Ultimate Photo-Thermo-Acoustic Efficiency of Graphene Aerogels

TL;DR

This paper demonstrates that graphene aerogels can achieve maximum photo-thermo-acoustic efficiency, acting as omnidirectional sound sources with no distortion, promising advancements in passive opto-acoustic devices.

Contribution

It shows that reducing the mass density of graphene aerogels maximizes PTA efficiency and enables distortion-free omnidirectional sound emission across audible frequencies.

Findings

Maximum PTA efficiency achieved by density reduction

Aerogels act as omnidirectional point-sources

No harmonic distortion in sound emission

Abstract

The ability to generate, amplify, mix, and modulate sound with no harmonic distortion in a passive opto-acoustic device would revolutionize the field of acoustics. The photo-thermo-acoustic (PTA) effect allows to transduce light into sound without any bulk electro-mechanically moving parts and electrical connections, as for conventional loudspeakers. Also, PTA devices can be integrated with standard silicon complementary metal-oxide semiconductor (CMOS) fabrication techniques. Here, we demonstrate that the ultimate PTA efficiency of graphene aerogels, depending on their particular thermal and optical properties, can be experimentally achieved by reducing their mass density. Furthermore, we illustrate that the aerogels behave as an omnidirectional point-source throughout the audible range with no harmonic distortion. This research represents a breakthrough for audio-visual consumer technologies and it could pave the way to novel opto-acoustic sensing devices.