We have performed nonperturbative time-dependent calculations of single and double ionization of atomic calcium by short and intense laser pulses using a two-active-electron model. It is shown that the significant enhancement of the [Formula Presented] yield observed in a recent experiment [E. Papastathopulous, M. Strehle, and G. Gerber (unpublished)] using feedback control techniques originates from the time asymmetry of the pulse shape. Numerical simulations have been performed for various asymmetrical pulses. The initial part of the pulse prepares a coherent superposition of excited states which is transferred into the double-electron continuum at later times. An asymmetric shape, with a slowly decreasing tail, therefore favors the production of [Formula Presented] Single-active-electron calculations have also been performed to demonstrate the significant role played by electron correlations and by doubly excited states.
|Original language||English (US)|
|Number of pages||1|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|State||Published - Jan 1 2002|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics