High-Q refractive index sensors based on all-dielectric metasurfaces. Issue 33 (2nd August 2022) - Wu, Pinghui
Abstract : A high-sensitivity refractive index sensor excited by the 2D periodic TiO2 dielectric grating structure. The nanosensor can excite guided-mode resonance with a 0.19 nm ultra-narrow linewidth. Low loss all-dielectric metasurface allows ultra-sensitive biosensor detection. Abstract : Possessing fantastic abilities to freely manipulate electromagnetic waves on an ultrathin platform, metasurfaces have aroused intense interest in the academic circle. In this work, we present a high-sensitivity refractive index sensor excited by the guided mode of a two-dimensional periodic TiO2 dielectric grating structure. Numerical simulation results show that the optimized nanosensor can excite guided-mode resonance with an ultra-narrow linewidth of 0.19 nm. When the thickness of the biological layer is 20 nm, the sensitivity, Q factor, and FOM values of the nanosensor can reach 82.29 nm RIU −1, 3207.9, and 433.1, respectively. In addition, the device shows insensitivity to polarization and good tolerance to the angle of incident light. This demonstrates that the utilization of low-loss all-dielectric metasurfaces is an effective way to achieve ultra-sensitive biosensor detection.