Graphene Aerogels for Ultrabroadband Thermoacoustics

TL;DR

This paper demonstrates that a single graphene aerogel-based thermoacoustic transducer can generate ultrabroadband sound spanning from infrasound to ultrasound without harmonic distortion, offering a new approach to sound transduction.

Contribution

The study introduces a novel graphene aerogel-based thermoacoustic transducer capable of emitting ultrabroadband sound across a vast frequency range without physical movement.

Findings

Emits sound from 1 Hz to 20 MHz

Operates without harmonic distortion

Potential alternative to conventional transducers

Abstract

Sound is usually generated in a medium by an electromechanical vibrating structure. The geometrical size and inertia of the structure set the frequency cutoff in the sound-transduction mechanism and, often, different vibrating structures are necessary to cover the whole range from infrasound to ultrasound. An alternative mechanism without any physical movement of the emitter is the thermoacoustic effect, where sound is produced by Joule heating in a conductive material. Here we show that a single thermoacoustic transducer based on a graphene aerogel can emit ultrabroadband sound from infrasound (1 Hz) to ultrasound (20 MHz), with no harmonic distortion. Since conventional acoustic transducers are frequency band limited due to their transduction mechanism, ultrabroadband graphene aerogels may offer a valid alternative to conventional hi-fi loudspeakers, and infrasound and ultrasound transducers.