Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 61: Plasmonics and Nanooptics 2
O 61.2: Vortrag
Donnerstag, 8. September 2022, 11:00–11:15, H2
Excitation of coherent phonon modes in plasmonic gold nanoparticles — •Dominik Höing1,2, Robert Salzwedel4, Malte Selig4, Kartik Ayyer2,3, Jochen Küpper2,3, Andreas Knorr4, and Holger Lange1,2 — 1Institute of Physical Chemistry, Universität Hamburg, Hamburg, Germany — 2The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany — 3Center for Free-Electron Laser Science, Hamburg, Germany — 4Institut für Theoretische Physik, Technische Universität Berlin, Berlin, Germany
The plasmonic properties of gold nanoparticles (AuNP) have been widely studied, because of their exhibition of strong light-matter coupling and hot carrier generation. The carrier dynamics that follow the optical excitation are presently understood as a series of events with increasing time-scales. Among them, the excitation of coherent acoustic phonon modes, also called breathing modes, is thought to result from the ultrafast heating of the lattice due to electron-phonon coupling. However, previous experimental studies were insufficient in detecting the onset of the breathing oscillation. Here, we use a combination of transient absorption spectroscopy, time-resolved X-ray scattering and a model combining quantum coherent and hydrodynamic theory to develop a different picture: We show that the gradient in electron density induced by the optical excitation instantaneously couples to coherent phonons, resulting in an immediate onset of the breathing oscillation with the optical excitation. Thus, the processes involved in the plasmon decay are more intertwined as previously assumed.