Polarized pass band for longitudinal waves in solid phononic crystals

Abstract

Elastic waves possess a rich variety of polarizations, and the wave propagation in solids is intricate due to the possible coupling and conversion between each wave mode. In this paper, we investigate the canonical solid phononic crystals (PCs) that can filter transverse waves in a purely longitudinal polarization band (PLPB). We numerically study the effects of the geometric parameters and material properties of the crystal components on the width and location of the PLPB. We find that the PCs considered here can be easily modulated to exhibit a wide PLPB due to their simple structures, that there is no connection between the PLPB and band gaps of the XY mode, and that the PLPB is independent of the Dirac cone. The reported findings could provide an alternative way for filtering certain types of elastic waves with the use of PCs.