Ultrafast Momentum Spectroscopy in Strong-Field and XUV Single-Photon Ionization

by Robert Boge (ETH Zurich Switzerland)

Friday 14 Nov 2014, 15:30 → 16:30 Europe/Berlin

222.EG.013 (DESY Hamburg)

Electron dynamics occurring during the photo-ionization of noble gases are studied in order to answer the fundamental question of how fast light can remove an electron from an atom. First the dynamics in strong-field ionization are investigated, followed by the dynamics in single-photon ionization. These two ionization channels are of fundamentally different nature: in strong-field ionization, when the electric field of the laser is sufficiently strong to bend the binding potential of the ion, it creates a barrier through which the valence electron might tunnel into the continuum. In a more figurative picture one could see the electron as being ripped out of the atom by the laser field, whereas during single-photon ionization the electron is promoted into the continuum via the absorption of a single photon of sufficiently high energy. It will be shown that the dynamics of the electron while tunneling can be addressed through the interaction of the electron with the remaining parent ion and the still present laser field during propagation in the continuum, while in single-photon ionization it is exactly this interaction that leads to the observed delay in photoemission.