Split arc based metasurface for refractive index sensing applications

In this paper, we have proposed and numerically investigated an all-dielectric metasurface consisting of a 2-dimensional periodic array of convex facing silicon asymmetric split arcs on the silica substrate. Due to split asymmetric arcs configuration, the structure exhibits Fano resonance at the wavelength of 967 nm. The maximum achieved quality factor (Q-Factor) and the spectral contrast ratio of the Fano resonance are 213.4 and 99.91%, respectively. The proposed metasurface can be used as a refractive index sensor as the resonance wavelength is linearly dependent on the refractive index of the surrounding. With the increase in the refractive index, the resonance wavelength shows the red-shift. We found that the wavelength shift per refractive index unit (RIU) is 250 nm/RIU and the figure of merit of this sensor is 50.