Multi-photon ionization of lithium

A systematic study of multi-photon ionization (MPI) of atomic lithium in ultra-short and intense near-infrared laser pulses has been conducted both experimentally and theoretically. The cross section was measured for intensities spanning across the transition from MPI to over-the-barrier ionization (OBI). It turns out that this transition manifests itself in a substantial change in the photo-electron angular distributions. In a second study pump-probe experiments exciting bound wave packets and probing their time evolution by ionization were performed.