A highly sensitive plasmonic refractive index sensor based on triangular resonator

Abstract

In this paper, metal-insulator-metal based plasmonic sensor with a straight waveguide and a side coupled equilateral triangular resonator (disc-type and ring-type) has been proposed and analyzed. The detection of refractive index change has been numerically simulated and analyzed using COMSOL Multiphysics. The sensitivity achieved using our proposed structure has been found to be 2713 nm/RIU with a high figure of merit (FOM) of 35.1. It is shown that the sensor can detect a refractive index change of 3.68×10-6, which is the sensing resolution of the sensor, for dielectrics whose refractive indices are between 1 to 1.03 and also between 1.33 to 1.42. Simplicity and compact design with high refractive index sensitivity and FOM of the plasmonic device helps to design bio-sensing devices, in biomedical applications like cancer cell detection, nano-sensing devices and also optical filter applications.