Abstract
Two XUV-photon double ionization of Kr and Ar by an intense superposition of higher-order harmonics of a Ti:sapphire laser is demonstrated. The logarithm of the and signals measured as a function of the logarithm of the XUV intensity depicts a linear dependence with a slope of . Under the XUV intensities and photon energies employed, this slope value provides evidence that to the observed double ionization the direct process has a significant contribution. Applications of the above process to attosecond pulse metrology are also discussed.
- Received 7 September 2006
DOI:https://doi.org/10.1103/PhysRevA.74.051402
©2006 American Physical Society