Anisotropic diffraction of light in a gallium phosphide crystal with induced anisotropy

Experimental and theoretical studies were made of the anisotropy of the Bragg diffraction of light by ultrasound in gallium phosphide crystals. An external static pressure produced a controlled optical anisotropy in the initially isotropic GaP samples. In this way a birefringence of ~10^–4 was induced and it corresponded to acoustic frequencies of hundreds of megahertz. This should make it possible to use effectively acoustooptic GaP crystals in anisotropic diffraction devices for the control of laser radiation.