A method is proposed for the simplified numerical estimation of the anisoplanatism of an adaptive optical system operating in the observational mode through the turbulent atmosphere. The method takes into account the finite value of the outer scale of turbulence and allows for the anisoplanatism to be estimated for the inhomogeneous atmosphere with different distributions of the parameters over the path. The different distributions of C-n(2) corresponding to vertical and horizontal atmospheric paths have been simulated. It is shown that the distribution of inhomogeneities on the path significantly affects the anisoplanatism.

A method utilizing a Hartmann sensor for obtaining estimates of the external scale L 0 of turbulent fluctuations and the structural constant C n 2 during the variation of the parameters of the wavefront of a light beam that has passed through turbulence is suggested. The method is based on Zernike polynomial decomposition of phase fluctuations at the given aperture and on analysis of this expansion coefficient’s statistics. Application of the method for making an estimate of the turbulence characteristics in a water cell yielded results that are in good agreement with the estimates obtained by other methods.

The energy exchange between coherent light beams with wave-front distortions in a photosensitive azopolymer film is experimentally studied. By using an adaptive interferometer with an azopolymer film as an element for combining the wave fronts of light beams, the phase visualisation is performed by transforming the spatial phase distortions of one of the beams incident on a medium to the amplitude distortions of another beam at the output. The experimental results agree with the theoretical conclusion that the spatial phase modulation at the input to a polymer is transformed to the amplitude modulation at the output and vice versa.

The influence of speckles on the performance of a Shark-Hartmann wavefront sensor is investigated in the eye aberration studies. The dependence of the phase distortion measurement error on the characteristic speckle size is determined experimentally. Scanning of the reference source was used to suppress the speckle structure of the laser beam scattered by the retina. The technique developed by us made it possible to study the time dependence of the human eye aberrations with a resolution of 30 ms.

A nonlinear optical system with spatially distributed feedback was studied both theoretically and experimentally. The phase-to-intensity transformation in this system was performed by a spatial filter capable of suppressing low spatial frequencies. Hard excitation of stationary spatial structures observed in this system was explained by an analysis of the phase space structure of the amplitude equations. The developed theoretical approach, which uses a step-function approximation of the steady-state solution, allows one to determine the main quantitative characteristics of the generated structures. The basic properties of the response of the system to external perturbations with various symmetries were investigated experimentally. The obtained experimental data qualitatively agree with the results of the theoretical analysis.

An adaptive optical system designed for the compensation of small-scale phase distortions, containing a liquid-crystal phase modulator and an optical feedback ring, was investigated. A new method was employed for the visualisation of the phase with the aid of a wedge-shaped wavefront-shearing interferometer incorporating a holographic filter. The stability of the system and the conditions governing the compensation of phase distortions were studied analytically. The suppression of small-scale phase distortions was observed experimentally.