Design of a plasmonic sensor based on a nanosized structure for biochemical application

A novel design of an integrated ring cavity consisting of two merged and opposite triangles formed on a metal-insulator-metal (MIM) waveguide is suggested and analyzed for refractive index sensing application. The cavity design can be optimized provide the best sensing performance. In this work, we simulated numerically the device design by utilizing the finite-difference-time-domain (FDTD) technique in a two-dimensional (2D) structure. The detection of the refractive index changes was numerically simulated and analyzed using RSoft™. Small variations in the geometric parameters can enhance the sensitivity achieved, which we found to be 3575 nm/RIU. We believe that the sensor can achieve a resolution of 2.79×10⁻⁶. The structure proposed has a simple design for easy and compact realization, paving the way of detecting rare biochemical analytes and for finding applications in optical filters.