▎ 摘　　要

We theoretically demonstrate a high-sensitivity graphene-plasmon-based refractive index sensor working in the mid-infrared at room temperature. The bulk figure of merit of our sensor reaches values above 10, but the key aspect of our proposed plasmonic sensor is its surface sensitivity, which we examine in detail. We have used realistic values regarding doping level and electron relaxation time, which is the limiting factor for the sensor performance. Our results show quantitatively the high performance of graphene-plasmon-based refractive index sensors working in the mid-infrared.