Acousto-optic interaction in an inhomogeneous acoustic field

Light diffraction in an inhomogeneous acoustic field of the near-field zone of a piezoelectric transducer has been investigated for two versions of acousto-optic interaction: collinear diffraction (at a Bragg angle of 90°) and quasi-orthogonal diffraction (at small Bragg angles). The amplitude, angular, and spectral characteristics have been numerically calculated for calcium molybdate and paratellurite crystals. It is established that the acoustic-field inhomogeneity reduces the diffraction efficiency, broadens the angular and spectral interaction ranges, and thus negatively affects characteristics of acousto-optic devices.