Antenna-Based Approach to Fine Control of Supercavity Mode Quality Factor in Metasurfaces

The utilization of photonic bound states in the continuum(BIC)is a very attractive approach for many applications requiring efficientresonators. High-Q modes related to symmetry-protected BIC are formeddue to perturbation defined by an asymmetry parameter, and the smallerthis parameter is, the bigger the Q factor can be achieved. Inevitablefabrication imperfectness limits precise control of the Q factor throughthe asymmetry parameter. Here we propose an antenna-based design ofmetasurfaces for accurate tailoring of the Q factor where strongerperturbation leads to the same effect in the conventional design.This approach allows the fabrication of samples with equipment havinglower tolerance keeping the Q factor at the same level. Furthermore,our findings reveal two regimes of the Q factor scaling law with saturatedand unsaturated resonances dependent on the ratio of antenna particlesto all particles. The boundary is defined by the efficient scatteringcross section of the metasurface constituent particles.