Formation of the multibeam pattern of the Bragg diffraction of light by a periodically phase modulated acoustic signal

Abstract

Formation of the multibeam pattern of a Bragg acoustooptical modulator in the case of diffraction by a periodically phase modulated acoustic wave is considered. The relation between the spatial spectrum of diffracted light and the spectrum of the input signal is investigated for the case of highly efficient diffraction. A technique of forming a given multibeam pattern is proposed. The technique is based on the frequency modulation of an acoustic wave by a set of multiple frequencies. The level and nature of interference distortions of the pattern that appear owing to the proximity of beams in the angular space are established for the stationary diffraction regime. The processes developing during the transition from one pattern to another are considered, and the conditions ensuring minimal distortions are formulated. The results of simulations are presented.