Extraordinary acoustic reflection enhancement by acoustically-transparent thin plates

TL;DR

This paper demonstrates that thin epoxy plates with subwavelength cuts can achieve extraordinary acoustic reflection in water due to resonant local modes, contrasting with their usual transparency.

Contribution

It introduces a novel structured plate design that significantly enhances acoustic reflection, supported by experimental and theoretical analysis.

Findings

Subwavelength cuts induce resonant local modes.

Structured plates reflect acoustic waves strongly.

Experimental results match theoretical predictions.

Abstract

We report an observation of the extraordinary high reflection of acoustic waves in water by thin epoxy plates partitioned by subwavelength cuts, whereas such plates without structure are acoustically-transparent as the acoustic properties of epoxy are close to water. It is demonstrated that this exotic phenomenon results from the resonant excitation of the local modes within the individual pieces derived by the cuts. The experiment agrees well with the theory.