Chiral quasi-bound states in the continuum 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 φ L . An enantiomer analysis method is proposed to obtain d - and l -enantiomer concentrations from peak wavelength and intensity of circular dichroism (CD). At φ L = 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 ( S RI = 436 nm/RIU, S CD = −247). Compared to the all-dielectric metasurface, the hybrid design achieves 11- and 80-fold improvements in S RI and S CD , enabling label-free, sensitive, and rapid detection for environmental, biomedical, and industrial applications.