UVX 2008 (2009) 107-111
DOI: 10.1051/uvx/2009017

High-contrast pump-probe spectroscopy with high-order harmonics

Y. 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. Corkum<sup>4

1</sup>  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

Abstract
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