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Q: Fachverband Quantenoptik und Photonik
Q 49: Poster – Photonics, Lasers, and Applications
Q 49.16: Poster
Mittwoch, 12. März 2025, 17:00–19:00, Tent
Floquet Topological Engineering in Graphene: Towards Ultrafast Device Control — •Selina Nöcker1, Daniel Lesko1, Weizhe Li1, and Peter Hommelhoff1,2 — 1Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen — 2Department Physik, Ludwig-Maximilians-Universität München (LMU), 80799 München
Topological insulators offer exciting prospects for both fundamental research and technological applications. Irradiation with strong laser light allows dressing any material into a non-equilibrium state known as a Floquet topological insulator. Graphene is a highly symmetric 2D material with exceptional properties and provides an ideal platform to explore laser-engineered topological phenomena. Upon irradiation with a circularly polarized pulse, we induce a topological phase transition to an inversion symmetric and time reversal symmetry-broken Chern insulator. With a phase-locked optical second harmonic field, we probe the sub-cycle properties measuring phase-dependent photocurrents. For this, we use strong few-cycle pulses generated from normal-dispersion highly nonlinear fibers. We employ precise control over their carrier-envelope-phase and two-color phase delay, enabling attosecond control of the Floquet topological state. The dressed graphene exhibits intriguing optical responses, including photocurrent circular dichroism and an all-optical anomalous Hall current. Our work highlights the potential of using short laser pulses to manipulate electronic states within matter, paving the way for ultrafast device engineering in graphene and other 2D materials.
Keywords: Graphene; Few-cycle laser pulses; Floquet topological insulator