Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 80: Surface Dynamics I

O 80.12: Vortrag

Donnerstag, 3. April 2014, 18:45–19:00, GER 38

Pump-laser-induced space-charge effects in time-resolved photoelectron spectroscopy — •Lars-Philip Oloff, Ankatrin Stange, Kerstin Hanff, Lutz Kipp, Michael Bauer, and Kai Rossnagel — Institute of Experimental and Applied Physics, University of Kiel, Germany

The development of ultrashort-pulsed extreme ultraviolet sources, such as high-harmonic generation sources (HHG) and free-electron lasers, has opened up a new field of physics by means of time-resolved pump-probe photoelectron spectroscopy experiments. The effects of these sources’ high brilliance on photoemission spectra, i.e., intensity-dependent broadenings and shifts towards higher kinetic energies ("space-charge effects"), have been extensively studied by experiments and simulations [1,2] and are now rather well understood. However, in time-resolved photoelectron spectroscopy a further effect can be recognized in the high-pump-intensity regime: pump-induced space-charge effects due to nonlinear multiphoton photoemission. We have systematically studied these effects as a function of various experimental parameters (pump-probe delay, pump energy, pump intensity, work function of the sample) at our HHG-based photoemission setup (22 eV probing, 390 nm/780 nm pumping). The obtained experimental results are compared with the results of self-consistent N-body numerical simulations.

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S. Hellmann et al., Phys. Rev. B 85, 075109 (2012)