Hannover 2013 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 22: Poster: Interaction with strong or short laser pulses
A 22.11: Poster
Dienstag, 19. März 2013, 16:00–18:30, Empore Lichthof
High-resolution electron momentum spectra for single ionization of atoms in strong laser fields for various wavelengths — •Lutz Fechner1, Nicolas Camus1, Andreas Krupp1, Thomas Pfeifer1, Joachim Ullrich1,2, and Robert Moshammer1 — 1Max-Planck-Institut für Kernphysik, Heidelberg — 2Physikalisch-Technische Bundesanstalt, Braunschweig
Using a Reaction Microscope we studied single ionization of noble-gas atoms and small molecules in femtosecond laser pulses over a large range of intensities and wavelengths. By means of an optical parametric amplifier (OPA) that is pumped by 25 fs laser pulses (at 800 nm) we generate intense pulses (>1013 W/cm2) with central wavelengths covering the range from 350 to 1300 nm. First results show unexpected and pronounced target specific features in the momentum distributions especially in the low energy region (up to 0.5 eV). The appearance of these "low-energy-rings" can be attributed to the decay highly excited states, which are populated during the laser pulse and autoionize long after. As a next step, and to further probe the dynamics of highly excited electronic states, we intend to perform two-color pump-probe experiments using the variable wavelength output of the OPA as a pump and the 800 nm pulse as probe (cf. poster A 159).