Molecular Sensing with Tunable Graphene Plasmons

Abstract

We study the potential of graphene plasmons for spectrometer-free sensing based on surfaceenhanced 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.

Graphene-plasmon polaritons: From fundamental properties to potential applications

“…Tunable plasmonic materials are essential in various areas of photonics, with applications ranging from perfect absorbers, high-technology frequency modulators and radiators to highly efficient chemical and biochemical sensing [24,32,[41][42][43][97][98][99][100][101][102][103]. Graphene supports plasmons that are tunable, providing a novel platform for tunable devices.…”

“…Compared to plasmon polaritons in noble metals [31], graphene-plasmon polaritons (GPPs) exhibit even stronger mode confinement and relatively longer propagation distance, with an additional unique ability of being electrically or chemi- [24,[32][33][34]. These extraordinary features of graphene plasmons have stimulated intense lines of investigation into both the fundamental properties of graphene plasmons [35][36][37] and potential applications in metamaterials [30,38], modulators [39,40], photodetectors [41], and sensors [42,43]. Naturally, plasmon properties depend on the charge-carrier density, and high doping levels of graphene can be achieved either by electrostatic top-gating [44] or by chemical doping with surface treatment [45].…”

Adsorption of sugars on Al- and Ga-doped boron nitride surfaces: A computational study

“…The adsorption process typically involves changes in the physical or chemical properties of the adsorbed molecule and the adsorbing surface. For example, the change in the electronic properties of some graphene structures has been used for molecular sensing [10][11][12]. Modelling these systems is important for a complete understanding and prediction of their properties so that sensor paradigms can be designed.…”

Monolayer Graphene Can Emit SHG Waves

“…Unlike most electronic properties, its optical properties are still being intensely researched and not fully understood. Similarly, novel and non-trivial features are expected [3], most notably in photonics for ultrafast photodetectors [4], optical modulation [5], molecular sensing [6] and several nonlinear applications [7,8]. Its optical response is characterised by a highly-saturated absorption at rather modest light intensities [9], a remarkable property which has already been exploited for mode-locking in ultrafast berlasers [10].…”