A metasurface comprising spiral shaped local resonators for surface acoustic waves

Abstract

The interaction of Rayleigh waves, propagating on lithium niobate, with a metasurface consisting of a square array of spiral-like vertical oscillators is investigated. We observe confinement of the acoustic energy throughout the height of the oscillators and note that this confinement also takes place at relatively low frequencies compared to circularly symmetric resonators of similar dimensions. A transmission study reveals that the bandgap attenuation is large (∼25 dB) at both high and low frequencies, a characteristic that could be exploited in the design of new RF filters.