▎ 摘　　要

The ability of graphene nanostructures to support strong plasmonic resonances in the infrared part of the spectrum makes them an ideal platform for plasmon-enhanced spectroscopy techniques. Here we propose to exploit the exceptional tunability of graphene plasmons to perform infrared detection of molecules with subwavelength spatial resolution. To that end, we investigate the optical response of finite arrays of graphene nanodisks that are divided into a number of identical subarrays, or pixels, each of them with a uniform level of doping. Using realistic conditions, we show that, by adjusting individually the doping level of each of these pixels, it is possible to bring them sequentially into resonance with the vibrational spectrum of the analyte. This enables the identification of the analyte and the simultaneous detection of its spatial location with a resolution determined by the size of the pixels. Our work brings new possibilities to plasmon-enhanced infrared sensing by combining the already demonstrated sensing abilities of graphene nanostructures with subwavelength spatial resolution. This could be exploited to develop actively tunable substrates for multiplexed sensing, which could be used to analyze the chemical composition of complex biological systems and to follow their temporal evolution with spatial resolution.