Anisotropy of acousto-optic figure of merit in the XZ plane of Pl5Ge3O11 crystals

. We use both numerical and analytical approaches when deriving phenomenological relations for the effective elasto-optic coefficients. Anisotropies of the effective elasto-optic coefficients and the acousto-optic (AO) figure of merit are calculated for a particular case of AO interactions in the principal XZ plane of Pb 5 Ge 3 O 11 crystals. Using the approximation of linearly polarized optical eigenwaves, we find that the maximal AO figure of merit for the isotropic diffraction is equal to 30.3×10 –15 s 3 /kg. It is achieved for the AO interactions of the type II at the angle  = 10 deg with respect to the X axis. In case of the anisotropic AO diffraction, the appropriate maximum, 12.4×10 –15 s 3 /kg, is reached for the AO interactions of the type IX at the angle  = 187.9 deg.