Papers by Vitaly Voloshinov
Proceedings of the Interntional Congress on Ultrasonics, 2007
Optics and Spectroscopy, 1996
Quantum Electronics, 2008
The nonreciprocal effect is studied theoretically and experimentally by the example of collinear ... more The nonreciprocal effect is studied theoretically and experimentally by the example of collinear acousto-optic interaction in a birefringent crystal. It is shown that this effect at ultrasonic frequencies ∼1 GHz and above considerably influences the parameters of modern acousto-optic devices, in particular, tunable acousto-optic filters. The nonreciprocal effect is estimated for different acousto-optic materials.
Optical Engineering, 2008
ABSTRACT Results of a theoretical analysis on tunable acousto-optic imaging filters using potassi... more ABSTRACT Results of a theoretical analysis on tunable acousto-optic imaging filters using potassium dihydrogen phosphate crystals are presented. It is found that the maximum angular aperture of an imaging filter at the optical wavelength 0.3 mu m is equal to 3 deg. The diffraction efficiency in the examined instrument reaches 30% at moderate levels (2W) of electric driving power. This performance may be obtained in a cell based on the (010) plane of acousto-optic interaction with the cut angle (18.8 deg) evaluated relative to the (100) axis. The device uses a piezoelectric transducer with dimensions 2.7 x 1.1 cm(2) generating a slow shear elastic wave in the crystal. The spectral resolution of the filter is equal to 12 cm(-1); the spatial resolution is characterized by 550 x 800 resolvable pixels in an image processed by means of the filter with linear aperture 0.8 x 1.1 cm2. (c) 2008 Society of Photo-Optical Instrumentation Engineers.
Acousto-optics and Photoacoustics, 2005
Theory of collinear acousto-optic interaction in anisotropic media has been considered. On the ba... more Theory of collinear acousto-optic interaction in anisotropic media has been considered. On the base of the statement that anisotropic diffraction of light by ultrasound originates from the acoustically induced changes of optical indicatrix in an anisotropic medium, the qualitative and quantitative analysis of the collinear AO interaction has been carried out. The collinear diffraction has been examined in the medium subdivided into a number of thin layers. In each of these layers, the axes of the indicatrix are rotated relatively to the neighboring ones. It has been shown that propagation of light through such system may be considered as propagation through a number of birefringent plates, rotated relatively to each other. The analytical expressions for the intensities of the incident and diffracted light have been derived. It has been shown that the diffraction efficiency depends on the angle of rotation of the axes and on birefringence of the crystal. In the case of a big number of the layers, the calculations have been carried out with the help of Jones calculus and the efficiencies of the collinear diffraction in the most commonly used acousto-optic materials such as paratellurite, alpha-quartz and tellurium crystals, have been calculated.
Results on investigation of thermal effects which appear during operation of an acousto-optic def... more Results on investigation of thermal effects which appear during operation of an acousto-optic deflector are presented in the paper. Influence of the effects on characteristics of the scanning device is evaluated. For a case of the tellurium dioxide deflector, it is proved that the most principal thermal effect consists in an undesirable spatial shift of a scanning optical beam. The
Optical Design and Engineering III, 2008
The report discusses operation principles of a hyperspectral imaging acousto-optic system intende... more The report discusses operation principles of a hyperspectral imaging acousto-optic system intended to process optical images in visible and infrared regions of spectrum. A diffraction grating induced by ultrasound in a birefringent crystal selects color of transmitted light and also controls polarization of the incident radiation. In the developed system, arbitrary polarized divergent or convergent optical beam is split at output of the system into two orthogonally polarized optical beams that are simultaneously scattered into symmetrically situated +1 and -1 diffraction orders. If the incident beam forms an arbitrary polarized non-monochromatic optical image then as much as two images are observed at output of the device. Application of two CCD cameras provides registration in real time of the filtered images possessing orthogonal polarizations. Optical wavelengths selected by the filter are tuned by means of driving ultrasonic frequency. The transmission coefficient of the acousto-optic device is regulated by magnitude of the driving RF power.
The paper presents results on research of tunable acousto- optic filters operating in ultraviolet... more The paper presents results on research of tunable acousto- optic filters operating in ultraviolet, visible and infrared regions of spectrum. High spectral and spatial resolution, perfect diffraction efficiency and low driving power provide application of the filters in optics and spectroscopy as well as in optical information processing and laser technology. Precise and efficient electronic control of laser light intensity
Some peculiarities of a process of non-polarized radiation diffraction on ultrasonic waves in uni... more Some peculiarities of a process of non-polarized radiation diffraction on ultrasonic waves in uniaxial crystals are examined. Particular calculations are made to single-crystals of paratellurite. The experimental design of an acousto-optical modulator operating with non- polarized multimode laser radiation is reported. Basic parameters of the device are presented as well.
Proceedings of the Interntional Congress on Ultrasonics, 2007
ABSTRACT The paper presents new results on analysis of propagation and reflection of acoustic wav... more ABSTRACT The paper presents new results on analysis of propagation and reflection of acoustic waves in the single crystal tellurium dioxide. The investigation was carried out by means of the acousto-optic methods. We observed in a cell with a specially chosen configuration, a simultaneous generation of two elastic modes provided by a single piezoelectric transducer. Maximum transformation of elastic energy into a quasi shear elastic wave with the efficiency about 100% was obtained during a reflection of a quasi longitudinal wave from a free surface. The reflected quasi shear wave was characterized by an extremely large acoustic walkoff angle. A close to back reflection of elastic waves was also observed in the crystal. This reflection was accompanied by a compression of the reflected beam to a factor of 8. Acousto-optic figure of merit of paralellurite was calculated along various directions in the crystal for different polarizations of the optic and acoustic waves. Good agreement was obtained between the experimental and the theoretical data.
