Diffraction of light by ultrasound in paratellurite crystals under Fresnel reflection conditions

We show that layers of acousto-optic gyrotropic paratellurite crystals perturbed by ultrasound can be used as efficient light modulators in transmission and reflection mode. We have established that the relative intensities of the diffracted waves are determined by the ratio of the refractive indices of the bounding media, the intensity of the ultrasound, and the thickness of the modulated layer. We show that for an asymmetric diffraction structure, efficient acousto-optic conversion is possible in reflection mode, and the weak effect of the gyrotropy is due to its suppression by Fresnel reflection at the boundaries of the layer. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 819–823, November–December, 2006.