[en] We study experimentally stimulated Brilluoin scattering (SBS) of vortex laser beams, namely, the LG₁¹ and LG₀¹ Laguerre -Gaussian modes. The wave front transformation is experimentally demonstrated in the case of SBS of the LG₁¹ laser mode, directly focused into the SBS cell, when the fundamental Gaussian mode LG₀⁰ rather than the conjugate mode is selected from the Stokes beam. It is shown that optical vortices become phase conjugate by destroying the laser mode structure in the SBS cell. Phase conjugation (PC) of the LG₀¹ and LG₁¹ modes is obtained in the SBS mirror using a regular aberrator (microlens raster) in the system of laser beam focusing into the SBS cell.

[en] We investigated the phasing of pulsed two- and fourchannel laser beams due to phase conjugation upon transient stimulated Brillouin scattering (SBS) in a double-pass amplification scheme. A high quality of beam phasing was experimentally demonstrated with the use of a microlens raster and an angular selector in the SBS-mirror scheme. The data obtained in the numerical simulation of transient SBS are in good agreement with experimental ones.

[en] The results of experimental investigations of wide-aperture (100 × 100 mm) plasma-electrode Pockels are presented. Time characteristics, contrast, transmission factor, and optical uniformity of the cell are measured. It has been found that the half-wave effective voltage of the cell is 10 kV, the duration of the transmission window can vary from 250 to 550 ns, its leading and trailing edges are 40–50 and 70–100 ns in duration, respectively, and the time of the cell plasma electrode formation is 40 ± 5 ns.

[en] A seven-channel fibre laser system operated by the master oscillator – multichannel power amplifier scheme is the phase locked using a stochastic parallel gradient algorithm. The phase modulators on lithium niobate crystals are controlled by a multichannel electronic unit with the microcontroller processing signals in real time. The dynamic phase locking of the laser system with the bandwidth of 14 kHz is demonstrated, the time of phasing is 3 – 4 ms. (fibre and integrated-optical structures)

[en] The optical scheme and radiation parameters of a neodymium glass laser system emitting high-power 40-ns pulses in the first-third-order Laguerre-Gaussian modes of energy up to 100 mJ are described. (lasers)

[en] The phasing of a multichannel laser beam by means of an iterative stochastic parallel gradient (SPG) algorithm has been numerically and experimentally investigated. The operation of the SPG algorithm is simulated, the acceptable range of amplitudes of probe phase shifts is found, and the algorithm parameters at which the desired Strehl number can be obtained with a minimum number of iterations are determined. An experimental bench with phase modulators based on lithium niobate, which are controlled by a multichannel electronic unit with a real-time microcontroller, has been designed. Phasing of 16 cw laser beams at a system response bandwidth of 3.7 kHz and phase thermal distortions in a frequency band of about 10 Hz is experimentally demonstrated. The experimental data are in complete agreement with the calculation results. (control of laser radiation parameters)

[en] A wide-aperture Pockels cell based on a DKDP crystal having an optical diameter of 70 mm is studied. Three silver ring electrodes deposited on the side surface of the crystal were used to apply a high-voltage rectangular pulse of variable duration from 50 to 150 ns to the cell. Chains of KT6117A (2N5551) transistors operating in the avalanche regime served as fast electron switches. The duration of the leading and trailing edges of the pulse formed by these switches did not exceed 15 ns. The nonuniformity of the transmission coefficient over the cross section of the cell caused by the inhomogeneity of the electric field inside the crystal was close to 3.5%. (laser applications and other topics in quantum electronics)