Ultrafast Dynamics

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.