Breaking symmetry dependency of symmetry-protected bound states in the continuum via metasurfaces

In this paper, we propose a new strategy based on the interconversion between two symmetry-protected bound states in the continuum (SP-BICs) to break the high symmetry dependency of the SP-BIC.The excitation of four high-Q quasi-BIC resonances is supported by disrupting both the translational and structural symmetry of the metasurface using spacing and length perturbations, respectively.Furthermore, interconversion between the two SP-BICs can be achieved via length perturbation, significantly diminishing the radiative attenuation rate of the quasi-BIC.Despite a relative asymmetric parameter reaching 97.2%, the Q-factor order of magnitude of the quasi-BIC can remain constant.Compared with previous studies, our approach significantly enhances the robustness of the Q-factor for the quasi-BIC by a minimum of two orders of magnitude, although our relative asymmetric parameter is approximately 10 times the corresponding work.