Sagittal elastic waves in infinite and semi-infinite superlattices

Abstract

Elastic waves, polarized in the sagittal plane, are investigated in infinite and semi-infinite superlattices made from alternate layers of two isotropic media. By the use of a transfer-matrix method, we obtain explicit equations for the dispersion of the bulk modes as well as of the surface modes of a semi-infinite superlattice. We present a few illustrations of the theory for Al-W superlattices in which the relative thicknesses of the two media or the thickness of the layer at the surface are varied.