▎ 摘　　要

In recent years, optical biosensors widely applicable for medical applications, have received much attention. In this paper, we propose a high-performance polarization-insensitive optical biosensor based on a graphene-dielectric metasurface. The metasurface consists of an asymmetric dielectric disk array that supports a high Q-factor Fano resonance. The provided sharp Fano resonance results in an enhanced light-matter interaction leading to a highly sensitive biosensor. The proposed structure is analyzed using the finite element method and the corresponding transmission and reflection spectra are calculated. According to the presented results, a sensitivity of as high as 550 nm/RIU, linearity R-2 value of 0.999 with a figure of merit (FOM) more than 378 RIU-1 around the operating wavelength of 1550 nm are obtained. This is the largest FOM ever reported for a polarization-insensitive biosensor. Such a large FOM accompanied by high sensitivity and linearity make our proposed graphene-based biosensor promising for the effective detection of biomolecules like hemoglobin.