Numerical Investigation of a Plasmonic Refractive Index Sensor Based on Rectangular MIM Topology

In this paper, a plasmonic structure consists of Metal-Insulator-Metal (M-I-M) waveguide with two rectangular cavities is presented. To asses the performance as a refractive index sensor, the structure has been simulated using the Finite Element Method (FEM). With the change of the refractive index of the material under sensing (MUS), transmission peaks differ linearly and this shift in peaks is used to detect the material. From the findings of the simulation, most sensitive structural parameters are configured for the designing of this spectrum-based sensing device which possesses a maximum sensitivity of 886.16 nm/RIU. High tolerance and simple rectangular geometry of the proposed structure make it attractive for easy-to-manufacture and nanoscale integration into optical devices.