Sensing analysis based on fano resonance in arch bridge structure

An arch bridge structure, comprising of a semiring cavity resonator coupled with bus waveguide, has been investigated numerically and theoretically. Due to the interaction of broad bright state and the narrow dark state caused by the semiring cavity and bus waveguide, respectively, fano resonance can be accrued in transmission spectra which possess a sheer asymmetrical profile that can be adjusted by changing the parameters of the structure with the finite-difference time-domain (FDTD) method. A plasmonic nanosensor is devised based on fano resonance in a metal-insulator-metal (MIM) waveguide system, which has a sensitivity of 1500 nm/RIU as well as a figure of merit (FOM) of 5500. Our findings can provide the guidance for fundermental research of nanosensor in highly integrated optical circuits. (paper)