9. Acousto-Optic Phenomena

Abstract

Publisher Summary This chapter describes the different aspects of acousto-optic phenomena. The theory of the acousto-optic interaction involving bulk and surface acoustic waves is well known. There are two light scattering mechanisms in the bulk of a material—namely, the elasto-optic and electro-optic effects. At a material surface, an acoustically produced surface corrugation also scatters light. The elasto-optic effect is the primary scattering mechanism in most acousto-optic interactions. This phenomenon has a simple origin in a liquid and arises from the spatial, and temporal modulation of the dielectric constant by the density fluctuations associated with a longitudinal sound wave. The relation between the modulated dielectric constant and the acoustic fields is of a tensorial nature in a solid, and scattering can take place from both shear and longitudinal waves. The corrugation effect is important when the incident light is reflected from or transmitted through an interface corrugated by the presence of surface or bulk waves. The two common interaction geometries for the scattering of light by surface acoustic waves are also elaborated.