is proposed. It explicitly formulates the physical observation process so that a model mismatch of the conventional methods is eliminated.

  10. Analysis of a crossed Bragg cell acousto-optical spectrometer for SETI.

    PubMed

    Gulkis, S

    1989-01-01

    The search for radio signals from extraterrestrial intelligent beings (SETI) requires the use of large instantaneous bandwidth (500 MHz) and high resolution (20 Hz) spectrometers. Digital systems with a high degree of modularity can be used to provide this capability, and this method has been widely discussed. Another technique for meeting the SETI requirement is to use a crossed Bragg cell spectrometer as described by Psaltis and Casasent. This technique makes use of the Folded Spectrum concept, introduced by Thomas. The Folded Spectrum is a 2-D Fourier Transform of a raster scanned 1-D signal. It is directly related to the long 1-D spectrum of the original signal and is ideally suited for optical signal processing. The folded spectrum technique has received little attention to date, primarily because early systems made use of photographic film which are unsuitable for the real time data analysis and voluminous data requirements of SETI. An analysis of the crossed Bragg cell spectrometer is presented as a method to achieve the spectral processing requirements for SETI. Systematic noise contributions unique to the Bragg cell system will be discussed.

  11. Acousto-optic signature analysis for inspection of the orbiter thermal protection tile bonds

    NASA Technical Reports Server (NTRS)

    Rodriguez, Julio G.; Tow, D. M.; Barna, B. A.

    1990-01-01

    The goal of this research is to develop a viable NDE technique for the inspection of orbiter thermal protection system (TPS) tile bonds. Phase 2, discussed here, concentrated on developing an empirical understanding of the bonded and unbonded vibration signatures of acreage tiles. Controlled experiments in the laboratory have provided useful information on the dynamic response of TPS tiles. It has been shown that several signatures are common to all the pedigree tiles. This degree of consistency in the tile-SIP (strain isolation pad) dynamic response proves that an unbond can be detected for a known tile and establish the basis for extending the analysis capability to arbitrary tiles for which there are no historical data. The field tests of the noncontacting laser acoustic sensor system, conducted at the Kennedy Space Center (KSC), investigated the vibrational environment of the Orbiter Processing Facility (OPF) and its effect on the measurement and analysis techniques being developed. The data collected showed that for orbiter locations, such as the body flap and elevon, the data analysis scheme, and/or the sensor, will require modification to accommodate the ambient motion. Several methods were identified for accomplishing this, and a solution is seen as readily achievable. It was established that the tile response was similar to that observed in the laboratory. Of most importance, however, is that the field environment will not affect the physics of the dynamic response that is related to bond condition. All of this information is fundamental to any future design and development of a prototype system.

  12. Acousto-Optical Method of Encoding and Visualization of Underwater Space

    DTIC Science & Technology

    2014-01-27

    neurons which are mathematically described as coupled nonlinear oscillators that are slightly unstable. They have a property called ’ Self - Referential ... self - regulating process which is represented by Equation (5) in the ensuing description. [0083] The input/output circuitry 64 outputs signals that...other words, self -correcting dynamics of the Na and Ca ions in the membranes are closely related to the sensing and the flopping of motion actuators

  13. 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.

  14. Acousto-optic tunable filter (AOTF) imaging spectrometer for NASA applications - System issues

    NASA Technical Reports Server (NTRS)

    Yu, Jeffrey; Chao, Tien H.; Cheng, Li-Jen

    1990-01-01

    A recently developed AOTF operating in the visible, 0.4-0.8 micron bandpass is presently compared with other spectrometer designs, with a view to the advantages it may uniquely offer for prospective NASA missions. Since spectral identification is accomplished by this system through the scanning of a few spectral bands, data storage requirements for spectral image analysis can be significantly reduced. Attention is given to spectral and imaging capabilities and their applicability to defense, remote sensing, and industrial uses.

  15. Acousto-optic tunable filter (AOTF) imaging spectrometer for NASA applications - Breadboard demonstration

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Yu, Jeffrey; Cheng, Li-Jen; Lambert, Jim

    1990-01-01

    Considerations of performance criteria in image quality, spectral response, programmability, and field-of-view, are presently discussed for a NASA AOTF system. Experimental data obtained with an AOTF imaging spectrometer breadboard are presented. Attention is given to the identification of Nd(3+) contained in bastanite rock by means of this imaging spectrometer.

  16. Real-time analysis of multi-laser-beam fluorescence for timed control of laser tweezers in a microfluidic cell-sorting device

    NASA Astrophysics Data System (ADS)

    Davis, Lloyd M.; Lubbeck, Jennifer L.; Dean, Kevin M.; Palmer, Amy E.; Jimenez, Ralph

    2012-10-01

    We have developed a microfluidic cell sorter for mammalian cells expressing intrinsic fluorescent proteins that enables selection of cells with proteins that have enhanced photophysical properties, such as reduced fluorescence photobleaching and/or reversible dark state conversion. Previous ensemble imaging studies have used an acousto-optic modulator (AOM) to provide millisecond pulsed laser illumination for in vivo assays that distinguish reversible darkstate conversion from irreversible photobleaching. However, in the sorter, cells are hydrodynamically focused into a stream, which flows through a series of 4 or 8 line-focused, continuous, 532 nm laser beams, such that each cell experiences a similar millisecond modulated excitation. The amplitude and timing of the fluorescence response from each of the beams are measured by a red-sensitive photomultiplier and analyzed in real time to separately determine initial fluorescence brightness and photobleaching characteristics. In addition, each cell's flow speed is found from its time of passage through the beams, and if the analysis results are within adjustable limits, a 1064 nm optical trap beam is switched on and moved along an intersecting trajectory at a matching speed, so that the cell becomes deflected by the optical gradient forces towards another exit channel of the microfluidic device. The optical sorting of cells is similar to that demonstrated by others, except that the motion of the trap beam is achieved using a piezo mirror under computer control, rather than an AOM; also, rather than a single-beam brightness measure using a hardwired circuit, a more complex multi-beam analysis is performed in software using the Real-Time module of LabView (National Instruments) on a separate computer to achieve deterministic timing and low latency. The software displays updated statistics of the sort, obtained by counting cells that pass through an extra laser beam in the exit channel. A mixture of cells expressing

  17. Development and Deployment of a Compact Eye-Safe Scanning Differential absorption Lidar (DIAL) for Spatial Mapping of Carbon Dioxide for Monitoring/Verification/Accounting at Geologic Sequestration Sites

    SciTech Connect

    Repasky, Kevin

    2014-03-31

    A scanning differential absorption lidar (DIAL) instrument for monitoring carbon dioxide has been developed. The laser transmitter uses two tunable discrete mode laser diodes (DMLD) operating in the continuous wave (cw) mode with one locked to the online absorption wavelength and the other operating at the offline wavelength. Two in-line fiber optic switches are used to switch between online and offline operation. After the fiber optic switch, an acousto- optic modulator (AOM) is used to generate a pulse train used to injection seed an erbium doped fiber amplifier (EDFA) to produce eye-safe laser pulses with maximum pulse energies of 66 {micro}J, a pulse repetition frequency of 15 kHz, and an operating wavelength of 1.571 {micro}m. The DIAL receiver uses a 28 cm diameter Schmidt-Cassegrain telescope to collect that backscattered light, which is then monitored using a photo-multiplier tube (PMT) module operating in the photon counting mode. The DIAL instrument has been operated from a laboratory environment on the campus of Montana State University, at the Zero Emission Research Technology (ZERT) field site located in the agricultural research area on the western end of the Montana State University campus, and at the Big Sky Carbon Sequestration Partnership site located in north-central Montana. DIAL data has been collected and profiles have been validated using a co-located Licor LI-820 Gas Analyzer point sensor.

  18. Doubly Q-switched Ho:LuAG laser with acoustic-optic modulator and Cr²⁺:ZnS saturable absorber.

    PubMed

    Cui, Z; Duan, X M; Yao, B Q; Yang, H Y; Li, J; Yuan, J H; Dai, T Y; Li, C Y; Pan, Y B

    2015-12-01

    A doubly Q-switched (DQS) Ho:LuAG laser resonantly pumped by a 1.91-μm laser was first presented with an acoustic-optic modulator (AOM) and a Cr2+:ZnS saturable absorber. A comparison among the active Q-switched (AQS), passively Q-switched (PQS), and DQS laser performances was carried out. The maximum continuous wave (CW) output power of 6 W with the central wavelength of 2100.65 nm was obtained at an incident pump power of 35.2 W. Compared with CW laser, the AQS, PQS, and DQS lasers shared the same central wavelength of 2098.34 nm under the same incident pump power. The central wavelength of the AQS and DQS lasers remained constant with the change of AOM repetition frequency (RF). When the incident pump power was 35.2 W and the AOM RF was 15 kHz, the DQS Ho:LuAG laser at a maximum RF of 2.13 kHz achieved the maximum average output power of 4.95 W. At the AOM RF of 10 kHz, the DQS Ho:LuAG laser achieved the shortest pulse width of 40.4 ns with the highest peak power of 61.5 kW. At an incident pump power of 35.2 W, the PQS Ho:LuAG laser obtained the shortest pulse width of 46.1 ns, corresponding to the RF of 2.25 kHz. Experiment results showed that the pulse width could be compressed effectively with a significant increase of peak power for a 2-μm DQS laser.

  19. Non-digestible fraction of beans (Phaseolus vulgaris L.) modulates signalling pathway genes at an early stage of colon cancer in Sprague-Dawley rats.

    PubMed

    Haydé, Vergara-Castañeda; Ramón, Guevara-González; Lorenzo, Guevara-Olvera; Dave, Oomah B; Rosalía, Reynoso-Camacho; Paul, Wiersma; Guadalupe, Loarca-Piña

    2012-08-01

    Colorectal cancer is one of the most common causes of morbidity and mortality in Western countries, the second cause of cancer mortality in the USA and a major public health problem in Mexico. A diet rich in legumes is directly related to the prevention of colon cancer, showing an inverse relationship with the development of colorectal adenomas in human subjects. The present study shows the results of molecular changes involved in the Tp53 pathway at an early stage in the distal colon tissue of azoxymethane (AOM)-induced colon cancer in rats evaluated by PCR array after exposure to diets containing the non-digestible fraction (NDF) of cooked bean (cultivar Bayo Madero). Significant differences were detected in seventy-two genes of the Tp53-mediated signalling pathway involved in apoptosis, cell-cycle regulation and arrest, inhibition of proliferation and inflammation, and DNA repair. Tp53, Gadd45a, Cdkn1a and Bax were highly expressed (9·3-, 18·3-, 5·5- and 3·5-fold, respectively) in the NDF+AOM group, whereas Cdc25c, Ccne2, E2f1 and Bcl2 were significantly suppressed ( - 9·2-, - 2·6-, - 18·4- and - 3·5-fold, respectively), among other genes, compared with the AOM group, suggesting that chemoprevention of aberrant crypt foci results from a combination of cell-cycle arrest in G1/S and G2/M phases and cell death by apoptotic induction. We demonstrate that the NDF from common bean modulates gene expression profiles in the colon tissue of AOM-induced rats, contributing to the chemoprotective effect of common bean on early-stage colon cancer.

  20. 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.

  1. Precision frequency measurement of 1S0-3P1 intercombination lines of Sr isotopes

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Gao, Feng; Ye-Bing, Wang; Xiao, Tian; Jie, Ren; Ben-Quan, Lu; Qin-Fang, Xu; Yu-Lin, Xie; Hong, Chang

    2015-01-01

    We report on frequency measurement of the intercombination (5s2)1S0-(5s5p)3P1 transition of the four natural isotopes of strontium, including 88Sr (82.58%), 87Sr (7.0%), 86Sr (9.86%), and 84Sr (0.56%). A narrow-linewidth laser that is locked to an ultra-low expansion (ULE) optical cavity with a finesse of 12000 is evaluated at a linewidth of 200 Hz with a fractional frequency drift of 2.8×10-13 at an integration time of 1 s. The fluorescence collector and detector are specially designed, based on a thermal atomic beam. Using a double-pass acousto-optic modulator (AOM) combined with a fiber and laser power stabilization configuration to detune the laser frequency enables high signal-to-noise ratios and precision saturated spectra to be obtained for the six transition lines, which allows us to determine the transition frequency precisely. The optical frequency is measured using an optical frequency synthesizer referenced to an H maser. Both the statistical values and the final values, including the corrections and uncertainties, are derived for a comparison with the values given in other works. Project supported by the National Natural Science Foundation of China (Grant No. 61127901) and the Key Project of the Chinese Academy of Sciences (Grant No. KJZD-EW-W02).

  2. Phase Analysis for Frequency Standards in the Microwave and Optical Domains.

    PubMed

    Kazda, Michael; Gerginov, Vladislav; Huntemann, Nils; Lipphardt, Burghard; Weyers, Stefan

    2016-07-01

    Coherent manipulation of atomic states is a key concept in high-precision spectroscopy and used in atomic fountain clocks and a number of optical frequency standards. Operation of these standards can involve a number of cyclic switching processes, which may induce cycle-synchronous phase excursions of the interrogation signal and thus lead to shifts in the output of the frequency standard. We have built a field-programmable gate array (FPGA)-based phase analyzer to investigate these effects and conducted measurements on two kinds of frequency standards. For the caesium fountains PTB-CSF1 and PTB-CSF2, we were able to exclude phase variations of the microwave source at the level of a few microradians, corresponding to relative frequency shifts of less than [Formula: see text]. In the optical domain, we investigated phase variations in PTB's Yb (+) optical frequency standard and made detailed measurements of acousto-optic modulator (AOM) chirps and their scaling with duty cycle and driving power. We ascertained that cycle-synchronous as well as long-term phase excursion do not cause frequency shifts larger than [Formula: see text].

  3. Near Infrared Cavity Ring-Down Spectroscopy for Isotopic Analyses of CH4 on Future Martian Surface Missions

    NASA Technical Reports Server (NTRS)

    Chen, Y.; Mahaffy P.; Holmes, V.; Burris, J.; Morey, P.; Lehmann, K.K.; Lollar, B. Sherwood; Lacrampe-Couloume, G.; Onstott, T.C.

