Stuttgart 2012 – scientific programme

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A: Fachverband Atomphysik

A 12: Interaction with strong or short laser pulses III

A 12.3: Talk

Tuesday, March 13, 2012, 11:15–11:30, V47.03

Noisy pulses enhance temporal resolution in pump–probe spectroscopy — •Kristina Meyer, Christian Ott, Philipp Raith, Andreas Kaldun, Yuhai Jiang, Arne Senftleben, Moritz Kurka, Robert Moshammer, Joachim Ullrich, and Thomas Pfeifer — Max-Planck Institut für Kernphysik, Heidelberg

Observing dynamical processes relies on the availability of timing-controlled events (e.g. laser pulses) that are shorter in duration than the typical time scale of the dynamics to be measured. The production of ultra-short pulses is nowadays typically based on the exceptional coherence properties of laser light, hiding the fact that noisy, only partially coherent, light sources could have benefits. The development of Free-Electron Laser (FEL) sources has led to a reevaluation of temporal noise since self-amplified spontaneous emission (SASE) FEL pulse shapes vary widely from shot to shot. Here, we show that such noisy electric fields can be used to resolve temporal features of quantum dynamics with high precision that would be inaccessible using fully coherent pulses of the same average pulse duration. Our concept of noise-enhanced pump–probe spectroscopy is demonstrated for the example of a recently performed experiment investigating the two-photon double ionization of D₂ [1]. The method enables the measurement of dynamics on time scales that are shorter than the average pulse duration by more than a factor of 10. This finding does not only have important consequences for FEL science, but can lead to general paradigm shifts in ultrafast physics, including attosecond spectroscopy.

[1] Y. H. Jiang et al., Phys. Rev. A 81, 051402 (2010)