title: High-energy cutoff in the spectrum of strong-field nonsequential double ionization.
abstract: Electron energy distributions of singly and doubly ionized helium in an intense 390 nm laser field have been measured at two intensities (0.8 PW/cm2 and 1.1 PW/cm2, where PW is defined as 10(15) W/cm2). Numerical solutions of the full-dimensional time-dependent helium Schrödinger equation show excellent agreement with the experimental measurements. The high-energy portion of the two-electron energy distributions reveals an unexpected 5U(p) cutoff for the double ionization (DI) process and leads to a proposed model for DI below the quasiclassical threshold.
authors.affiliation: DAMTP, Queen's University Belfast, Belfast, BT7 1NN, United Kingdom.
authors.forename: J S
authors.initials: JS
authors.lastname: Parker
authors.forename: B J S
authors.initials: BJ
authors.lastname: Doherty
authors.forename: K T
authors.initials: KT
authors.lastname: Taylor
authors.forename: K D
authors.initials: KD
authors.lastname: Schultz
authors.forename: C I
authors.initials: CI
authors.lastname: Blaga
authors.forename: L F
authors.initials: LF
authors.lastname: DiMauro