Fig. 3: Merging accidental BICs and the split BICs at off-Γ points.
From: Merging bound states in the continuum by harnessing higher-order topological charges
a Simulated polarization vectors around BICs with Q factors as background at different thicknesses. When t is tuned from 338 nm to 332 nm, accidental BICs and the split BICs with opposite topological charges annihilate each other. The transition (t = 334.1 nm) corresponds to a merging BIC. b Simulated Q factors (dotted lines) and fitting curves (solid lines). The merging BIC case has considerably enhanced Q factors for nearby states compared with the isolated BICs case. In these simulations, we consider the same system as shown in Fig. 2a and only vary t
