Problems on acousto-optic Fourier transform

The author investigated the acoustooptic Fourier transform for three and four coherent acoustic beams, recorded the patterns of Bragg-diffracted intensity distributions produced by three and four acoustic beams, respectively, and studied the pattern for the phase difference of π between three acoustic beams. He extends the concept of the diffraction of a single equivalent slit to that of N equivalent slits, proposes an arranged mode of N equivalent slits in the acoustooptic medium, and obtains expressions for the spacing between equivalent slits