Investigation of close to collinear anisotropic acousto-optic interaction in a biaxial crystal of alpha-iodic acid

We present results of theoretical investigation of anisotropic close to collinear acousto-optic interaction in alpha-iodic acid crystal. A comparative analysis of the characteristics of quasi-collinear filters and filters based on close to collinear variant of interaction is carried out. The calculations have shown that filters based on close to collinear variant of interaction are almost as good as quasi-collinear filters in spectral resolution at the same interaction length. It is established that the effect of angular shift of geometry due to the dispersion of directions of biaxial crystal optical axes on the interaction characteristics, in this case, is much less distinct than for the wide-aperture filter in the region of small Bragg angles. This fact opens up possibilities of practical implementation of such devices without geometry of acoustooptic interaction correction.