Eur. Phys. J. D 33, 307-311 (2005)
https://doi.org/10.1140/epjd/e2005-00049-1

Coherent control calculations for helium atom in short and intensive XUV laser pulses

Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria

Corresponding author: ^a barna@concord.itp.tuwien.ac.at

Received: 24 September 2004
Revised: 17 March 2005
Published online: 26 April 2005

Abstract

Coherent control calculations are presented for helium. With the help of a genetic algorithm (GA) phase-modulated extreme ultra violet (XUV) laser pulses were controlled to maximize or minimize the non-resonant two-photon excitation. Linearly polarized laser pulses were chosen at the frequency of 0.4 a.u. with a duration of about 15 fs and 10¹⁴ Wcm^-2 peak intensity. We verified the theory that an antisymmetric spectral phase around the two-photon resonance frequency maximizes the transition probability. Dark pulses which do not excite the system at all have however symmetric spectral phases around the two-photon resonance frequency.