Study of acoustooptic effect in the region of interference of laser beams

Analytic expressions describing the interference field of two laser beams in a medium with an acoustic wave are derived. The quantitative parameters characterising a degree of manifestation of the acoustooptic effect (AOE) in the interference region are introduced. These parameters are analysed for the model of a plane acoustic wave taking into account the refraction of laser beams and for the model of an acoustic wave with a spherical phase front for different radiation patterns. Based on the differential scheme of a laser Doppler anemometer (LDA), an experimental setup is built for the detection and study of the AOE characteristics. The values of one of the AOE parameters are measured and good agreement with calculations is obtained. Recommendations are given for performing LDA measurements in the presence of AOE.