Design and Performance Analysis of an Ultra-compact Nano-plasmonic Refractive Index Sensor

In this paper, a Dielectric-Metal-Dielectric (DMD) plasmonic waveguide coupled with a rectangular slot is proposed and analyzed numerically with the Finite Element Method (FEM) as a refractive index sensor. Different structural parameters are varied to obtain maximum sensitivity of the proposed structure. In this geometry, silver is used as the metal and it is surrounded by Material Under Sensing (MUS) which is dielectric in nature. The linear correlation between both the refractive index and the position of the transmission peaks is used for the detection of the materials. From this simpler geometry, maximum sensitivity is obtained to be 818 nm/RIU; RIU means Refractive Index Unit. Due to the ease in the nanoscale fabrication of the proposed simplistic structure, it can have potential applications in nanoscale optical devices and the nano chip sensors.