A Monolithic Graphene-Functionalized Microlaser for Multispecies Gas Detection

TL;DR

This paper presents a graphene-functionalized microlaser sensor capable of multispecies gas detection with high sensitivity, leveraging intracavity scattering to generate beat notes for identifying multiple gases at the single-molecule level.

Contribution

The study introduces a novel monolithic graphene-coated microlaser that enables multispecies gas detection and ultra-sensitive sensing through intracavity mode interference.

Findings

Achieved multispecies gas identification from mixtures.

Demonstrated ultrasensitive detection down to single molecules.

Generated beat notes with sub-kHz accuracy for gas sensing.

Abstract

Optical microcavity enhanced light-matter interaction offers a powerful tool to develop fast and precise sensing techniques, spurring applications in the detection of biochemical targets ranging from cells, nanoparticles, and large molecules. However, the intrinsic inertness of such pristine microresonators limits their spread in new fields such as gas detection. Here, a functionalized microlaser sensor is realized by depositing graphene in an erbium-doped over-modal microsphere. By using a 980 nm pump, multiple laser lines excited in different mode families of the microresonator are co-generated in a single device. The interference between these splitting mode lasers produce beat notes in the electrical domain (0.2-1.1 MHz) with sub-kHz accuracy, thanks to the graphene-induced intracavity backward scattering. This allows for multispecies gas identification from a mixture, and ultrasensitive gas detection down to individual molecule.