Inverse acoustooptic problem: Coherent summing of optical beams into a single optical channel

Abstract

A highly efficient summing of mutually coherent beams (channels) into a single beam with the same divergence and aperture (an inverse acoustooptic problem) is realized via diffraction in a Bragg cell. The multibeam field to be converged is formed as a result of the diffraction (splitting) of a single laser beam. Theoretical and experimental evidence is obtained for the fact that the repeated diffraction can provide a highly efficient (up to 100%) reconstruction of beam with initial parameters. The experiments are performed with a single-mode laser radiation at 0.63 μm and multimode radiation at 0.96 μm. The virtually attained summing efficiency is on the order of 70%. The factors that act to diminish the experimental efficiency below the predicted value, the ways to raise the efficiency, and possible applications of the results of this study are discussed.