Ultrasound diffraction of light beams in gyrotropic crystals

The features of the Bragg diffraction of Gaussian light beams at ultrasound waves in gyrotropic crystals were investigated. The dependence of the diffraction efficiency on the intensity of an ultrasound beam, the cross-section radius of a light beam, and their divergence ratio was found. An asymptotic expression for the transverse distribution of a diffracted beam was derived. The crystal gyrotropy has been found to affect significantly the change in the amplitude profile of the diffracted light at ultrasound frequencies of f ∼ 10²–10³ MHz. The maximum diffraction efficiency in the gyrotropic medium is shown to be reached at a certain ratio between the divergences, ultrasound intensity, and specific gyration of the crystal. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 370–374, May–June, 2000.