    2014-01-01

    A compact Near Infrared Continuous Wave Cavity Ring-Down Spectrometer (near-IR-cw-CRDS) was developed as a candidate for future planetary surface missions. The optical cavity was made of titanium with rugged quartz windows to protect the delicate super cavity from the harsh environmental changes that it would experience during space flight and a Martian surface mission. This design assured the long-term stability of the system. The system applied three distributed feedback laser diodes (DFB-LD), two of which were tuned to the absorption line peaks of (sup 12)CH4 and (sup 13)CH4 at 6046.954 inverse centimeters and 6049.121 inverse centimeters, respectively. The third laser was tuned to a spectral-lines-free region for measuring the baseline cavity loss. The multiple laser design compensated for typical baseline drift of a CRDS system and, thus, improved the overall precision. A semiconductor optical amplifier (SOA) was used instead of an Acousto-Optic Module (AOM) to initiate the cavity ring-down events. It maintained high acquisition rates such as AOM, but consumed less power. High data acquisition rates combined with improved long-term stability yielded precise isotopic measurements in this near-IR region even though the strongest CH4 absorption line in this region is 140 times weaker than that of the strongest mid-IR absorption band. The current system has a detection limit of 1.4 times 10( sup –12) inverse centimeters for (sup 13)CH4. This limit corresponds to approximately 7 parts per trillion volume of CH4 at 100 Torrs. With no further improvements the detection limit of our current near IR-cw-CRDS at an ambient Martian pressure of approximately 6 Torrs (8 millibars) would be 0.25 parts per billion volume for one 3.3 minute long analysis.

  4. Near infrared cavity ring-down spectroscopy for isotopic analyses of CH4 on future Martian surface missions

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Mahaffy, P.; Holmes, V.; Burris, J.; Morey, P.; Lehmann, K. K.; Sherwood Lollar, B.; Lacrampe-Couloume, G.; Onstott, T. C.

    2015-01-01

    A compact Near Infrared Continuous Wave Cavity Ring-down Spectrometer (near-IR-cw-CRDS) was developed as a candidate for future planetary surface missions. The optical cavity was made of titanium with rugged quartz windows to protect the delicate super cavity from the harsh environmental changes that it would experience during space flight and a Martian surface mission. This design assured the long-term stability of the system. The system applied three distributed feedback laser diodes (DFB-LD), two of which were tuned to the absorption line peaks of 12CH4 and 13CH4 at 6046.954 cm-1 and 6049.121 cm-1, respectively. The third laser was tuned to a spectral-lines-free region for measuring the baseline cavity loss. The multiple laser design compensated for typical baseline drift of a CRDS system and, thus, improved the overall precision. A semiconductor optical amplifier (SOA) was used instead of an Acousto-Optic Module (AOM) to initiate the cavity ring-down events. It maintained high acquisition rates such as AOM, but consumed less power. High data acquisition rates combined with improved long-term stability yielded precise isotopic measurements in this near-IR region even though the strongest CH4 absorption line in this region is 140 times weaker than that of the strongest mid-IR absorption band., The current system has a detection limit of 1.4×10-12 cm-1 for 13CH4. This limit corresponds to ~7 pptv of CH4 at 100 Torr. With no further improvements the detection limit of our current near IR-cw-CRDS at an ambient Martian pressure of ~6 Torr (8 mbar) would be 0.25 ppbv for one 3.3 minute long analysis.

  5. Modulation techniques

    NASA Technical Reports Server (NTRS)

    Schilling, D. L.

    1982-01-01

    Bandwidth efficient digital modulation techniques, proposed for use on and/or applied to satellite channels, are reviewed. In a survey of recent works on digital modulation techniques, the performance of several schemes operating in various environments are compared. Topics covered include: (1) quadrature phase shift keying; (2) offset - QPSK and MSK; (3) combined modulation and coding; and (4) spectrally efficient modulation techniques.

  6. Application thinking on Bian-stone of the acousto-optic effect in the treatment of primary dysmenorrhea

    NASA Astrophysics Data System (ADS)

    Ge, Shu; Chen, Gui-Zhen; Liu, Song-Hao

    2009-08-01

    In order to identify the relations between the Si-Bin Bian-stone of the mineral composition characteristics and Bian-stone of the good infrared emission features. A detailed study of the Sibin Bian-stone samples was conducted by using the laser Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM). The study is to provide theoretical physical support for Bian-stone in the treatment of primary dysmenorrhea. And Thermal tomography technology (TTM) is intended to be carried out to assess the effects of Bian-stone. The Raman spectroscopic study confirmed the existence of fine-grained pyrite, anatase, calcitepyrite and graphite. It is believed that the combination of good thermal properties of the above 4 minerals make the Sibin Bian-stone as a useful material with very good physiotherapical functions. The ultrasonic has a resonance with the body's biological molecules so that it can improve meridians microcirculation. Hence, the Sibin Bian-stones can be used to make acupuncture tools for stimulating the circulation of the blood in vessels and relieving pains of human beings by utilizing its infrared thermal radiation property. TTM which accepts the heat produced by the metabolism process of life can reflect the energy status information, TTM will be introduced to evaluate effect at the overall level of the abdomen from the thermal image and analyze to derive a comprehensive diagnosis. In sum, this experiment is explored to provide a new idea for the modernization of traditional Chinese medicine.

  7. Acousto-optic effect in a nematic liquid-crystal layer under the binary effect of sound and viscous waves

    SciTech Connect

    Kozhevnikov, E. N.

    2010-03-15

    The optical effect in a liquid crystal cell containing a homeotropic layer of nematic liquid crystal (NLC) is analyzed. An NLC layer, located between crossed polaroids and opaque in the absence of external effect, is cleared after irradiation by an ultrasonic beam with a sharp spatial boundary. This enlightenment is suggested to be caused by the reorientation of crystal molecules in the acoustic flows that arise under the binary effect of the layer compression in the irradiated region and the viscous waves propagating from the layer boundaries. The flows were calculated taking into account the stress caused by the velocity convection and crystal structure relaxation. An expression is derived for the cell transparency, and the relative role of the convection and relaxation processes in the effect is determined.

  8. 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.

  9. Calibration of a wide-field frequency-domain fluorescence lifetime microscopy system using light emitting diodes as light sources.

    PubMed

    Elder, A D; Frank, J H; Swartling, J; Dai, X; Kaminski, C F

    2006-11-01

    High brightness light emitting diodes are an inexpensive and versatile light source for wide-field frequency-domain fluorescence lifetime imaging microscopy. In this paper a full calibration of an LED based fluorescence lifetime imaging microscopy system is presented for the first time. A radio-frequency generator was used for simultaneous modulation of light emitting diode (LED) intensity and the gain of an intensified charge coupled device (CCD) camera. A homodyne detection scheme was employed to measure the demodulation and phase shift of the emitted fluorescence, from which phase and modulation lifetimes were determined at each image pixel. The system was characterized both in terms of its sensitivity to measure short lifetimes (500 ps to 4 ns), and its capability to distinguish image features with small lifetime differences. Calibration measurements were performed in quenched solutions containing Rhodamine 6G dye and the results compared to several independent measurements performed with other measurement methodologies, including time correlated single photon counting, time gated detection, and acousto optical modulator (AOM) based modulation of excitation sources. Results are presented from measurements and simulations. The effects of limited signal-to-noise ratios, baseline drifts and calibration errors are discussed in detail. The implications of limited modulation bandwidth of high brightness, large area LED devices ( approximately 40 MHz for devices used here) are presented. The results show that phase lifetime measurements are robust down to sub ns levels, whereas modulation lifetimes are prone to errors even at large signal-to-noise ratios. Strategies for optimizing measurement fidelity are discussed. Application of the fluorescence lifetime imaging microscopy system is illustrated with examples from studies of molecular mixing in microfluidic devices and targeted drug delivery research.

  10. Module Configuration

    DOEpatents

    Oweis, Salah; D'Ussel, Louis; Chagnon, Guy; Zuhowski, Michael; Sack, Tim; Laucournet, Gaullume; Jackson, Edward J.

    2002-06-04

    A stand alone battery module including: (a) a mechanical configuration; (b) a thermal management configuration; (c) an electrical connection configuration; and (d) an electronics configuration. Such a module is fully interchangeable in a battery pack assembly, mechanically, from the thermal management point of view, and electrically. With the same hardware, the module can accommodate different cell sizes and, therefore, can easily have different capacities. The module structure is designed to accommodate the electronics monitoring, protection, and printed wiring assembly boards (PWAs), as well as to allow airflow through the module. A plurality of modules may easily be connected together to form a battery pack. The parts of the module are designed to facilitate their manufacture and assembly.

  11. Heterodyne holography with full control of both the signal and reference arms.

    PubMed

    Gross, Michel

    2016-01-20

    Heterodyne holography is a variant of phase-shifting holography in which the reference and signal arms are controlled by acousto-optic modulators. In this review paper, we will briefly describe the method and its properties, and we will illustrate its advantages in experimental applications.

  12. Frequency noise in frequency swept fiber laser.

    PubMed

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2013-04-01

    This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto- optical modulators and forward propagating Brillouin scattering appear in the spectrum.

  13. Two-dimensional ultrafast fourier transform spectroscopy in the deep ultraviolet.

    PubMed

    Tseng, Chien-hung; Matsika, Spiridoula; Weinacht, Thomas C

    2009-10-12

    We demonstrate two-dimensional ultrafast fourier transform spectroscopy in the deep ultraviolet (approximately 260 nm) using an acousto-optic modulator based pulse shaper. The use of a pulse shaper in the ultraviolet allows for rapid scanning, high phase (time) stability (approximately 0.017 rad) and phase cycling. We present measurements on the DNA nucleobase Adenine.

  14. Module Evaluation

    DTIC Science & Technology

    2006-02-01

    various testing methodologies for the evaluation and characterization of Transmit /Receive (T/R) modules for phased array radars. Discussed are techniques...for characterizing T/R modules in transmit and receive modes under ideal and emulated operation environments. Further, techniques for life testing...characteristics of T/R modules developed during the early and mid 1980’s. Data provided shows the performance in terms of gain and phase for both transmit

  15. Modulated Entry

    NASA Technical Reports Server (NTRS)

    Grant, Frederick C.

    1960-01-01

    The technique of modulation, or variable coefficients, is discussed and the analytical formulation is reviewed. Representative numerical results of the use of modulation are shown for the lifting and nonlifting cases. These results include the effects of modulation on peak acceleration, entry corridor, and heat absorption. Results are given for entry at satellite speed and escape speed. The indications are that coefficient modulation on a vehicle with good lifting capability offers the possibility of sizable loading reductions or, alternatively, wider corridors; thus, steep entries become practical from the loading standpoint. The amount of steepness depends on the acceptable heating penalty. The price of sizable fractions of the possible gains does not appear to be excessive.

  16. Firefighting Module

    NASA Technical Reports Server (NTRS)

    1978-01-01

    NASA and the U.S. Coast Guard are working jointly to develop a helicopter transportable firefighting module that can shave precious minutes in combating shipboard or harbor fires. The program was undertaken in 1975, after a series of disastrous fires on oil tankers indicated a need for a lightweight, self-contained system that could be moved quickly to the scene of a fire. A prototype module was delivered to the Coast Guard last year and service testing is under way. The compact module weighs little more than a ton but it contains everything needed to fight a fire. The key component is a high output pump, which delivers up to 2,000 gallons of sea water a minute; the pump can be brought up to maximum output in only one minute after turning on the power source, a small Allison gas turbine engine. The module also contains hose, a foam nozzle and a spray nozzle, three sets of protective clothing for firefighters, and fuel for three hours operation. Designed to be assembled without special tools, the module can be set up for operation in less than 20 minutes.

  17. Firefighting Module

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Aviation Power Supply's mobile firefighting module called Firefly II is mounted on a trailer pulled by a pickup truck. Trailer unit has two three- inch water cannons, and the pickup carries a six inch cannon. Completely self contained, module pumps 3,000 gallons of water a minute from hydrants or open bodies of water. Stream can go as far as 400 feet or can be employed in a high-loft mode to reach the tops of tall refinery towers. Compact Firefly II weighs only 2,500 pounds when fully fueled. Key component is a specially designed two stage pump. Power for the pump is generated by a gas turbine engine. Module also includes an electronic/pump controller, multiple hose connections, up to 1,500 feet of hose and fuel for four hours operation. Firefly trailer can be backed onto specially-built large fireboat.

  18. Firefighting Module

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Aviation Power Supply's mobile firefighting module called Firefly II is mounted on a trailer pulled by a pickup truck. Trailer unit has two three- inch water cannons, and the pickup carries a six inch cannon. Completely self contained, module pumps 3,000 gallons of water a minute from hydrants or open bodies of water. Stream can go as far as 400 feet or can be employed in a high-loft mode to reach the tops of tall refinery towers. Compact Firefly II weighs only 2,500 pounds when fully fueled. Key component is a specially designed two stage pump. Power for the pump is generated by a gas turbine engine. Module also includes an electronic/pump controller, multiple hose connections, up to 1,500 feet of hose and fuel for four hours operation. Firefly trailer can be backed onto specially-built large fireboat.

  19. Thermionic modules

    DOEpatents

    King, Donald B.; Sadwick, Laurence P.; Wernsman, Bernard R.

    2002-06-18

    Modules of assembled microminiature thermionic converters (MTCs) having high energy-conversion efficiencies and variable operating temperatures manufactured using MEMS manufacturing techniques including chemical vapor deposition. The MTCs incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. The MTCs also exhibit maximum efficiencies of just under 30%, and thousands of the devices and modules can be fabricated at modest costs.

