A Nanoscale Refractive Index Sensor Based on Asymmetric Plasmonic Waveguide With a Ring Resonator: A Review

A novel and simple refractive index sensor based on the asymmetrical coupling of two metal-insulator-metal waveguides with a ring resonator is proposed and investigated numerically by finite-difference time domain. The results show that the resonance wavelengths of the sensor have an approximate linear correlation with the refractive index of the materials under sensing. With optimum design, the value of sensitivity can be achieved as high as 3960 nm RIU^-1. The sensor can also be used for other types of sensors, and working for temperature sensing is analyzed as follows. This work is significant for design and application of the sensitive nanometer scale refractive index sensor and temperature sensor.