SAMOP 2021 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 6: Atomic systems in external fields
A 6.2: Poster
Dienstag, 21. September 2021, 16:30–18:30, P
Coherent control mechanisms in bichromatic multiphoton ionization — •Lea-Christin Feld, Kevin Eickhoff, Darius Köhnke, Lars Englert, Tim Bayer, and Matthias Wollenhaupt — Carl von Ossietzky Universität, Oldenburg, Deutschland
We study two basic physical mechanisms underlying the coherent control of atomic multiphoton ionization (MPI) with bichromatic polarization-shaped femtosecond laser pulses, termed interband and intraband interference. The simultaneous measurement of energetically separated photoelectrons from both mechanisms in a single photoelectron momentum distribution (PMD) allows to compare the corresponding phase and polarization control of the angular distributions. Experimentally, we combine bichromatic polarization pulse shaping of a carrier-envelope phase-stable supercontinua with photoelectron tomography. The controllability of the PMD is investigated in three scenarios. First, counterrotating circularly polarized pulses are employed to contrast phase-insensitive angular momentum eigenstates created by intraband interference with a phase-sensitive c7 rotationally symmetric free electron vortex (FEV) from pure interband interference. Second, orthogonal linearly polarized pulses are used to compare the phase-independence of a six-lobed angular momentum wave packet from intraband interference to the sensitivity of a complex shaped interband PMD in the presence of phase fluctuations. Finally, we demonstrate phase control of a photoelectron hologram from mixed interband interference. The azimuthal rotation of the hologram maps the time evolution of the bound state wave packet, allowing for FEV spectroscopy.