  20. Multiple Isotope Magneto Optical Trap from a single diode laser

    NASA Astrophysics Data System (ADS)

    Gomez, Eduardo; Valenzuela, Victor; Hamzeloui, Saeed; Gutierrez, Monica

    2013-05-01

    We present a simple design for a Dual Isotope Magneto Optical Trap. The system requires a single diode laser, a fiber modulator and a tapered amplifier to trap and completely control both 85Rb and 87Rb. We generate all the frequencies needed for trapping both species using the fiber intensity modulator. All the frequencies are amplified simultaneously with the tapered amplifier. The position and power of each frequency is now controlled independently on the RF rather than on the optical side. This introduces an enormous simplification for laser cooling that often requires an acousto-optic modulator for each frequency. The range of frequency changes is much bigger than what is available with acousto-optic modulators since in our case is determined by the modulator bandwidth (10 GHz). Additional isotopes can be simply added by including additional RF frequencies to the modulator and extra beams for other uses can be produced the same way. Support from CONACYT, PROMEP and UASLP.

  1. Towards understanding initiation reactions of explosives via ultrafast laser quantum control

    SciTech Connect

    Greenfield, Margo T; Mc Grane, Shawn D; Moore, David S; Scharff, R. Jason

    2010-12-08

    Optimal control can be utilized to control the initiation reaction of explosives, where time dependent phase shaped electric fields drive the chemical systems towards a desired state. For quantum controlled initiation (QCI) of explosives a pulse is created which seeks to achieve initiation by employing shaped ultraviolet light. QCI will enhance the understanding of energetic material reactions by yielding insight into the characteristics, such as critical 'hot spot' size and reaction dynamics, necessary for initiation. Quantum control experiments require the ability to: (1) phase and amplitude shape an ultrafast laser pulse, (2) measure the effect of pulse shape, and (3) optimize the desired outcome. Pulse shaping is performed with a 4-focal length dispersed fused silica acousto-optic modulator (AOM) at 400 nm in the ultraviolet (UV). Transient absorption spectroscopy is used to measure the pulse shape effects. Both global and local optimization search routines such as genetic algorithm, differential evolution, and downhill simplex are used to search for the optimal pulse shape. Hexanitroazobenzene (HNAB), Trinitroanaline (TNA) and Diaminoazozyfurazan (DAAF) are excited to the first electronic state with 400 nm light. Our initiation experiments are studying the effect of phase shaped 400 nm pulses on HNAB, TNA and DAAF. Novel transient absorption spectra for each material have been obtained and note worthy regions further investigated with single parameter control (second order spectral phase and energy). Many systems have simple intensity control such as that shown by DAAF. TNA and HNAB have spectral features that are not single parameter driven and are being further investigated with complex control.

  2. Towards mitigating explosive threats using quantum controlled initiation

    SciTech Connect

    Greenfield, Margo T; Mc Grane, Shawn D; Moore, David S; Scharff, R. Jason

    2010-12-08

    Quantum control of localized energy deposition into an energetic material is being investigated as a method to allow controlled initiation and propagation of action without transition to detonation. Quantum controlled initiation (QCI) of explosives utilize time dependent phase shaped ultraviolet (UV) electric fields to drive the energetic chemical systems towards reaction. QCI searches for an optimally shaped ultrafast laser pulse that will guide energy flow along a desired path. QCI can be exploited as a stand-off mitigation technology that strives to reduce the impact of explosive blasts on people and property by initiating controlled low order reaction. Quantum controlled initiation experiments require: (1) optimally shaped light pulses, (2) pulse shaping measurement, (3) feedback control algorithms, and (4) feedback measurement methods. Femtosecond laser pulse shaping in the UV at 400 nm employs a fused silica acousto-optic modulator (AOM) pulse shaper that consists of a 4-f zero dispersion compressor. Tr sient absorption spectroscopy is used to measure the pulse shaper effects. Both global and local optimization search routines such as genetic algorithm, differential evolution, and downhill simplex are used to search for the optimal pulse shape. Hexanitroazobenzene (HNAB), Trinitroanaline (TNA) and Diaminoazozyfurazan (DAAF) are excited to the first electronic state with 400 nm light. Our initiation experiments are studying the effect of phase shaped 400 nm pulses on HNAB, TNA and DAAF. The transient absorption spectra for each material have been obtained and note worthy regions further investigated with single parameter control (second order spectral phase and energy). Many systems have simple intensity control such as that shown by DAAF. TNA and HNAB have spectral features that are not single parameter driven and are being further investigated to obtain fully optimized complex control.

  3. A novel fiber laser development for photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Yavas, Seydi; Aytac-Kipergil, Esra; Arabul, Mustafa U.; Erkol, Hakan; Akcaalan, Onder; Eldeniz, Y. Burak; Ilday, F. Omer; Unlu, Mehmet B.

    2013-03-01

    Photoacoustic microscopy, as an imaging modality, has shown promising results in imaging angiogenesis and cutaneous malignancies like melanoma, revealing systemic diseases including diabetes, hypertension, tracing drug efficiency and assessment of therapy, monitoring healing processes such as wound cicatrization, brain imaging and mapping. Clinically, photoacoustic microscopy is emerging as a capable diagnostic tool. Parameters of lasers used in photoacoustic microscopy, particularly, pulse duration, energy, pulse repetition frequency, and pulse-to-pulse stability affect signal amplitude and quality, data acquisition speed and indirectly, spatial resolution. Lasers used in photoacoustic microscopy are typically Q-switched lasers, low-power laser diodes, and recently, fiber lasers. Significantly, the key parameters cannot be adjusted independently of each other, whereas microvasculature and cellular imaging, e.g., have different requirements. Here, we report an integrated fiber laser system producing nanosecond pulses, covering the spectrum from 600 nm to 1100 nm, developed specifically for photoacoustic excitation. The system comprises of Yb-doped fiber oscillator and amplifier, an acousto-optic modulator and a photonic-crystal fiber to generate supercontinuum. Complete control over the pulse train, including generation of non-uniform pulse trains, is achieved via the AOM through custom-developed field-programmable gate-array electronics. The system is unique in that all the important parameters are adjustable: pulse duration in the range of 1-3 ns, pulse energy up to 10 μJ, repetition rate from 50 kHz to 3 MHz. Different photocoustic imaging probes can be excited with the ultrabroad spectrum. The entire system is fiber-integrated; guided-beam-propagation rendersit misalignment free and largely immune to mechanical perturbations. The laser is robust, low-cost and built using readily available components.

  4. Blueberry consumption inhibits gastrointestinal tumorigenesis in AOM-treated rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Epidemiological studies show inverse or no association of fruit consumption with relative risk for colorectal cancers. Such studies did not examine specific fruits and in particular, those enriched in polyphenols with high antioxidant capacities. We examined blueberry (BB), a fruit rich in anthocy...

  5. Two-dimensional RI spectroscopy: Automation with pulse shaping and application to amyloid folding

    NASA Astrophysics Data System (ADS)

    Shim, Sang-Hee

    Two dimensional infrared (2D IR) spectroscopy has proven itself as a unique tool for probing the structures and dynamics of chemical and biological systems. Now, 2D IR spectroscopy has progressed to the point of being a ready-to-operate method for general researchers to address novel scientific questions. For that purpose, this thesis includes three practices: inventing a technique for mid-infrared pulse shaping; developing an automated method of collecting 2D IR spectra; applying it to delineate the pathway of amyloid formation. First, we developed a means to shape femtosecond pulses in the mid-infrared using a germanium acousto-optic modulator (Ge AOM). The Ge AOM directly modulates the amplitude and phase of mid-IR light between 2-18 mum, producing intense shaped pulses with high resolution and good phase stability. Second, we combined the pulse shaper with a pump-probe geometry to develop a new method of 2D IR spectroscopy. The pump-probe geometry simplifies the optical setup and produces properly phased absorptive lineshapes without additional data processing. The pulse shaper not only reproduces most conventional methods, but also allows new pulse shapes and phase combinations to further enhance 2D IR spectroscopy. Moreover, eliminating moving parts accelerates data collection so that an entire 2D IR spectrum can be obtained in <1 sec. Such ease of use, versatility and speed of our pulse shaping 2D IR method enables more sophisticated and reliable experiments. Finally, we tracked amyloid formation of human Islet amyloid polypeptide (hIAPP), related to type II diabetes. By continuously scanning 2D IR spectra, we can follow the hIAPP fibril formation indefinitely by collecting data on-the-fly without reinitiating the aggregation for each data point. We used isotope-labeling to probe the structural evolution of six different residues along the 37-residue hIAPP peptide. By separately monitoring the six residues, we found that the peptides nucleate near the turn

  6. Firefighting Module

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Firefly II pump module is NASA's Marshall Space Flight Center's commercial offshoot of a NASA/US Coast Guard program involving development of a lightweight, helicopter-transportable firefighting module for a quick response in combating shipboard or harbor fires. Operable on land or water, the Amphib One is equipped with 3 water cannons. When all 3 are operating, unit pumps more than 3,000 gallons a minute. Newly developed model used by U.S. Coast Guard can pump 5,000 gallons per minute. It was designed for applications such as firefighting onboard ship fires, emergency dockside water pumping, dewatering ships in danger of sinking, flood control, and emergency water supply at remote locations.

  7. Thermoelectric module

    DOEpatents

    Kortier, William E.; Mueller, John J.; Eggers, Philip E.

    1980-07-08

    A thermoelectric module containing lead telluride as the thermoelectric mrial is encapsulated as tightly as possible in a stainless steel canister to provide minimum void volume in the canister. The lead telluride thermoelectric elements are pressure-contacted to a tungsten hot strap and metallurgically bonded at the cold junction to iron shoes with a barrier layer of tin telluride between the iron shoe and the p-type lead telluride element.

  8. Linear modulator

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A study of frequency division multiplexing (FDM) systems was made for the purpose of determining the system performance that can be obtained with available state of the art components. System performance was evaluated on the basis of past experience, system analysis, and component evaluation. The system study was specifically directed to the area of FDM systems using subcarrier channel frequencies from 4 kHz to 200 kHz and channel information bandwidths of dc to 1, 2, 4, 8, and 16 kHz. The evaluation also assumes that the demodulation will be from a tape recorder which produces frequency modulation of + or - 1% on the signal due to the tape recorder wow and flutter. For the modulation system it is assumed that the pilot and carrier channel frequencies are stable to within + or - .005% and that the FM on the channel carriers is negligible. The modulator system was evaluated for the temperature range of -20 degree to +85 degree while the demodulator system was evaluated for operation at room temperature.

  9. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Lenox, Carl J. S. [Oakland, CA; Culligan, Matthew [Berkeley, CA; Danning, Matt [Oakland, CA

    2012-07-17

    A photovoltaic (PV) module including a PV device and a frame. The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  10. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Lenox, Carl J. S.; Culligan, Matthew; Danning, Matt

    2013-08-27

    A photovoltaic (PV) module including a PV device and a frame, The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  11. Optical aberration compensation in a multiplexed optical trapping system

    NASA Astrophysics Data System (ADS)

    Čižmár, T.; Dalgarno, H. I. C.; Ashok, P. C.; Gunn-Moore, F. J.; Dholakia, K.

    2011-04-01

    In this paper we discuss optical aberrations within a multiplexed optical trapping system. We analyze two of the most powerful methods for optical trap multiplexing: time-shared beam steering and holographic beam shaping in a tandem system with an acousto-optic deflector and spatial light modulator. We show how to isolate and correct for the aberrations introduced by these individual optical components using the spatial light modulator and demonstrate the enhancement this provides to optical trapping.

  12. Supported PV module assembly

    DOEpatents

    Mascolo, Gianluigi; Taggart, David F.; Botkin, Jonathan D.; Edgett, Christopher S.

    2013-10-15

    A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

  13. A Modified Monte Carlo Model of Speckle Tracking of Shear Wave Induced by Acoustic Radiation Force for Acousto-Optic Elasticity Imaging

    NASA Astrophysics Data System (ADS)

    Li, Yu-Jiao; Huang, Wei-Jun; Ma, Feng-Chao; Wang, Rui; Lu, Ming-Zhu; Wan, Ming-Xi

    2016-11-01

    Not Available Supported by the National Key Scientific Instrument and Equipment Development Projects of China under Grant No 81127901, and the National Natural Science Foundation of China under Grant Nos 61372017 and 30970828.

  14. Lunar Module Ascent Stage

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The Lunar Module 'Spider' ascent stage is photographed from the Command/Service Module on the fifth day of the Apollo 9 earth-orbital mission. The Lunar Module's descent stage had already been jettisoned.

  15. Wide deviation phase modulator

    NASA Technical Reports Server (NTRS)

    Couch, R. H.; Hearn, C. P.; Wilson, L. R.

    1974-01-01

    Modulator produces phase-modulated waveform having high modulating linearity. Technique is inherently wideband with respect to carrier frequency and can operate over decade carrier frequency range without adjustments. Circuit performance is both mathematically predictable and highly reproducible.

  16. Ballasted photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA

    2011-11-29

    A photovoltaic (PV) module assembly including a PV module and a ballast tray. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes an arm. The ballast tray is adapted for containing ballast and is removably associated with the PV module in a ballasting state where the tray is vertically under the PV laminate and vertically over the arm to impede overt displacement of the PV module. The PV module assembly can be installed to a flat commercial rooftop, with the PV module and the ballast tray both resting upon the rooftop. In some embodiments, the ballasting state includes corresponding surfaces of the arm and the tray being spaced from one another under normal (low or no wind) conditions, such that the frame is not continuously subjected to a weight of the tray.

  17. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  18. Remote, Aerial, Trans-Layer, Linear and Non-Linear Downlink Underwater Acoustic Communication

    DTIC Science & Technology

    2006-09-01

    with the acousto-optic detection using the laser Doppler vibrometer has also been used to demonstrate the initial feasibility of a remote, aerial...rate, modulation parameters, and sound pressure level requirements. Figure 4 shows an acoustic shockwave , time waveform produced by a single...and picosecond regime exist that do not produce additional acoustic transients following the optical breakdown shockwave in water. It is possible

  19. Quantitative phase microscopy with asynchronous digital holography.

    PubMed

    Chalut, Kevin J; Brown, William J; Wax, Adam

    2007-03-19

    We demonstrate a new method of measuring quantitative phase in imaging of biological materials. This method, asynchronous digital holography, employs knowledge of a moving fringe created by acousto-optic modulators to execute phase-shifting interferometry using two near-simultaneous interferograms. The method can be used to obtain quantitative phase images of dynamic biological samples on millisecond time scales. We present results on a standard sample, and on live cell samples.

