Vitaly B. Voloshinov

Bio: Vitaly B. Voloshinov is an academic researcher from Moscow State University. The author has contributed to research in topics: Diffraction & Acoustic wave. The author has an hindex of 21, co-authored 156 publications receiving 1639 citations.

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

Abstract: 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.

Improvement in performance of a TeO2 acousto-optic imaging spectrometer

Abstract: This paper concerns the problem of the optimization of parameters in acousto-optic image processing systems. The optimization was carried out with the purpose of obtaining the best performance and minimum driving power. A choice of optimal geometry of acousto-optic interaction in the crystal is discussed. Longitudinal aberrations in the device caused by dispersion of refractive indices of acousto-optic media are studied. Calculations prove that a specific choice of distances between optical elements in the device can reduce the aberration to a value less than the focal depth of a filtered image. Spectral analysis of radiation reflected from artificial test objects demonstrates operationaal capability of the imager.

Tunable acoustooptic filters and equalizers for WDM applications

Abstract: We describe a high performance acoustooptic tunable filter for add-drop application and for signal equalization in WDM telecommunication crossconnects. It results from a thorough investigation in TeO/sub 2/ of bulk collinear interaction, the geometry of which, particularly the direction of propagation of the acoustic wave, has been chosen in order to obtain the best compromise between the spectral resolution of the device and the acoustooptic figure of merit. Less than 40 mW of electric power is needed either to deviate 100% of a selected light wavelength /spl lambda/ at resonance, or to induce a 30-dB attenuation of its intensity. The sidelobes practically vanish for this configuration and the resolution is equal to 0.75 nm (or 94 GHz) for /spl lambda/=1.55 /spl mu/m. Polarization splitters combined with half-wave plates allow to completely get rid of polarization sensitivity problems. The use of optical fibers to collect the signal at the filter outputs, actually contributes to the high performance of the device as a whole. Experiments have been performed by multiplexing three signals in the input fiber, separated by 4, 2, and 1 nm. The transmission of the filter has been examined through the bar and cross state.

Close to collinear acousto-optical interaction in paratellurite

Abstract: First results on the investigation of close to collinear coustooptical interaction in paratellurite single crystals are presented Anisotropic Bragg diffraction of light on ultrasound in TeO2 with a length of interaction of up to several centimeters is examined A peculiarity of the interaction is optical beam propagation in the crystal collinearly with group velocity of ultrasound It is shown and verified experimentally that the interaction is characterized by an extremely high selectivity of scattering Some applications of the examined regime of diffraction are discussed

Development and characterization of two-transducer imaging acousto-optic tunable filters with extended tuning range

Abstract: We developed two high-quality large-aperture acousto-optic tunable filter cells in TeO2 with more than two octaves spectral coverage for hyperspectral imaging applications from the visible to the midwave infrared: the first cell covers from 0.43 to 2.1 μm and the second from 0.69 to 4.0 μm. The key feature of these cells is a special design of two transducers in tandem with a special bonding technique that results in such a wide spectral coverage with virtually no acoustic and electrical loss due to careful matching of both acoustic and electrical impedances. Each of these cells has high spectral transmission, as well as low power requirement. We discuss the design, characterization, and performance results for these cells.

Optical switching: switch fabrics, techniques, and architectures

Abstract: The switching speeds of electronics cannot keep up with the transmission capacity offered by optics. All-optical switch fabrics play a central role in the effort to migrate the switching functions to the optical layer. Optical packet switching provides an almost arbitrary fine granularity but faces significant challenges in the processing and buffering of bits at high speeds. Generalized multiprotocol label switching seeks to eliminate the asynchronous transfer mode and synchronous optical network layers, thus implementing Internet protocol over wavelength-division multiplexing. Optical burst switching attempts to minimize the need for processing and buffering by aggregating flows of data packets into bursts. In this paper, we present an extensive overview of the current technologies and techniques concerning optical switching.

