Molecular Sensing with Tunable Graphene Plasmons

TL;DR

This paper explores how tunable graphene plasmons can be used for spectrometer-free molecular sensing through enhanced infrared absorption and Raman scattering, enabling label-free identification of molecular fingerprints.

Contribution

It introduces a novel sensing method leveraging graphene plasmon tunability and high quality factors for cost-effective, spectrometer-free molecular detection.

Findings

Enhanced absorption and scattering cross-sections by 3-4 orders of magnitude.

Capable of label-free identification of molecular vibrational fingerprints.

Potential for developing low-cost, spectrometer-free sensors.

Abstract

We study the potential of graphene plasmons for spectrometer-free sensing based on surface-enhanced infrared absorption and Raman scattering. The large electrical tunability of these excitations enables an accurate identification of infrared molecular resonances by recording broadband absorption or inelastic scattering, replacing wavelength-resolved light collection by a signal integrated over photon energy as a function of the graphene doping level. The high quality factor of graphene plasmons plays a central role in the proposed detection techniques, which we show to be capable of providing label-free identification of the molecular vibration fingerprints. We find an enhancement of the absorption and inelastic scattering cross-sections by 3-4 orders of magnitude for molecules in close proximity to doped graphene nanodisks under currently feasible conditions. Our results pave the way for the development of novel cost-effective sensors capable of identifying spectral signatures of molecules without using spectrometers and laser sources.