Electromagnetic Dressing of Graphene

We present a theory to describe the interaction of electrons in gapped and gapless graphene with a strong off-resonant electromagnetic field (dressing field). This interaction (electromagnetic dressing) is shown to renormalize substantially electron velocities and the band gap in gapped graphene. Particularly, renormalized electronic parameters depend strongly on the field polarization: linearly polarized fields always reduce the gap, while circularly polarized fields break the equivalence of the valleys at various points of the Brillouin zone and can increase or decrease the corresponding band gaps. Moreover, a linearly polarized dressing field induces anisotropy of electron dispersion in the graphene plane. Consequently, dressing fields can be an effective tool to control electronic properties of graphene and be prospectively used in various optoelectronic devices.