Extremely high figure of merit in all-dielectric split asymmetric arc metasurface for refractive index sensing

In this paper, we have proposed the design of an all-dielectric metasurface that consists of a 2-dimensional periodic array of split asymmetric silicon arcs, making closed rings, on a silica substrate. The numerical simulation shows that the proposed metasurface exhibit Fano resonance due to close loop current density in asymmetric silicon arcs, at the wavelength of 967 nm for air as analyte surrounding the metasurface. The maximum achieved spectral contrast of the Fano resonance peak is 99%. It is also observed from the numerical simulation that the Fano-resonance wavelength and its linewidth is dependent on the refractive index and the thickness of the analyte above the silica substrate. The calculated sensitivity, quality factor (Q-Factor) and extremely high figure of merit (FoM) of the proposed sensor are 324 nm/RIU, 8720 and 2465, respectively.