Hannover 2020 – scientific programme
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A: Fachverband Atomphysik
A 9: Poster Session - Atomic Physics I
A 9.7: Poster
Monday, March 9, 2020, 16:00–18:00, Empore Lichthof
Spatial phase modulation of electron beams meets spectral interference of electron wave packets — •Darius Köhnke1, Christopher Rathje1, Kevin Eickhoff1, Stefanie Kerbstadt1,2, Tim Bayer1, Sascha Schäfer1, and Matthias Wollenhaupt1 — 1Carl von Ossietzky Universität Oldenburg, Institut für Physik, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg — 2Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Hamburg
Recently, vortex beams have attracted significant attention. We compare the generation and manipulation of tailored free electron vortices via atomic multiphoton ionization (MPI) by polarization-shaped ultrashort laser pulses on the one and transmission electron microscopy (TEM) with customized diffraction masks (Verbeeck et al., Nature 467, 301-304 (2010)) on the other hand, focussing here on the creation of free electron vortices with c7 rotational symmetry (Kerbstadt et al. Nat. Comm. 10, 658 (2019)). Photoelectron vortices are generated by MPI of Na atoms using counterrotating bichromatic (3ω:4ω) laser pulses created by a white light polarization shaper. The electron vortex beams are generated in a TEM using Au masks on a SiN substrate. Although ultrafast polarization shaping is performed in frequency domain while electron beam shaping operates in momentum space, the two techniques are strongly related. Important analogies and differences are discussed. In addition, we analyze the topological charge of the tailored free electron vortices and investigate the respective capabilities of the different technical approaches.