Search results for: A. I. Vodchits

Items from 1 to 19 out of 19 results

article

Nonlinear Refraction of Dielectric Single Crystals under Excitation with Ultrashort Near-Infrared Laser Pulses

A. I. Vodchits, V. S. Gorelik, V. A. Orlovich, P. A. Apanasevich

Optics and Spectroscopy > 2019 > 127 > 4 > 625-628

Nonlinear refraction in a number of crystals (KGW, KGW:Eu³⁺, Ba(NO₃)₂, BaWO₄, PbMoO₄, and CdWO₄) that are promising for excitation of multifrequency stimulated Raman scattering is investigated by a single-beam Z-scan method. Picosecond laser pulses with a wavelength of 1064 nm generated by a YAG:Nd³⁺ laser were used for excitation of nonlinear optical processes. The values of n₂ are compared depending...

article

Spontaneous and Stimulated Raman Scattering in Protium and Deuterium Water

V. S. Gorelik, Dongxue Bi, Yu. P. Voinov, A. I. Vodchits, more

Optics and Spectroscopy > 2019 > 126 > 6 > 687-692

The Raman spectra of different specimens of protium and deuterium water have been compared. The spectra have been recorded using a fiber-optic technique and a compact BWS465-785H spectrometer. The spectra of spontaneous Raman scattering have been excited using a cw laser with a wavelength of 785 nm. Significant differences in the low-frequency Raman spectra from different specimens of water have been...

article

Raman Scattering in LiOH and LiOD Polycrystals

V. S. Gorelik, A. I. Vodchits, Dongxue Bi, V. V. Koltashev, more

Inorganic Materials > 2019 > 55 > 3 > 271-276

— We have studied spontaneous and stimulated Raman spectra of polycrystalline LiOH and LiOD. The observed spontaneous Raman spectra contain low-frequency high-quality-factor lattice modes corresponding to translational and librational oscillations of the ions. The stimulated Raman spectrum has been found to contain several Stokes and anti-Stokes satellites with a large frequency shift.

article

Isofrequency Opalescence in Ferroelectrics

V. S. Gorelik, P. P. Sverbil, A. I. Vodchits, Yu. P. Voinov

Bulletin of the Russian Academy of Sciences: Physics > 2018 > 82 > 3 > 257-260

Isofrequency dependences of the spectral intensities of inelastic scattering in LiTaO₃, Pb₅Ge₃O₁₁, BaTiO₃, and KNbO₃ crystals are registered at a fixed frequency of the spectrometer close to that of the exciting radiation. Results from soft mode analysis are presented.

article

Reflection spectra of 1D photonic crystals based on aluminum oxide

V. S. Gorelik, M. M. Yashin, A. I. Vodchits

Physics of Wave Phenomena > 2017 > 25 > 3 > 175-179

Optical properties (transmission and reflection) of 1D photonic crystals (PCs) based on mesoporous anodic aluminum oxide with the lattice periods of 188 and 194nm are investigated. The experimentally measured reflection spectrum is compared in its first bandgap region with the theoretical dependence obtained from the dispersion relation for the 1D PC. Angular dependence is established for spectral...

article

Multifrequency stimulated Raman scattering of light in liquid nitrogen infiltrated into 3D photonic crystals

V. S. Gorelik, A. D. Kudryavtseva, M. V. Tareeva, N. V. Tcherniega, more

Bulletin of the Lebedev Physics Institute > 2017 > 44 > 2 > 46-49

Spectral characteristics of stimulated Raman scattering at least in synthetic opal matrices infiltrated with liquid nitrogen upon excitation by nanosecond laser pulses are studied. The effect of the stop band position on the generation efficiency of anti-Stokes components of stimulated Raman scattering up to the third order is demonstrated. The excitation threshold of stimulated Raman scattering in...

article

Optical properties of lithium niobate and lithium tantalate crystals with impurities and defects

