THz plasmonic resonances in hybrid reduced-graphene-oxide and graphene patterns for sensing applications

Abstract

In this contribution, we effectively combine important developments of nowadays technology: graphene based THz plasmonics, reduced-graphene-oxide (rGO) based sensors, and capability of patterning graphene materials at micro and nano scale. Surface waves in graphene were observed for the first time only few years ago, confirming the ability of this exceptional material to support plasmons at relatively low frequencies - a few THz - due to its intrinsically huge selfinductance. On the other hand, graphene oxide, and its reduced forms, has emerged as a very interesting material for several applications, including gas sensors and biosensors. In this work, the possibility of a _ne and controlled patterning of the above materials is considered as a useful degree of freedom to govern plasmon resonances and consequent electromagnetic absorption. In particular, the excitation of THz plasmons in arrays of nanoribbons, made of graphene and rGO, has been deeply investigated, in order to quantify the sensitivity to surface changes of conductivity, due to possible external perturbations. Fullwave analysis of hybrid metal-graphene-rGO is also presented and discussed. The effects of substrate thickness and of higher diffraction modes are rigorously taken into account, as a possible mean to enhance the sensing capability of the proposed device.