Multiple Fano resonances based on all-dielectric metasurface for optical refractive index sensor

Abstract

Fano resonance with high quality (Q) factor is of great significance to enhance the interaction between light and matter. The all-dielectric metasurface has low loss and can be used to realize the Fano resonance with high Q-factor. Herein , we propose a novel metasurface and apply it to the optical refractive index sensor in the near infrared. It consists of a silicon layer based on four rectangular holes and the substrate is silica. By introducing a new rectangular hole, the symmetry of the structure is broken and two new Fano resonance peaks are excited at the same time. The maximum Q-factor is 7709 (at 1304.4 nm). It can be applied to optical refractive index sensor with sensitivity of 296.7 nm/RIU and FOM of 1483.5.