T6: High-Harmonic Spectroscopy of Solids, Nanostructures and Quantum Materials - Peter Jürgens

We explore high-harmonic generation (HHG) in a broad class of solid materials ranging from wide-bandgap dielectrics to two-dimensional semiconductors, strongly correlated oxides, and topological insulators. We use ultrashort near- and mid-infrared laser pulses to generate HHG across the visible to the extreme ultraviolet (XUV) spectral range. We pursue three interconnected directions: (i) XUV high-harmonic interferometry to monitor excitation-induced bandgap dynamics; (ii) phase-resolved interferometry to uncover fundamental mechanisms of excitation-related harmonic generation; and (iii) time-resolved high-harmonic spectroscopy to track photoinduced carrier and lattice dynamics as well as ultrafast quantum phase transitions. Together, these approaches provide highly symmetry-sensitive insight into non-equilibrium electronic structure and many-body interactions in solids. The project is conducted in close collaboration with project 4.1 “Implementation of Lasers and Measuring Techniques”(M. Meroe), ensuring optimized light sources, stability, and detection strategies.