One-dimensional phononic crystal slabs bordered with asymmetric uniform layers

We study the propagation of Lamb waves in a one-dimensional phononic crystal slabs bordered with asymmetric uniform layers based on the supercell plane wave expansion method (SC-PWE). The phononic crystal slabs are made of silicon and tungsten. The uniform substrate and superstrate layers can be tungsten layer, rubber layer or one is a tungsten layer and another is a rubber layer. The thickness or material of the substrate is different from that of the superstrate. The validity is proved by using the finite-element (FE) method with the Comsol Multiphysics 3.5a. The results show that the band structure can be tuned by changing the thickness of the substrate or the superstrate. These structures may be used as filters, sensors or wave guides.