Physikalisches Kolloquium

Dec. 6, 2022 at 4:15 p.m. in HS KPH

Prof. Dr. Dmitry Budker
Helmholtz Institute Mainz
Excellence Cluster PRISMA+

Prof. Dr. Frank Maas
HI Mainz, GSI Darmstadt / JGU Mainz
Excellence Cluster PRISMA+

Ultrafast currents in graphene: approaching lightwave electronics
Prof. Dr. Peter Hommelhoff (University of Erlangen)

Optical fields can now be controlled with similar degrees of freedom as microwave fields for many decades already: we can now control not just
the pulse envelope but also the optical carrier field. With few cycle laser pulses, this allows steering of electrons in unprecedented ways. I
will give an overview over recent experiments we performed mainly with the atomically thin material graphene. Here we can drive the intraband
motion of electrons but also interband transitions. For the intense ultrashort fields we employ, these processes become intricately coupled
- a hallmark of strongfield physics. In particular, we could observe subsequent coherent Landau-Zener transitions, leading to
Landau-Zener-Stückelberg-Majorana interferometry, representing fully coherent electron dynamics in a room-temperature material. In the
second part of the talk, we will shine light on the graphene-gold interface and how it will add to the currents we can excite. Because of
the different symmetries involved, we can disentangle virtual and real carrier excitations. With these insights, we have recently demonstrated
a first Boolean logic gate based on two laser pulses carrying the logic information in the carrier envelope phase, which might bring lightwave
or petahertz electronics closer to reality.