Hannover 2020 – scientific programme
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A: Fachverband Atomphysik
A 9: Poster Session - Atomic Physics I
A 9.6: Poster
Monday, March 9, 2020, 16:00–18:00, Empore Lichthof
Control of free electron wave packets by polarization-tailored ultrashort bichromatic laser fields — Stefanie Kerbstadt1,2, Kevin Eickhoff1, •Lea-Christin Feld1, Tim Bayer1, 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
We use polarization-shaped bichromatic laser pulses to control three-dimensional photoelectron momentum distributions from atomic multiphoton ionization. To analyze the underlying physical mechanisms, we consider two bichromatic control schemes based on intra-pulse frequency mixing and inter-band N- vs. M-photon interference, respectively. In the first scheme, interferometric (ω:2ω) fields are used to select or suppress specific ionization channels in the resonance-enhanced two-photon ionization of potassium atoms by second-order intra-pulse frequency mixing. In the second scheme, we utilize a white light polarization pulse shaper to generate carrier-envelope phase-stable (3ω:4ω ) fields in order to manipulate the symmetry properties of photoelectron wave packets from 3- vs. 4-photon ionization of sodium atoms. In both cases, bichromatic polarization control of free electron wave packets is based on the creation of a superposition of multiple angular momentum states with different kinetic energy spectra. We show that the latter are determined by the bichromatic multiphoton spectra, emphasizing the close relationship between bichromatic multiphoton ionization and nonlinear optical spectroscopy.