Fig. 4. Experimental verification of the intrinsic planar chiral q-BIC with various in-plane geometry asymmetry parameters.

a The top view of the SEM image of five fabricated DSS metasurfaces with asymmetry parameters δ = 0 nm, 20 nm, 40 nm, 60 nm, and 80 nm, respectively. The inset shows the slant view of the metasurface. Scale bar: 1 µm. b Simulated and measured transmission Jones matrix spectra (T_lr, T_rl, T_rr and T_ll) of the five DSS metasurface samples with different δ. c Simulated and measured CD spectra for different δ extracted from the Jones matrix spectra in (b).