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

Bound states in the continuum (BICs) have attracted broad research interest owing to their excellent performance in light confinement, which can boost light-matter interaction. BICs can eliminate the radiation loss to theoretically achieve an infinity quality factor Q. However, in practical on-chip resonators, there are inevitable fabrication imperfections that couple BICs to nearby radiative states by scattering, thus limiting the available Q.