Figure 4
Symmetry-protected Brewster BIC characterization through experimental and theoretical spectra. (a,b) Contour maps of the S-polarized reflectance R(ν,θ) intensity as in Fig. 3a,c from a square array (lattice period = 12 mm) of dielectric resonator disks (as in Fig. 2), zooming in the BIC region around ν = 5.6 GHz and θ = 0°: (a) Experimental measurements for a finite 11 × 11 disk array; (b) iCEMD theoretical calculations for an infinite metasurface. (c) Phase map of the BIC vortex. (d) Q factors at resonance (ν = 5.6 GHz) obtained from the theoretical (reflectivity) and experimental (extinction cross section) spectral full width at half maximum in a and b, as a function of the angle of incidence θ; the Q-factors from the finite CEMD calculation of the extinction spectra are included too. (e) Same as in d, but for arrays of tilted disks with tilt angle ϕ = 10° (only theoretical iCEMD) and ϕ = 30° (see Fig. 5).
