Observation of nonsequential double ionization of helium with optical tunneling
Abstract
We have measured the ion yields for helium ionized by 120 fs, 614 nm laser pulses for intensities near 1016 W/cm2. We have found that for these ultrashort pulses the He+2 data exhibit a feature which saturates in parallel with the He+ signal indicating that the ionization may proceed nonsequentially. We propose a new mechanism, which can exist only in the tunneling regime, for such nonsequential ionization.
- Publication:
-
Physical Review Letters
- Pub Date:
- November 1992
- DOI:
- Bibcode:
- 1992PhRvL..69.2642F
- Keywords:
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- 32.80.Rm;
- 32.90.+a;
- 42.50.Hz;
- Multiphoton ionization and excitation to highly excited states;
- Other topics in atomic properties and interactions of atoms with photons;
- Strong-field excitation of optical transitions in quantum systems;
- multiphoton processes;
- dynamic Stark shift