  20. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.; Xie, Jinchun

    1999-01-01

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

  1. Development of a broadband laser in the UV region

    NASA Astrophysics Data System (ADS)

    Atutov, S. N.; Biancalana, V.; Calabrese, R.; Guidi, V.; Lenisa, P.; Mai, B.; Mariotti, E.; Moi, L.; Tomassetti, L.

    2000-08-01

    A frequency comb in the UV region with a bandwidth greater than 100 MHz is generated by successive frequency shifts of a single mode laser by an acousto-optic modulator coupled to a passive ring cavity. The obtained spectrum is particularly suitable for laser cooling when a large velocity capture range is required as in the case, for example, of ions confined in a storage ring.

  2. Module utilization committee

    NASA Technical Reports Server (NTRS)

    Volkmer, K.; Praver, G.

    1984-01-01

    Photovoltaic collector modules were declared surplus to the needs of the U.S. Dept. of Energy. The Module Utilization Committee was formed to make appropriate disposition of the surplus modules on a national basis and to act as a broker for requests for these modules originating outside of the National Photovoltaics Program.

  3. Almond brush module cutter

    SciTech Connect

    Zohns, M.A.; Jenkins, B.M.; Mehlschau, J.J.; Morrison, D.

    1983-06-01

    This paper addresses the design, construction, and evaluation of an almond brush module cutter. The module cutter is one link in a system which processes tree prunings for fuel and fiber. This system includes a modified cotton module builder, a module mover, the cutter, and a tub grinder. An economic analysis of the cutter is presented along with the problems involved in cutting brush modules.

  4. Two-dimensional analytic modeling of acoustic diffraction for ultrasonic beam steering by phased array transducers.

    PubMed

    Wang, Tiansi; Zhang, Chong; Aleksov, Aleksandar; Salama, Islam; Kar, Aravinda

    2017-04-01

    Phased array ultrasonic transducers enable modulating the focal position of the acoustic waves, and this capability is utilized in many applications, such as medical imaging and non-destructive testing. This type of transducers also provides a mechanism to generate tilted wavefronts in acousto-optic deflectors to deflect laser beams for high precision advanced laser material processing. In this paper, a theoretical model is presented for the diffraction of ultrasonic waves emitted by several phased array transducers into an acousto-optic medium such as TeO2 crystal. A simple analytic expression is obtained for the distribution of the ultrasonic displacement field in the crystal. The model prediction is found to be in good agreement with the results of a numerical model that is based on a non-paraxial multi-Gaussian beam (NMGB) model.

  5. Optimization Of Shear Modes To Produce Enhanced Bandwidth In Ghz GaP Bragg Cells

    NASA Astrophysics Data System (ADS)

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

    1988-02-01

    Applications of Gallium Phosphide (GaP) acousto-optic devices, at wavelengths from 570nm - 1.06um seem to be ideal for fiber optic modulators, scanners, deflectors, frequency shifters, Q-switches and mode lockers. One of the major applications are for RF spectrometers in early warning radar receivers and auto-correlators. Longitudinal GaP acousto-optic Bragg cells which have respectively operational frequencies in the range of 200 MHz - 3 GHz and diffraction efficiencies in the range of 120%/RF watt to 1%/RF watt have recently been fabricated. Comparatively, shear GaP devices which have operational frequencies in the range of 200 MHz to 2 GHz and diffraction efficiencies from 80%/RF watt to 7%/RF watt have also been constructed.

  6. Actively coupled cavity ringdown spectroscopy with low-power broadband sources.

    PubMed

    Petermann, Christian; Fischer, Peer

    2011-05-23

    We demonstrate a coupling scheme for cavity enhanced absorption spectroscopy that makes use of an intracavity acousto-optical modulator to actively switch light into (and out of) a resonator. This allows cavity ringdown spectroscopy (CRDS) to be implemented with broadband nonlaser light sources with spectral power densities of less than 30μW/nm. Although the acousto-optical element reduces the ultimate detection limit by introducing additional losses, it permits absorptivities to be measured with a high dynamic range, especially in lossy environments. Absorption measurements for the forbidden transition of gaseous oxygen in air at ∼760nm are presented using a low-coherence cw-superluminescent diode. The same setup was electronically configured to cover absorption losses from 1.8×10-8cm-1 to 7.5% per roundtrip. This could be of interest in process analytical applications.

  7. Wideband Linear Phase Modulator

    NASA Technical Reports Server (NTRS)

    Mysoor, Narayan R.; Mueller, Robert O.

    1994-01-01

    Phase modulator for transmission in X band provides large phase deviation that remains nearly linear with voltage over relatively wide range. Operates with low loss over wide frequency band and with stable characteristics over wide temperature range. Phase modulator contains two varactor-diode phase shifters coupled via circulators. Separate drive circuit applies modulating voltages to varactor diodes. Modulation voltages vary in accordance with input to drive circuit.

  8. Modulating lignin in plants

    SciTech Connect

    Apuya, Nestor; Bobzin, Steven Craig; Okamuro, Jack; Zhang, Ke

    2013-01-29

    Materials and methods for modulating (e.g., increasing or decreasing) lignin content in plants are disclosed. For example, nucleic acids encoding lignin-modulating polypeptides are disclosed as well as methods for using such nucleic acids to generate transgenic plants having a modulated lignin content.

  9. Temporal Aperture Modulation

    NASA Technical Reports Server (NTRS)

    Proctor, R. J.

    1981-01-01

    The two types of modulation techniques useful to X-ray imaging are reviewed. The use of optimum coded temporal aperature modulation is shown, in certain cases, to offer an advantage over a spatial aperture modulator. Example applications of a diffuse anisotropic X-ray background experiment and a wide field of view hard X-ray imager are discussed.

  10. Curriculum Development: Cultural Modules

    ERIC Educational Resources Information Center

    Hill, John C.

    1978-01-01

    Language and cultural modules are multimedia in nature and non-sequential. Modules should be used in association with the themes and vocabulary found in the main course textbook. Reference is made to the "A-LM German Language Programs" and modules produced by Ontario German teachers in 1976 in West Germany. (SW)

  11. Rescue Manual. Module 5.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Instructional Materials Lab.

    This learner manual for rescuers covers the current techniques or practices required in the rescue service. The fifth of 10 modules contains information on hazardous materials. Key points, an introduction, and conclusion accompany substantive material in this module. In addition, the module contains a Department of Transportation guide chart on…

  12. Integrating Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Provides an overview of the complete National Energy Modeling System (NEMS) model, and includes brief descriptions of the modules with which the Integrating Module interacts. The emphasis and focus, however, is on the structure and function of the Integrating Module of NEMS.

  13. Spatial Light Amplifier Modulators

    NASA Technical Reports Server (NTRS)

    Eng, Sverre T.; Olsson, N. Anders

    1992-01-01

    Spatial light amplifier modulators (SLAM's) are conceptual devices that effect two-dimensional spatial modulation in optical computing and communication systems. Unlike current spatial light modulators, these provide gain. Optical processors incorporating SLAM's designed to operate in reflection or transmission mode. Each element of planar SLAM array is optical amplifier - surface-emitting diode laser. Array addressed electrically with ac modulating signals superimposed on dc bias currents supplied to lasers. SLAM device provides both desired modulation and enough optical gain to enable splitting of output signal into many optical fibers without excessive loss of power.

  14. Small modulation ellipsometry

    NASA Technical Reports Server (NTRS)

    Ducharme, Stephen P. (Inventor); El Hajj, Hassanayn M. (Inventor); Johs, Blaine D. (Inventor); Woollam, John A. (Inventor)

    1995-01-01

    In an ellipsometer, a phase-modulated, polarized light beam is applied to a sample, electrical signals are obtained representing the orthogonal planes of polarization of the light after it has interacted with the sample and the constants of the sample are calculated from the two resulting electrical signals. The phase modulation is sufficiently small so that the calibration errors are negligible. For this purpose, the phase modulator phase modulates the light within a range of no more than ten degrees modulations peak to peak. The two electrical signals are expanded by Fourier analysis and the coefficients thereof utilized to calculate psi and delta.

  15. Flammability of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Sugimura, R. S.; Otth, D. H.; Ross, R. G., Jr.; Lewis, K. J.; Arnett, J. C.

    1984-01-01

    A series of Class B burning-brand tests were performed on experimental modules using high-temperature, back-surface materials to develop the technology base required to construct fire-ratable modules. Results indicate the existence of synergistic relationships between hydrocarbon encapsulation materials and the experimental module configurations that provide increased fire resistance. These configurations use Kapton, fiberglass, neoprene rubber, stainless-steel foil or aluminum foil as the back surface. Successful test results occur when the structural integrity of the module back surface is maintained. Test failures of these modules always occur for one of three reasons: the outermost back cover melts, rips, or is too porous. In each case flammable molten encapsulant, its gaseous byproducts, or both, penetrates the back surface of the module and bursts into flame. Future efforts to complete the technology base will concentrate on the spread-of-flame test, focusing on the more promising configurations identified in the initial series of tests.

  16. Flammability of photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Sugimura, R. S.; Otth, D. H.; Ross, R. G., Jr.; Lewis, K. J.; Arnett, J. C.

    A series of Class B burning-brand tests were performed on experimental modules using high-temperature, back-surface materials to develop the technology base required to construct fire-ratable modules. Results indicate the existence of synergistic relationships between hydrocarbon encapsulation materials and the experimental module configurations that provide increased fire resistance. These configurations use Kapton, fiberglass, neoprene rubber, stainless-steel foil or aluminum foil as the back surface. Successful test results occur when the structural integrity of the module back surface is maintained. Test failures of these modules always occur for one of three reasons: the outermost back cover melts, rips, or is too porous. In each case flammable molten encapsulant, its gaseous byproducts, or both, penetrates the back surface of the module and bursts into flame. Future efforts to complete the technology base will concentrate on the spread-of-flame test, focusing on the more promising configurations identified in the initial series of tests.

  17. THERMOELECTRIC POWER MODULES.

    DTIC Science & Technology

    During this reporting period the four thermo electric power modules which were put on life test completed 2000 hours of unattended operation. A hot...junction temperature of 800 C was main tained. During this time period satisfactory performance of the modules was observed and the test is continuing...Two additional modules were started on a cycled life test , one hour on and one and one half hours off for an eight hour period, and continuous

  18. Telemetry remote modules

    NASA Technical Reports Server (NTRS)

    Silverman, J. R.

    1972-01-01

    A fully operational engineering telemetry remote module is reported that forms the basis for a decentralized telemetry system which employs small low powered modules capable of distributing the multiplexer input gates around a spacecraft. The module operates mainly as a harness reducer, allowing data to be transmitted back to a central control core for inclusion in the telemetry bit stream. Each unit is capable of accepting 32 data points in various combinations.

  19. Cavity enhanced terahertz modulation

    SciTech Connect

    Born, N.; Scheller, M.; Moloney, J. V.; Koch, M.

    2014-03-10

    We present a versatile concept for all optical terahertz (THz) amplitude modulators based on a Fabry-Pérot semiconductor cavity design. Employing the high reflectivity of two parallel meta-surfaces allows for trapping selected THz photons within the cavity and thus only a weak optical modulation of the semiconductor absorbance is required to significantly damp the field within the cavity. The optical switching yields to modulation depths of more than 90% with insertion efficiencies of 80%.

  20. Bubble memory module

    NASA Technical Reports Server (NTRS)

    Bohning, O. D.; Becker, F. J.

    1980-01-01

    Design, fabrication and test of partially populated prototype recorder using 100 kilobit serial chips is described. Electrical interface, operating modes, and mechanical design of several module configurations are discussed. Fabrication and test of the module demonstrated the practicality of multiplexing resulting in lower power, weight, and volume. This effort resulted in the completion of a module consisting of a fully engineered printed circuit storage board populated with 5 of 8 possible cells and a wire wrapped electronics board. Interface of the module is 16 bits parallel at a maximum of 1.33 megabits per second data rate on either of two interface buses.

  1. Bubble memory module

    NASA Astrophysics Data System (ADS)

    Bohning, O. D.; Becker, F. J.

    1980-12-01

    Design, fabrication and test of partially populated prototype recorder using 100 kilobit serial chips is described. Electrical interface, operating modes, and mechanical design of several module configurations are discussed. Fabrication and test of the module demonstrated the practicality of multiplexing resulting in lower power, weight, and volume. This effort resulted in the completion of a module consisting of a fully engineered printed circuit storage board populated with 5 of 8 possible cells and a wire wrapped electronics board. Interface of the module is 16 bits parallel at a maximum of 1.33 megabits per second data rate on either of two interface buses.

  2. Advanced module development overview

    NASA Technical Reports Server (NTRS)

    Smokler, M. I.

    1984-01-01

    Crystalline silicon solar power modules are examined for reliability and cost effectiveness. A goal of 12% solar energy conversion efficiency is considered feasible at a cost of 12/kWh, and a decision is made to limit consideration to float zone silicon wafer and dendritic web silicone modules. A preliminary module packaging configuration of glass/ethylene vinyl acetate/plastic film is selected. Anticipated module efficiency levels are 12.6% at 25 C and 11.5% at NOCT (Nominal Operating Cell Temperature).

  3. Bracket for photovoltaic modules

    SciTech Connect

    Ciasulli, John; Jones, Jason

    2014-06-24

    Brackets for photovoltaic ("PV") modules are described. In one embodiment, a saddle bracket has a mounting surface to support one or more PV modules over a tube, a gusset coupled to the mounting surface, and a mounting feature coupled to the gusset to couple to the tube. The gusset can have a first leg and a second leg extending at an angle relative to the mounting surface. Saddle brackets can be coupled to a torque tube at predetermined locations. PV modules can be coupled to the saddle brackets. The mounting feature can be coupled to the first gusset and configured to stand the one or more PV modules off the tube.

  4. Membrane module assembly

    DOEpatents

    Kaschemekat, J.

    1994-03-15

    A membrane module assembly is described which is adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation. 2 figures.

  5. Lunar Module Communications

    NASA Technical Reports Server (NTRS)

    Interbartolo, Michael A.

