Quasi-bound states in the continuum with robust resonance wavelength in all-dielectric planar metasurface

Abstract Bound states in the continuum (BIC) supported by metasurface broadens the possibilities for enhancing light-matter interaction. Yet the shift of resonance wavelength towards asymmetry perturbation and polarization states variation affects its practical application. In the present work, we design a metasurface to achieve quasi-BICs with both asymmetry and polarization independence through in-plane perturbation with geometry compensation and rotational symmetry. Through multipole decomposition, we reveal the internal physical mechanism that the dual-bands BIC modes are originated from magnetic dipole (MD) and toroidal dipole (TD), respectively. Furthermore, based on the designed metasurface, a promising application as an environmental sensor is discussed. The present work provides potential scenarios on the manipulation of BICs with higher robustness and better performance.