“…Quasi-BICs with finite but high Q-factors, transformed from a real BIC, have been used to achieve resonant metamaterials for applications including biosensors, 17 – 19 lasers, 20 – 22 and nonlinear optics 23 – 25 Currently, quasi-BICs obtained in metamaterials are more through the introduction of geometry asymmetry in the single particle, such as tilted bars, 26 split-ring structures, 27 asymmetric nanobar, 7 , 28 , 29 and dielectric nanodisks with asymmetric holes 30 . In addition, symmetric breaking induced by permittivity asymmetry of single particle in the unit cell has also been used to enhance the interaction between light and matter based on the quasi-BIC 31 , 32 .…”