V. S. Gorelik, N. V. Sidorov, A. I. Vodchits

Physics of Wave Phenomena > 2017 > 25 > 1 > 10-19

The photoinduced and Raman scattering in lithium niobate and lithium tantalate crystals with impurities and defects have been studied. An exciting laser beam propagated either along the ferroelectric Z axis or perpendicular to it. The conditions for exciting transverse and longitudinal polar optical modes in Raman spectra are established. The regularities of the excitation of Raman spectra in several...

article

Reduction of the threshold of stimulated Raman scattering in Raman-active media introduced into pores of a globular photonic crystal

Y. Almohamed, R. Barille, A. I. Vodchits, Yu. P. Voinov, more

JETP Letters > 2015 > 101 > 6 > 365-370

The characteristics of stimulated Raman scattering in benzene and carbon disulfide introduced in pores of globular photonic crystals—opal matrices formed from close-packed balls (globules) of amorphous quartz (silica)—have been experimentally studied. Stimulated Raman scattering spectra have been excited by giant pulses of the second optical harmonic (532 nm) of a YAG laser. The spectra have been...

article

Multifrequency Stimulated Raman Scattering in Light and Heavy Water

V. S. Gorelik, A. I. Vodchits, V. A. Orlovich

Journal of Russian Laser Research > 2015 > 36 > 6 > 562-569

We establish the regularities of changes in the spectra of stimulated Raman scattering in light water (H₂O) and heavy water (D₂O) under changing laser excitation regimes. We find several satellites occurring in Stokes and anti-Stokes regions at high pumping intensities. We study the spectra of stimulated Raman scattering in H₂O and D₂O under excitation by the second optical harmonic (532 nm) of a...

article

Raman Scattering in Light and Heavy Waters

V. S. Gorelik, A. D. Kudryavtseva, V. A. Orlovich, P. P. Sverbil, more

Journal of Russian Laser Research > 2013 > 34 > 6 > 523-530

We present the results of an experimental study of the spontaneous and stimulated Raman scattering (SRS) spectra and luminescence spectra of light and heavy waters. Also we investigate various samples of light water. We show the possibility of using spectral methods to detect impurities in water and determine the degree of its structuredness, which can serve as an additional criterion of the water...

article

A method for reducing the stimulated Raman scattering threshold in liquids embedded into photonic crystals

V. S. Gorelik, A. D. Kudryavtseva, N. V. Tcherniega, A. I. Vodchits, more

Journal of Russian Laser Research > 2013 > 34 > 1 > 50-58

We study stimulated Raman scattering (SRS) in liquids (water and ethanol) embedded into photonic crystals (artificial opals) under excitation with 60 ps laser pulses at 532 nm. We observe a substantial decrease of the SRS threshold when the focused laser beam excites the crystals near their surface. The spatial distance between the beam center and the surface of the crystals is close to their nanoscale...

article

Stimulated Raman scattering in light and heavy water under picosecond laser excitation

A. I. Vodchits, Yu. P. Voinov, V. S. Gorelik, A. D. Kudryavtseva, more

Bulletin of the Lebedev Physics Institute > 2013 > 40 > 12 > 329-334

The spectra of stimulated Raman scattering in ordinary and heavy water under excitation by second harmonic of a picosecond Nd:YAG laser were compared. It was shown that when stimulated Raman scattering is excited in water in cavities of a photonic crystal (synthetic opal matrix constructed of silica nanoglobules) or a photonic glass in the form of close-packed monodimensional millimeter-size amorphous-quartz...

article

Nonlinear refractive index of vanadate crystals in the near IR region

A. I. Vodchits, V. A. Orlovich, P. A. Apanasevich

Journal of Applied Spectroscopy > 2012 > 78 > 6 > 918-921

We used the single-beam Z-scan method, employing picosecond laser pulses with λ = 1064 nm, to measure the nonlinear refractive index and nonlinear absorption in vanadate crystals, which are promising for design of laser sources. We have established that there is practically no nonlinear absorption in these crystals in the near IR range and that doping them with neodymium ions leads to a significant...

