Fig. 3: Investigation for the polarization-driven modulation of symmetry-protected bound states in the continuum.
a Unit cell of an array with periodicity (px or py) for the ultrahigh asymmetry sample where the asymmetry parameter, α = 100%. The arrows indicate the directions of the electric field (E), magnetic field (H), and propagation (k) vector incident on the sample surface at an angle θ. b Experimental (dashed lines) and simulated (solid lines) transmission spectra for different rotational angles ϕ corresponding to different linear polarization states confirm the complete disappearance of the Fano mode at ϕ = 30° due to SP-BIC. c Contour plot illustrating the transmission amplitude for different rotational angles between 0° and 90°, respectively, and within 0.3 and 0.8 THz with the cross symbol indicating the SP-BIC position with vanishing linewidth. d Transmission (Trans.) amplitude and quality (Q-) factor of the Fano resonance near 0.4 THz calculated from the simulated transmission spectra are plotted as a function of rotation angle ϕ. The transmission peak indicates the SP-BIC point induced by rotation. Under similar conditions of simulation, error bars are smaller than data points and are imperceptible to be represented here.
