Multiple adjustable Fano resonance based on double half ring resonator and its application

In this paper, a compact nanostructure is proposed that includes a metal insulator metal (MIM) waveguide with a metal wall and a side-coupled half-ring resonator. The transmission characteristics of the system are studied numerically by using the finite element method (FEM). The simulation results show that double Fano resonances can be produced in the structure, and the two Fano resonances can be controlled independently by two different half rings. The position and intensity of the Fano resonance peaks can be adjusted flexibly and easily by changing the refractive index of the filling medium. The waveguide is sensitive to the refractive index of the filling medium inside the resonator and the maximum sensitivity and figure of merit (FOM) are 1260 nm/RIU and 26,000 respectively. By adding two more half-rings below, four independently adjustable Fano resonances are obtained. The structure of this paper can be used as a sensor which can detect the glucose concentration, so it has a broad application prospect in biomedical and chemical sensing fields. (paper)