Multifrequency Acousto-Optic Diffraction in Optically Birefringent Media

This paper presents theoretical and experimental results on the nonlinearities of acousto-optic diffraction of a collimated light beam, by multiple finite amplitude acoustic waves in an optically birefringent medium. of interest is the regime where there is degenerate acousto-optic phase matching among the 0, +1, and +2 optical diffraction orders. interactions were measured in TeO2 crystals with acoustic propagation along the (110) axis, with degenerate operation near 37.4 MHz and nondegenerate operation near 70 MHz. device, degenerate operation occurred near 115 MHz, and nondegenerate operation near 160 MHz. In the nondegenerate regime nonlinear responses approximate those in isotropic diffraction. In the degenerate regime, the primary nonlinear responses are: beams in second order equal to those in thin grating isotropic diffraction; difference frequency beams in the zeroth order equal to those in thick grating (Bragg) isotropic diffraction; and third order intermodulation beams in the first order which are 6 dB above the Bragg limit. The primary new case