2 Ultrafast and Nonlinear Phenomena: Atoms, Molecules, and Clusters

This research area is the home of MBI´s attosecond science program. This research targets the elucidation of time-resolved electron dynamics and coupled electron-nuclear dynamics, in particular using novel tools resulting from recent concentrated efforts in OPCPA development. Novel attosecond experiments performed at high repetition rate permit coincident detection of all electrons and ions formed in an attosecond XUV-IR or IR-XUV pump-probe sequence, providing unprecedented opportunities to investigate the roles of entanglement, electron correlation and the coupling of electronic and nuclear degrees of freedom on attosecond to few-femtosecond time scales. The availability of attosecond pulses at high intensity will permit the development of attosecond XUV pump-attosecond XUV probe spectroscopy, as well as the use of coherent diffractive imaging as a probe of attosecond dynamics in mesoscopic systems. Close collaboration between theory and experiment opens further avenues, prominent examples being studies of the attosecond electron dynamics underlying high-harmonic generation in solids and the generation of attosecond spin-polarized electron pulses using intense light fields for attosecond spectroscopy of spin-dependent hole dynamics in atoms and molecules.

MBI´s attosecond science program is complemented by a number of research activities made possible by the exploitation of attosecond/high-harmonic generation technology, including time-resolved XUV/soft X-ray photoelectron spectroscopy, as well as experiments pursuing XUV/soft X-ray coherent diffractive imaging and transient absorption on femtosecond time scales, with the latter having strong links to research activities in topical area 3. In addition to the predominantly XUV/soft X-ray based research lines, strong field ionization is investigated as a topic of fundamental interest and as a tool for the development of novel probes of time-resolved molecular dynamics (strong field photoelectron holography and time-resolved electron diffraction).