ABSTRACT

The problem of the diffraction of light by ultrasound was considered by many authors [133-143]. At present, there are two most common approaches to solving this problem, which, in principle, allow one to obtain a solution with a predetermined degree of accuracy. The first approach is based on solving a system of coupled differentialdifference equations describing the interaction between different diffraction orders. This method found the most complete expression in [144-148], and also in [149-151]. Another approach is based on solving the integral equation for a field obtained by introducing equivalent currents and expanding the desired field over plane waves [152-155], which allows one to obtain an analytical expression for the diffracted field in the form of relatively rapidly converging series. The practical interest that causes the TeO2 crystal requires consideration of the problem of diffraction of light by ultrasound in an anisotropic medium with gyrotropic properties. Usually when considering the diffraction of light in such a crystal, the authors confine themselves to an investigation of the Bragg regime. In this chapter we give a generalized solution of the diffraction problem in the case of an anisotropic medium with gyrotropy, based on the method proposed in Refs. [152-155], which ultimately yields an

expression for the diffracted field after an acousto-optical modulator from TeO2 with its amplitude modulation with respect to the harmonic law in the intermediate diffraction regime.