ausblenden:
Schlagwörter:
Physics, Atomic Physics, physics.atom-ph,Quantum Physics, quant-ph
MPINP:
Research group K. Z. Hatsagortsyan – Division C. H. Keitel
Zusammenfassung:
Tunneling ionization is characterized by a negative time delay, observed asymptotically as a specific shift of the photoelectron momentum distribution, which is caused by the interference of the sub-barrier recolliding and direct
ionization paths. In contrast, a \textit{Gedankenexperiment} following the peak
of the wavefunction shows a positive tunneling time delay at the tunnel exit,
considering only the direct ionization path. In this paper, we investigate the
effects of sub-barrier recollisions on the time delay pattern at the tunnel
exit. We conclude that the interference of the direct and recolliding
trajectories decreases the tunneling time delay at the exit by the value equal
to the asymptotic time delay maintaining, however, its sizeable positive value.
Finally, we discuss the recent experiment [Light: Science \& Applications 11, 1
(2022)] addressing the tunneling time in a modified two-color attoclock setup.
The analysis of the experimental findings with our theoretical model indicates
the physical necessity to introduce a new time characteristic for tunneling
ionization -- the time delay describing the initiation of the tunneling wave
packet.
