Precision measurement of strong field double ionization of helium
The production of He+ and He2+ by a 160 fs, 780 nm laser has been measured over an unprecedented 12 orders of magnitude in counting range. Enhanced double electron emission, called nonsequential (NS) ionization, was observed over an intensity range where the single ionization dynamics is evolving from multiphoton to pure tunneling. The NS yield is found to scale with the ac-tunneling rate for the neutral, even when tunneling is not the dominant ionization pathway. A rescattering mechanism fails to predict the observed NS threshold or magnitude. © 1994 The American Physical Society.
Publication Source (Journal or Book title)
Physical Review Letters
Walker, B., Sheehy, B., Dimauro, L., Agostini, P., Schafer, K., & Kulander, K. (1994). Precision measurement of strong field double ionization of helium. Physical Review Letters, 73 (9), 1227-1230. https://doi.org/10.1103/PhysRevLett.73.1227