Kübel, M.Betsch, K. J.Kling, Nora G.Alnaser, A. S.Schmidt, J.Kleineberg, U.Deng, Y.Ben-Itzhak, ItzikPaulus, G. G.Pfeifer, T.Ullrich, J.Moshammer, R.Kling, M. F.Bergues, B.2014-05-062014-05-062014-03-05http://hdl.handle.net/2097/17687The transition from the near-single to the multi-cycle regime in non-sequential double ionization of argon is investigated experimentally. Argon atoms are exposed to intense laser pulses with a center wavelength around 790 nm and the momenta of electrons and ions generated in the double ionization process are measured in coincidence using a reaction microscope. The duration of the near transform-limited pulses is varied from 4 to 30 fs. We observe an abrupt collapse of the cross-shaped two-electron momentum distribution [17] in the few-cycle regime. The transition to longer pulses is further accompanied by a strong increase in the fraction of anti-correlated to correlated electrons.en-USAttribution 3.0 Unported (CC BY 3.0)Non-sequential double ionizationCoincidence spectroscopyStrong field physicsArticle (publisher version)