    2009-01-01

    This slide presentation reviews the Apollo lunar module communications. It describes several changes in terminology from the Apollo era to more recent terms. It reviews: (1) Lunar Module Antennas and Functions (2). Earth Line of Sight Communications Links (3) No Earth Line of Sight Communications Links (4) Lunar Surface Communications Links (5) Signal-Processing Assembly (6) Instrumentation System (7) Some Communications Problems Encountered

  6. Modules in Death Education.

    ERIC Educational Resources Information Center

    McCartney, K. Ann; And Others

    Designed for use with accompanying videotapes as single presentations or as a series for professionals or laypeople, or as supplementary modules in academic courses in psychology, marriage and family, health occupations, etc., these four learning modules focus on common phases of dying and grief as part of the normal cycle of living. The modules…

  7. Water electrolysis module

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.

    1971-01-01

    Module utilizes static water-feed electrolysis system and air-cooled fins to remove heat generated by cell inefficiencies. Module generates 0.15 pounds of oxygen and 0.0188 pounds of hydrogen at current density of 100 amps per square foot. Generator operates in aircraft, spacecraft, or submarine cabins.

  8. Logs Perl Module

    SciTech Connect

    Owen, R. K.

    2007-04-04

    A perl module designed to read and parse the voluminous set of event or accounting log files produced by a Portable Batch System (PBS) server. This module can filter on date-time and/or record type. The data can be returned in a variety of formats.

  9. Human Development Student Modules.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This set of 61 student learning modules deals with various topics pertaining to human development. The modules, which are designed for use in performance-based vocational education programs, each contain the following components: an introduction for the student, a performance objective, a variety of learning activities, content information, a…

  10. Rescue Manual. Module 7.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Instructional Materials Lab.

    This learner manual for rescuers covers the current techniques or practices required in the rescue service. The seventh of 10 modules contains information on extrication from vehicles. Key points, an introduction, and conclusion accompany substantive material in this module. In addition, suggested tools and equipment for extrication procedures are…

  11. Module Safety Issues (Presentation)

    SciTech Connect

    Wohlgemuth, J.

    2012-02-01

    Description of how to make PV modules so that they are less likely to turn into safety hazards. Making modules inherently safer with minimum additional cost is the preferred approach for PV. Safety starts with module design to ensure redundancy within the electrical circuitry to minimize open circuits and proper mounting instructions to prevent installation related ground faults. Module manufacturers must control the raw materials and processes to ensure that that every module is built like those qualified through the safety tests. This is the reason behind the QA task force effort to develop a 'Guideline for PV Module Manufacturing QA'. Periodic accelerated stress testing of production products is critical to validate the safety of the product. Combining safer PV modules with better systems designs is the ultimate goal. This should be especially true for PV arrays on buildings. Use of lower voltage dc circuits - AC modules, DC-DC converters. Use of arc detectors and interrupters to detect arcs and open the circuits to extinguish the arcs.

  12. Membrane module assembly

    DOEpatents

    Kaschemekat, Jurgen

    1994-01-01

    A membrane module assembly adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation.

  13. Applied Algebra Curriculum Modules.

    ERIC Educational Resources Information Center

    Texas State Technical Coll., Marshall.

    This collection of 11 applied algebra curriculum modules can be used independently as supplemental modules for an existing algebra curriculum. They represent diverse curriculum styles that should stimulate the teacher's creativity to adapt them to other algebra concepts. The selected topics have been determined to be those most needed by students…

  14. Cosmetology. Computerized Learning Modules.

    ERIC Educational Resources Information Center

    Finnerty, Kathy, Ed.

    Intended to help reading-limited students meet course objectives, these 11 modules are based on instructional materials in cosmetology that have a higher readability equivalent. Modules cover bacteriology, chemical waving, scalp and hair massage, chemistry, hair shaping, hairstyling, chemical hair relaxing, hair coloring, skin and scalp,…

  15. Solar energy modulator

    NASA Technical Reports Server (NTRS)

    Hale, R. R. (Inventor); Mcdougal, A. R.

    1984-01-01

    A module is described with a receiver having a solar energy acceptance opening and supported by a mounting ring along the optic axis of a parabolic mirror in coaxial alignment for receiving solar energy from the mirror, and a solar flux modulator plate for varying the quantity of solar energy flux received by the acceptance opening of the module. The modulator plate is characterized by an annular, plate-like body, the internal diameter of which is equal to or slightly greater than the diameter of the solar energy acceptance opening of the receiver. Slave cylinders are connected to the modulator plate for supporting the plate for axial displacement along the axis of the mirror, therby shading the opening with respect to solar energy flux reflected from the surface of the mirror to the solar energy acceptance opening.

  16. Japanese Experiment Module (JEM)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Japanese Experiment Module (JEM) pressure module is removed from its shipping crate and moved across the floor of the Space Station Processing Facility at Kennedy Space Center (KSC) to a work stand. A research laboratory, the pressurized module is the first element of the JEM, named 'Kibo' (Hope) to arrive at KSC. Japan's primary contribution to the International Space Station, the module will enhance unique research capabilities of the orbiting complex by providing an additional environment in which astronauts will conduct experiments. The JEM also includes an exposed facility or platform for space environment experiments, a robotic manipulator system, and two logistics modules. The various JEM components will be assembled in space over the course of three Shuttle missions.

  17. Narrow-linewidth Q-switched random distributed feedback fiber laser.

    PubMed

    Xu, Jiangming; Ye, Jun; Xiao, Hu; Leng, Jinyong; Wu, Jian; Zhang, Hanwei; Zhou, Pu

    2016-08-22

    A narrow-linewidth Q-switched random fiber laser (RFL) based on a half-opened cavity, which is realized by narrow-linewidth fiber Bragg grating (FBG) and a section of 3 km passive fiber, has been proposed and experimentally investigated. The narrow-linewidth lasing is generated by the spectral filtering of three FBGs with linewidth of 1.21 nm, 0.56 nm, and 0.12 nm, respectively. The Q switching of the distributed cavity is achieved by placing an acousto-optical modulator (AOM) between the FBG and the passive fiber. The maximal output powers of the narrow-linewidth RFLs with the three different FBGs are 0.54 W, 0.27 W, and 0.08 W, respectively. Furthermore, the repetition rates of the output pulses are 500 kHz, and the pulse durations are about 500 ns. The corresponding pulse energies are about 1.08 μJ, 0.54 μJ, and 0.16 μJ, accordingly. The linewidth of FBG can influence the output characteristics in full scale. The narrower the FBG, the higher the pump threshold; the lower the output power at the same pump level, the more serious the linewidth broadening; and thus the higher the proportion of the CW-ground exists in the output pulse trains. Thanks to the assistance of the band-pass filter (BPF), the proportion of the CW-ground of narrow-linewidth Q-switched RFL under the relative high-pump-low-output condition can be reduced effectively. The experimental results indicate that it is challenging to demonstrate a narrow-linewidth Q-switched RFL with high quality output. But further power scaling and linewidth narrowing is possible in the case of operating parameters, optimization efforts, and a more powerful pump source. To the best of our knowledge, this is the first demonstration of narrow-linewidth generation in a Q-switched RFL.

  18. A Polarization-Diversity Homodyne Image-Reject Optical Tranceiver Architecture for Improved Range and Signal Detection in Coherent Doppler Lidars

    NASA Astrophysics Data System (ADS)

    Abari, C. F.; Chu, X.; Mann, J.

    2014-12-01

    Doppler light detection and ranging (lidar) has been used for a few decades for the characterization of wind fields and turbulence structures in the atmosphere. More recently, due to the advances in fiber optic communications, all-fiber coherent Doppler lidars (CDL) have been developed and widely used as a primary instrument for probing the atmospheric boundary layer wind fields. Due to a variety of reasons, all-fiber CDLs have gradually replaced their counterparts benefiting from technologies other than fiber optics. Most CDLs suffer from a number of drawbacks inherent to their principle of operation. For instance, one of the main challenges in CDLs is extracting the signal information from noisy observations, which is common to most opto-electronic systems. Moreover, it is sometimes challenging to extract the sign of the measured radial velocity. Conventionally, CDLs have benefitted from an intermediate frequency (IF) heterodyne receiver architecture for the determination of the radial velocity. In such systems, either the transmitted or the local oscillator (LO) signal is shifted in frequency. Such architectures may suffer from increased noise and spurious effects due to the employment of additional active components, e.g., acousto-optic modulator (AOM), limited measurement bandwidth (BW), and a more sophisticated electronic front-end for signal detection. On the other hand, one of the main challenges in long-range (pulsed) CDLs is the limitations imposed on the pulse repetition rate (PRR) as well as the available transmit power. These restrictions are more significant in all-fiber pulsed CDLs in which Erbium doped fiber amplifiers (EDFA) are employed for the amplification of the optical pulses. In this study, we propose an alternative reconfigurable opto-electronic front-end transceiver architecture in all-fiber CDLs where there is no compromise in the detection BW. Additionally, by benefiting from a polarization diversity architecture we show that both the PRR

  19. Open Path Trace Gas Laser Sensors for UAV Deployment

    NASA Astrophysics Data System (ADS)

    Shadman, S.; Mchale, L.; Rose, C.; Yalin, A.

    2015-12-01

    Novel trace gas sensors based on open-path Cavity Ring-down Spectroscopy (CRDS) are being developed to enable remote and mobile deployments including on small unmanned aerial systems (UAS). Relative to established closed-path CRDS instruments, the use of open-path configurations allows removal of the bulky and power hungry vacuum and flow system, potentially enabling lightweight and low power instruments with high sensitivity. However, open path operation introduces new challenges including the need to maintain mirror cleanliness, mitigation of particle optical effects, and the need to measure spectral features that are relatively broad. The present submission details open-path CRDS instruments for ammonia and methane and their planned use in UAS studies. The ammonia sensor uses a quantum cascade laser at 10.3 mm in a configuration in which the laser frequency is continuously swept and a trigger circuit and acousto-optic modulator (AOM) extinguish the light when the laser is resonant with the cavity. Ring-down signals are measured with a two-stage thermoelectrically cooled MCT photodetector. The cavity mirrors have reflectivity of 0.9995 and a noise equivalent absorption of 1.5 ppb Hz-1/2 was demonstrated. A first version of the methane sensor operated at 1.7um with a telecom diode laser while the current version operates at 3.6 um with an interband cascade laser (stronger absorption). We have performed validation measurements against known standards for both sensors. Compact optical assemblies are being developed for UAS deployment. For example, the methane sensor head will have target mass of <4 kg and power draw <40 W. A compact single board computer and DAQ system is being designed for sensor control and signal processing with target mass <1 kg and power draw <10 W. The sensor size and power parameters are suitable for UAS deployment on both fixed wing and rotor style UAS. We plan to deploy the methane sensor to measure leakage and emission of methane from

  20. Photovoltaic module and interlocked stack of photovoltaic modules

    DOEpatents

    Wares, Brian S.

    2014-09-02

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame. A plurality of individual male alignment features and a plurality of individual female alignment features are included on each frame. Adjacent photovoltaic modules are interlocked by multiple individual male alignment features on a first module of the adjacent photovoltaic modules fitting into and being surrounded by corresponding individual female alignment features on a second module of the adjacent photovoltaic modules. Other embodiments, features and aspects are also disclosed.

  1. Optical modulator system

    NASA Technical Reports Server (NTRS)

    Brand, J.

    1972-01-01

    The fabrication, test, and delivery of an optical modulator system which will operate with a mode-locked Nd:YAG laser indicating at either 1.06 or 0.53 micrometers is discussed. The delivered hardware operates at data rates up to 400 Mbps and includes a 0.53 micrometer electrooptic modulator, a 1.06 micrometer electrooptic modulator with power supply and signal processing electronics with power supply. The modulators contain solid state drivers which accept digital signals with MECL logic levels, temperature controllers to maintain a stable thermal environment for the modulator crystals, and automatic electronic compensation to maximize the extinction ratio. The modulators use two lithium tantalate crystals cascaded in a double pass configuration. The signal processing electronics include encoding electronics which are capable of digitizing analog signals between the limit of + or - 0.75 volts at a maximum rate of 80 megasamples per second with 5 bit resolution. The digital samples are serialized and made available as a 400 Mbps serial NRZ data source for the modulators. A pseudorandom (PN) generator is also included in the signal processing electronics. This data source generates PN sequences with lengths between 31 bits and 32,767 bits in a serial NRZ format at rates up to 400 Mbps.

  2. Autonomous cotton module forming system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton producers often have difficulty finding adequate labor during harvest. Module builder operators are often inexperienced and may build poorly shaped modules. Equipment manufacturers have recently introduced harvesters with on-board module building capabilities to reduce labor requirements; h...

  3. Amplitude Modulator Chassis

    SciTech Connect

    Erbert, G

    2009-09-01

    The Amplitude Modulator Chassis (AMC) is the final component in the MOR system and connects directly to the PAM input through a 100-meter fiber. The 48 AMCs temporally shape the 48 outputs of the MOR using an arbitrary waveform generator coupled to an amplitude modulator. The amplitude modulation element is a two stage, Lithium Niobate waveguide device, where the intensity of the light passing through the device is a function of the electrical drive applied. The first stage of the modulator is connected to a programmable high performance Arbitrary Waveform Generator (AWG) consisting of 140 impulse generators space 250 ps apart. An arbitrary waveform is generated by independently varying the amplitude of each impulse generator and then summing the impulses together. In addition to the AWG a short pulse generator is also connected to the first stage of the modulator to provide a sub 100-ps pulse used for timing experiments. The second stage of the modulator is connect to a square pulse generator used to further attenuate any pre or post pulse light passing through the first stage of the modulator. The fast rise and fall time of the square pulse generator is also used to produce fast rise and fall times of the AWG by clipping the AWG pulse. For maximum extinction, a pulse bias voltage is applied to each stage of the modulator. A pulse voltage is applied as opposed to a DC voltage to prevent charge buildup on the modulator. Each bias voltage is adjustable to provide a minimum of 50-dB extinction. The AMC is controlled through ICCS to generate the desired temporal pulse shape. This process involves a closed-loop control algorithm, which compares the desired temporal waveform to the produced optical pulse, and iterates the programming of the AWG until the two waveforms agree within an allowable tolerance.

