Recoil-Ion momentum distributions for single and double ionization of helium in strong laser fields

Phys Rev Lett. 2000 Jan 17;84(3):443-6. doi: 10.1103/PhysRevLett.84.443.

Abstract

We have measured the momentum distributions of singly and doubly charged helium ions created in the focus of 220 fs, 800 nm laser pulses at intensities of (2.9-6.6)x10(14) W/cm(2). All ions are emitted strongly aligned along the direction of polarization of the light. We find the typical momenta of the He2+ ions to be 5-10 times larger than those of the He1+ ions and a two peak structure at the highest intensity.