Multi-channel electronic and vibrational dynamics in polyatomic resonant high-order harmonic generation

A. Ferré (1) , A. E. Boguslavskiy (2) , M. Dagan (3) , Valérie Blanchet (1) , B. D. Bruner (3) , F. Burgy (1) , A. Camper (4) , D. Descamps (1) , B. Fabre (1) , N. Fedorov (1) , J. Gaudin (1) , G. Geoffroy (1) , J. Mikosch (2, 5) , S. Patchkovskii (2, 5) , S. Petit (1) , T. Ruchon (4, 6) , H. Soifer (3) , David Staedter (7) , I. Wilkinson (2) , A. Stolow (2, 8) , N. Dudovich (3) , Y. Mairesse (1)

1 CELIA - Centre d'Etudes Lasers Intenses et Applications
2 NRC - National Research Council of Canada
3 Department of Physics of Complex System
4 LIDyl - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
5 MBI - Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie
6 ATTO - Attophysique
7 Femto (LCAR)
8 Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, Canada KIN 6N5

High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence of resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present a multi-modal approach for the investigation of unaligned polyatomic molecules, using ​SF6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology. Fragment-resolved above-threshold ionization measurements reveal that strong-field ionization opens at least three channels. A shape resonance in one of them is found to dominate the signal in the 20–26 eV range. This resonance induces a phase jump in the harmonic emission, a switch in the polarization state and different dynamical responses to molecular vibrations. This study demonstrates a method for extending high-harmonic spectroscopy to polyatomic molecules, where complex attosecond dynamics are expected.

Domains: Physics [physics]; Physics [physics]; Optics [physics.optics]

A. Ferré, A. E. Boguslavskiy, M. Dagan, Valérie Blanchet, B. D. Bruner, et al.. Multi-channel electronic and vibrational dynamics in polyatomic resonant high-order harmonic generation. Nature Communications, 2015, 6, pp.5952. ⟨10.1038/ncomms6952⟩. ⟨cea-01244391⟩