The influence of acoustic activity and elliptical polarization of the eigen acoustic waves on the efficiency of acousto-optic diffraction: the example of quartz crystals

The present work is devoted to analyzing the influence of the ellipticity of acoustic waves caused by acoustic activity on the efficiency of acousto-optic interaction. It has been shown that the peak-like increase of the effective elastic-optic coefficients and acousto-optic figure of merit is manifested in the case when the acousto-optic diffraction appears on the quasi-transverse elliptical (or circular) acoustic waves that propagate in the directions that are close to the acoustic axes. In this paper, the analysis has been carried out on the example of quartz crystals, and it has been shown that the increase of acousto-optic figure of merit is peculiar for all types of acousto-optic interactions with the quasi-transverse acoustic waves. We have shown that accounting for the ellipticity of diffracted optical waves in the analysis of acousto-optic interaction in optically active crystals leads to more correct results than those obtained in our recent works.