Correlated two-electron momentum spectra for strong-field nonsequential double ionization of He at 800 nm

Phys Rev Lett. 2007 Dec 31;99(26):263003. doi: 10.1103/PhysRevLett.99.263003. Epub 2007 Dec 28.

Abstract

We report on a kinematically complete experiment on nonsequential double ionization of He by 25 fs 800 nm laser pulses at 1.5 PW/cm;{2}. The suppression of the recollision-induced excitation at this high intensity allows us to address in a clean way direct (e,2e) ionization by the recolliding electron. In contrast with earlier experimental results, but in agreement with various theoretical predictions, the two-electron momentum distributions along the laser polarization axis exhibit a pronounced V-shaped structure, which can be explained by the role of Coulomb repulsion and typical (e,2e) kinematics.