A comprehensive analysis of surfacehyphen;acoustichyphen;wave reflections. II. Secondhyphen;order effects

摘要

Three methods of evaluating the secondhyphen;order contributions to the mechanical velocity shift and reflection coefficient for isotropic groove gratings are presented. The secondhyphen;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 selfhyphen;consistently, verifying the validity of all three within their respective limitations. The extension of these methods to arbitrary anisotropic substrates and overlays is discussed.