This research focus is devoted to ultrafast and nonlinear processes in atoms, molecules, clusters and plasmas induced by short laser pulses. It covers a broad range of intensities from ultra-strong fields where the external field is the dominant interaction down to light-matter interaction at perturbative field strengths.

Few-particle interactions are typically investigated with novel spectroscopic methods yielding comprehensive kinematical information, and allowing for detailed comparison with elaborate theories. The detailed understanding of few-particle and plasma dynamics in ultrafast and strong laser pulses has proven to be one of the keys to novel applications in nonlinear optics.

Fundamental processes in strong fields presently focus on multi-electron dynamics and correlations in atoms, molecules and clusters, including multiple ionisation, harmonic generation and strong field reaction control. Processes in ultra-strong fields focus on relativistic effects in multi-electron ionisation of atoms and ions, and on relativistic plasma dynamics including the generation and application of laser accelerated protons (proton imaging) and coherent EUV radiation (“X-ray lasers, XRL”)