  Ultrafast control of electron dynamics in solid state systems has recently
found particular attention. By increasing the electric field strength of laser
pulses, the light-matter interaction in solids might turn from a perturbative
into a novel non-perturbative regime, where interband transitions from the
valence to the conduction band become strongly affected by intraband motion. We
have demonstrated experimentally and numerically that this combined dynamics
can be controlled in graphene with the electric field waveform of
phase-stabilized few-cycle laser pulses. Here we show new experimental data and
matching simulation results at comparably low optical fields, which allows us
to focus on the highly interesting transition regime where the light-matter
interaction turns from perturbative to non-perturbative. We find a 5th order
power-law scaling of the laser induced waveform-dependent current at low
optical fields, which breaks down for higher optical fields, indicating the
transition.
