The present work deals with a theoretical research on the emission and radiation properties of a dipole emitter source close to a dimer graphene plasmonic antenna. Modification of the radiation and the quantum efficiencies resulting from varying the position of the emitter and the orientation of its dipole moment are calculated by using a rigorous electromagnetic method based on Green's second identity. Large enhancements in the emission and the radiation of the emitter occur due to the coupling with the antenna surface plasmons in the spectral region from 4THz to 15THz. Our results show that the radiation efficiency can be enhanced by four orders of magnitude and that the quantum efficiency reaches values close to 0.8 when the emission frequency coincides with one of the resonant dipolar frequencies. On the other hand, these quantities can be reduced in a great measure at a specific frequency for a given emitter location. We present calculations of the near-field distribution and the far field intensity which reveal the role of the plasmonic antenna resonance in the emitter enhanced radiation. We show that the spectral region where the radiation is enhanced can be chosen over a wide range by varying the chemical potential of graphene from 0.2eV to 1eV.
Mauro Cuevas
https://www.sciencedirect.com/science/article/pii/S0022407317305964
We present a theoretical study of the spontaneous emission of a line dipole source embedded in a graphene–coated subwavelength wire of arbitrary shape. The modification of the emission and the radiation efficiencies are calculated by means of a rigorous electromagnetic method based on Green’s second identity. Enhancement of these efficiencies is observed when the emission frequency coincides with one of the plasmonic resonance frequencies of the wire. The relevance of the dipole emitter position and the dipole moment orientation are evaluated. We present calculations of the near–field distribution for different frequencies which reveal the multipolar order of the plasmonic resonances.
