Shear horizontal surface acoustic waves on large amplitude gratings

Abstract

We calculate the dispersion curves of surface acoustic waves of shear horizontal polarization propagating perpendicular to the grooves of a lamellar grating ruled on the surface of a cubic elastic medium. The calculation is based on a formulation of the problem that employs a coordinate-dependent elastic modulus tensor and mass density, and is valid for an arbitrary ratio of the height of the ridges to the period of the grating. It is found that as this ratio increases the dispersion curve acquires additional, high-frequency branches in addition to the one already known from earlier studies of this problem. An explanation for this result is proposed.