Terahertz hyperspectral imaging and control of collective dynamics in two-dimensional quantum systems

• Applicant: Dr. Alexander von Hoegen
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 563334832

The goal of this project is to visualize and control light-matter coupling at meV energies in atomically thin van der Waals materials. The proposed experiments will initially investigate the meV collective phenomena in these materials and how confinement to two dimensions alters their properties. To study this dimensional crossover, we will employ THz near-field techniques to directly visualize collective phenomena in real space. Building on these results, we will then explore how light-matter coupling can be actively controlled by deliberately designing the sample’s shape as a platform for THz cavity electrodynamics in 2D quantum materials. The aim is to enhance THz light-matter coupling to the point where interactions with the cavity alter material properties. Finally, we will use strong THz laser pulses for periodic driving to transiently control the properties of engineered light-matter systems. Such strong driving can induce dynamical phase transitions, pushing systems out of thermodynamic equilibrium to reveal otherwise inaccessible states.

• DFG Programme: Emmy Noether Independent Junior Research Groups
• International Connection: USA
• Major Instrumentation: Closed-cycle cryostat ; amplified laser systems ; nonlinear pulse compression ; oscillator laser systems
• Instrumentation Group: 5700 Festkörper-Laser ; 8550 Spezielle Kryostaten (für tiefste Temperaturen)
• Cooperation Partners: Professor Dr. Philip Kim; Professor Dr. Angel Rubio