Pump laser-induced space-charge effects in HHG-driven time- and angle-resolved photoelectron spectroscopy

Journal Article · Tue Jun 14 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4953643· OSTI ID:22596795

Hanff, K.; Stange, A.; Rohde, G.; Diekmann, F.; Bauer, M.

With the advent of ultrashort-pulsed extreme ultraviolet sources, such as free-electron lasers or high-harmonic-generation (HHG) sources, a new research field for photoelectron spectroscopy has opened up in terms of femtosecond time-resolved pump-probe experiments. The impact of the high peak brilliance of these novel sources on photoemission spectra, so-called vacuum space-charge effects caused by the Coulomb interaction among the photoemitted probe electrons, has been studied extensively. However, possible distortions of the energy and momentum distributions of the probe photoelectrons caused by the low photon energy pump pulse due to the nonlinear emission of electrons have not been studied in detail yet. Here, we systematically investigate these pump laser-induced space-charge effects in a HHG-based experiment for the test case of highly oriented pyrolytic graphite. Specifically, we determine how the key parameters of the pump pulse—the excitation density, wavelength, spot size, and emitted electron energy distribution—affect the measured time-dependent energy and momentum distributions of the probe photoelectrons. The results are well reproduced by a simple mean-field model, which could open a path for the correction of pump laser-induced space-charge effects and thus toward probing ultrafast electron dynamics in strongly excited materials.

• OSTI ID: 22596795
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 22; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COULOMB EXCITATION
DISTRIBUTION
ELECTRONS
ENERGY SPECTRA
EXTREME ULTRAVIOLET RADIATION
FREE ELECTRON LASERS
GRAPHITE
HARMONIC GENERATION
MEAN-FIELD THEORY
NONLINEAR PROBLEMS
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
PHOTONS
PROBES
PULSES
SPACE CHARGE
TIME DEPENDENCE
TIME RESOLUTION
WAVELENGTHS