High Ultrasonic Transmission Loss Metasurfaces in Water

TL;DR

This paper demonstrates ultrasonic metasurfaces in water that achieve over 24 dB sound transmission loss at 0.7 MHz through wave cancellation, offering potential for low-loss acoustic devices and underwater sound barriers.

Contribution

The study introduces a new class of ultrasonic metasurfaces with high transmission loss using patterned silicon and Si3N4 films, advancing underwater acoustic metamaterials design.

Findings

Achieved over 24 dB sound transmission loss at 0.7 MHz.

Wave cancellation mechanism verified through experiments.

Potential applications in low-loss acoustic cavities and underwater barriers.

Abstract

We report the experimental demonstration of a class of ultrasonic metasurfaces made of patterned silicon thin wafers partially covered by Si3N4 film that exhibit over 24 dB of sound transmission loss around 0.7 MHz, which is caused by the cancelation of sound waves emitted by the resonant Si3N4 membrane and the ones through the silicon backbone in each unit cell. These metasurfaces are expected to have high reflection with little total loss even at ultrasonic frequency. They could be good candidates as the building blocks for low-loss cavities, phase zone plates, and other underwater acoustic metamaterials. As the working principle is scalable, it provides guidance for the designs of audible underwater sound barriers as well.