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Title: Amplification of Stokes signals with phase conjugation by combined laser and SBS amplifiers

Abstract

Various schemes for amplification of Stokes signals are investigated. Some new systems, such as an SBS amplifier in the transient amplification regime and a combined laser amplifier-SBS amplifier, are proposed and realised. Conditions are found under which amplification is accompanied by small distortions of the spatial structure of a signal. A two-pass system for small-signal amplification with phase conjugation is developed by using a PC mirror in the combined amplification system. The gains up to 10{sup 16} were obtained for the phase conjugation quality {approx}80%, the output energy {approx}1 J, and pulse duration {approx}30 ns. (nonlinear optical phenomena)

Authors:
 [1]; ; ; ;  [2]
  1. 'Astrofizika' Research and Production Association (Russian Federation)
  2. P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
21466604
Resource Type:
Journal Article
Resource Relation:
Journal Name: Quantum Electronics (Woodbury, N.Y.); Journal Volume: 37; Journal Issue: 1; Other Information: DOI: 10.1070/QE2007v037n01ABEH013265
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AMPLIFIERS; BRILLOUIN EFFECT; LASERS; MIRRORS; PRODUCTION; PULSES; SIGNALS; STIMULATED EMISSION; STOKES PARAMETERS; COHERENT SCATTERING; ELECTRONIC EQUIPMENT; EMISSION; ENERGY-LEVEL TRANSITIONS; EQUIPMENT; SCATTERING

Citation Formats

Bel'dyugin, Igor' M, Efimkov, V F, Zubarev, I G, Mikhailov, S I, and Sobolev, V B. Amplification of Stokes signals with phase conjugation by combined laser and SBS amplifiers. United States: N. p., 2007. Web. doi:10.1070/QE2007V037N01ABEH013265.
Bel'dyugin, Igor' M, Efimkov, V F, Zubarev, I G, Mikhailov, S I, & Sobolev, V B. Amplification of Stokes signals with phase conjugation by combined laser and SBS amplifiers. United States. doi:10.1070/QE2007V037N01ABEH013265.
Bel'dyugin, Igor' M, Efimkov, V F, Zubarev, I G, Mikhailov, S I, and Sobolev, V B. Wed . "Amplification of Stokes signals with phase conjugation by combined laser and SBS amplifiers". United States. doi:10.1070/QE2007V037N01ABEH013265.
@article{osti_21466604,
title = {Amplification of Stokes signals with phase conjugation by combined laser and SBS amplifiers},
author = {Bel'dyugin, Igor' M and Efimkov, V F and Zubarev, I G and Mikhailov, S I and Sobolev, V B},
abstractNote = {Various schemes for amplification of Stokes signals are investigated. Some new systems, such as an SBS amplifier in the transient amplification regime and a combined laser amplifier-SBS amplifier, are proposed and realised. Conditions are found under which amplification is accompanied by small distortions of the spatial structure of a signal. A two-pass system for small-signal amplification with phase conjugation is developed by using a PC mirror in the combined amplification system. The gains up to 10{sup 16} were obtained for the phase conjugation quality {approx}80%, the output energy {approx}1 J, and pulse duration {approx}30 ns. (nonlinear optical phenomena)},
doi = {10.1070/QE2007V037N01ABEH013265},
journal = {Quantum Electronics (Woodbury, N.Y.)},
number = 1,
volume = 37,
place = {United States},
year = {Wed Jan 31 00:00:00 EST 2007},
month = {Wed Jan 31 00:00:00 EST 2007}
}
  • The phase conjugation (PC) of a focused Gaussian laser beam with a partial spatial coherence of the wave front is studied numerically and theoretically upon SBS within the framework of a three-dimensional nonstationary SBS model, which takes into account transient processes and SBS saturation. The dependences of the PC coefficient h on the laser radiation power are obtained for different excesses of the angular divergence over the diffraction limit {xi}. It is found that for the given reflectance of laser radiation from the SBS mirror, the PC coefficient monotonically decreases with increasing the divergence. For example, under the near thresholdmore » SBS conditions, h decreases from 70% to 30%, when {xi} increases from 1 to 10. For the given divergence, the PC coefficient increases with increasing the reflectance and approaches the ideal one (h > 90%) upon deep SBS saturation, when the reflectance exceeds 90%-95%. (nonlinear optical phenomena)« less
  • We report the three-dimensional simulation results of phase conjugation upon nonstationary stimulated Brillouin scattering of a focused laser beam. It is shown that in the case of deep focusing of laser radiation in the SBS cell, the phase conjugation quality decreases with increasing laser power and reflection coefficient, in agreement with experimental results. In calculations, the process of Stokes radiation generation is studied in detail, the reasons for a decrease in the phase conjugation quality are explained, and a means of its improvement is proposed. (nonlinear optical phenomena)
  • The theory of phase conjugation in laser amplifiers by saturable-gain degenerate four-wave mixing with copolarized beams is developed for pulses of arbitrary temporal shape and duration in the limit of a weak signal beam. The influence of the input pulse{close_quote}s characteristics (energy, temporal pulse shape, duration) on the phase-conjugate reflectivity and on the conjugate pulse shape is analyzed. A sharp instantaneous peak of phase-conjugate reflectivity is predicted at high intensities of the four-wave mixing beams. This effect is experimentally demonstrated at {lambda}{sub 0}=1064 nm in a Nd:YVO{sub 4} amplifier pumped by a cw Ti:sapphire laser. A transient peak reflectivity ofmore » {ital R}{approximately}50{percent} is thus obtained, corresponding to an enhancement of 1.6{times} compared with the maximum steady-state reflectivity. The experimental results and the theoretical predictions are in good agreement. {copyright} {ital 1996 Optical Society of America.}« less
  • Phase conjugation of laser radiation is studied by SBS in a capillary filled with TiCl{sub 4}. A combination of a relatively low SBS threshold for spatially inhomogeneous radiation, a high quality of phase conjugation, and a wide dynamic range of the phase conjugated radiation energy was obtained. PBr{sub 3} is proposed and investigated as a nonlinear optical medium for further decreasing the SBS threshold. (nonlinear optical phenomena)
  • An investigation was made of the emission of high-power continuously tunable signals in a CO/sub 2/ laser stage consisting of a master oscillator and an amplifier. The active medium in the oscillator and the amplifier was excited by an electric discharge sustained by an electron beam of 1 ..mu..sec duration with a current density of 3 A/cm/sup 2/. The pressure of the CO/sub 2/:N/sub 2/ = 1:1 active medium in the master oscillator was kept at 6.5 atm and that in the amplifier was varied between 1 and 6 atm. It was found that when signals were amplified under similarmore » conditions at frequencies corresponding to the peak of the P/sub 18/ line and to the dip between the P/sub 18/ and P/sub 16/ lines of the 00/sup 0/1--10/sup 0/0 transition, the radiation energy changed no less than twofold as a result of a single passage through the amplifier. Moreover, it was found that the pressure in the amplifier could be reduced considerably compared with that of the active medium in the master oscillator whilst retaining continuous frequency tuning, which meant that the requirements on the excitation system could be reduced and the efficiency of the amplifier could be enhanced.« less