Andreev, Yury M.

Antsygin, Valery D.

Ezhov, Dmitry M.

Losev, V. F.

Lubenko, D. M.

Mamrashev, Alexander A.

Nikolaev, Nazar A.

Svetlichnyi, Valerii A.

English

Tomsk State University Repository

PULSED LASERS AND LASER APPLICATIONSTHE 15th  INTERNATIONAL CONFERENCEThe 15th International Conference AMPL-2021 PULSED LASERS AND LASER APPLICATIONS September 12–17, 2021 Tomsk, Russia ABSTRACTS GENERAL SPONSOR Special Systems. Photonics, St. Petersburg, Russia CONFERENCE ORGANIZERS Institute of Atmospheric Optics SB RAS Institute of High Current Electronics SB RAS Tomsk State University Tomsk Polytechnic University CONFERENCE SPONSORS Ministry of Education and Science of Russian Federation, Russia Russian Academy of Sciences, Russia Siberian Branch of Russian Academy of Science, Russia Laser Association, Russia  CONFERENCE SPONSORS TOPAZ Research and Inculcation Enterprise, Tomsk, Russia Young Scientists Counsil IAO SB RAS, Tomsk, Russia SP Equipment, Novosibirsk, Russia Azimut Photonics, Moscow, Russia LOTIS TII, Minsk, Belarus Special Systems. Photonics, St.-Petersburg, Russia CLZ Ltd, Moscow, Russia Leningrad Laser Systems, St.-Petersburg, Russia MEDIA SPONSORS Atmospheric and Oceanic Optics Journal, Tomsk, Russia Photonics Journal, Moscow, Russia  Tomsk, 2021  106  CONVERSION OF LASER RADIATION, OPTOELECTRONIC DEVICES AND NONLINEAR OPTICS SESSION F  In this work, we study the spectral angular characteristics of THz radiation generated in a single-color filament, both in the presence and in the absence of an external electrostatic field. The transition of the angular distribution from a hollow cone, observed in the absence of an external field, to a filled cone, inherent to filamentation in an external field, is investigated. We demonstrate that various spectral components of THz radiation have different angular distributions, and also under the influence of an external electrostatic field their behavior differs significantly. With an increase in the strength of the electrostatic field, the maximum on the axis appears due to the generation of higher frequency THz components, while the low frequency THz radiation still propagates in a hollow cone. It is shown that the angular distribution of various THz frequencies depends on the focusing conditions and the wavelength of the initial laser pulse. We acknowledge financial support by Russian Foundation for Basic Research (RFBR), Project 20-02-00114. F-10 THE DIELECTRIC TENSOR ROTATION ANGLE  AND OPTICAL PROPERTIES OF A NONLINEAR CRYSTAL  OF BISMUTH TRIBORATE IN THE MILLIMETER WAVE RANGE N.A. Nikolaev1,2, A.A. Mamrashev1, V.D. Antsygin1, D.M. Ezhov3, D.M. Lubenko4, V.A. Svetlichnyi3, Yu.M. Andreev4,5, and V.F. Losev4 1Institute of Automation and Electrometry SB RAS, 1 Koptyug Ave., 630090, Novosibirsk, Russia, Nazar@iae.nsk.su; 2Institute of Laser Physics SB RAS, 13/3 Lavrent’ev Ave., 630090, Novosibirsk, Russia; 3Tomsk State University, 36 Lenin Ave., 634050, Tomsk, Russia; 4Institute of High Current Electronics SB RAS, 2/3 Akademichesky Ave., 634055, Tomsk, Russia; 5Institute of Monitoring of Climatic and Ecological Systems SB RAS, 10/3 Akademichesky Ave., 634055, Tomsk, Russia Today, there is an unsolved problem of developing compact tunable radiation sources of the millimeter-wave (mm-) range with high performance characteristics, spectral selectivity, and brightness, suitable for out-of-laboratory applications. The solution could be the use of nonlinear optical crystals for downconversion of the frequencies of compact high power lasers into the subterahertz range. A potentially suitable crystal for these tasks is bismuth triborate BiB3O6 (BIBO), which is inert to moisture, has a high laser induced damage threshold, a wide transparency window, and low absorption in the visible and near-IR spectra. BIBO has higher nonlinear coefficients than the other crystals of the borate family. Thus, the study of the optical properties of BIBO and the assessment of the prospects for its application in the mm-wavelength range is important. In this work, the absorption coefficients, and the refractive indices of the principal optical axes of the crystal were measured at room temperature and 77 K. The measurements were carried out with high accuracy by the means of terahertz time domain spectroscopy in the range 0.1—2 THz on samples with a thickness of 5 mm and an aperture of  10  10 mm2. Such thickness allows us to determine the absorption coefficient in the mm range to be below 0.2 cm–1 for both temperatures. Since the BIBO crystal has the spatial symmetry C2 and is monoclinic, its dielectric coordinates rotate around the main optical axis x (crystallophysical axis Y) depending on the wavelength. We have shown that the angle of rotation between the mm-range and the 660 nm wavelength is  4 degrees. This work was supported by the Russian Science Foundation (Grant No. 19-19-00241). The authors thank the shared equipment center "Spectroscopy and Optics" at the Institute of Automation and Electrometry SB RAS for the provided instrumental support. 

The dielectric tensor rotation angle and optical properties of a nonlinear crystal of bismuth triborate in the millimeter wave range

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The dielectric tensor rotation angle and optical properties of a nonlinear crystal of bismuth triborate in the millimeter wave range

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