Graphene in ultrafast and superstrong laser fields

For graphene interacting with a few-fs intense optical pulse, we predict unique and rich behavior dramatically different from three-dimensional solids. Quantum electron dynamics is shown to be coherent but highly nonadiabatic and effectively irreversible due to strong dephasing. Electron distribution in reciprocal space exhibits hot spots at the Dirac points and oscillations whose period is determined by nonlocality of electron response and whose number is proportional to the field amplitude. The optical pulse causes net charge transfer in the plane pf graphene in the direction of the instantaneous field maximum at relatively low fields and in the opposite direction at high fields. These phenomena promise ultrafast optoelectronic applications with petahertz bandwidth.