Plasmonic nanosensor based on sharp Fano resonances induced by aperture-coupled slot system

Abstract

We theoretically investigate a plasmonic nanostructure, which comprises a groove and aperture-coupled slot resonators integrated on a metal–dielectric–metal (MDM) waveguide. The interference between the mode of the slot resonator and groove give rise to the Fano resonances which can be easily tuned by changing the parameters of the slot. Furthermore, this structure can be extended to generate double Fano resonances by introducing another slot. The calculated wavelength shift between the peak and valley of the Fano line shape is reduced to 10 nm, and the sensitivity and FOM for the structure serving as a nanosensor can reach ∼850 nm/RIU and ∼14000. Thus, our results reveal that the structures may have great potential for highly integrated circuits, nanosensors and slow-light.