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A method for controlling the asymmetry sign of the spectral intensity of light reflected from a narrow-band filter by fitting the dielectric layer thickness adjacent to the thin metal layer is proposed.

The geometry of anisotropic light diffraction in ultrasound waves excited by a multi-element converter in an optically uniaxial negative crystal of lithium niobate is analyzed. An expression for the refractive index of a diffracted wave was found on the basis of a study of the optical indicatrices of the refractive indices of ordinary and extraordinary light waves in the crystal. A method for calculating the angular frequency characteristics of anisotropic acousto-optic Bragg cells with multi-element converters is proposed.

Two copper mirrors with different surface roughness are studied by means of spectroscopic ellipsometry. It is established that spectral dependences of optical conductivity are qualitatively similar, but shifted along the ordinate, and some of their peaks may be related to light absorption by the surface oxide layer.

Gallium arsenide ion-doped field-effect transistors with a Schottky barrier and various doping profiles are modeled. Dependences of static transistor characteristics on doping profile parameters are calculated and analyzed. The physical processes that determine the transistor characteristics with variation in doping profile parameters are studied.

One possible approach to determining the minimum set of parameters of an adaptive system whose operation is aimed at minimizing distortions arising in modern optoelectronic systems is considered. The basic source of distortions is assumed to be atmospheric turbulence, which imposes the most severe constraints on optical radiation in the atmosphere. The following basic parameters of the system are proposed: number of degrees of freedom, required frequency band (dynamic characteristic, and constraint on the spectral characteristics). Some parameters of the reference source (its size, position, and properties) are determined. The results are obtained in the form of analytical functions, which allows calculating the parameters of the adaptive system that can be used in numerous scenarios in the atmosphere.

Software for computer simulations of adaptive optics systems for atmospheric laser applications designed on the basis of advanced parallel programming techniques is developed. The adaptive optics system model includes the emitting aperture geometry and beam propagation path scenario, vertical profiles of atmospheric parameters, fast parallel split-step Fourier algorithm for solving wave diffraction and propagation equations, time-dependent models of "frozen" atmospheric turbulence with a wide range of scales, and models of the wavefront sensor and controlled deformable mirror. The hardware system for computer simulations is an off-the-shelf desktop with a 6-core 12-thread Intel® Core™ i7-970 CPU at the maximum frequency of 3.5 GHz and an NVIDIA® GeForce GTX 580 graphic accelerator with 512 universal processors operating at 1.5 GHz. Results of simulations of adaptive imaging and laser beam shaping, aimed at estimating the efficiency of adaptive optics systems on atmospheric paths are presented.

Results of an investigation and a comparison of schemes used for recording dynamic holographic gratings in a liquid-crystal spatial light modulator, which ensure grating profile asymmetrization and, thus, a significant increase in its diffraction efficiency, are presented. Three approaches are considered: digital, analog, and self-asymmetrization of the profile due to the effect of a secondary field induced in the nematic volume. It is demonstrated that the first two approaches provide recording of gratings with low spatial frequencies (several mm−1) and with an approximately equal rate of asymmetry (the potential efficiency of diffraction to the first order is 70-75 %), while the third approach provides recording of gratings with a much higher spatial frequency (hundreds of mm−1), but with a lower efficiency (about 50 %).

Results obtained at the Institute of Laser Physics Research (which is part of the Russian Federal Nuclear Center - Institute of Experimental Physics) on phase correction of pulsed and continuous wave laser radiation by closed-loop adaptive optical systems (AOS) with flexible deformable mirrors are described. With the help of a conventional AOS including a Hartmann-Shack wavefront sensor and an adaptive mirror having a 220 × 220 mm aperture, aberrations of the beam of a powerful pulsed laser facility called Luch have been reduced by an order of magnitude. The development of special software for reconstruction of singular wavefronts by the Hartmann-Shack sensor has allowed us to perform the correction of a doughnut-shaped Laguerre-Gaussian vortex laser beam in an AOS with a bimorph mirror and to focus it into a bright axial spot that drastically increases the Strehl ratio. Adaptive optical systems have been developed where the adaptive mirror control is ensured by searching for an extremum of a chosen criterion functional with the help of a stochastic parallel gradient algorithm rather than by means of wavefront measurements. Embedding of microcontrollers into the control unit has allowed us to reach an AOS bandwidth of 5 kHz and to demonstrate the dynamic phase correction of tip-tilts and higher aberrations of the wavefront caused by turbulence induced by heating of the beam propagation path under laboratory conditions.

A technique for experimental studies of the compensatory abilities of adaptive mirrors (AM) is developed and substantiated. The structure of the static residual error of correction is analyzed on the basis of experimental data for a particular AM. The theory of optimal placement of drives on the AM aperture is confirmed by experimental results.

High-resolution cameras are used as photodetectors in the image recording plane of a Shack-Hartmann wavefront sensor to record centroid coordinates which provide basic information for wavefront reconstruction. A comparative analysis is made of the accuracy of determining the centroid coordinates for CCD and CMOS cameras. The modes of instantaneous sampling and frame-by-frame accumulation of information from the cameras are considered.