ABSTRACT The optic, acoustic, and acousto-optic properties of tellurium single crystals are consi... more ABSTRACT The optic, acoustic, and acousto-optic properties of tellurium single crystals are considered to analyze the possibilities of applying this material in acousto-optic filters to control mid- and far-IR radiation. The results of measuring the optic and acousto-optic parameters of a tellurium crystal are reported. The isotropic and anisotropic light diffraction by ultrasound in the crystal is investigated. The wide-aperture geometry of interaction in tellurium is implemented and an acousto-optic figure of merit M 2 of a tellurium crystal exceeding 10 × 10−15 s3 g−1 is experimentally obtained.
Peculiarities of light diffraction on ultrasonic waves in glasses and birefringent crystals are e... more Peculiarities of light diffraction on ultrasonic waves in glasses and birefringent crystals are examined thoeretically and experimentally. Isotropic dense flint glass material DF-7 and optically anisotropic crystal of tellurium dioxide were chosen for the investigation. The diffraction was observed in intermediate and Bragg regimes of aocusto-optical interaction. From five to seven diffractional maxima in a diffractional pattern were considered in
Quantum Electronics, 2005
Optical multipass schemes of the interaction of light and sound, which are promising for filtrati... more 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. (control of laser radiation parameters)
Ultrasonics, 2011
The Raman-Nath, intermediate and Bragg regimes of acousto-optic interaction in an acoustically an... more The Raman-Nath, intermediate and Bragg regimes of acousto-optic interaction in an acoustically anisotropic medium are theoretically examined in the paper. The general model of the interaction is extended over the case of an elastically anisotropic medium. Basic results of computer modeling of diffraction processes taking place in crystals are presented in the paper. The interaction of light and ultrasound is investigated in media with arbitrary elastic anisotropy in a wide range of the Klein-Cook and Raman-Nath parameters. The influence of the acoustic anisotropy on the process of light diffraction, especially on the light intensity in diffraction maxima, is also discussed.
Technical Physics, 2008
The optical, acoustic, and acoustooptic properties of tellurium crystals viewed as a candidate ma... more The optical, acoustic, and acoustooptic properties of tellurium crystals viewed as a candidate material for mid-and far-IR acoustooptic devices are considered. The phase velocities, polarization, and drift angles of the acoustic energy in different crystal planes are calculated. The acoustooptic figure of merit for tellurium under the anisotropic diffraction conditions is estimated, and light-sound interaction geometries promising for acoustooptic applications are discussed. Measuring data for the optical and acoustooptic parameters of tellurium crystals are given.
Quantum Electronics, 2005
The results of recent studies on coherent acousto-optic image processing performed at the chair o... more The results of recent studies on coherent acousto-optic image processing performed at the chair of physics of oscillations at the Department of Physics of Moscow State University are reported. It is shown that this processing method is based on the filtration of the spatial spectrum of an optical signal in an acousto-optic cell. The main attention is paid to the
Optics Letters, 2005
A compact UV hyperspectral imager can be designed with an acousto-optic tunable filter (AOTF) ins... more A compact UV hyperspectral imager can be designed with an acousto-optic tunable filter (AOTF) installed in front of an enhanced CCD camera. Tellurium dioxide ͑TeO 2 ͒ is the most commonly used crystal for AOTFs from 0.4 to 4 m. We conducted an experiment to determine the UV spectral response of an imaging TeO 2 AOTF in tandem with a known KDP AOTF and obtained good-quality hyperspectral images by using the TeO 2 filter down to 365 nm. We compared the performance of the TeO 2 filter-based hyperspectral imager with an imager based on a KDP filter because currently the latter is the best available material for the UV, and we found the performance of the TeO 2 imager in the range 355-480 nm to be superior to that of a KDP imager. We present our experiments and the results obtained.
Optics Express, 2009
A cascaded system of two acousto-optical cells is proposed for equalization of multichannel optic... more A cascaded system of two acousto-optical cells is proposed for equalization of multichannel optical signal satisfying coarse wavelengthdivision multiplexing standard. Two similar acousto-optical modulators for unpolarized light on the basis of 10 • -cut paratellurite crystals were used in a free-space gap of a fiber line. The system controlled intensity of several optical carriers in the spectral range from 1200 to 1700 nm. The device was tested in a four-channel regime of operation in the range 1510-1570 nm. Overall optical insertion losses did not exceed −2 dB and less than 1 W electric power per channel was necessary for −20 dB intensity attenuation of the signal in a continuous operation mode. Compensation for birefringence in paratellurite provided diffraction regime that was insensitive to polarization of light. Interchannel crosstalk was less than −10 dB.
Optics Communications, 2013
The paper presents results on the theoretical and experimental investigations of an acousto-optic... more The paper presents results on the theoretical and experimental investigations of an acousto-optic modulator based on single crystal lithium niobate. The modulator uses a regime of operation with a standing longitudinal acoustic wave generated in the material along the axis X. The optimum cut in the LiNbO 3 crystal has been calculated and it is shown that the highest figure of merit can be obtained in the YZ-plane of the crystal if light propagates not along the crystalline axis Z or Y but at an angle of 371 with respect to the axis Y. Application to the instrument of a harmonic driving electric signal at a frequency included in the range 450-550 MHz resulted in modulation of light intensity and generation of a sequence of laser pulses having repetition frequencies 0.9-1.1 GHz. The efficiency of light diffraction in the examined laser chopper was equal to 7-10% depending on frequency and power at a driving electric power of 1.0 W or higher and a wavelength of light equal to 532 nm. The possibilities to develop a similar acousto-optic modulator but with repetition frequencies up to 10 GHz are discussed.
Uploads
Papers by Vitaly Voloshinov