Heidelberg 2015 – scientific programme

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A: Fachverband Atomphysik

A 28: Poster: Interaction with VUV and X-ray light II

A 28.12: Poster

Wednesday, March 25, 2015, 17:00–19:00, C/Foyer

Coulomb-THz-Field-Coupling Induced Time Shifts in Atomic Photoemission — •Georg Schmid¹, Kirsten Schnorr¹, Sven Augustin¹, Jakob Kunz¹, Arne Senftleben^1,9, Shaofeng Zhang¹, Artem Rudenko³, Matthias Kübel⁴, Lutz Foucar⁸, Michael Gensch⁵, Yuhai H. Jiang⁶, Joachim Ullrich⁷, Alaa Al-Shemmary², Torsten Golz², Nikola Stojanovic², Claus-Dieter Schröter¹, Thomas Pfeifer¹, and Robert Moshammer¹ — ¹MPI für Kernphysik, Heidelberg — ²DESY, Hamburg — ³Kansas State University, Manhattan, KS — ⁴MPI für Quantenoptik, Garching — ⁵HZDR, Dresden — ⁶SARI, Shanghai — ⁷PTB, Braunschweig — ⁸MPI für medizinische Forschung, Heidelberg — ⁹Universität Kassel

XUV pump - THz probe experiments were carried out at the free-electron laser in Hamburg. At a photon energy of 59.4 eV, neon 2p, 2s and valence shake-up photoelectrons (PEs) were emitted into a THz probe field of 152 um. Using a reaction microscope, the 3-dim PE momentum vectors were measured as a function of the pump-probe delay. By tracing the delay-dependent streaking spectrograms, a relative time shift in the emission of valence shake-up PEs and direct 2p PEs was observed. In the framework of attosecond streaking, it was shown that so-called Coulomb-laser-coupling leads to measurement-induced time shifts in addtion to the quantum mechanical EWS time shift. It is predicted that low-energetic PEs are strongly effected by the combined action of Coulomb and long-wave THz field. By selecting shake-up PEs with energies < 1 eV, we experimentally confirm Coulomb-laser-coupling time shifts in the range of low PE energies.