Edge Mode Excitation Induced Fano Resonance in an X-Shaped Plasmonic System
摘要
Fano resonance is an optical phenomenon arising from the coherent coupling and interference between a continuum state and a Lorentzian state in plasmonic waveguide–resonator systems. Owing to its distinctive spectral profile, it plays a pivotal role in nanophotonics. Here, based on the X-shaped cavity system, a new method for generating Fano resonance is obtained, which is induced by the excitation of the system’s edge mode and confirmed by the field distributions. To the best of our knowledge, this phenomenon of Fano resonance induced by edge mode excitation is reported for the first time. Simulation results reveal that the Fano resonance can be easily tuned by altering the structure’s parameters, and multi-Fano resonances can be observed by the structural expansion. The proposed structure can be used as a plasmonic nanosensor with a sensitivity of ~ 700 nm/RIU and a figure of merit of ~ 1.5 × 104 based on Fano resonance. The proposal of this method further enriches the forms of Fano resonance generation, and the special features of our suggested structure are applicable in realization of various integrated components for the development of multifunctional high-performance nano-photonic devices.