Joint Research Group
Our joint resarch group from University of Potsdam and HZB studies structural dynamics in condensed matter on ultrafast time scales. The principal experimental method is Ultrafast X-Ray Diffraction (UXRD). At the XPP/KMC3-Beamline, we can resolve atomic motion in a solid with a temporal resolution of 10-100 picoseconds.The upgraded beamline provides focused x-rays with 1011 photons/s in a 150 micrometer spot. A high-power ultrafast laser allows for pump-probe experiments at repetition rates between 200 kHz and 1.25 MHz, e.g. by providing a laser pulse for each x-ray pulse in the single bunch mode.
Complementary UXRD experiments with higher temporal resolution are conducted at the Plasma X-ray Source (PXS) at the University of Potsdam. At HZB we have investigated manifold processes such as heat diffusion, the propagation and the decay of coherent phonons, nonlinear phonon-phonon interactions and phase transitions in complex materials. With the higher photon flux and tuneable x-ray wavelength resonant probes will be tested soon. We can also combine the ultrafast x-ray probe with x-ray absorption spectroscopy. We employ nanostructured samples that allow for a selective excitation and probing. In addition to UXRD experiments, optical experiments are realized in the Laser Lab, e.g. optical pump-probe experiments using our home-built non-collinear parametric amplifier (NOPA) setup.