Heidelberg 2015 – wissenschaftliches Programm
A 11.5: Poster
Montag, 23. März 2015, 17:00–19:00, C/Foyer
Microscopic description of single-shot diffractive imaging of atomic clusters — •Katharina Sander, Christian Peltz, and Thomas Fennel — Institute of Physics, University of Rostock
The availability of intense femtosecond laser pulses in the XUV and soft x-ray spectral range from free-electron lasers has made it possible to investigate the structure and dynamics of nanosystems via single-shot diffractive imaging experiments, as recently demonstrated with single clusters . To study the linear light scattering in clusters theoretically we employ the discrete dipole approximation (DDA) . The DDA method relies on a dyadic Greens function approach and allows to model arbitrarily shaped targets down to the atomic level. We propose a modified complex mixing scheme to increase convergence of the iterative DDA model. As a first application, we examine the possibility of imaging the recently predicted IR induced nonlinear internal plasma waves in clusters . Our analysis supports that distinct features of the sub-fs dynamics can be extracted from time-resolved scattering pictures. Second, we investigate the scattering of strongly absorbing silver clusters. A comparison with experimental results highlights the necessity to include absorption, which is neglected in the regularly applied treatment of x-ray scattering (Born approximation). Finally, we analyze the limits for the applicability of the single-frequency approximation in the modelling of scattering images.
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