Determination of acousto-optical effect maxima for optically isotropic crystalline material on the example of GaP cubic crystal

The peculiarities of the acousto-optic interaction geometry optimization in the optically isotropic crystalline material are demonstrated on the example of GaP cubic crystal. The calculation algorithm takes into account the change of the optical indicatrix form during acoustic wave propagation through the crystal. On this basis, the highest achievable value of the acousto-optic figure of merit M2=98·10−15 s3/kg is determined by the extreme surfaces method. This value is achieved in the case of the isotropic diffraction of the light beam on the longitudinal acoustic wave. The approach developed in this work can be used for optimization of the acousto-optic interaction in other optically isotropic crystalline materials.