TY  - JOUR
A1  - Reinhardt, Matthias
A1  - Koc, Azize
A1  - Leitenberger, Wolfram
A1  - Gaal, Peter
A1  - Bargheer, Matias
T1  - Optimized spatial overlap in optical pump-X-ray probe experiments with high repetition rate using laser-induced surface distortions
JF  - Journal of synchrotron radiation
N2  - 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.
KW  - ultrafast X-ray diffraction
KW  - nanostructures
KW  - surface deformation
KW  - heat diffusion
KW  - optical pump
Y1  - 2016
U6  - https://doi.org/10.1107/S1600577515024443
SN  - 1600-5775
VL  - 23
SP  - 474
EP  - 479
PB  - International Union of Crystallography
CY  - Chester
ER  - 
TY  - JOUR
A1  - Gaal, Peter
A1  - Schick, Daniel
A1  - Herzog, Marc
A1  - Bojahr, Andre
A1  - Shayduk, Roman
A1  - Goldshteyn, Jevgeni
A1  - Leitenberger, Wolfram
A1  - Vrejoiu, Ionela
A1  - Khakhulin, Dmitry
A1  - Wulff, Michael
A1  - Bargheer, Matias
T1  - Ultrafast switching of hard X-rays
JF  - Journal of synchrotron radiation
N2  - A new concept for shortening hard X-ray pulses emitted from a third-generation synchrotron source down to few picoseconds is presented. The device, called the PicoSwitch, exploits the dynamics of coherent acoustic phonons in a photo-excited thin film. A characterization of the structure demonstrates switching times of <= 5 ps and a peak reflectivity of similar to 10(-3). The device is tested in a real synchrotron-based pump-probe experiment and reveals features of coherent phonon propagation in a second thin film sample, thus demonstrating the potential to significantly improve the temporal resolution at existing synchrotron facilities.
KW  - ultrafast X-ray diffraction
KW  - thin film
KW  - coherent phonons
KW  - X-ray switching
KW  - pulse shortening
KW  - optical pump X-ray probe
KW  - time-resolved
Y1  - 2014
U6  - https://doi.org/10.1107/S1600577513031949
SN  - 0909-0495
SN  - 1600-5775
VL  - 21
SP  - 380
EP  - 385
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -