Strongly directed electron emission in non-sequential double ionization of Ne by intense laser pulses

Double ionization of Ne by 25 fs, 1.0 PW cm(-2) laser pulses has been explored in a kinematically complete experiment using a 'reaction microscope'. Electrons are found to be emitted into a narrow cone along the laser polarization (s), much more confined than for single ionization, with a broad maximum in their energy distribution along s. Correlated momentum spectra show both electrons being ejected into the same hemisphere, in sharp contrast to predictions based on field-free (e, 2e) recollision dynamics, but in overall agreement with recent semiclassical calculations for He.