Plasmonic refractive index sensor based on M-I-M square ring resonator

In this paper, we proposed a plasmonic square ring resonator design based on the metal-insulator-metal waveguide. Finite element method (FEM) is used to simulate the transmission spectra and electric field distribution of the sensor structure. The effect of structural parameters on the spectral characteristics and sensing performance are studied carefully. The maximum attained sensitivity and figure of merit of the sensor extended 1200 nm/RIU and 19.7, respectively. Due to the excellent performance and flexible fabrication, this kind of plasmonic structures can find significant applications in integrated optical circuits and on-chip nano-sensors.