▎ 摘　　要

The optical response of free standing graphene, with or without a perpendicular magnetic field, doping or gap, is studied theoretically by solving Maxwell's equations. Formulae for the reflection coefficient and the reflected polarization are derived in terms of the polarization of the incident electromagnetic wave in the microwave region, its angle of incidence and the azimuthal angle on the graphene plane. These formulae involve the conductivity tensor of graphene. The behaviour of the reflection coefficient and the reflected polarization with the variation of these parameters may be used to infer the optical conductivity tensor and the anisotropy of the conductivity (by this we mean the presence of non-vanishing off-diagonal components of the conductivity tensor). The conductivity of graphene is important since it provides indirect evidence of the effective relativistic dispersion of the energy of the quasi-particles involved.