  4. DOT Transmit Module

    NASA Technical Reports Server (NTRS)

    Quirk, Kevin J.; Gin, Jonathan W.; Sahasrabudhe, Adit; Patawaran, Ferze D.; Nguyen, Danh H.; Nguyen, Huy

    2013-01-01

    The Deep Space Optical Terminal (DOT) transmit module demonstrates the DOT downlink signaling in a flight electronics assembly that can be qualified for deep space. The assembly has the capability to generate an electronic pulse-position modulation (PPM) waveform suitable for driving a laser assembly to produce the optical downlink signal. The downlink data enters the assembly through a serializer/ deserializer (SERDES) interface, and is encoded using a serially concatenated PPM (SCPPM) forward error correction code. The encoded data is modulated using PPM with an inter-symbol guard time to aid in receiver synchronization. Monitor and control of the assembly is via a low-voltage differential signal (LVDS) interface

  5. Optimized solar module design

    NASA Technical Reports Server (NTRS)

    Santala, T.; Sabol, R.; Carbajal, B. G.

    1978-01-01

    The minimum cost per unit of power output from flat plate solar modules can most likely be achieved through efficient packaging of higher efficiency solar cells. This paper outlines a module optimization method which is broadly applicable, and illustrates the potential results achievable from a specific high efficiency tandem junction (TJ) cell. A mathematical model is used to assess the impact of various factors influencing the encapsulated cell and packing efficiency. The optimization of the packing efficiency is demonstrated. The effect of encapsulated cell and packing efficiency on the module add-on cost is shown in a nomograph form.

  6. Optical modulator including grapene

    DOEpatents

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  7. Water heater control module

    SciTech Connect

    Hammerstrom, Donald J

    2013-11-26

    An advanced electric water heater control system that interfaces with a high temperature cut-off thermostat and an upper regulating thermostat. The system includes a control module that is electrically connected to the high-temperature cut-off thermostat and the upper regulating thermostat. The control module includes a switch to open or close the high-temperature cut-off thermostat and the upper regulating thermostat. The control module further includes circuitry configured to control said switch in response to a signal selected from the group of an autonomous signal, a communicated signal, and combinations thereof.

  8. Sonication standard laboratory module

    DOEpatents

    Beugelsdijk, Tony; Hollen, Robert M.; Erkkila, Tracy H.; Bronisz, Lawrence E.; Roybal, Jeffrey E.; Clark, Michael Leon

    1999-01-01

    A standard laboratory module for automatically producing a solution of cominants from a soil sample. A sonication tip agitates a solution containing the soil sample in a beaker while a stepper motor rotates the sample. An aspirator tube, connected to a vacuum, draws the upper layer of solution from the beaker through a filter and into another beaker. This beaker can thereafter be removed for analysis of the solution. The standard laboratory module encloses an embedded controller providing process control, status feedback information and maintenance procedures for the equipment and operations within the standard laboratory module.

  9. The ANTARES optical module

    NASA Astrophysics Data System (ADS)

    ANTARES Collaboration; Amram, P.; Anghinolfi, M.; Anvar, S.; Ardellier-Desages, F. E.; Aslanides, E.; Aubert, J.-J.; Azoulay, R.; Bailey, D.; Basa, S.; Battaglieri, M.; Bellotti, R.; Benhammou, Y.; Bernard, F.; Berthier, R.; Bertin, V.; Billault, M.; Blaes, R.; Bland, R. W.; Blondeau, F.; de Botton, N.; Boulesteix, J.; Brooks, C. B.; Brunner, J.; Cafagna, F.; Calzas, A.; Capone, A.; Caponetto, L.; Cârloganu, C.; Carmona, E.; Carr, J.; Carton, P.-H.; Cartwright, S. L.; Cassol, F.; Cecchini, S.; Ciacio, F.; Circella, M.; Compère, C.; Cooper, S.; Coyle, P.; Croquette, J.; Cuneo, S.; Danilov, M.; van Dantzig, R.; De Marzo, C.; DeVita, R.; Deck, P.; Destelle, J.-J.; Dispau, G.; Drougou, J. F.; Druillole, F.; Engelen, J.; Feinstein, F.; Festy, D.; Fopma, J.; Gallone, J.-M.; Giacomelli, G.; Goret, P.; Gosset, L.; Gournay, J.-F.; Heijboer, A.; Hernández-Rey, J. J.; Herrouin, G.; Hubbard, J. R.; Jaquet, M.; de Jong, M.; Karolak, M.; Kooijman, P.; Kouchner, A.; Kudryavtsev, V. A.; Lachartre, D.; Lafoux, H.; Lamare, P.; Languillat, J.-C.; Laubier, L.; Laugier, J.-P.; Le Guen, Y.; Le Provost, H.; Le Van Suu, A.; Lemoine, L.; Lo Nigro, L.; Lo Presti, D.; Loucatos, S.; Louis, F.; Lyashuk, V.; Magnier, P.; Marcelin, M.; Margiotta, A.; Massol, A.; Masullo, R.; Mazéas, F.; Mazeau, B.; Mazure, A.; McMillan, J. E.; Michel, J. L.; Migneco, E.; Millot, C.; Mols, P.; Montanet, F.; Montaruli, T.; Morel, J. P.; Moscoso, L.; Musumeci, M.; Navas, S.; Nezri, E.; Nooren, G. J.; Oberski, J.; Olivetto, C.; Oppelt-Pohl, A.; Palanque-Delabrouille, N.; Papaleo, R.; Payre, P.; Perrin, P.; Petruccetti, M.; Petta, C.; Piattelli, P.; Poinsignon, J.; Potheau, R.; Queinec, Y.; Racca, C.; Raia, G.; Randazzo, N.; Rethore, F.; Riccobene, G.; Ricol, J.-S.; Ripani, M.; Roca-Blay, V.; Rolin, J. F.; Rostovstev, A.; Russo, G. V.; Sacquin, Y.; Salusti, E.; Schuller, J.-P.; Schuster, W.; Soirat, J.-P.; Souvorova, O.; Spooner, N. J. C.; Spurio, M.; Stolarczyk, T.; Stubert, D.; Taiuti, M.; Tao, C.; Tayalati, Y.; Thompson, L. F.; Tilav, S.; Triay, R.; Valente, V.; Varlamov, I.; Vaudaine, G.; Vernin, P.; de Witt Huberts, P.; de Wolf, E.; Zakharov, V.; Zavatarelli, S.; de D. Zornoza, J.; Zún~iga, J.

    2002-05-01

    The ANTARES collaboration is building a deep sea neutrino telescope in the Mediterranean Sea. This detector will cover a sensitive area of typically 0.1km2 and will be equipped with about 1000 optical modules. Each of these optical modules consists of a large area photomultiplier and its associated electronics housed in a pressure resistant glass sphere. The design of the ANTARES optical module, which is a key element of the detector, has been finalized following extensive R&D studies and is reviewed here in detail.

  10. HIGHER FREQUENCY ULTRASONIC LIGHT MODULATORS.

    DTIC Science & Technology

    LIGHT ), (*MODULATORS, (*ULTRASONIC RADIATION, MODULATORS), OPTICAL COMMUNICATIONS, BANDWIDTH, TRANSDUCERS, HIGH FREQUENCY, VERY HIGH FREQUENCY, ATTENUATION, DATA PROCESSING, OPTICAL EQUIPMENT, ANALOG COMPUTERS, THEORY.

  11. Module bay with directed flow

    DOEpatents

    Torczynski, John R.

    2001-02-27

    A module bay requires less cleanroom airflow. A shaped gas inlet passage can allow cleanroom air into the module bay with flow velocity preferentially directed toward contaminant rich portions of a processing module in the module bay. Preferential gas flow direction can more efficiently purge contaminants from appropriate portions of the module bay, allowing a reduced cleanroom air flow rate for contaminant removal. A shelf extending from an air inlet slit in one wall of a module bay can direct air flowing therethrough toward contaminant-rich portions of the module bay, such as a junction between a lid and base of a processing module.

  12. TRANSIMS environmental module

    SciTech Connect

    Williams, M.D.; Thayer, G.R.; Brown, M.J.

    1996-09-01

    The purpose of the environmental module is to translate traveler behavior into consequent air quality, energy consumption, watershed nitrate deposition, and carbon dioxide emissions. The TRANSIMS environmental module is composed of a system of environmental modules which can describe both the average conditions and the fluctuations about the averages. It uses a prognostic meteorological model, HOTMAC, to describe the atmospheric conditions. The environmental module will use modal emissions models to define the emissions. Transport and dispersion of conservative pollutants will be described with a Monte-Carlo Kernel model (RAPTAD). Air chemistry will be described by an airshed model with the current choice being the CIT model developed at the California Institute of Technology and the Carnegie Mellon Institute of Technology.

  13. Silicon optical modulators

    NASA Astrophysics Data System (ADS)

    Reed, G. T.; Mashanovich, G.; Gardes, F. Y.; Thomson, D. J.

    2010-08-01

    Optical technology is poised to revolutionize short-reach interconnects. The leading candidate technology is silicon photonics, and the workhorse of such an interconnect is the optical modulator. Modulators have been improved dramatically in recent years, with a notable increase in bandwidth from the megahertz to the multigigahertz regime in just over half a decade. However, the demands of optical interconnects are significant, and many questions remain unanswered as to whether silicon can meet the required performance metrics. Minimizing metrics such as the device footprint and energy requirement per bit, while also maximizing bandwidth and modulation depth, is non-trivial. All of this must be achieved within an acceptable thermal tolerance and optical spectral width using CMOS-compatible fabrication processes. This Review discusses the techniques that have been (and will continue to be) used to implement silicon optical modulators, as well as providing an outlook for these devices and the candidate solutions of the future.

  14. Autonomous Module Builder

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional cotton harvesting requires many seasonal laborers. To reduce labor requirements, equipment manufacturers have recently introduced harvesters with on-board module building capabilities; however, this feature is only available on pickers and these machines are expensive. Conventional mo...

  15. Digital optical conversion module

    DOEpatents

    Kotter, Dale K.; Rankin, Richard A.

    1991-02-26

    A digital optical conversion module used to convert an analog signal to a computer compatible digital signal including a voltage-to-frequency converter, frequency offset response circuitry, and an electrical-to-optical converter. Also used in conjunction with the digital optical conversion module is an optical link and an interface at the computer for converting the optical signal back to an electrical signal. Suitable for use in hostile environments having high levels of electromagnetic interference, the conversion module retains high resolution of the analog signal while eliminating the potential for errors due to noise and interference. The module can be used to link analog output scientific equipment such as an electrometer used with a mass spectrometer to a computer.

  16. Digital optical conversion module

    DOEpatents

    Kotter, D.K.; Rankin, R.A.

    1988-07-19

    A digital optical conversion module used to convert an analog signal to a computer compatible digital signal including a voltage-to-frequency converter, frequency offset response circuitry, and an electrical-to-optical converter. Also used in conjunction with the digital optical conversion module is an optical link and an interface at the computer for converting the optical signal back to an electrical signal. Suitable for use in hostile environments having high levels of electromagnetic interference, the conversion module retains high resolution of the analog signal while eliminating the potential for errors due to noise and interference. The module can be used to link analog output scientific equipment such as an electrometer used with a mass spectrometer to a computer. 2 figs.

  17. Module encapsulation technology

    NASA Technical Reports Server (NTRS)

    Willis, P.

    1986-01-01

    The identification and development techniques for low-cost module encapsulation materials were reviewed. Test results were displayed for a variety of materials. The improved prospects for modeling encapsulation systems for life prediction were reported.

  18. Investigating Quantum Modulation States

    DTIC Science & Technology

    2016-03-01

    INVESTIGATING QUANTUM MODULATION STATES MARCH 2016 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED STINFO COPY AIR...3. DATES COVERED (From - To) OCT 2012 – SEP 2015 4. TITLE AND SUBTITLE INVESTIGATING QUANTUM MODULATION STATES 5a. CONTRACT NUMBER IN-HOUSE 5b...NOTES 14. ABSTRACT This effort was primarily concerned with quantum aspects of optical communications. Two quantum communications technologies were

  19. Firefighting module development

    NASA Technical Reports Server (NTRS)

    Burns, R. A.

    1981-01-01

    The firefighting module is a lightweight, compact, self contained, helicopter-transportable unit for fighting harbor and other specialty fires as well as for use in emergency water pumping applications. Units were fabricated and tested. A production type unit is undergoing an inservice evaluation and demonstration program at the port of St Louis. The primary purpose is to promote enhanced harbor fire protection at inland and coastal ports. The module and its development are described.

  20. Extended Range Support Module

    DTIC Science & Technology

    2015-10-07

    missions requiring enhanced navigational support to allow Attorney Docket No. 300077 3 of 12 navigation of the vehicles in the open ocean. It is...capable of accommodating the undersea vehicle therein. A navigation module is positioned on the outer hull and capable of being joined to the...undersea vehicle. Controllable fins are provided on the outer hull and joined to allow control by the navigation module. A buoyancy control system is

  1. Columbus pressurized module verification

    NASA Technical Reports Server (NTRS)

    Messidoro, Piero; Comandatore, Emanuele

    1986-01-01

    The baseline verification approach of the COLUMBUS Pressurized Module was defined during the A and B1 project phases. Peculiarities of the verification program are the testing requirements derived from the permanent manned presence in space. The model philosophy and the test program have been developed in line with the overall verification concept. Such critical areas as meteoroid protections, heat pipe radiators and module seals are identified and tested. Verification problem areas are identified and recommendations for the next development are proposed.

  2. Photovoltaic module reliability workshop

    SciTech Connect

    Mrig, L.

    1990-01-01

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986--1990. The reliability Photo Voltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warranties available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the US, PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  3. Photovoltaic module reliability workshop

    NASA Astrophysics Data System (ADS)

    Mrig, L.

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986 to 1990. The reliability photovoltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warrantees available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the U.S., PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  4. Binaural modulation detection interference.

