基于法诺共振的全介质硫系化合物超表面高性能中红外折射率传感OA

We propose a high-performance mid-infrared refractive index sensor based on an all-dielectric metasurface,operating at a wavelength of approximately 5.36 μm.The metasurface unit consists of four sym-metrically arranged Sb2Se3 semi-elliptical structures and a central Sb2Se3 cylinder,periodically arranged on a BaF2 substrate.Numerical simulations were performed using the finite-difference time-domain(FDTD)method to obtain the reflection spectrum and to analyze the electromagnetic field vector distribution at the resonance peak,as well as the influence of geometric parameters on the spectral response.The observed Fano resonance in the reflection spectrum is explained by the theory of quasi-bound states in the continuum(Q-BIC).Through systematic parameter scanning,we investigate the influence of structural parameters on the quality factor(Q)and full width at half-maximum(FWHM)under the constraint of fixed resonance intensity,and compare the spectral linewidth responses when adjusting parameters in different directions.Furthermore,by varying the background refractive index,the refractive-index sensing characteristics based on the Fano resonance are studied.The results show that the sensor achieves a maximum sensitivity of 1 985 nm/RIU,a peak Q-factor of 1 096.6,and a figure of merit(FOM)of 400.Compared with previously reported mid-in-frared refractive index sensors,the proposed design demonstrates significant advantages in key performance metrics such as sensitivity,Q-factor,and FOM.This work provides a feasible design strategy and perform-ance reference for developing high-performance mid-infrared optical sensors based on chalcogenide com-pounds.