Two-dimensional selection of optical spatial frequencies by acousto-optic methods

We theoretically and experimentally examine the selection of spatial frequencies of optical beams carried out by acousto-optic meth- ods. Control of the optical rays is provided in two orthogonal directions with the help of a single acousto-optic cell fabricated of a birefringent paratellurite single crystal. The investigation is performed using a cell of a tunable acousto-optic filter illuminated by coherent radiation of a He-Ne laser at optical wavelength l5633 nm. The filter is capable of a 2-D selection of optical beams propagating all over the range of spatial fre- quencies un xu5un yu5<300 cm 21 in the spectral passband Dn550 to 100 cm 21 . Optimal regimes of the acousto-optical interaction character- ized by high efficiency of the filtration are considered during the re- search. New results on processing of optical images formed by divergent optical rays are presented and regular trends of the processing are dis- cussed.