Science with strong laser fields: the Keldysh tunneling time and the photoelectron circular dichroism
Date | Mo, 18.11.2013 | |
Time | 16:45 | |
Speaker | Prof. Manfred Lein, Institut für Theoretische Physik, Leibnitz Universität Hannover, Hannover, Germany | |
Location | ETH Zurich, Hönggerberg Campus, HPF G-6 | |
Program | The Keldysh tunneling time is a concept that can be thought of as an indicator for the degree of nonadiabaticity in laser-induced tunneling ionization. We describe a method to retrieve this tunneling time from measureable two-color high-harmonic generation spectra, similar to the analysis used in the recent experiment by Shafir et al. [Nature 2012]. We apply the method to our data obtained from the numerical solution of the 3D time-dependent Schrödinger equation for a He atom. The retrieved tunneling time is in good agreement with the Keldysh formula evaluated at the instantaneous ionizing field strength. On the application side of strong-field science, we present a theory of the circular dichroism observed in the photoelectron momentum distributions from multiphoton ionization of chiral molecules. The forward-backward asymmetry of the electron emission from camphor and fenchone is compared to recent experimental data by Lux et al. [Angew. Chem. Int. Ed. 2012]. Host: Ursula Keller, Ultrafast Laser Physics, IQE |
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Link | Mafred Lein, Leibnitz Universität |