Аннотация:A quantitative method of evaluation of phase mismatches and calculation of intensities of diffracted light is described in the paper. The analysis is carried out for the case of the acousto-optic interaction taking place in an acoustically anisotropic medium at Bragg angle of light incidence. An example of the calculation is provided for the particular regime of light diffraction in the single crystal of TeO2 possessing the walkoff angle between directions of acoustic phase and group velocities as large as 74 degrees.