Simultaneously enhance electric and magnetic Purcell factor by strong coupling between toroidal dipole quasi-BIC and electric dipole

Abstract

The larger electric or magnetic Purcell factor demonstrates that the structure can be utilized as an electric or magneto-optical emission project. Their simultaneous realization offers the potential for integrated circuits to achieve selective photon sources. In this study, we put forth a proposal for the simultaneous attainment of substantial electrical and magnetic Purcell enhancements. In our hybrid metal–dielectric metasurface, the toroidal dipole (TD) quasi bound states in the continuum mode and the electric dipole (ED) mode are strongly coupled, so the hybrid mode combines the advantages of both, with a large Q factor and a small mode volume. The design implements a Rabi splitting energy of 222 meV between the TD quasi-BIC and ED modes, achieving an electric Purcell factor of 43 and a magnetic Purcell factor of 684, which are greater than those observed for the metal rod and dielectric structure, respectively. This paves the way for the development of high-performance hybrid optoelectronic applications.