Room temperature gas sensing of p-type TeO2 nanowires

Abstract: Tellurium dioxide (TeO2) nanowires with a tetragonal structure have been grown by thermally evaporating tellurium metal at 400°C in air. The nanowires produced have diameters ranging from 30to200nm and have lengths of several tens of micrometers. Gas sensors were fabricated using the obtained TeO2 nanowires. The sensing behavior to NO2, NH3, and H2S gases at room temperature showed typical characteristics of a p-type semiconductor. The results demonstrate the potential to develop TeO2 nanowire based gas sensors with low power consumption.

Optoelectronic Oscillators (OEOs) to Sensing, Measurement, and Detection

Abstract: Besides distinct features on RF/optical signal generation, optoelectronic oscillators (OEOs) have also been rapidly developed as emerging techniques towards sensing, measurement, and detection. In this paper, we start with the conceptual architecture and the analytical model of OEOs. Then, three operation principles behind sensing, measurement, and detection applications are categorized, including the variation on the time delay of loop, the passband reconfiguration of microwave photonic filter in loop, and the oscillation gain from injection locking, which clearly clarify the X-to-frequency mapping (X denotes target parameter or signal) for supporting practical solutions and approaches. Next, a comprehensive review to advances in OEO-based sensing, measurement, and detection applications is presented, including length change and distance measurement, refractive index estimation, load and strain sensing, temperature and acoustic sensing, optical clock recovery, and low-power RF signal detection. As a new application example, a novel approach for in-line position finding is proposed. When a long fiber Bragg grating inserted into OEO is locally heated to slightly broaden its reflection spectrum, the target position heated is mapped into the oscillating frequency shift, according to the first operation principle. A sensitivity of 254.66 kHz/cm is obtained for position finding in the experiment. Afterward, solutions for calibration and stabilization are briefly introduced, which enable us to improve the accuracy and reliability. Finally, features and future prospects on the sensing, measurement, and detection applications are discussed, such as compact and integrated OEOs.

SPICAM IR acousto-optic spectrometer experiment on Mars Express

Abstract: SPICAV IR, a part of SPICAV/SOIR suite on Venus Express, is a compact single pixel spectrometer for the spectral range of 0.65–1.7 mm based on acousto-optical tunable filter (AOTF) technology. SPICAV IR is derived from SPICAM IR operating on Mars Express, the first AOTF spectrometer in the deep space, and adapted for Venus atmosphere measurements. The spectrometer sequentially measures spectra of reflected solar radiation from Venus on the dayside and the emitted Venus radiation in spectral ‘‘windows’’ on the nightside, and works also in solar occultation mode. The spectral range is 0.65– 1.1 mm with spectral resolution of 7.8 cm � 1 , and 1–1.7 mm with spectral resolution of 5.2 cm � 1 .A description of this near-IR instrument, its calibration, in-flight performances, and the modes of operations on Venus’ orbit are presented. A brief overview of the science measurements is given: water vapor measurements in the mesosphere on the day-side and near surface on the nightside, mapping of the O2(a 1 Dg) emission at 1.27 mm, aerosol studies via polarization and scattering solar radiation at the day-side, and measurements of aerosol properties at the tops of the clouds in solar occultations.

Optical time-stretch imaging: Principles and applications

Abstract: Breathtaking innovations in optical imaging have opened new exciting avenues for science, industry, and medicine over the last few decades. One of such innovations is optical time-stretch imaging—an emerging method for ultrafast optical imaging that builds on temporally stretching broadband pulses by using dispersive properties of light in both spatial and temporal domains. It achieves continuous image acquisition at an ultrahigh frame rate of 10–1000 million frames per second by overcoming technical and fundamental limitations that exist in traditional imaging methods. By virtue of its inherent affinity with optical signal processing, optical time-stretch imaging can be combined with various optical techniques such as amplification, nonlinear processing, compressive sensing, and pattern correlation to realize unique capabilities that are not possible with the traditional imaging methods. Applications enabled by such capabilities are versatile and include surface inspection, surface vibrometry, particle analysis, and cell screening. In this paper, we review the principles and limitations of conventional optical imaging, the principles and applications of optical time-stretch imaging, and discuss our future perspective.