title: Optimized spatial overlap in optical pump-X-ray probe experiments with high repetition rate using laser-induced surface distortions.
abstract: Ultrafast X-ray diffraction experiments require careful adjustment of the spatial overlap between the optical excitation and the X-ray probe pulse. This is especially challenging at high laser repetition rates. Sample distortions caused by the large heat load on the sample and the relatively low optical energy per pulse lead to only tiny signal changes. In consequence, this results in small footprints of the optical excitation on the sample, which turns the adjustment of the overlap difficult. Here a method for reliable overlap adjustment based on reciprocal space mapping of a laser excited thin film is presented.
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Wilhelm-Conrad-Röntgen Campus, BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Reinhardt
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Wilhelm-Conrad-Röntgen Campus, BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
authors.forename: Azize
authors.initials: A
authors.lastname: Koc
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Wilhelm-Conrad-Röntgen Campus, BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Leitenberger
authors.affiliation: Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Gaal
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Wilhelm-Conrad-Röntgen Campus, BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
authors.forename: Matias
authors.initials: M
authors.lastname: Bargheer
keywords: heat diffusion; nanostructures; optical pump; surface deformation; ultrafast X-ray diffraction