Mariyenko I. Diffraction of light beams with optical vortices.

The first section of the dissertation is devoted to investigation of diffraction, both by experiment and numerical simulations, of beams containing optical vortices (OV) on an edge of thin nontransparent screen and slit aperture. It is observed and studied the rotation of on-axies OV beam around its axis and effect of OV regeneration of its nonsingular part.Theoretical researches of wavefront structure in the vicinity of ring edge dislocation, which can be used as an Airy ring model, for example, is the subject of the second section. It was discovered a vortex structure of phase and Poynting vector near zero amplitude line, calculated its dimensions and proposed the explanations of such a structure. ase conjugation of singular beams was carried out by four-wave mixing in photorefractive SBN crystal. Topological sign conservation of OV under phase conjugation is the result of the first experiment. Second, for non-singular laser beam was obtained reversal space evolution with following topological reacti on of nucleation of OV "dipole". The last experiment is a base of a new method of wavefront quality test for the process of phase conjugation.