Acousto-optic laser frequency shifters with a large angle between direct and diffracted beams

We propose designs of laser frequency shifters providing a large separation angle between direct and diffracted beams. Two variants of frequency shifters are analysed, differing in the mutual arrangement of ordinary and extraordinary beams with respect to the crystal optical axis. An 80 MHz acousto-optic frequency shifter developed on a TeO₂ crystal for laser light with a wavelength of 532 nm provided a separation of direct and diffracted beams by ∼12° for both ordinary and extraordinary input beams.