Noisy pulses enhance temporal resolution in pump-probe spectroscopy

• Published in: arXiv.org
• Main Authors: Meyer, Kristina, Ott, Christian, Raith, Philipp, Kaldun, Andreas, Jiang, Yuhai, Senftleben, Arne, Kurka, Moritz, Moshammer, Robert, Ullrich, Joachim, Pfeifer, Thomas
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 24.01.2012
• Subjects: Coherent light; Deuterium; Free electron lasers; Molecular ions; Physics - Atomic and Molecular Clusters; Physics - Optics; Pulse duration; Spectroscopic analysis; Spectrum analysis; Temporal resolution; Variation
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1110.5536

Time-resolved measurements of quantum dynamics are based on the availability of controlled events (e.g. pump and probe pulses) that are shorter in duration than the typical evolution time scale of the dynamical processes to be observed. Here we introduce the concept of noise-enhanced pump-probe spectroscopy, allowing the measurement of dynamics significantly shorter than the average pulse duration by exploiting randomly varying, partially coherent light fields consisting of bunched colored noise. It is shown that statistically fluctuating fields can be superior by more than a factor of 10 to frequency-stabilized fields, with important implications for time-resolved pump-probe experiments at x-ray free-electron lasers (FELs) and, in general, for measurements at the frontiers of temporal resolution (e.g. attosecond spectroscopy). As an example application, the concept is used to explain the recent experimental observation of vibrational wave packet motion in a deuterium molecular ion on time scales shorter than the average pulse duration.