DIFFRACTION OF LIGHT BY ULTRASOUND IN OPTICALLY ACTIVE UNIAXIAL CRYSTALS.

This paper examines the diffraction of light by ultrasound in uniaxial crystals, exhibiting optical activity (OA) at very small angles, formed by the incident wave with the crystal axis, when the OA masks diffraction effects, and at angles of the order of the Bragg angles. Expressions are found for the fundamental and diffraction components of the light field. It is shown that in the presence of OA two new Bragg angles appear; these are close to the normal Bragg angles for the usual values of the components of the gyration tensor. The nonreciprocal effect, which in order of magnitude is no different from the case when OA is absent for the usual values of the gyration components, is examined.