Magnetic and electric Purcell enhancement in a hybrid metal-dielectric nanostructure

Hybrid metal-dielectric structures combine the advantages of both metal and dielectric materials,enabling high-confined but low-loss magnetic and electric resonances through deliberate arrangements.However,their potential for enhancing magnetic emission has yet to be fully explored.Here,we study the magnetic and electric Purcell enhancement supported by a hybrid structure composed of a dielectric nanoring and a silver nanorod.This structure enables low Ohmic loss and highlyconfined field under the mode hybridization of magnetic resonances on a nanoring and electric resonances on a nanorod in the optical communication band.Thus,the 60-fold magnetic Purcell enhancement and 45-fold electric Purcell enhancement can be achieved.Over 90%of the radiation can be transmitted to the far field.For the sufficiently large Purcell enhancement,the position of emitter has a tolerance of several tens of nanometers,which brings convenience to experimental fabrications.Moreover,an array formed by this hybrid nanostructure can further enhance the magnetic Purcell factors.The system provides a feasible option to selectively excite magnetic and electric emission in integrated photonic circuits.It may also facilitate brighter magnetic emission sources and light-emitting metasurfaces with a more straightforward design.