Micro-size graphene strip as a surface plasmon resonance based bulk refractive index sensor

We have studied numerically the potential use of a micro-size graphene strip as a surface plasmon resonance based bulk refractive index sensor in the THz frequency regime. Our accurate computational instrument was in-house algorithm based on integral equations (IE) and Nystrom discretization. The refractive-index sensitivities and figure-of-merit (FOM) values of the associated plasmon resonances have been calculated. It has been found that the primary plasmon mode P1 is more sensitive to the refractive-index changes than plasmons of the higher orders P3 and P5 however the latter ones demonstrate much larger FOM values explained by the higher Q-factors. The FOM values of the higher-order resonances on a graphene strip in the THz range are at the same level as FOM values of the localized surface plasmon resonances on a noble-metal strip in the optical range.