Diffraction of light by hypersound in gyrotropic cubic crystals with electro-induced anisotropy

For the purposes of optimization of acoustooptic (AO) devices and also the experimental determination of the parameters of acoustic crystals (photoelastic constants, ultrasonic wave attenuation coefficients, elasticity moduli, optical and acoustic gyrotropy parameters, etc.), it is necessary to know the special features of the Bragg diffraction of light by ultrasound in different media [1,2]. There are already a number of papers [3-5] devoted to the study of the effect of the attenuation of high frequency ultrasound (hypersound) on the polarization and energy characteristics of the diffracted light. With increasing ultrasound frequency, acoustic gyrotropy becomes significant in addition to optical gyrotropy. In a number of cases it is then necessary, for the correct calculation of AO devices, to allow for the effect of the acoustic gyrotropy [6]. It is shown in [7] that the combined effect of optical gyrotropy and acousto- and electro-induced anisotropy leads to a considerable change in the polarization and energy characteristics of the diffracted waves. It should be noted that in uniaxial and biaxial crystals the optical and acoustic gyrotropy appear only for special directions - the optical and acoustic axes of the crystals [6,8]. In gyrotropic cubic crystals the gyrotropy has to be taken into account for any light and ultrasound interaction geometry [7,8].