Wideband subwavelength acoustic edge detection via trapped modes with breaking structural periodicity

Abstract

The wave manipulation through acoustic metamaterials and the application in realizing the super-resolution edge detection has been achieved by the trapped resonance coupling with evanescent waves. Here, we numerically and experimentally demonstrate that the working bandwidth of such edge detection can be effectively broadened by increasing the side length ratio of the narrow segments to the wide segments, and the imaging resolution is mainly determined by the size of the first narrow segment of the edge detector. By breaking the periodicity of these segments, the wide working bandwidth (∼900 Hz) and the imaging resolution of 0.11λ are experimentally verified.