Visualization of short laser pulse ionization and dissociation processes

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Nearly all previous experimental studies on the intense-field induced dynamic response of atoms and molecules suffer from the fact that signals are collected from all over the focal volume, so that important input parameters of the experiment such as intensity, time profile and phase of the radiation field are not well-defined. Particularly in short laser pulse interaction, it cannot be excluded that the distribution of the intensity of a laser focus is influenced by a complicate dependency of spatial time/pulse/laser-frequency distributions in the focus region due to a distortion of the laser wavefront or the influence of dispersive optical elements. This general problem can be solved with a new generation of time-of-flight mass spectrometer which offers the ability to record the ion yield of a well defined volume outside of the focus regime, where the laser intensity is nearly constant. This will allow us to measure the ion yield and the intensity distribution at focus as well as the pulse length/intensity/wavelength dependence form short pulse laser ionization processes.  Secondly, we want to use an electron - imaging spectrometer to understand a possible influence of Rydberg states on the ionization process. The measurement of the wavelength dependency will be completed with the search for non-linear inner shell ionization processes in atoms.