A comprehensive analysis of surface-acoustic-wave reflections. II. Second-order effects

Abstract

Three methods of evaluating the second-order contributions to the mechanical velocity shift and reflection coefficient for isotropic groove gratings are presented. The second-order terms contain the effect of evanescent and bulk modes generated through the interaction of a surface acoustic wave with a periodic overlay. All three methods will be shown to be numerically equivalent when calculated self-consistently, verifying the validity of all three within their respective limitations. The extension of these methods to arbitrary anisotropic substrates and overlays is discussed.