Plasmonics refractive index sensor based on tunable ultra-sharp Fano resonance

Abstract:

In this paper, a plasmonics refractive index sensor with the semiring-stub system coupled to a bus waveguide is proposed. The structure can achieve wavelength band tunable and ultra-sharp Fano resonance. The coupling mechanism between the bright mode and dark mode is investigated in detail, and apparent plasmon induced transparency (PIT) is realized on the resonance wavelength. The full width at half maximum (FWHM) of the resonant wavelength is modulated by adjusting the coupled distance. The sensitivity and figure of merit (FOM) of the proposed sensor can reach up to 600 nm/RIU and 120 on the visible region, respectively, and this performance can be helpful for designing the photonic integrated circuit and optical communication, in addition, it can be applied for bio-sensing