  Based on a solution of the Floquet Hamiltonian we have studied the
time-evolution of electronic states in graphene nanoribbons driven out of
equilibrium by time-dependent electromagnetic fields in different regimes of
intensity, polarization and frequency. We show that the time-dependent band
structure contains many unconventional features that are not captured by
considering the Floquet eigenvalues alone. By analyzing the evolution in time
of the state population we have identified regimes for the emergence of
time-dependent edge states responsible of charge oscillations across the
ribbon.
