Active manipulation of accidental quasi bound states in the continuum in Sb2Se3-Silicon hybridized metasurfaces.

High quality factor resonances with enhanced light-mater interactions are of great importance for diverse applications such as nano-lasering and biosensing. Recently, Fano-sharp resonances with ultrahigh Q factor up to hundreds of thousands have been realized in all-dielectric metasurfaces based on the concept of bound states in the continuum (BIC). However, once being fabricated, these metasurfaces only offer unique characteristics and cannot be modulated. Here, we numerically demonstrate a tunable electromagnetic induced transparency (EIT) analogous resonances based on the interaction between two accidental quasi-BICs in an Se 2 Sb 3 -silicon hybridized metasurface. The silicon metasurface consists of a silicon square with two rectangular slots in the unit cell. Two accidental quasi-BICs (A-qBICs) are excited by changing the spacing between slots, and further results in EIT-analogous resonances when the spacing between slots and the polarization angle of incident light are varied simultaneously. Owing to the tunable characteristic of Sb 2 Se 3 , we demonstrate the active control of EIT effects by integrating the Sb 2 Se 3 film with the silicon metasurface supporting A-qBICs, which yields excellent tunable performances in terms of both the transmission amplitude and group delay of EIT analogous resonances. These results provide a new pathway to dynamically tunable and reconfigurable metadevices with high performances. • Accidental quasi-BIC resonances are excited in a silicon metasurface by tuning the structural parameter without breaking the symmetry. • EIT analogous resonances are excited due to the interaction between accidental quasi-BICs by varying the structural parameter and the polarization angle of incident light. • Active modulations of the transmission and group delay of EIT analogous resonances are achieved in the Se 2 Sb 3 -silicon metasurface due to the phase transition of Se 2 Sb 3. [ABSTRACT FROM AUTHOR]