Effect of third-order nonlinearity on the acoustooptical interaction in uniaxial gyrotropic paratellurite crystals

Features of Bragg diffraction of high-intensity light waves by ultrasound in uniaxial gyrotropic paratellurite crystals are analyzed. Energy characteristics of the diffracted waves are studied by the numerical methods. It is shown that the inclusion of the Kerr nonlinearity in uniaxial gyrotropic paratellurite crystal into consideration considerably changes the periodic dependence of the diffraction efficiency on the length of the acoustooptical interaction and the ultrasound intensity. In the case of diffraction with an increase of frequency of the diffracted wave, the efficiency of the acoustooptical interaction is considerably higher than in the case of diffraction with a decrease of frequency. It is shown that an increase of the incident light intensity is accompanied by an increase of diffraction efficiency, which agrees with the experimental results on the acoustooptical diffraction of IR radiation in paratellurite crystals.