Refractive Plasmonic Sensor Based on Fano Resonances in an Optical System
Wei-Jie Mai1,2, Yi-Lin Wang1,2, Yun-Yun Zhang1,2, Lu-Na Cui1,2, Li Yu1,2**
1State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 2School of Science, Beijing University of Posts and Telecommunications, Beijing 100876
Abstract：A symmetric plasmonic structure consisting of metal–insulator–metal waveguide, groove and slot cavities is studied, which supports double Fano resonances deriving from two different mechanisms. One of the Fano resonances originates from the interference between the resonances of groove and slot cavities, and the other comes from the interference between slot cavities. The spectral line shapes and the peaks of the double Fano resonances can be modulated by changing the length of the slot cavities and the height of the groove. Furthermore, the wavelength of the resonance peak has a linear relationship with the length of the slot cavities. The proposed plasmonic nanosensor possesses a sensitivity of 800 nm/RIU and a figure of merit of 3150, which may have important applications in switches, sensors, and nonlinear devices.
2017, Vol. 34 
