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Your search keyword '"Bufetova, G A"' showing total 29 results
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29 results on '"Bufetova, G A"'

2. Measurement of the refractive index of an Er3+:YAG crystal melt.

Author

Bufetova, G. A., Kashin, V. V., Rusanov, S. Ya., Seregin, V. F., and Tsvetkov, V. B.

Subjects
*MELTING points, *HEAT radiation & absorption, *REFRACTIVE index, *CRYSTALS, *HIGH temperatures, *ND-YAG lasers, *PEDESTALS
Abstract

A new method for measuring the refractive index of crystals and melts at high temperatures is presented. The refractive index of an Er3+:YAG crystal melt is determined during the laser-heated pedestal growth process close to the melting point. The main idea is to use the maximal difference in the intensities of two polarizations of thermal radiation passing the melt-air interface. From the Fresnel equations, it follows that this difference is almost proportional to the refractive index. Angular diagrams of the thermal radiation of the melt for two polarizations are analyzed. The obtained value of the refractive index of the Er3+:YAG melt is n = 1.84 ± 0.01 in the wavelength range of 550–620 nm. [ABSTRACT FROM AUTHOR]

Published
2020
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21. Absorption spectra and nonlinear transmission (at ? = 2940 nm) of a diffusion-doped Fe2+:ZnSe single crystal

Author

Bufetova, G A, Gulyamova, E S, Il, N N, Nasibov, A S, Pashinin, P P, and Shapkin, P V

Abstract

Transmission spectra of a ZnSe sample diffusion-doped with Fe2+ ions have been measured in the wavelength range 500 - 7000 nm. A broad absorption band in the range 500 - 1500 nm has been observed in both doped and undoped regions of the sample. This band is possibly due to deviations from stoichiometry in the course of diffusion doping. The transmission of the Fe2+:ZnSe sample at a wavelength of 2940 nm has been measured at various dopant concentrations and high peak pulse intensities (up to 8 MW cm-2). The samples have been shown to be incompletely bleached: during a laser pulse, the transmission first increases, reaches a maximum, and then falls off. Our results suggest that the incomplete bleaching cannot be accounted for by excited-state absorption. The incomplete bleaching (as well as the transmission maximum) is due to the heating of the sample, which leads to a reduction in upper level lifetime and, accordingly, to an increase in absorption saturation intensity.

Published
2015

23. Study of thermo-optical distortions in a plate active element with zigzag beam path.

Author

Lyashed'ko, A., Bufetova, G., Seregin, V., Tsvetkov, V., and Shcherbakov, I.

Abstract

Phase distortions introduced into the laser beam propagating in a plate under diode pumping of the active element (AE) and for intentionally caused temperature gradients in the AE are studied. The temperature distribution along the optical axis of the active element is measured during its end diode pumping. Phase distortions of the test beam propagating through the nonuniformly heated active element are studied. Interference patterns are obtained and optical distortions of the test beam are measured at various temperature gradients in the crystal. [ABSTRACT FROM AUTHOR]

Published
2012
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24. Nd3+:GGG and Cr4+:GGG epitaxial films for neodymium lasers.

Author

Bufetova, G., Gusev, M., Ivanov, I., Neustroev, N., Nikolaev, D., Seregin, V., Tsvetkov, V., and Shcherbakov, I.

Abstract

An efficient technology was developed for growing the gadolinium gallium garnet (GGG) single-crystal films doped with Nd3+ or Cr and Ca ions. The films with thickness up to 100 µm have been grown by liquid-phase epitaxy method on undoped GGG substrates of small and big sizes (5–8 mm and up to 76 mm in diameter, respectively). The dependence of absorption, luminescence spectra and optical losses at the wavelength of 1 µm on growth temperature and melt-solution composition was studied. We demonstrated that Cr4+ centers have been implemented in epitaxial films and these films may be used as passive Q-switches for laser systems. [ABSTRACT FROM AUTHOR]

Published
2009
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25. Linear and nonlinear transmission of Fe2+-doped ZnSe crystals at a wavelength of 2940 nm in the temperature range 20-220 °C

Author

Il, N N, Pashinin, P P, Gulyamova, E S, Bufetova, G A, Shapkin, P V, and Nasibov, A S

Abstract

The linear and nonlinear transmission of Fe2+:ZnSe crystals is measured at a wavelength of 2940 nm in the temperature range 20 - 220 degC. It is found that, with increasing temperature from 20 degC to 150 - 220 degC, the transmission of Fe2+:ZnSe crystals decreases in the case of incident radiation with an intensity of [?]5.5 MW cm-2 and increases in the case of radiation with an intensity of 28 kW cm-2. At a temperature of 220 degC, the linear transmission almost coincides with the nonlinear transmission. The transmission spectra of Fe2+:ZnSe crystals at temperatures of 22 and 220 degC in the wavelength range 500 - 7000 nm are presented.

Published
2014

28. Preparation and study of epitaxial Cr4+: GGG films for passive Qswitches in neodymium lasers

Author

Bufetova, G A, Gusev, M Yu, Ivanov, I A, Nikolaev, D A, Seregin, V F, Tsvetkov, V B, and Shcherbakov, Ivan A

Abstract

The efficient technology is developed for growing Cr- and Ca-doped gadolinium—gallium garnet single-crystal films of thickness up to 100 μm on large substrates (76 mm) by the method of liquid-phase epitaxy from a solution—melt. The dependences of the absorption spectra of films and optical losses at 1 μm on the growth conditions and the solution—melt composition are studied. It is shown that Cr4+ions are formed in the films, and these films can be used as passive Qswitches in lasers.

Published
2006
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