Highly Sensitive Multichannel Fano Resonance-Based Plasmonic Sensor for Refractive Index and Temperature Sensing Application

Abstract

We propose a susceptible multichannel plasmonic sensor for sensing refractive index (RI) and temperature media working in the visible to near-infrared range. The proposed structure’s resonator consists of an elliptical-shaped ring with two stubs at two sides and four metal nanorods side-coupled to two separated metal–insulator–metal waveguides. The optical responses of the structure, including transmittance spectra and magnetic and electric field distributions, are investigated using the finite element method (FEM) to obtain the optimal structural parameters. The designed structure supports five channels of Fano resonance modes because of the interaction between the narrowband mode of the elliptical-shaped ring resonator and the broadband mode of two separated MIM WGs. The maximum sensitivity values can reach 4500 nm/RIU for RI sensing, and the temperature sensitivity can get 1.00 nm/°C. The designed device exhibits excellent sensing performance and could pave the way for sensing devices with significantly higher sensitivity.

Keywords

• multichannel sensor
• metal–insulator–metal
• temperature sensitivity
• Fano resonances