TY  - JOUR
A1  - Zeuschner, S. P.
A1  - Mattern, M.
A1  - Pudell, Jan-Etienne
A1  - von Reppert, A.
A1  - Rössle, M.
A1  - Leitenberger, Wolfram
A1  - Schwarzkopf, J.
A1  - Boschker, J. E.
A1  - Herzog, Marc
A1  - Bargheer, Matias
T1  - Reciprocal space slicing
BT  - a time-efficient approach to femtosecond x-ray diffraction
JF  - Structural Dynamics
N2  - An experimental technique that allows faster assessment of out-of-plane strain dynamics of thin film heterostructures via x-ray diffraction is presented. In contrast to conventional high-speed reciprocal space-mapping setups, our approach reduces the measurement time drastically due to a fixed measurement geometry with a position-sensitive detector. This means that neither the incident (ω) nor the exit (2θ) diffraction angle is scanned during the strain assessment via x-ray diffraction. Shifts of diffraction peaks on the fixed x-ray area detector originate from an out-of-plane strain within the sample. Quantitative strain assessment requires the determination of a factor relating the observed shift to the change in the reciprocal lattice vector. The factor depends only on the widths of the peak along certain directions in reciprocal space, the diffraction angle of the studied reflection, and the resolution of the instrumental setup. We provide a full theoretical explanation and exemplify the concept with picosecond strain dynamics of a thin layer of NbO2.
Y1  - 0202
U6  - https://doi.org/10.1063/4.0000040
SN  - 2329-7778
VL  - 8
PB  - AIP Publishing LLC
CY  - Melville, NY
ER  - 
TY  - JOUR
A1  - Sander, Mathias
A1  - Herzog, Marc
A1  - Pudell, Jan-Etienne
A1  - Bargheer, Matias
A1  - Weinkauf, N.
A1  - Pedersen, M.
A1  - Newby, G.
A1  - Sellmann, J.
A1  - Schwarzkopf, J.
A1  - Besse, V.
A1  - Temnov, V. V.
A1  - Gaal, P.
T1  - Spatiotemporal Coherent Control of Thermal Excitations in Solids
JF  - Physical review letters
N2  - X-ray reflectivity measurements of femtosecond laser-induced transient gratings (TG) are applied to demonstrate the spatiotemporal coherent control of thermally induced surface deformations on ultrafast time scales. Using grazing incidence x-ray diffraction we unambiguously measure the amplitude of transient surface deformations with sub-angstrom resolution. Understanding the dynamics of femtosecond TG excitations in terms of superposition of acoustic and thermal gratings makes it possible to develop new ways of coherent control in x-ray diffraction experiments. Being the dominant source of TG signal, the long-living thermal grating with spatial period. can be canceled by a second, time-delayed TG excitation shifted by Lambda/2. The ultimate speed limits of such an ultrafast x-ray shutter are inferred from the detailed analysis of thermal and acoustic dynamics in TG experiments.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevLett.119.075901
SN  - 0031-9007
SN  - 1079-7114
VL  - 119
SP  - 102
EP  - 110
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Sander, Mathias
A1  - Koc, A.
A1  - Kwamen, C. T.
A1  - Michaels, H.
A1  - von Reppert, Alexander
A1  - Pudell, Jan-Etienne
A1  - Zamponi, Flavio
A1  - Bargheer, Matias
A1  - Sellmann, J.
A1  - Schwarzkopf, J.
A1  - Gaal, P.
T1  - Characterization of an ultrafast Bragg-Switch for shortening hard x-ray pulses
JF  - Journal of applied physics
N2  - We present a nanostructured device that functions as photoacoustic hard x-ray switch. The device is triggered by femtosecond laser pulses and allows for temporal gating of hard x-rays on picosecond (ps) timescales. It may be used for pulse picking or even pulse shortening in 3rd generation synchrotron sources. Previous approaches mainly suffered from insufficient switching contrasts due to excitation-induced thermal distortions. We present a new approach where thermal distortions are spatially separated from the functional switching layers in the structure. Our measurements yield a switching contrast of 14, which is sufficient for efficient hard x-ray pulse shortening. The optimized structure also allows for utilizing the switch at high repetition rates of up to 208 kHz. Published by AIP Publishing.
Y1  - 2016
U6  - https://doi.org/10.1063/1.4967835
SN  - 0021-8979
SN  - 1089-7550
VL  - 120
PB  - American Institute of Physics
CY  - Melville
ER  -