article

Influence of compressed gas circulation on SRS conversion of ultrashort laser pulses

A. I. Vodchits, V. A. Orlovich, P. A. Apanasevich

Journal of Applied Spectroscopy > 2012 > 79 > 4 > 567-576

Comparative studies on SRS conversion of 1 kHz ultrashort laser pulses (0.9–1.2 ps) at 401 and 802 nm in circulated and non-circulated compressed methane and hydrogen were carried out in SRS generation (SRSG) and stimulated Raman amplification (SRA) modes. It was shown that circulation of the gases weakened substantially the thermal lens, which facilitated reaching higher efficiencies of radiation...

article

Stimulated Raman scattering of light in artificial opal filled by water

V. S. Gorelik, A. D. Kudryavtzeva, V. A. Orlovich, M. V. Tareeva, more

Journal of Russian Laser Research > 2011 > 32 > 3 > 277-286

We investigate stimulated scattering of light in globular photonic crystals infiltrated by water. Excitation of stimulated scattering of light is realized using powerful ultrashort (70 ps) laser pulses with an energy of 35 mJ and a frequency repetition of 15 Hz. We use the second-harmonic generation (532 nm) of the master oscillator and amplifier with a wavelength of 1064 nm. The photonic crystals...

article

Kilohertz raman lasers based on bno and kgw crystals for a wide spectral range

A. I. Vodchits, D. N. Busko, V. A. Orlovich, P. A. Apanasevich, more

Journal of Applied Spectroscopy > 2010 > 77 > 4 > 534-540

Efficient Raman lasers based on Ba(NO₃)₂ and KGd(WO₄)₂ crystals which produce nanosecond pulses with repetition rates of 1 and 4 kHz at 26 wavelengths between 280 and 1600 nm are developed and studied. A maximum SRS conversion efficiency of 25% is obtained. It is found that the divergence of the beams generated by the Raman laser can be significantly reduced by using quasi-Bessel pump beams and an...

article

Stimulated globular scattering of laser radiation in photonic crystals: Temperature dependences

V. S. Gorelik, A. D. Kudryavtseva, N. V. Tcherniega, A. I. Vodchits

Journal of Russian Laser Research > 2007 > 28 > 6 > 567-575

The characteristics of stimulated globular scattering such as the frequency shift, threshold, and conversion efficiency are studied in photonic crystals (synthetic opal matrices and opal nanocomposites) at different temperatures. The results are compared with the study of stimulated Raman scattering in calcite single crystals. In both cases, a decrease in temperature from +20° C to −196° C resulted...

article

Comparative studies of eye-safe intracavity and extracavity optical parametric oscillators with an unstable telescopic cavity

V. I. Dashkevich, A. I. Vodchits, V. A. Orlovich, N. S. Kazak, more

Journal of Applied Spectroscopy > 2006 > 73 > 4 > 604-612

We have experimentally studied the lasing characteristics of an eye-safe optical parametric oscillator (OPO) with an unstable telescopic cavity when it is placed inside (intracavity OPO) and outside (extracavity OPO) the plane-parallel cavity of a pulsed, nearly single-mode KGW:Nd pump laser. We used a KTP crystal as the nonlinear medium for the OPO. We have shown that the intracavity OPO has the...

article

Eye-safe radiation source based on an optical parametric oscillator

A. I. Vodchits, V. I. Dashkevich, N. S. Kazak, V. K. Pavlenko, more

Journal of Applied Spectroscopy > 2006 > 73 > 2 > 285-291

We have studied an optical parametric oscillator (OPO) with an unstable telescopic cavity, placed inside the cavity of an actively Q-switched multimode Nd³⁺:KGW pump laser. We used a KTP crystal as the nonlinear medium for the OPO. We have compared the emission characteristics of OPOs with unstable telescopic and planar cavities. We have established that compared with the planar cavity, the unstable...

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