Abstract
Spontaneous emission control of emitters hold great promise for applications in pho-tonics and quantum optics. As a definition of the spontaneous emission lifetime of an atom or molecule, the Purcell factor of an emitter coupled with graphene plasmons by a static magnetic field is studied. The results show that the Purcell factor can be effectively modulated by the applying of external magnetic field to graphene at lower terahertz frequencies. In addition, in the presence of a magnetic field, the coupling between the graphene and emitter becomes stronger, which results in a strong enhancement of the emission of the emitter and the numerically calculated Purcell factor is increased. More specifically, the Purcell factor increases by almost an order of magnitude when the applied magnetic field is 10T. Moreover, the Purcell factor also depends on the polarization direction of the emitter, especially when the polarization direction of the emitter is parallel to the graphene plane, the Purcell factor will show anisotropy with the change of polarization angle. Bias of the applied magnetic field extends a new path for the realization of Purcell factor modulation based on graphene-emitter interaction, it may provides a promising application value for the design of the photo-magnetic based quantum devices.