Chiral Bound states in the continuums based on Hybrid Metasurfaces for Enantiomer Analysis

Optical sensing offers an effective and promising method for molecular detection, yet quantifying enantiomer concentrations remains a critical challenge. Here, we present a SiC-Au hybrid metasurface supporting the chiral quasi-bound state in the continuum (BIC) mode, manipulated by the rotation angle φL. An enantiomer analysis method is proposed to obtain d- and l-enantiomer concentrations from peak wavelength and intensity of circular dichroism (CD). At φL = 20°, the hybrid design yields a strong CD value (0.62) and a high quality (Q) factor (295). Moreover, the electric field (EF) and the optical chirality (C) are both strongly localized near the structural surface, enhancing the sensitivity of refractive index (RI) and CD sensing (SRI = 436 nm/RIU, SCD = -247). Compared to the all-dielectric metasurface, the hybrid design achieves 11- and 80-fold improvements in SRI and SCD, enabling label-free, sensitive, and rapid detection for environmental, biomedical, and industrial applications.