Optical Properties of Multiple Fano Resonance in MIM Waveguide System Coupled with a Semi-Elliptical Ring Resonator

A metal-insulator-metal (MIM) waveguide structure consists of semi-elliptical ring resonator (SERR) and a baffle was proposed and numerically investigated by using the finite element method (FEM). By changing the geometrical parameters such as the radii of SERR and the width of the baffle, the transmission characteristics and line shape can be easily tuned. The simulation results show that the proposed plasmonic system is used as a sensor by filling the insulator region with different refractive index. The sensitivity and figure of merit of this sensor can reach 1783 nm/RIU and 27, respectively. It is found that the proposed structure exhibits a slow light effect, and it is shown that the optical delay achieved is 0.887 ps. The results clarified that the developed structure could have a great potential in nanosensor devices and slow light systems.