A.P. Velmuzhov
Russian Academy of Sciences
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Publication
Featured researches published by A.P. Velmuzhov.
Journal of Lightwave Technology | 2013
Clément Conseil; V.S. Shiryaev; Shuo Cui; Catherine Boussard-Plédel; Johann Troles; A.P. Velmuzhov; Alexander M. Potapov; Alexander I. Suchkov; M. F. Churbanov; Bruno Bureau
Te rich glasses in the ternary Ge-Te-Se system are stable against crystallization and remain transparent enough for application in the far infrared beyond 15 μm. Four protocoles of preparation of highly-purified Te-rich Ge-Te-Se glasses are developed and compared. These methods are based on different distillation procedures to remove water, oxides, hydrogen and carbon impurities from glasses. The final residual impurity content in glasses was determined by the IR spectroscopy and laser mass spectrometry. Then, unclad optical fibers were drawn from each synthetized glass. At room temperature, the minimum of attenuation is about 7 dB/m at 10.6 μm whatever the purification procedure, showing that the residual optical losses are intrinsic to the chemical nature of the glasses. On the other hand, at 77 K, the optical losses are lowered to 1 dB/m confirming that losses are mainly due to the high charge carrier concentration inherent to the semi-conducting behavior of these glasses. Finally, this low level of losses is rather a promising news in view of application in space where optical filtering devices working beyond 15 μm are needed.
Optical Materials Express | 2014
V. G. Plotnichenko; Denis Philippovskiy; V. O. Sokolov; M.V. Sukhanov; A.P. Velmuzhov; M. F. Churbanov; E. M. Dianov
Experimental and theoretical studies of spectral properties of chalcogenide Ge–S and As–Ge–S glasses and fibers are performed. A broad infrared (IR) luminescence band which covers the 1.2 – 2.3 μm range with a lifetime about 6 μs is discovered. Similar luminescence is also present in optical fibers drawn from these glasses. Arsenic addition to Ge–S glass significantly enhances both its resistance to crystallization and the intensity of the luminescence. Computer modeling of Bi-related centers shows that interstitial Bi+ ions adjacent to negatively charged S vacancies are most likely responsible for the IR luminescence.
IEEE Journal of Selected Topics in Quantum Electronics | 2017
Elena A. Romanova; Svetlana Korsakova; Matej Komanec; Tomas Nemecek; A.P. Velmuzhov; M.V. Sukhanov; V.S. Shiryaev
Evanescent wave spectroscopy in the mid-infrared (MIR) is a powerful tool for remote real-time sensing. Chalcogenide fibers transparent in MIR are considered as a base for creation of a fiber-optical platform for the MIR sensing. In this paper, a rigorous theoretical approach has been applied for the analysis of evanescent modes propagation in a multimode chalcogenide fiber surrounded by an absorbing medium. A role of particular evanescent mode in power delivering through the fiber has been revealed. Strong absorption of water in this spectral range has been shown to be a main factor limiting sensitivity of the evanescent wave sensor. Possibilities of sensitivity enhancement by using waveguiding properties of the fiber have been discussed. The analysis is supported with an experimental measurement of a [GeSe4]95I5 glass fiber partially immersed in an aqueous acetone solution, in the wavelength range of 2-5 μm.
Inorganic Materials | 2016
A.P. Velmuzhov; M.V. Sukhanov; A. I. Suchkov; M. F. Churbanov; E. A. Tyurina
We have carried out thermodynamic modeling of the GaI3–S and ZnI2–S systems by the method of equilibrium constants and calculated the chemical compositions of the condensed and vapor phases in the temperature range 200–500°C. Our experimental data demonstrate the feasibility of preparing zinc thiogallate by reacting gallium(III) iodide and zinc(II) iodide with sulfur. Synthesis was carried out at a temperature of 450°C over a period 2 h, followed by calcination of the product at 650°C in order to remove the residual iodine. The practical ZnGa2S4 yield was 92–94%.
Fiber Lasers and Glass Photonics: Materials through Applications | 2018
Elena A. Romanova; V.S. Shiryaev; Andrei Afanasiev; A.P. Velmuzhov; Maxim Sukhanov
Two realizations of the time-resolved pump-probe method have been applied to study comparatively the nonlinear optical response of chalcogenide glasses of the system As-S-Se illuminated by femtosecond laser pulses near their fundamental absorption band edge and near the two-photon absorption band edge. In such conditions, charge carrier’s photo-excitation is going on with participation of gap states. By comparison of the results of measurements and numerical modeling, we have demonstrated that character of the nonlinear optical response depends on how a glass samples was illuminated. If the pump pulse frequency corresponded to the Urbach tail of a glass sample, the carriers trapping and excitons formation was followed by the excitons absorption and excitation of conduction electrons. If a sample was illuminated at the red-edge of its Urbach tail, the photo-excitation was going through the gap states, but excitation of conduction electrons was followed by excitons formation. Due to these peculiarities, calculated spacial distribution of the photo-induced refractive index variation in the sample was different depending on the illumination conditions.
Proceedings of SPIE | 2017
Laurent Calvez; Anna Novikova; Alexander Potapov; A.P. Velmuzhov
In this paper, the possibility to fasten the amorphization process of chalcogenide glasses by mechanical alloying is described. Several ways were investigated to optimize the time of milling permitting a faster production and also avoiding a higher contamination. Thus, the influence of gallium addition which could act as a solvent because of its low melting point and its low vapor pressure has been studied. Then, two conventional ways of milling were compared using a PM100 planetary grinder and a SPEX MILL 8000D, which present two different ways of rotation. Finally, the pollution by WC during mechanical alloying and by carbon during sintering has been investigated by LMS measurements.
Optical Materials | 2014
V.S. Shiryaev; A.P. Velmuzhov; Zhuoqi Tang; M. F. Churbanov; Angela B. Seddon
Journal of Luminescence | 2016
E.V. Karaksina; V.S. Shiryaev; T.V. Kotereva; A.P. Velmuzhov; L. A. Ketkova; G.E. Snopatin
Optical Materials | 2015
Leonid Mochalov; M. F. Churbanov; A.P. Velmuzhov; A.S. Lobanov; R. A. Kornev; G.P. Sennikov
Journal of Luminescence | 2017
V.S. Shiryaev; E.V. Karaksina; T.V. Kotereva; M. F. Churbanov; A.P. Velmuzhov; M.V. Sukhanov; L. A. Ketkova; N.S. Zernova; V. G. Plotnichenko; V. V. Koltashev