title: Spin-resolved photoelectron spectroscopy using femtosecond extreme ultraviolet light pulses from high-order harmonic generation.
abstract: The fundamental mechanism responsible for optically induced magnetization dynamics in ferromagnetic thin films has been under intense debate since almost two decades. Currently, numerous competing theoretical models are in strong need for a decisive experimental confirmation such as monitoring the triggered changes in the spin-dependent band structure on ultrashort time scales. Our approach explores the possibility of observing femtosecond band structure dynamics by giving access to extended parts of the Brillouin zone in a simultaneously time-, energy- and spin-resolved photoemission experiment. For this purpose, our setup uses a state-of-the-art, highly efficient spin detector and ultrashort, extreme ultraviolet light pulses created by laser-based high-order harmonic generation. In this paper, we present the setup and first spin-resolved spectra obtained with our experiment within an acquisition time short enough to allow pump-probe studies. Further, we characterize the influence of the excitation with femtosecond extreme ultraviolet pulses by comparing the results with data acquired using a continuous wave light source with similar photon energy. In addition, changes in the spectra induced by vacuum space-charge effects due to both the extreme ultraviolet probe- and near-infrared pump-pulses are studied by analyzing the resulting spectral distortions. The combination of energy resolution and electron count rate achieved in our setup confirms its suitability for spin-resolved studies of the band structure on ultrashort time scales.
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Plötzing
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Adam
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Weier
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Plucinski
authors.affiliation: University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Eich
authors.affiliation: University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Emmerich
authors.affiliation: University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Rollinger
authors.affiliation: University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Aeschlimann
authors.affiliation: Georg-August-Universität Göttingen, I. Physikalisches Institut, 37077 Göttingen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Mathias
authors.affiliation: Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany.
authors.forename: C M
authors.initials: CM
authors.lastname: Schneider