UVX 2008 (2009) 65-70
DOI: 10.1051/uvx/2009011

Measuring the complex recombination dipole of aligned CO₂ molecules in high-order harmonic generation

S. Haessler¹, W. Boutu¹, H. Merdji¹, P. Breger¹, R. Taïeb^{2, 3}, J. Caillat^{2, 3}, A. Maquet^{2, 3}, P. Monchicourt¹, B. Carré¹ and P. Salières<sup>1

1</sup>  CEA Saclay, IRAMIS, Service des Photons, Atomes et Molécules, 91191 Gif-sur-Yvette, France
²  UMPC Univ. Paris 06, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France
³  CNRS, UMR 7614, LCPMR, 75005 Paris, France

Published online: 7 July 2009

Abstract
We generate high order harmonics in aligned CO₂ molecules and measure the spectral amplitudes and phases as a function of the alignment angle. We control the quantum interference occurring in the recombination of an ultrafast laser-driven electron wavepacket with the highest occupied molecular orbital of CO₂. By comparing to the emission of the reference system krypton, we obtain an experimental measure of the complex recombination dipole matrix element between the CO₂ HOMO and a continuum state. The measured phase jump contains signatures of Coulombic wavepacket distortion.

© EDP Sciences 2009