All-dielectric tunable Q-factor guided-mode resonance using quasi-bound states in the continuum

we designed tunable guided-mode resonance filter (GMRF). To control the Q-factor, we propose a dual ridge GMRF structure with ridges on both sides of the core waveguide. all-dielectric GMR can adjust the Q-factor at a fixed frequency by using quasi-bound state in the continuum (BIC). By changing the structural symmetry and asymmetry of the two ridges, the Q-factor can be maximized and minimized at a fixed resonant frequency, enabling a tunable filter. The proposed filter design was simulated using rigorous coupled wave analysis (RCWA) methods and finite-difference frequency-domain (FDFD) in the THz region.