Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid
One of the hallmarks of the optical properties of (suspended) graphene is that a simply-observable quantity as the optical transparency is defined solely by the fine structure constant . In the first part of this talk, I will give the theoretical explanation to this experiment, i.e., show that even in the visible-optics regime the corrections to the Dirac cone approximation are small (a few percent) and the effect of next-nearest neighbor hopping is negligible . I will also discuss the infrared conductivity of graphene on a substrate where electron-phonon and impurity scattering become important .
In the second part, I will look at the optical properties of double layer graphene with respect to their plasmonic excitations, near-field amplification and extraordinary (perfect) transmission . Also graphene’s fluorescence quenching including transverse decay channels and full retardation will be discussed . Finally, the current-current correlation function of the full hexagonal tight-binding model will be derived  and I will show that lattice effects lead to a paramagnetic response for graphene with intrinsic doping at low temperatures .
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