Ionization of atoms by short laser pulses: Resonance and interference effects

Dynamics of the interactions of atoms with intense electromagnetic fields is considered. The theory of ionization and excitation of atoms by the short laser pulses is developed on the basis of the close-coupling approach for solving the time-dependent Schrodinger equation. Studies of the interactions of atoms with intense electromagnetic fields require the use all the continuous states of the system, without discretezation of the continuum. The systematic investigations have been done in the case of femtosecond laser pulses with linear and circular polarization, for the different values of the laser frequency, intensity and duration times. Interactions of the intermediate discrete states with the continuum (bound-free transitions) are found to be very important for structures of the energy spectra of the ejected electrons. It is shown that these bound-free transitions give the larger contributions than the rescattering process (free-free transitions) at the medium energies of the ejected electrons. The resonance and interference structures in populations of the discrete and continuum atomic states are displayed as functions of the laser pulse parameters in the case of the H-atoms and H-like ions.