A5041681954- Laser-Plasma Interactions and Diagnostics
- High-pressure geophysics and materials
- Advanced X-ray Imaging Techniques
- Ion-surface interactions and analysis
- Laser-Matter Interactions and Applications
- Laser Material Processing Techniques
- Photorefractive and Nonlinear Optics
- Laser-induced spectroscopy and plasma
- X-ray Spectroscopy and Fluorescence Analysis
- Spectroscopy and Quantum Chemical Studies
- nanoparticles nucleation surface interactions
- Material Dynamics and Properties
- Nuclear Physics and Applications
- Phase-change materials and chalcogenides
- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Glass properties and applications
- Magnetism in coordination complexes
- Ultrasonics and Acoustic Wave Propagation
- Phase Equilibria and Thermodynamics
- Magnetic properties of thin films
- Geomagnetism and Paleomagnetism Studies
- Force Microscopy Techniques and Applications
- Chalcogenide Semiconductor Thin Films
- Theoretical and Computational Physics
University of Duisburg-Essen
2006-2020
University of Cologne
2009-2013
Coherent (United States)
2007
University of Michigan–Ann Arbor
2007
Emerald Coast Science Center
2007
Stanford Synchrotron Radiation Lightsource
2007
SLAC National Accelerator Laboratory
2007
Argonne National Laboratory
2007
Intense femtosecond laser excitation can produce transient states of matter that would otherwise be inaccessible to laboratory investigation. At high densities, the interatomic forces bind solids and determine many their properties substantially altered. Here, we present detailed mapping carrier densityâdependent potential bismuth approaching a solid-solid phase transition. Our experiments combine stroboscopic techniques use high-brightness linear electron acceleratorâbased x-ray source...
Structural switch for fast switching Phase-change materials are important computer memory. They can quickly from glassy to crystalline using a thermal pulse and then lock in that structure long time at lower temperature. Zalden et al. probed the underlying atomic of two phase-change during this ultrafast x-rays simulations (see Perspective by Rao ). A liquid-liquid phase transition both allowed high temperatures. The lower-temperature glass locks structure, allowing long-term memory storage....
We show that light drives large-amplitude structural changes in thin films of the prototypical ferroelectric ${\mathrm{PbTiO}}_{3}$ via direct coupling to its intrinsic photovoltaic response. Using time-resolved x-ray scattering visualize atomic displacements on femtosecond time scales, photoinduced unit-cell tetragonality are observed. These driven by motion photogenerated free charges within and can be simply explained a model including both shift screening currents, associated with...
We apply time-resolved x-ray diffraction using ultrashort pulses from a laser-produced plasma to probe the picosecond acoustic response of thin laser-heated gold film. Measurements temporal changes in angular distribution diffracted x-rays provide direct quantitative information on transient evolution lattice strain. This allows disentangle electronic and thermal pressure contributions driving expansion after impulsive laser excitation. The electron-lattice energy equilibration time...
Femtosecond time-resolved small and wide angle x-ray diffuse scattering techniques are applied to investigate the ultrafast nucleation processes that occur during ablation process in semiconducting materials. Following intense optical excitation, a transient liquid state of high compressibility characterized by large-amplitude density fluctuations is observed buildup these measured real time. Small-angle measurements reveal snapshots spontaneous nanoscale voids within metastable support...
We investigate the generation of ultrashort Kalpha pulses from plasmas produced by intense femtosecond p-polarized laser on Copper and Titanium targets. Particular attention is given to interplay between angle incidence beam target a controlled prepulse. It observed experimentally that yield can be optimized for correspondingly different prepulse plasma scale-length conditions. For steep electron-density gradients, maximum yields achieved at larger angles. somewhat expanded expected in case...
We present a time-resolved absorption study on the light-induced generation of reversible linkage NO isomers in single crystals Na2[Fe(CN)5NO]·2H2O using laser pulses 160 fs width. Using pump wavelength λ = 500 nm singlet–singlet 1A1 → 1E excitation induces rotation by about 90° from linear Fe–N–O configuration to side-on Fe<NO. The formation isomer is monoexponential with characteristic time τ 300(20) and proceeds along diabatic potential surface without occupation further intermediate...
We present a setup for time-resolved X-ray diffraction based on short pulse, laser-driven plasma source. The employed modular design provides high flexibility to adapt the specific requirements (e.g., optics and sample environment) of particular applications. configuration discussed here has been optimized toward angular/momentum resolution uses Kα-radiation (4.51 keV) from Ti wire-target in combination with toroidally bent crystal collection, monochromatization, focusing emitted radiation....
We present a table-top setup for femtosecond time-resolved x-ray diffraction based on Cu Kα (8.05 keV) laser driven plasma source. Due to its modular design, it provides high accessibility individual components (e.g., optics and sample environment). The Kα-yield of the source is optimized using pre-pulse scheme. A magnifying multilayer mirror with Montel–Helios geometry used collect emitted radiation, resulting in quasi-collimated flux more than 105 photons/pulse impinging under...
In the last few years, bent crystal x-ray mirrors have played an important role in time-resolved diffraction experiments when pulses from femtosecond laserproduced plasmas were used. Improvements manufacturing techniques significantly increased quality of this type mirror.
The transient acoustic response of a free-standing, polycrystalline thin Au-film upon femtosecond optical excitation has been studied by time-resolved Debye–Scherrer x-ray diffraction using ultrashort Cu Kα pulses from laser-driven plasma source. temporal strain evolution determined the shifts multiple Bragg peaks. experimental data are in good agreement with results calculations based on two-temperature model and an assuming uniaxial propagation laser-excited film.
An elliptical glass capillary has been used to focus ultrashort Cu K alpha x-ray pulses emitted from a femtosecond laser-produced plasma. Due its high magnification (7x), the optic transforms divergent emission of plasma into quasicollimated beam with divergence only 0.18 degrees. As an application we demonstrate possibility perform Debye-Scherrer diffraction experiments simultaneous detection several orders. This will allow one extend time-resolved laser-plasma sources much wider range...
Time-resolved diffuse X-ray scattering with 50 fs, 9.5 keV pulses from the Linear Coherent Light Source was used to study structural dynamics in materials undergoing rapid melting and ablation after fs laser excitation.
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation U. Shymanovich, M. Nicoul, W. Lu, A. Tarasevitch, Kammler, Horn von Hoegen, D. der Linde, K. Sokolowski‐Tinten; Coherent acoustic optical phonons in laser‐excited solids studied by ultrafast time‐resolved X‐ray diffraction. AIP Conference Proceedings 8 October 2010; 1278 (1): 558–566....
Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text K. Sokolowski-Tinten, U. Shymanovich, M. Nicoul, J. Blums, A. Tarasevitch, Horn-von-Hoegen, D. von der Linde, Morak, and T. Wietler, "Energy relaxation anomalies in the thermo-acoustic response of femtosecond laser-excited Germanium," 15th International Conference Ultrafast Phenomena, OSA Technical Digest Series (CD) (Optica Publishing Group, 2006), paper MG5. Export...
We present a table-top setup for femtosecond time-resolved X-ray diffraction based on Cu K{\alpha} (8.05 keV) laser driven plasma source. Due to its modular design it provides high accessibility individual components (e.g. optics and sample environment). The K{\alpha}-yield of the source is optimized using pre-pulse scheme. A magnifying multilayer mirror with Montel-Helios geometry used collect emitted radiation, resulting in quasi-collimated flux more than 105 photons/pulse impinging under...