High-contrast pump-probe spectroscopy with high-order harmonicsY. Mairesse1, W. Boutu2, P. Breger2, E. Constant1, D. Descamps1, N. Dudovich3, B. Fabre1, S. Haessler2, J. Higuet1, E. Mével1, S. Petit1, P. Salières2, D.M. Villeneuve4 and P.B. Corkum4
1 CELIA, Université Bordeaux I, UMR 5107 (CNRS, Bordeaux 1, CEA), 351 cours de la Libération, 33405 Talence Cedex, France
2 CEA-Saclay, DSM, Service des Photons, Atomes et Molécules, 91191 Gif-sur-Yvette, France
3 Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
4 Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
Published online: 7 July 2009
The high order harmonic generation process from molecules can be used to probe the structure of the emitting medium with high spatial resolution [1, 2]. The measurements of molecular dynamics with such a probe is thus very appealing. Contrast is an important issue in pump probe spectroscopy: in general the probe only excites part of the molecules, so that the detected signal can be dominated by contributions from non-excited molecules. In this article we review two techniques that can be used to enhance the contrast of pump probe measurements: transient grating spectroscopy and polarization-resolved spectroscopy. We use these techniques to detect rotational wavepackets and demonstrate a dramatic improvement in the contrast of the measured signal.
© EDP Sciences 2009