    PubMed

    Sheft, S; Yost, W A

    1997-09-01

    The ability to detect amplitude modulation (AM) of a tonal probe can be disrupted by the presence of modulated masking tones. Two experiments examined whether a disparity in the interaural parameters of the probe and masker can reduce the amount of interference. In the first experiment, the effects of interaural time and intensity differences were studied in separate sets of conditions. With low-frequency carriers, the detection of 10-Hz probe modulation in the presence of 10-Hz masker modulation was not significantly affected by interaural time differences. With higher-frequency carriers, dichotic stimuli were generated through combinations of diotic, dichotic, or monotic probe and masker presentations in which the probe and masker did not share a common interaural intensity difference. In these conditions, the amount of interference was affected by the interaural configuration. However, monotic level differences between the probe and masker may have contributed to the effect of interaural configuration. In the second experiment, the probe and masker were presented through separate speakers in an enclosed listening environment. Spatial separation between the sources for the probe and masker led to a small reduction in the amount of interference. When the masker modulation rate was varied with the probe AM rate fixed at 10 Hz, the extent of tuning in the modulation domain in the sound-field conditions was similar to that obtained with diotic stimulus presentation over headphones.

  5. "Smart" Sensor Module

    NASA Technical Reports Server (NTRS)

    Mahajan, Ajay

    2007-01-01

    An assembly that contains a sensor, sensor-signal-conditioning circuitry, a sensor-readout analog-to-digital converter (ADC), data-storage circuitry, and a microprocessor that runs special-purpose software and communicates with one or more external computer(s) has been developed as a prototype of "smart" sensor modules for monitoring the integrity and functionality (the "health") of engineering systems. Although these modules are now being designed specifically for use on rocket-engine test stands, it is anticipated that they could also readily be designed to be incorporated into health-monitoring subsystems of such diverse engineering systems as spacecraft, aircraft, land vehicles, bridges, buildings, power plants, oilrigs, and defense installations. The figure is a simplified block diagram of the "smart" sensor module. The analog sensor readout signal is processed by the ADC, the digital output of which is fed to the microprocessor. By means of a standard RS-232 cable, the microprocessor is connected to a local personal computer (PC), from which software is downloaded into a randomaccess memory in the microprocessor. The local PC is also used to debug the software. Once the software is running, the local PC is disconnected and the module is controlled by, and all output data from the module are collected by, a remote PC via an Ethernet bus. Several smart sensor modules like this one could be connected to the same Ethernet bus and controlled by the single remote PC. The software running in the microprocessor includes driver programs for operation of the sensor, programs that implement self-assessment algorithms, programs that implement protocols for communication with the external computer( s), and programs that implement evolutionary methodologies to enable the module to improve its performance over time. The design of the module and of the health-monitoring system of which it is a part reflects the understanding that the main purpose of a health

  6. Universal enveloping crossed module of Leibniz crossed modules and representations

    NASA Astrophysics Data System (ADS)

    Casado, Rafael F.; García-Martínez, Xabier; Ladra, Manuel

    2016-03-01

    The universal enveloping algebra functor UL: Lb → Alg, defined by Loday and Pirashvili [1], is extended to crossed modules. Then we construct an isomorphism between the category of representations of a Leibniz crossed module and the category of left modules over its universal enveloping crossed module of algebras. Note that the procedure followed in the proof for the Lie case cannot be adapted, since the actor in the category of Leibniz crossed modules does not always exist.

  7. Optical modulation goes external

    NASA Astrophysics Data System (ADS)

    Loni, A.

    1995-02-01

    Digital or analog modulation of continuous-wave laser sources forms the basis of encoding and transmitting of information through optical fiber link systems. In digital systems, data are formatted in a simple periodic two-bit configuration, represented by high or low light intensities, whereas in analog systems data are represented by selective portions of a time-varying electronic waveform applied to the optical carrier. High speed optical communications and the distribution of cable television (CATV) signals are just two examples of digital and analog systems, respectively, that involve the transmission of data, voice and video over fiber networks. The basic layout of a fiber-optic link system is presented. The optical source wavelength is determined by the characteristics of the optical fiber. If the optical sources used is a semiconductor laser diode, information can be imprinted on the optical output by directly modulating the laser drive current with a radio frequency (RF) signal. In digital systems, the low (off) state generally corresponds to a position just below the lasing threshold on the characteristic intensity-current curve of the diode. This position is preferred to the zero current locus because the turn-on delays are then minimized. Analog systems require a bias current in addition to the threshold current in order to push the modulation into the linear region of the power-current curve. The main disadvantages associated with the direct modulation approach are discussed. The main disadvantage of the solid-state approach is its inability to modulate directly the laser at the data rates nominally entailed in optical communications. This inability causes further limitations associated with the inherently long excited state lifetime of the lasing species. External modulation overcomes this drawback by modulating the optical output from the laser rather than the material properties of the laser itself, and consequently, is set to play an increasingly

  8. Intensity modulated proton therapy

    PubMed Central

    Grassberger, C

    2015-01-01

    Intensity modulated proton therapy (IMPT) implies the electromagnetic spatial control of well-circumscribed “pencil beams” of protons of variable energy and intensity. Proton pencil beams take advantage of the charged-particle Bragg peak—the characteristic peak of dose at the end of range—combined with the modulation of pencil beam variables to create target-local modulations in dose that achieves the dose objectives. IMPT improves on X-ray intensity modulated beams (intensity modulated radiotherapy or volumetric modulated arc therapy) with dose modulation along the beam axis as well as lateral, in-field, dose modulation. The clinical practice of IMPT further improves the healthy tissue vs target dose differential in comparison with X-rays and thus allows increased target dose with dose reduction elsewhere. In addition, heavy-charged-particle beams allow for the modulation of biological effects, which is of active interest in combination with dose “painting” within a target. The clinical utilization of IMPT is actively pursued but technical, physical and clinical questions remain. Technical questions pertain to control processes for manipulating pencil beams from the creation of the proton beam to delivery within the patient within the accuracy requirement. Physical questions pertain to the interplay between the proton penetration and variations between planned and actual patient anatomical representation and the intrinsic uncertainty in tissue stopping powers (the measure of energy loss per unit distance). Clinical questions remain concerning the impact and management of the technical and physical questions within the context of the daily treatment delivery, the clinical benefit of IMPT and the biological response differential compared with X-rays against which clinical benefit will be judged. It is expected that IMPT will replace other modes of proton field delivery. Proton radiotherapy, since its first practice 50 years ago, always required the

  9. Superconducting optical modulator

    NASA Astrophysics Data System (ADS)

    Bunt, Patricia S.; Ference, Thomas G.; Puzey, Kenneth A.; Tanner, David B.; Tache, Nacira; Varhue, Walter J.

    2000-12-01

    An optical modulator based on the physical properties of high temperature superconductors has been fabricated and tested. The modulator was constructed form a film of Yttrium Barium Copper Oxide (YBCO) grown on undoped silicon with a buffer layer of Yttria Stabilized Zirconia. Standard lithographic procedures were used to pattern the superconducting film into a micro bridge. Optical modulation was achieved by passing IR light through the composite structure normal to the micro bridge and switching the superconducting film in the bridge region between the superconducting and non-superconducting states. In the superconducting state, IR light reflects from the superconducting film surface. When a critical current is passed through the micro bridge, it causes the film in this region to switch to the non-superconducting state allowing IR light to pass through it. Superconducting materials have the potential to switch between these two states at speeds up to 1 picosecond using electrical current. Presently, fiber optic transmission capacity is limited by the rate at which optical data can be modulated. The superconducting modulator, when combined with other components, may have the potential to increase the transmission capacity of fiber optic lines.

  10. Bunch identification module

    SciTech Connect

    Fox, J.D.

    1981-01-01

    This module provides bunch identification and timing signals for the PEP Interaction areas. Timing information is referenced to the PEP master oscillator, and adjusted in phase as a function of region. Identification signals are generated in a manner that allows observers in all interaction regions to agree on an unambiguous bunch identity. The module provides bunch identification signals via NIM level logic, upon CAMAC command, and through LED indicators. A front panel ''region select'' switch allows the same module to be used in all regions. The module has two modes of operation: a bunch identification mode and a calibration mode. In the identification mode, signals indicate which of the three bunches of electrons and positrons are interacting, and timing information about beam crossing is provided. The calibration mode is provided to assist experimenters making time of flight measurements. In the calibration mode, three distinct gating signals are referenced to a selected bunch, allowing three timing systems to be calibrated against a common standard. Physically, the bunch identifier is constructed as a single width CAMAC module. 2 figs., 1 tab.

  11. NREL module energy rating methodology

    SciTech Connect

    Whitaker, C.; Newmiller, J.; Kroposki, B.

    1995-11-01

    The goals of this project were to develop a tool for: evaluating one module in different climates; comparing different modules; provide a Q&D method for estimating periodic energy production; provide an achievable module rating; provide an incentive for manufacturers to optimize modules to non-STC conditions; and to have a consensus-based, NREL-sponsored activity. The approach taken was to simulate module energy for five reference days of various weather conditions. A performance model was developed.

  12. Autonomous radar pulse modulation classification using modulation components analysis

    NASA Astrophysics Data System (ADS)

    Wang, Pei; Qiu, Zhaoyang; Zhu, Jun; Tang, Bin

    2016-12-01

    An autonomous method for recognizing radar pulse modulations based on modulation components analysis is introduced in this paper. Unlike the conventional automatic modulation classification methods which extract modulation features based on a list of known patterns, this proposed method classifies modulations by the existence of basic modulation components including continuous frequency modulations, discrete frequency codes and discrete phase codes in an autonomous way. A feasible way to realize this method is using the features of abrupt changes in the instantaneous frequency rate curve which derived by the short-term general representation of phase derivative. This method is suitable not only for the basic radar modulations but also for complicated and hybrid modulations. The theoretical result and two experiments demonstrate the effectiveness of the proposed method.

  13. Deep frequency modulation interferometry.

    PubMed

    Gerberding, Oliver

    2015-06-01

    Laser interferometry with pm/Hz precision and multi-fringe dynamic range at low frequencies is a core technology to measure the motion of various objects (test masses) in space and ground based experiments for gravitational wave detection and geodesy. Even though available interferometer schemes are well understood, their construction remains complex, often involving, for example, the need to build quasi-monolithic optical benches with dozens of components. In recent years techniques have been investigated that aim to reduce this complexity by combining phase modulation techniques with sophisticated digital readout algorithms. This article presents a new scheme that uses strong laser frequency modulations in combination with the deep phase modulation readout algorithm to construct simpler and easily scalable interferometers.

  14. Power module assembly

    DOEpatents

    Campbell, Jeremy B [Torrance, CA; Newson, Steve [Redondo Beach, CA

    2011-11-15

    A power module assembly of the type suitable for deployment in a vehicular power inverter, wherein the power inverter has a grounded chassis, is provided. The power module assembly comprises a conductive base layer electrically coupled to the chassis, an insulating layer disposed on the conductive base layer, a first conductive node disposed on the insulating layer, a second conductive node disposed on the insulating layer, wherein the first and second conductive nodes are electrically isolated from each other. The power module assembly also comprises a first capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the first conductive node, and further comprises a second capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the second conductive node.

  15. GREET Pretreatment Module

    SciTech Connect

    Adom, Felix K.; Dunn, Jennifer B.; Han, Jeongwoo

    2014-09-01

    A wide range of biofuels and biochemicals can be produced from cellulosic biomass via different pretreatment technologies that yield sugars. Process simulations of dilute acid and ammonia fiber expansion pretreatment processes and subsequent hydrolysis were developed in Aspen Plus for four lignocellulosic feedstocks (corn stover, miscanthus, switchgrass, and poplar). This processing yields sugars that can be subsequently converted to biofuels or biochemical. Material and energy consumption data from Aspen Plus were then compiled in a new Greenhouses Gases, Regulated Emissions, and Energy Use in Transportation (GREETTM) pretreatment module. The module estimates the cradle-to-gate fossil energy consumption (FEC) and greenhouse gas (GHG) emissions associated with producing fermentable sugars. This report documents the data and methodology used to develop this module and the cradle-to-gate FEC and GHG emissions that result from producing fermentable sugars.

  16. Adaptive modulations of martensites.

    PubMed

    Kaufmann, S; Rössler, U K; Heczko, O; Wuttig, M; Buschbeck, J; Schultz, L; Fähler, S

    2010-04-09

    Modulated phases occur in numerous functional materials like giant ferroelectrics and magnetic shape-memory alloys. To understand the origin of these phases, we employ and generalize the concept of adaptive martensite. As a starting point, we investigate the coexistence of austenite, adaptive 14M phase, and tetragonal martensite in Ni-Mn-Ga magnetic shape-memory alloy epitaxial films. We show that the modulated martensite can be constructed from nanotwinned variants of the tetragonal martensite phase. By combining the concept of adaptive martensite with branching of twin variants, we can explain key features of modulated phases from a microscopic view. This includes metastability, the sequence of 6M-10M-14M-NM intermartensitic transitions, and the magnetocrystalline anisotropy.

  17. Waveform Sampler CAMAC Module

    SciTech Connect

    Freytag, D.R.; Haller, G.M.; Kang, H.; Wang, J.

    1985-09-01

    A Waveform Sampler Module (WSM) for the measurement of signal shapes coming from the multi-hit drift chambers of the SLAC SLC detector is described. The module uses a high speed, high resolution analog storage device (AMU) developed in collaboration between SLAC and Stanford University. The AMU devices together with high speed TTL clocking circuitry are packaged in a hybrid which is also suitable for mounting on the detector. The module is in CAMAC format and provides eight signal channels, each recording signal amplitude versus time in 512 cells at a sampling rate of up to 360 MHz. Data are digitized by a 12-bit ADC with a 1 ..mu..s conversion time and stored in an on-board memory accessible through CAMAC.

  18. Modulated infrared radiant source

    NASA Technical Reports Server (NTRS)

    Stewart, W. F.; Edwards, S. F.; Vann, D. S.; Mccormick, R. F.

