E. Wells, I. Ben-Itzhak, and R.R. Jones
Abstract:Ionization of atoms by the spatial gradient of the pondermotive potential in a focussed laser beam is investigated. Rydberg ions, formed during the interaction of noble gas atoms with an intense laser pulse, are used to probe the gradient-field. Rydberg ion species with higher ionization potentials are produced at locations where the gradient-field is largest. The measured Rydberg ion yields differ dramatically from estimates that ignore gradient-field ionization, but are in good agreement with predictions that include the effect.
Status: Published Phys. Rev. Lett. 93 023001 (2004).