Characteristics analysis of Fano resonances in MIM waveguide coupled to p-shaped resonator system with nanorod defect

In this paper, triple Fano resonance (FR) is studied in a defect waveguide coupled to p-shaped resonator structure. The optical response of the p-shaped resonator and the nanorod defect can be seen as discrete state and continuous state. The interaction between the narrow discrete states and the broad continuous state produces the triple Fano resonance. Results show that the spectral line shapes of the Fano resonances can be independently tuned by the geometrical parameters. The resonant wavelength of the FR peak has a linear relation with the height and length of the p-shaped resonator. The sensitivity and maximum FOM (figure of merit) can be up to 1340nm/RIU, and 7817, respectively. For asymmetrical structure design, a sextuple Fano resonance spectrum is observed. The structure may have potential applications in the field of slow light, plasmonic filters, sensors in complicated environments.