Acoustic stop bands of surface and bulk modes in two-dimensional phononic lattices consisting of aluminum and a polymer

Spatial and frequency distributions of forbidden bands of both surface and hulk acoustic waves are studied theoretically for two-dimensional (2D) peri odic elastic structures consisting of aluminum and polymer. The surface is perpendicular to the 2D periodic arrays of circular cylinders embedded in a background material. The dispersion relations of the surface and bulk mode s with wave vectors parallel to the surface are calculated for triangular l attices, and the stop hand distributions are plotted in a form relevant to the comparison with ultrasound imaging experiments. [S0163-1829(99)03033-X] .