Hannover 2013 – scientific programme

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MO: Fachverband Molekülphysik

MO 14: Poster 1: Cluster, Femtosecond Spectroscopy

MO 14.13: Poster

Tuesday, March 19, 2013, 16:00–18:30, Empore Lichthof

Wave Packet Interferometry at Potassium Atoms Applying a Band-pass Filtering Technique — •Lukas Bruder, Sabrina Lipps, and Frank Stienkemeier — Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany

The achievements in generating ultra-short laser pulses have opened opportunities for studying wave packet dynamics in quantum systems. However, experiments for demonstrating coherent dynamics of electronic states are often very sensitive to laboratory noise. Especially controlling the relative phase of the temporal envelopes in a coherent fs-pulse train remains a difficult task. In our collinear pump-probe setup we investigate electronic wave packet interference of atomic potassium. On the basis of [1], we greatly reduce the influence of laboratory noise applying a band-pass filtering technique: Acousto-optical phase modulation imparts a characteristic signature on the fluorescence signal that is demodulated using a lock-in amplifier. Simultaneous acquisition of in-phase and in-quadrature components yields the full phase information. This technique leads to a strongly undersampled quantum beating of the coherences and greatly reduces the scaling of laboratory noise. These characteristics are great advantages in view of a setup for 2D-spectroscopy. [1] P. F. Tekavec, T. R. Dyke, and A. H. Marcus, J. Chem. Phys. 125, 194303 (2006).