Paratellurite-Based Acoustooptical Deflectors. Methods for Increasing their Efficiency and Widening the Scanning Angle

Resumo

Deflectors that are based on the Bragg nonaxial anisotropic diffraction in a paratellurite crystal are considered. Practically significant relationships were obtained and factors that limit the diffraction efficiency and the angular scanning range were determined. A review of several new methods for increasing the main functional parameters of deflectors, which were realized in devices, is presented. In particular, a double-crystal deflector scheme is considered, which makes it possible to significantly increase the diffraction efficiency, extend the scanning range, and create a polarization-insensitive deflector. It is shown that the diffraction mode in the second Bragg maximum (with respect of the acoustic amplitude) can be used for bandwidth broadening. It is proposed to use a two-element optimally phased piezoelectric transducer for extending the frequency scanning range.