Heidelberg 2015 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 16: Posters 3: Novelties in Molecular Physics

MO 16.5: Poster

Mittwoch, 25. März 2015, 17:00–19:00, C/Foyer

Pump-Probe Photo-Ionization Experiments in a Collinear Phase Modulation Scheme — •Marcel Binz, Lukas Bruder, Daniel Uhl, Marcel Mudrich, Aaron LaForge, and Frank Stienkemeier — Physikalisches Institut, Universität Freiburg, Germany

Due to the low target densities in molecular beam experiments, coherent fs spectroscopy of these systems has remained a challenging task. Within this context, we are investigating a phase-modulation technique established by Marcus et al. [1]. In this fs pump-probe scheme, the signal to noise ratio is greatly improved by combining continuous acousto-optical phase modulation with lock-in detection. One drawback of this method is its requirement of a high repetition rate laser system to sufficiently sample the modulation frequency.

Using a 80MHz Ti:Sa oscillator, we have so far applied this scheme to investigating alkali metals by means of fluorescence detection in a vapor cell as well as photo electron and mass resolved photo ion detection in a molecular and a doped helium droplet beam. The implementation of this method into a 5kHz repetition rate laser system is discussed in view of applications to even lower repetition rate lasers.

[1] P. F. Tekavec, T. R. Dyke, and A. H. Marcus, J. Chem. Phys. 125, 194303 (2006).