Identification and application of quantum trajectories in above-threshold ionization

We discuss two recent photoionization experiments with atoms in intense laser fields: First we study the dependence of photoelectron spectra on the intensity of the laser pulse. In a second experiment a photoelectron spectrum for elliptical polarization is discussed. With a quantum mechanical model the contribution of specific electron trajectories to the photoelectron spectra can be analyzed. In the presented cases, trajectories with long travel times are of significant importance. Despite of the distinctive quantum nature of the effects, some key features can be explained by classical electron trajectories.