Geometric interpretation of acousto-optic interaction with three-dimensional light and sound fields

Abstract

We present a novel approach for analyzing acousto-optic diffraction, applicable to 3-D sound and light fields. The technique decomposes light and sound fields as a linear superposition of plane waves. A geometric model of 3-D acousto-optic interaction, based on the wave-vector diagram, can be used to generate a system of equations that fully describe the interacting plane waves of light and sound. The geometric model offers an intuitive look into 3-D acousto-optic interaction without any implicit assumptions except weak interaction. The angular plane wave spectrum of the diffracted light can be found by solving the system of equations together with a single numerical integration over the product of the incident light and sound spectra. This form of solution coupled with the 2-D FFT algorithm offers the possibility of numerically computing the diffracted light field from arbitrary incident light and sound fields. Results are presented and compared with those from ray-tracing methods.