Broadband Coherent Perfect Absorption of Acoustic Waves with Bubble Meta-Screens

TL;DR

This paper demonstrates broadband coherent perfect absorption of acoustic waves using bubble meta-screens, achieving near-total energy absorption at low frequencies with phase control, representing a significant advancement in acoustic wave manipulation.

Contribution

It introduces a novel bubble meta-screen design that enables broadband coherent perfect absorption of acoustic waves at low frequencies, with tunable phase control for absorption management.

Findings

Achieves 99.9% absorption of acoustic energy

Bubbles are 75 times smaller than the wavelength

Absorption is broadband and tunable via phase control

Abstract

A bubble meta-screen is an exceptionally effective and low frequency resonator which can be optimized in order to exactly balance the energy provided by radiative process and lost under a viscous mechanism (critical coupling). Under this condition, one can absorb 99.9% of the energy carried by two phase-matched counter propagating acoustic beams. This phenomenon, called coherent perfect absorption, is here observed with bubbles 75 times smaller than the incident wavelength and is shown to be remarkably broadband. Finally, tuning the relative phases of the two beams turns out to be an efficient way to control the absorption in the medium.