Optimization of high-order harmonic generation in laser-driven atomic and molecular systems

When an atom or a molecule is subject to a strong laser pulse a recollision-recombination mechanism gives rise to the emission of high-order harmonic radiation containing frequency multiples of the irradiating laser field. This radiation is nowadays the basis for the highly active research field of attosecond physics. The laser magnetic field is responsible for the drift of ejected electron wave packets in the laser propagation direction. In the context of the first project of this thesis, it has been found that the harmonic radiation which is induced by this drift motion can be sensitively influenced by means of an additional relatively weak static magnetic field. In the second project, a novel mechanism is proposed which combines the drift in the laser propagation direction with the properties of antisymmetric orbitals. In a regime of high laser intensities, efficient high-order harmonic generation is proven to be possible without the common limitations due to the drift in the laser propagation direction. From a different viewpoint, it has been shown for the first time that this drift leads to an increase in harmonic intensity. The main results have been obtained by numerical integration of the time-dependent Schr¨odinger equation