Double chiral resonances in a quasi-BIC metasurface with both strong circular dichroism and high quality factor

when they are used separately in refractive index sensing. For the case of using them jointly by tracking their frequency interval, a slightly smaller sensitivity of 8.73 THz/RIU is revealed in simulation. In addition, frequency shifts of the two chiral resonances are also suitable for distinguishing enantiomers in chiral sensing. These findings suggest that quasi-BIC-based metasurfaces offer a route to obtain multiple high-Q chiral resonant modes, which could boost the performance of metamaterial applications in sensing, light polarization control, spectroscopy, etc.