Bonn 2025 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
A: Fachverband Atomphysik
A 17: Interaction with Strong or Short Laser Pulses I (joint session A/MO)
A 17.6: Vortrag
Mittwoch, 12. März 2025, 16:00–16:15, GrHS Mathe
A theoretical perspective on high-harmonic generation in organic molecular crystals — •Samuel Schöpa1, Lina Bielke1, Falk-Erik Wiechmann1, Felipe Morales2, Serguei Patchkovskii2, Maria Richter2, Franziska Fennel1, and Dieter Bauer1 — 1Institute of physics, University of Rostock, 18059 Rostock — 2Max Born Institute (MBI) for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin
We investigate the underlying mechanism of high-harmonic generation (HHG) in the novel target class of organic molecular crystals (OMCs). Compared to covalent and ionic-bonded solids, the molecules that bond to form OMCs are much more weakly coupled, which is reflected in an energy band structure dominated by single-molecule excitations and charge-transfer states of neighbouring molecules. But does the intramolecular response of the aligned molecules dominate the HHG process? Or can we exploit HH spectroscopy to study the solid-state properties of OMCs, which are characterized by the intermolecular couplings? We addressed this by simulating the HHG process using full time-dependent density-functional theory (TD-DFT) for different polarizations of the driving field and compared it with experimental results. We find in both, that the rotation of the driver polarization reveals maxima in the harmonic yield when the polarization is aligned with the axes connecting neighbouring molecules. A simple tight-binding model shows, that lower harmonic orders are primarily governed by the intramolecular response, while higher orders depend mainly on the intermolecular coupling.
Keywords: High-harmonic generation; Organic molecular crystals; Pentacene; Intermolecular coupling; Polarization dependence