Surface acoustic waves in acoustic superlattice lithium niobate coated with a waveguide layer

Abstract

The effects of the waveguide layer on the band structure of Rayleigh waves are studied in this work based on a one-dimensional acoustic superlattice lithium niobate substrate coated with a waveguide layer. The present phononic structure is formed by the periodic domain-inverted single crystal that is the Z-cut lithium niobate substrate with a waveguide layer on the upper surface. The plane wave expansion method (PWE) is adopted to determine the band gap behavior of the phononic structure and validated by the finite element method (FEM). The FEM is also used to investigate the transmission of Rayleigh waves in the phononic structure with the interdigital transducers by means of the commercial package COMSOL. The results show that, although there is a homogeneous waveguide layer on the surface, the band gap of Rayleigh waves still exist. It is also found that increasing the thickness of the waveguide layer, the band width narrows and the band structure shifts to lower frequency. The present approach can be taken as an efficient tool in designing of phononic structures with waveguide layer.

Spatial Decomposition of a Broadband Pulse Caused by Strong Frequency Dispersion of Sound in Acoustic Metamaterial Superlattice

“…A recent study shows that the introduction of randomness in the periodicity of a superlattice structure leads to Anderson localization of thermal phonons [ 30 ], leading to higher efficiency than conventional designs. At the macroscope scale, solid-solid periodic superlattices are used to steer a propagating Rayleigh wave and realize filtering [ 31 ] and waveguiding [ 32 ].…”