Highly efficient isolation of waterborne sound by an air-sealed metasurface

TL;DR

This paper introduces an air-sealed metasurface that significantly improves underwater sound isolation by drastically reducing sound transmission across a wide frequency and angle range.

Contribution

It proposes a novel air-sealed metasurface design that achieves superior underwater sound isolation by impedance mismatch and low sound speed, validated through experiments.

Findings

Deep sound transmission suppression (~10-5) achieved

Effective impedance greatly reduced compared to non-air-filled samples

Wide frequency and incident angle range of sound isolation

Abstract

Underwater sound isolation has been a long-standing fundamental issue in industry and military fields. Starting from a simple theoretical model, here an air-sealed metasurface is proposed to overcome this problem. Comparing with the sample without filling air, the effective impedance of the air-sealed one is greatly reduced and strikingly mismatch with water, accompanying another merit of low sound speed. Deeply suppressed sound transmission (~10-5) through such a metasurface is observed experimentally over a wide range of ultrasonic frequencies and incident angles.