Loss-induced enhanced transmission in anisotropic density-near-zero acoustic metamaterials

TL;DR

This paper demonstrates that introducing material loss in anisotropic density-near-zero acoustic metamaterials significantly enhances wave transmission by leveraging the interplay of near-zero density, loss, and impedance matching, enabling new wave manipulation methods.

Contribution

It reveals that material loss can be used to enhance transmission in ADNZ acoustic metamaterials, a novel approach for acoustic wave control.

Findings

Loss induces extraordinary transmission in ADNZ metamaterials.

Numerical simulations confirm collimation due to induced loss.

Enhanced propagating and evanescent modes are observed.

Abstract

Anisotropic density-near-zero (ADNZ) acoustic metamaterials are investigated theoretically and numerically in this letter and are shown to exhibit extraordinary transmission enhancement when material loss is induced. The enhanced transmission is due to the enhanced propagating and evanescent wave modes inside the ADNZ medium thanks to the interplay of near-zero density, material loss, and high wave impedance matching in the propagation direction. The equi-frequency contour (EFC) is used to reveal whether the propagating wave mode is allowed in ADNZ metamaterials. Numerical simulations based on plate-type acoustic metamaterials with different material losses were performed to demonstrate collimation enabled by the induced loss in ADNZ media. This work provides a different way for manipulating acoustic waves.