Various atomic and molecular processes in strong laser fields are reviewed with emphasis on high-order above-threshold ionization (ATI) and high-order harmonic generation (HHG). The probability of high-order processes is maximal for linear polarization and decreases with the increase of the laser field ellipticity. An exception is the bicircular field which consists of two coplanar counterrotating circularly polarized fields of different frequencies. This field has recently become a hot topic because the generated high harmonics are circularly polarized and can be used to study chiral molecules, magnetic materials, etc. We show some of our recent results for atomic and molecular ATI and HHG by bicircular field. We will also explain common features of different high-order atomic processes, using the following sequence of theoretical methods: S-matrix formalism, strong-field approximation (SFA), and quantum-orbit theory. It will be shown how two different approximative methods, SFA and semiclassical approximation, can be derived from the path integral formalism.

Seminarraum HI-Jena, Fröbelstieg 3
Datum (Start der Veranstaltung)