Improving the robustness of bound states in the continuum with higher topological charges

Accidental BICs can be simultaneously tuned to merge with the higher-order charged BIC at the Γ point by varying thickness. Once the symmetry is reduced, the higher-order charged BIC is broken and split into two off-Γ BICs. Subsequently, they can be tuned to form merging BICs with another accidental BIC at off-Γ points. The merging … Read more