Experimental work concentrates on the investigation of excitation and ionization processes at light intensities between 10¹⁴ W/cm² and 10²⁰ W/cm². It focuses on the significance and the manifestations of electron-electron correlation, the influence of relativistic effects on multiple ionization and on the manipulation of multiple ionization processes via laser pulse characteristics. In particular, few-cycle pulses with stabilized carrier-envelope phase and defined state of polarization are applied as well as two-color pulses, which typically consist of an (intense) infrared laser pulse with an ultrashort high-order harmonic superimposed. The latter can be timed with respect to the former. The physics is dominated by the interplay between tunneling processes, free electron motion and electron-ion collisions in the presence of time-dependent external fields. Furthermore, part of the research is devoted to the investigation of excitation and acceleration of neutral atomic particles in strong laser fields. Finally, one subproject is focused on the interaction between correlated electron dynamics in tightly bound inner shells and relativistic laser fields.

Theoretical work concentrates on the description of intense-laser atom processes in terms of an “S-matrix” together with the "strong-field approximation". As applications, single and multiple ionization of atoms and molecules are considered, at intensities reaching up into the relativistic regime. The whole gamut of theoretical methods is applied to devise suitable schemes for time dependent molecular imaging.

 

Subprojects