Mainz 2017 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 6: Time-resolved spectroscopy
A 6.5: Vortrag
Montag, 6. März 2017, 18:30–18:45, HS 20
Two-electron dynamics in Helium driven by intense XUV radiation — •Lennart Aufleger1, Thomas Ding1, Marc Rebholz1, Maximilian Hartmann1, Alexander Magunia1, David Wachs1, Veit Stooß1, Paul Birk1, Gergana Borisova1, Andrew Attar2, Thomas Gaumnitz3, Zhi Heng Loh4, Stefan Düsterer5, Christian Ott1, and Thomas Pfeifer1 — 1MPI für Kernphysik, Heidelberg, Germany — 2UC Berkeley, Berkeley, USA — 3ETHZ, Zürich, Switzerland — 4NTU Singapore, Singapore — 5DESY, Hamburg, Germany
The measurement of laser-induced strong-field dynamics in few-electron systems provides a way to investigate their correlated nature. Using a lab-based HHG source we have studied such correlations that are imprinted on the XUV absorption line shape and investigated them by modification with strong fields in the near infrared and visible (VIS) spectral region. [C. Ott et al., Science 340, 716 (2013)]. Here, we present an extension of the strong-field modification scheme to the XUV-only spectral region. Using intense and partially coherent light of a FEL source (FLASH@DESY), the transition into the doubly-excited state 2s2p in Helium at 60.15 eV was driven. This excitation scenario represents a most basic two level system with a cooperative excitation of two electrons. The variation of pulse intensities between 1012 W/cm2 and 1014 W/cm2 induces a change in the experimentally observed XUV absorption line shape. A transformation from a Fano to a Lorentzian line shape is also confirmed by few-level simulations that were carried out.