Datensatz

Zusammenfassung

The electron dynamics in the classically forbidden region during relativistic tunnel-ionization process is investigated. The classical forbidden region in the relativistic regime is identified by defining a gauge invariant total energy operator. Introducing position dependent energy levels inside the tunneling barrier, we demonstrate that the relativistic tunnel-ionization can be well described by a one-dimensional intuitive picture. This picture predicts that, in contrast to the well-known nonrelativisitic regime, the ionized electron wave packet in the relativistic regime arises with a momentum shift along the laser propagation direction. This is compatible with results from a strong field approximation calculation where the binding potential is assumed to be zero-range. Further, the tunneling time delay, stemming from Wigner's definition, is investigated for model configurations of tunneling and compared with results obtained from the exact propagator. By adapting Wigner's time delay definition the tunneling time is investigated in the deep-tunneling and in the near-threshold-tunneling regimes. It is shown that while in the deep-tunneling regime signatures of the tunneling time delay are not measurable at remote distance, it is detectable, however, in the latter regime.