Basic Equations and Conservation Theorems for the Electrostriction Phonon Maser

Abstract

Brillouin scattering of light by phonons and the phonon maser are usually described in terms of an approximate set of linearized equations. Here we give a more exact set of equations for a lossless polarizable fluid; only relativistic effects are disregarded. When these equations are linearized and higher order terms in the ratio of sound speed to light speed are disregarded, they reduce to the customary set of equations. The more exact equations permit the derivation of the law of conservation of energy with a simple physical interpretation. From these equations the Manley-Rowe relations and other conservation laws also follow relatively easily.