    1981-01-01

    A modulated, infrared radiant energy source was developed to calibrate an airborne nadir-viewing pressure modulated radiometer to be used to detect from Earth orbit trace gases in the troposphere. The technique used an 8 cm long, 0.005 cm diameter platinum-iridium wire as an isothermal, thin line radiant energy source maintained at 1200 K. A + or - 20 K signal, oscillating at controllable frequencies from dc to 20 Hz, was superimposed on it. This periodic variation of the line source energy was used to verify the pressure modulated radiometer's capability to distinguish between the signal variations caused by the Earth's background surface and the signal from the atmospheric gases of interest.

  19. Microchannel spatial light modulator

    NASA Technical Reports Server (NTRS)

    Warde, C.

    1981-01-01

    The Microchannel Spatial Light Modulator (MSLM), a versatile, highly sensitive, and optically addressed device being developed for real time optical information processing is discussed. The MSLM operates by converting an input optical image into a charge distribution at the surface of an electro-optic crystal. The charge distribution generates an electric field which modulates the refractive index of the crystal and thereby the phase or intensity of an image readout beam. Prototype devices employing 250 micron thick crystals exhibited a spatial resolution of 5 cycles/mm at 50% contrast, an exposure sensitivity of 2.2 nJ/cu cm and framing rates of 40 Hz with full modulation depth. The image processing operations that have been achieved using the internal processing mode of the MSLM include contrast reversal, contrast enhancement, edge enhancement, image addition and subtraction, analog and digital intensity thresholding, and binary level logic operations such as AND, OR, EXCLUSIVE OR, and NOR.

  20. Printed Module Interconnects

    SciTech Connect

    Stockert, Talysa R.; Fields, Jeremy D.; Pach, Gregory F.; Mauger, Scott A.; van Hest, Maikel F. A. M.

    2015-06-14

    Monolithic interconnects in photovoltaic modules connect adjacent cells in series, and are typically formed sequentially involving multiple deposition and scribing steps. Interconnect widths of 500 um every 10 mm result in 5% dead area, which does not contribute to power generation in an interconnected solar panel. This work expands on previous work that introduced an alternative interconnection method capable of producing interconnect widths less than 100 um. The interconnect is added to the module in a single step after deposition of the photovoltaic stack, eliminating the need for scribe alignment. This alternative method can be used for all types of thin film photovoltaic modules. Voltage addition with copper-indium-gallium-diselenide (CIGS) solar cells using a 2-scribe printed interconnect approach is demonstrated. Additionally, interconnect widths of 250 um are shown.

  1. Space Experiment Module (SEM)

    NASA Technical Reports Server (NTRS)

    Brodell, Charles L.

    1999-01-01

    The Space Experiment Module (SEM) Program is an education initiative sponsored by the National Aeronautics and Space Administration (NASA) Shuttle Small Payloads Project. The program provides nationwide educational access to space for Kindergarten through University level students. The SEM program focuses on the science of zero-gravity and microgravity. Within the program, NASA provides small containers or "modules" for students to fly experiments on the Space Shuttle. The experiments are created, designed, built, and implemented by students with teacher and/or mentor guidance. Student experiment modules are flown in a "carrier" which resides in the cargo bay of the Space Shuttle. The carrier supplies power to, and the means to control and collect data from each experiment.

  2. Solar site test module

    NASA Technical Reports Server (NTRS)

    Kissel, R. R.; Scott, D. R.

    1980-01-01

    A solar site test module using the Rockwell AIM 65microcomputer is described. The module is designed to work at any site where an IBM site data acquisition system (SDAS) is installed and is intended primarily as a troubleshooting tool. It collects sensor information (temperatures, flow rates, etc.) and displays or prints it immediately in calibrated engineering units. It will read one sensor on demand, periodically read up to 10sensors or periodically read all sensors. Performance calculations can also be included with sensor data. Unattended operation is possible to, e.g., monitor a group of sensors once per hour. Work is underway to add a data acquisition system to the test module so that it can be used at sites which have no SDAS.

  3. Thin film module development

    NASA Technical Reports Server (NTRS)

    Jester, T.

    1985-01-01

    The design of ARCO Solar, Inc.'s Genesis G100 photovoltaic module was driven by several criteria, including environmental stability (both electrical and mechanical), consumer aesthetics, low materials costs, and manufacturing ease. The module circuitry is designed as a 12 volt battery charger, using monolithic patterning techniques on a glass superstrate. This patterning and interconnect method proves amenable to high volume, low cost production throughput, and the use of glass serves the dual role of handling ease and availability. The mechanical design of the module centers on environmental stability. Packaging of the glass superstrate circuit must provide good resistance to thermal and humidity exposure along with hi-pot insulation and hailstone impact resistance. The options considered are given. Ethylene vinyl acetate (EVA) is chosen as the pottant material for its excellent weatherability.

  4. 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.

  5. Artificial long-delay optical processor

    NASA Astrophysics Data System (ADS)

    Kornreich, Philipp G.; Smith, Jacqueline D.

    1993-02-01

    The Artificial Long Delay Optical Processor (ALDOP) generates a large variable delay of a band limited pulse modulated RF signal. The proposed prototype ALDOP has potential use in a Passive Radio Ranging (PRR) system operating in the 82.5 - 97.5 MHz frequency band. The complete system will combine a passive electronic band pass filter with the optically based ALDOP to impart a unique phase shift to each frequency component of an incoming RF signal. The phase shift is generated using optical heterodyne methods that incorporate the transmission and modulation of light through a series of optical components including an acousto-optical cell and a Fresnel Zone Plate.

  6. Unbalanced Michelson's interferometer as a fiber optic distributed sensor of external signals

    NASA Astrophysics Data System (ADS)

    Chojnacki, M.; Szustakowski, Mieczyslaw; Zyczkowski, Marek

    2001-08-01

    The subject of this work is a novel fiber optic distributed sensor system. The system uses a technique called multiplexed reflectometric interferometry to measure dynamic strain in a network of single mode optical fiber sensors. The sensor is constructed on unbalanced fiber optic Michelson's interferometer is activated by series of double pulse. The time interval between those pulses depends on the length of the section of sensor. Acousto-optical modulator acts as an optical frequency shifter. A change in a frequency of electrical pulses exciting the modulator result in a frequency shift in each generated wave packet.

  7. Electro-Optic Modulator.

    DTIC Science & Technology

    An electro - optic modulator is used to modulate coherent light beams by the application of an electric potential. It combines a Fabry-Perot etalon and...a diffraction grating in a single unit. An etalon is constructed with an electro - optic material between reflecting surfaces. A voltage applied...between alternate, spaced-apart electrodes of a metal grid attached to one reflecting surface induces a diffraction grating in the electro optic material. Light entering the etalon is diffracted, reflected and efficiently coupled out.

  8. Lunar Module Illustration

    NASA Technical Reports Server (NTRS)

    1969-01-01

    This concept is a cutaway illustration of the Lunar Module (LM) with detailed callouts. The LM was a two part spacecraft. Its lower or descent stage had the landing gear, engines, and fuel needed for the landing. When the LM blasted off the Moon, the descent stage served as the launching pad for its companion ascent stage, which was also home for the two astronauts on the surface of the Moon. The LM was full of gear with which to communicate, navigate, and rendezvous. It also had its own propulsion system, and an engine to lift it off the Moon and send it on a course toward the orbiting Command Module.

  9. Lunar Module Illustration

    NASA Technical Reports Server (NTRS)

    1967-01-01

    This illustration is the Lunar Module (LM) configuration. The LM was a two part spacecraft. Its lower or descent stage had the landing gear, engines, and fuel needed for the landing. When the LM blasted off the Moon, the descent stage served as the launching pad for its companion ascent stage, which was also home for the two astronauts on the surface of the Moon. The LM was full of gear with which to communicate, navigate, and rendezvous. It also had its own propulsion system, and an engine to lift it off the Moon and send it on a course toward the orbiting Command Module.

  10. Flexible programmable logic module

    DOEpatents

    Robertson, Perry J.; Hutchinson, Robert L.; Pierson, Lyndon G.

    2001-01-01

    The circuit module of this invention is a VME board containing a plurality of programmable logic devices (PLDs), a controlled impedance clock tree, and interconnecting buses. The PLDs are arranged to permit systolic processing of a problem by offering wide data buses and a plurality of processing nodes. The board contains a clock reference and clock distribution tree that can drive each of the PLDs with two critically timed clock references. External clock references can be used to drive additional circuit modules all operating from the same synchronous clock reference.

  11. Air modulation apparatus

    NASA Technical Reports Server (NTRS)

    Lenahan, D. T.; Corsmeier, R. J.; Sterman, A. P. (Inventor)

    1983-01-01

    An air modulation apparatus, such as for use in modulating cooling air to the turbine section of a gas turbine engine is described. The apparatus includes valve means disposed around an annular conduit, such as a nozzle, in the engine cooling air circuit. The valve means, when in a closed position, blocks a portion of the conduit, and thus reduces the amount and increases the velocity of cooling air flowing through the nozzle. The apparatus also includes actuation means, which can operate in response to predetermined engine conditions, for enabling opening and closing of the valve means.

  12. The laboratory module

    NASA Astrophysics Data System (ADS)

    Of the five modules comprising the Orbiting Quarantine Facility, the Laboratory Module must provide not only an extensive research capability to permit execution of the protocol, but also the flexibility to accommodate second-order testing if nonterrestrial life is discovered in the sample. The biocontainment barriers that protect the sample and the researchers from cross contamination are described. Specifically, the laboratory layout, laboratory equipment, the environmental control and life support system, and containment assurance procedures are discussed. The metal manipulation arm proposed for use within the biocontainment cabinets is described. Sample receipt and processing procedures are outlined.

  13. The laboratory module

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Of the five modules comprising the Orbiting Quarantine Facility, the Laboratory Module must provide not only an extensive research capability to permit execution of the protocol, but also the flexibility to accommodate second-order testing if nonterrestrial life is discovered in the sample. The biocontainment barriers that protect the sample and the researchers from cross contamination are described. Specifically, the laboratory layout, laboratory equipment, the environmental control and life support system, and containment assurance procedures are discussed. The metal manipulation arm proposed for use within the biocontainment cabinets is described. Sample receipt and processing procedures are outlined.

  14. Stirling Module Development Overview

    NASA Technical Reports Server (NTRS)

    Livingston, F. R.

    1984-01-01

    The solar parabolic dish Stirling engine electrically generating module consists of a solar collector coupled to a Stirling engine powered electrical generator. The module is designed to convert solar power to electrical power in parallel with numerous identical units coupled to an electrical utility power grid. The power conversion assembly generates up to 25 kilowatts at 480 volts potential/3 phase/alternating current. Piston rings and seals with gas leakage have not occurred, however, operator failures resulted in two burnt out receivers, while material fatigue resulted in a broken piston rod between the piston rod seal and cap seal.

  15. Differentiating spatial light modulator

    NASA Astrophysics Data System (ADS)

    Armitage, D.

    1985-04-01

    A differentiating spatial light modulator device in which a photoreceptor and an electro-optic crystal are isolated by a dielectric mirror is discussed. The electro-optic crystal is configured to have low or zero longitudinal response, yet is sensitive to transverse electric fields. The fringe field generated by the photoreceptor (photodiode) modulates the crystal birefringence. Readout via a polarizing beamsplitter gives an output light related to the spatial gradient of the input light. In a liquid crystal embodiment of the invention, reversal of the applied voltage gives a driven off state which speeds the erasure. Storage is possible in the smectic liquid crystal phase.

  16. Avionic standard module development

    NASA Astrophysics Data System (ADS)

    Maki, Stanley C.; Cormier, Edmond P.; Piszkin, Thomas A.

    Avionics standard modules with redundancy offer substantial economic benefits compared to special-purpose processor units for the orbital transfer vehicle and advanced launch vehicle programs. A fiber optic, serial vehicle bus provides high throughput with modest hardware. A bistage, split tapered, star optical coupler uses a token-pass/token-demand protocol. It is reported that a standard module implementation of the above is a feasible, cost-effective approach to avionics design using standard buses and standard packaging. The VHSIC integrated package readily accommodates higher-speed VLSI chips as they become available.

  17. Photovoltaic module and interlocked stack of photovoltaic modules

    DOEpatents

    Wares, Brian S.

    2012-09-04

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame having at least a top member and a bottom member. A plurality of alignment features are included on the top member of each frame, and a plurality of alignment features are included on the bottom member of each frame. Adjacent photovoltaic modules are interlocked by the alignment features on the top member of a lower module fitting together with the alignment features on the bottom member of an upper module. Other embodiments, features and aspects are also disclosed.

  18. Rescue Manual. Module 8.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Instructional Materials Lab.

    This learner manual for rescuers covers the current techniques or practices required in the rescue service. The eighth of 10 modules contains 6 chapters: (1) trench rescue; (2) shoring and tunneling techniques; (3) farm accident rescue; (4) wilderness search and rescue; (5) aircraft rescue; and (6) helicopter information. Key points, an…

  19. Evolutionary and Developmental Modules

    PubMed Central

    Lacquaniti, Francesco; Ivanenko, Yuri P.; d’Avella, Andrea; Zelik, Karl E.; Zago, Myrka

    2013-01-01

    The identification of biological modules at the systems level often follows top-down decomposition of a task goal, or bottom-up decomposition of multidimensional data arrays into basic elements or patterns representing shared features. These approaches traditionally have been applied to mature, fully developed systems. Here we review some results from two other perspectives on modularity, namely the developmental and evolutionary perspective. There is growing evidence that modular units of development were highly preserved and recombined during evolution. We first consider a few examples of modules well identifiable from morphology. Next we consider the more difficult issue of identifying functional developmental modules. We dwell especially on modular control of locomotion to argue that the building blocks used to construct different locomotor behaviors are similar across several animal species, presumably related to ancestral neural networks of command. A recurrent theme from comparative studies is that the developmental addition of new premotor modules underlies the postnatal acquisition and refinement of several different motor behaviors in vertebrates. PMID:23730285

  20. Rescue Manual. Module 3.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Instructional Materials Lab.

    This learner manual for rescuers covers the current techniques or practices required in the rescue service. The third of 10 modules contains 4 chapters: (1) forcible entry; (2) structure search and rescue; (3) rescue operations involving electricity; and (4) cutting torches. Key points, an introduction, and conclusion accompany substantive…