Fig. 4: Experimental demonstration of BZF-BICs and GRs.
From: Brillouin zone folding driven bound states in the continuum
a Scanning electron microscope (SEM) image of the fabricated gap perturbed (ΔL = 18 μm) THz-PhC sample. Simulated and measured angle-resolved transmission spectra of THz-PhC (ΔL = 30 μm) along the Γ-X direction under (b) TE and (c) TM polarizations. The linewidths of TE40, TE21, and TE51 modes become narrower as the incident angle decreases, while it’s nearly unchanged for GRs TE11, TE31, and TE41 modes. d Measured transmission spectra of THz-PhC samples with different gap perturbations under TE and TM polarizations at normal incidence. e Extracted Q factor of GRs TE11, TE31, and TE41 modes from the measured (solid circles) and simulated (hollow squares) transmittance spectra. The simulated Q factor is fitted by Q ∝ 1/α2 (solid line). f Measured and fitted transmission spectra of TE31 mode at normal incidence for ΔL = 2 μm.
