ONLINE Halbleiter zum Frühstück - Ultrafast coherent carrier dynamics in graphene - on the way to lightwave electronics?

A good ten years ago, strongfield and attosecond physics have been demonstrated inside of a solid. Hence, electrons can now be steered on sub-optical timescales – inside of matter. Until recently, the materials of choice were large bandgap dielectrics and semiconductors. We set out to explore if also electrons in an electrical conductor could be steered with the carrier field of ultrashort laser pulses. Turns out that graphene is ideally suited to do so. This semi-metal has allowed us to observe fully coherent electron dynamics, namely coupled intraband motion and interband transition dynamics (Landau-Zener-Stückelberg interferometry). We further investigated how a graphene-gold interface could help to read out the virtual carrier excitations in graphene, i.e., the transiently excited conduction band population. Based on these points, we could now demonstrate a first ultrafast logic element, where the logic inputs are encoded in the carrier-envelope phase of two laser pulses.