Tunable plasmon refractive index sensor and slow light characteristics based on a stub coupled with an ellipse resonator and its derived structure

In this paper, a structure consisting of a stub metal-insulator-metal (MIM) waveguide coupled with an ellipse resonator is proposed. The finite element method (FEM) is used to analyze the transmission characteristics and magnetic field distributions of the structure in detail. The basic structure can support triple Fano resonances. In addition, multi-spectrum characteristics can be achieved by increasing the complexity of the structure. All Fano resonances can be tuned by altering the geometric parameters of the structure. Furthermore, each of the proposed structures has applications in both sensing and slow light devices. The maximum sensitivity of refractive index sensing is up to 1400 nm/RIU. The MIM waveguide structures have potential applications in the field of on-chip optical integration.