Stuttgart 2012 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 10: Interaction with strong or short laser pulses II
A 10.4: Vortrag
Montag, 12. März 2012, 17:15–17:30, V55.01
Higher order Kerr terms vs. plasma: Saturation of the nonlinear refractive index — •Christian Köhler1, Roland Guichard2, Emmanuel Lorin3, Szczepan Chelkowski4, André D. Bandrauk4, Luc Bergé5, and Stefan Skupin1,6 — 1Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany — 2CNRS, UMR 7614, LCPMR, 75231 Paris Cedex 05, France — 3University of Montréal, Montréal (Québec) H3T 1J4, Canada — 4Département de chimie, Université de Sherbrooke, Sherbrooke (Québec) J1K 2R1, Canada — 5CEA-DAM, DIF, F-91297 Arpajon, France — 6Friedrich-Schiller-University, Institute of Condensed Matter Theory and Solid State Optics, 07743 Jena, Germany
We numerically study the susceptibility of atomic hydrogen and several noble gases in a strong laser field. The susceptibility enters the laser pulse propagation equation via the effective refractive index, whose nonlinear part is found to saturate for intensities where the medium is partially ionized. This saturation can be due to either negatively-valued higher order Kerr terms [1] or plasma contributions [2]. In order to clarify the mechanism of saturation, we calculate the electronic dipole from numerical solutions of the time dependent Schrödinger equation. This non-perturbative method allows us to separate the optical responses from bound electrons and ionized contributions, and to clearly identify the mechanism responsible for saturation.
[1] V. Loriot et al., Opt. Express 17, 13429 (2009).
[2] L. Bergé et al., Reports on Progress in Physics 70, 1633 (2007).