Spontaneous Emission in a Dielectric Cube-Graphene Substrate Gap

This work deals with the spontaneous emission (SE) study of a point-like emitter placed in close proximity of a graphene dielectric structure. This structure is formed by a dielectric micro-cube placed above a plane graphene sheet covering a dielectric substrate. The electromagnetic interplay between the emitter and the fields scattered back to the emitter’s site by the cube and the graphene substrate drives the emitter to modify the field emission rate. The size of the micro-cube, the graphene constitutive parameters, as well as the gap between dielectric cube and graphene determine the enhancement level of the spontaneous emission decay rate. We have developed a method based in the coupled dipole approximation (CDA) including the surface Green tensor to take into account the scattering with the graphene substrate. We show that the results obtained by using the rigorous theory can be well approximated by those calculated by extracting the plasmonic contribution from the surface Green tensor.