Freiburg 2024 – scientific programme
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A: Fachverband Atomphysik
A 33: Poster VI
A 33.4: Poster
Thursday, March 14, 2024, 17:00–19:00, Tent A
Coherent control of electron emission direction in helium with ω-2ω SASE FEL pulses — •Muwaffaq Ali Mourtada1, Harijyoti Mandal1, Alexander Magunia1, Weiyu Zhang1, Yu He1, Hannes Lindenblatt1, Florian Trost1, Lina Hedewig1, Cristian Medina1, Arikta Saha1, Marc Rebholz1, Ulrike Frühling2, Carlo Kleine1, Gergana D. Borisova1, Steffen Palutke2, Evgeny Schneidmiller2, Mikhail Yurkov2, Stefan Düsterer2, Rolf Treusch2, Chris H. Greene3, Yimeng Wang3, Robert Moshammer1, Christian Ott1, and Thomas Pfeifer1 — 1Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — 2Deutsches Elektronen Synchrotron DESY, 22607 Hamburg, Germany — 3Purdue University, West Lafayette, IN 47907, USA
Measurements of the photoelectron angular distribution of two-photon single-ionisation in the vicinity of singly excited intermediate states in helium are presented. Using extreme-ultraviolet pulses generated at the high-repetition-rate free-electron laser in Hamburg (FLASH), helium atoms are ionized and the recoil ion momenta are measured with a reaction microscope. In a previous experiment [1], first indications for interfering pathways between FEL fundamental and its second harmonic have been observed. Here we present new measurements to further investigate the possibility of directional asymmetry in the photoelectron angular distribution of interfering one-photon and two-photon single ionization in helium. In this poster we will discuss the ongoing data analysis and show first results.
[1] Straub et al., PRL 129, 183204 (2022)
Keywords: Single- and double-photon ionization & excitation; Coherent control; Free-electron laser (FEL)