INTERMEDIATE REGIME FOR THE DIFFRACTION OF LIGHT ON ULTRASOUND IN GYROTROPIC ANISOTROPIC CRYSTALS

An intermediate regime for the diffraction of light on ultrasound in g yrotropic anisotropic and cubic crystals in an external electric field is considered. A system of equations of the coupled waves, which desc ribes acoustooptic diffraction in gyrotropic anisotropic crystals with consideration of the electrically induced optical anisotropy for a st rong interaction between light and ultrasound, is presented. An interm ediate regime for the diffraction of light on ultrasound in gyrotropic anisotropic crystals which is close to the Bragg regime for a weak ac oustooptic interaction is studied. It is shown that the diffracted lig ht is elliptically polarized and that the ellipticity and polarization azimuth of the diffracted wave depend on the anisotropy of the photoe lasticity, the electrically induced anisotropy of the crystal in the e xternal electric held, the gyrotropy, and the asymmetry of the diffrac tion structure. (C) 1997 American Institute of Physics.