Polarization at light Bragg diffracted by sound on optically isotropic solids

It is demonstrated that the polarization of light which has been diffracted from shear ultrasonic waves is not, in general, perpendicular to that of the incident lights but depends on the relative orientation of light and sound polarizations and propagation directions. The polarization of light diffracted by longitudinal sound waves depends as well on the relative magnitudes of the photoelastic constants.