Acoustic frequency combs using gas bubble cluster oscillations in liquids: a proof of concept

TL;DR

This paper introduces a novel method for generating acoustic frequency combs using nonlinear oscillations of gas bubble clusters in liquids, which could enhance sensing and measurement technologies beyond optical limitations.

Contribution

The study demonstrates, for the first time, that gas bubble clusters can produce acoustic frequency combs through nonlinear oscillations under ultrasound excitation.

Findings

Gas bubble clusters generate equidistant spectral peaks.

The AFCs have characteristics similar to optical frequency combs.

Potential applications in sensing and measurement fields.

Abstract

We propose a new approach to the generation of acoustic frequency combs (AFC) -- signals with spectra containing equidistant coherent peaks. AFCs are essential for a number of sensing and measurement applications, where the established technology of optical frequency combs suffers from fundamental physical limitations. Our proof-of-principle experiments demonstrate that nonlinear oscillations of a gas bubble cluster in water insonated by a low-pressure single-frequency ultrasound wave produce signals with spectra consisting of equally spaced peaks originating from the interaction of the driving ultrasound wave with the response of the bubble cluster at its natural frequency. The so-generated AFC posses essential characteristics of optical frequency combs and thus, similar to their optical counterparts, can be used to measure various physical, chemical and biological quantities.