Perfect electromagnetic and sound absorption via subwavelength holes array

Yanqin Wang,Xiangang Luo,Xiong Li,Xiaoliang Ma,Mingbo Pu

doi:10.29026/oea.2018.180013

Abstract

Broadband sound absorption at low frequency is notoriously difficult because the thickness of the absorber should be proportional to the working wavelength. Here we report an acoustic metasurface absorber following the recent theory developed for electromagnetics. We first show that there is an intrinsic analogy between the impedance description of sound and electromagnetic metasurfaces. Subsequently, we demonstrated that the classic Salisbury and Jaumann absorbers can be realized for acoustic applications with the aid of micro-perforated plates. Finally, the concept of coherent perfect absorption is introduced to achieve ultrathin and ultra-broadband sound absorbers. We anticipate that the approach proposed here can provide helpful guidance for the design of future acoustic and electromagnetic devices.

Highlights

Perhaps all things around us are some types of waves, such as the light waves, acoustic waves, matter waves and even gravitational waves
The time-reversed sub-diffraction focusing technique was first developed by the acousticians and utilized in the optical domain to break the diffraction limit[9,10,11,12]
It is surprising that many metasurface concepts such as Salisbury and Jaumann absorbers in the electromagnetic design have not been extended into the acoustic domain

Summary

Introduction

Perhaps all things around us are some types of waves, such as the light waves, acoustic waves, matter waves and even gravitational waves. It is surprising that many metasurface concepts such as Salisbury and Jaumann absorbers in the electromagnetic design have not been extended into the acoustic domain. We theoretically compared the boundary conditions for electromagnetic and acoustic metasurfaces.

Results

Conclusion