Acoustic surface modes on metasurfaces with embedded next-nearest neighbor coupling

TL;DR

This paper introduces an acoustic metasurface with embedded next-nearest neighbor couplings, demonstrating novel surface wave behaviors and potential for enhanced sensing through experimental and simulation studies.

Contribution

It presents a new design of acoustic metasurfaces with BNN couplings, experimentally verifying negatively dispersing surface waves and their unique dispersion properties.

Findings

Supported localized acoustic surface waves with extrema in dispersion spectra.

Experimental verification of negatively dispersing 'backwards' waves.

Potential for improved acoustic sensing applications.

Abstract

We design, simulate, and experimentally characterize an acoustic metasurface comprising of a 1D array of open, sound-hard, cavities, modulated with beyond-nearest-neighbor (BNN) couplings in the form of additional connecting cavities embedded beneath the surface. The hidden complex structure is realized readily with additive manufacturing techniques (3D printing). The dispersive properties of the supported localized acoustic surface waves are influenced by competing power-flow channels provided by the BNN couplings, that generate extrema in the dispersion spectra within the first Brillouin zone. The structure supports negatively dispersing 'backwards' waves that we experimentally verify. Such structures thereby provide a route to enhanced acoustic sensing by acoustic metasurfaces.