Subwavelength Interferometric Control of Absorption in Three-port Acoustic Network

TL;DR

This paper demonstrates how subwavelength 3-port acoustic networks can achieve coherent perfect absorption and transmission by controlling input wave phases and amplitudes, with theoretical and experimental validation.

Contribution

It introduces a novel method for controlling absorption and transmission in acoustic networks through phase and amplitude tuning, supported by theoretical analysis and experimental results.

Findings

Symmetric 3-port devices can exhibit coherent perfect absorption.

Asymmetric inputs with different amplitudes and phases can be perfectly absorbed.

Optimized structures can achieve both perfect absorption and transmission.

Abstract

Utilizing the effect of losses, we show that symmetric 3-port devices exhibit coherent perfect absorption of waves and we provide the corresponding conditions on the reflection and transmission coefficients. Infinite combinations of asymmetric inputs with different amplitudes and phase at each port as well as a completely symmetric input, are found to be perfectly absorbed. To illustrate the above we study an acoustic 3-port network operating in a subwavelength frequency both theoretically and experimentally. In addition we show how the output from a 3-port network is altered, when conditions of perfect absorption are met but the input waves phase and amplitude vary. In that regard, we propose optimized structures which feature both perfect absorption and perfect transmission at the same frequency by tuning the amplitudes and phases of the input waves.