Peculiarities of the Ionization of Many-Electron Systems and Generation of Attosecond Pulses in Ultrashort Laser Fields

摘要

The ionization of a model two-electron atom in the field of a strong ultrashort laser pulse is studied by numerical integration of the nonstationary Schrodinger equation describing the dynamics of a quantum system in the field of an electromagnetic wave. Peculiarities of the two-electron ionization are analyzed for pulses whose duration amounts to one to two periods of oscillation of the electric field of the wave at different frequencies of the incident radiation. For extremely short pulses, the double ionization is found to be suppressed. This effect is caused by the finiteness of the interelectron energy exchange time during the laser action. Peculiarities of the generation of high-order harmonics and single XUV attosecond pulses upon ionization of atoms by laser pulses, whose duration is within one to two optical cycles, are investigated.