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A: Fachverband Atomphysik
A 17: Interaction with Strong or Short Laser Pulses II (joint session A/MO)
A 17.1: Hauptvortrag
Mittwoch, 8. März 2023, 14:30–15:00, F107
Adiabatic properties of the bicircular attoclock — •Paul Winter and Manfred Lein — Leibniz University Hannover
If the right field-strength ratio between a circularly polarized laser pulse and its counter-rotating second harmonic is chosen, one can create a quasilinear electric field in the temporal vicinity of the maximal field. In contrast to conventional linear polarization, rescattering is avoided and a detailed study of direct ionization in strong fields is possible.
The well-defined direction of the field at the ionization time enables us to investigate orientation dependencies in the ionization of molecules in a controlled manner. As our main observables, the ionization yield and the orientation-dependent attoclock shift (i.e. the potential-induced shift of the peak of the electron momentum distribution) are obtained by solving the two-dimensional time-dependent Schrödinger equation for HeH+ and H2.
In the regime of small Keldysh parameter γ=√2Ipω/E≪ 1, ionization can be described by two-step models, in which the electron travels classically after tunneling out. A crucial factor in these adiabatic models (and hence for the predicted attoshift) is the location of the exit point, which is sensitive to molecular properties such as the dipole moment and the polarizability of the ionized orbital.