Momentum mapping of multi-electron strong-field ionization dynamics with fully controlled light wave forms

01.01.2010 - 31.12.2013
Forschungsförderungsprojekt

Chemical events are generally perceived as a bond breaking and bond creation which proceed on time-scales ranging from tens of femtoseconds to microseconds. These processes, however, are preceded and ultimately determined by much faster processes ¿ intra-molecular electron dynamics ¿ that occur on an attosecond time-scale. The broader goal of this project is to apply the methods of Attophysics to the study of electronic processes in atoms and molecules to bridge the gap between the conventional understanding of ¿slow¿ chemistry and the underlying much faster electronic dynamics. To gain access to the dynamics of the chemically-relevant outer shell electrons in our project we will detect the emerging charged particles. Our approach is based on the powerful apparatus for cold target recoil ion momentum spectroscopy (COLTRIMS) ¿ recently constructed and tested in the Vienna lab ¿ which is capable of measuring three-dimensional momentum vectors of the electrons and ions originating from the interaction of a single atom/molecule with a strong laser field. Information on attosecond dynamics can be retrieved from the measured momentum spectra of the electrons or ions, provided their emission is linked to a suitably fast reference process such as the oscillations of the electric field in a strong laser pulse, which can modulate the measured spectra on a sub-femtosecond time-scale. The aim of the proposed project is to study correlated multi-electron ionization dynamics in atoms and (dissociating) molecules. The complexity of tracing attosecond electron dynamics dramatically scales with the number of the electrons that need to be resolved. To gain the extra degrees of freedom required to manipulate a complex multi-electron system, we will drive the COLTRIMS experiment with fully controlled two-color polarization- and phase-encoded strong laser fields synthesized with a carrier-envelope phase (CEP) stabilized Ti:sapphire laser setup in our lab. By combining these two advanced techniques ¿ particle momentum mapping and controllable strong laser field shaping ¿ we strive to observe the internal electron dynamics that lead to the ionization event. The proposed project will consist of two main research routes: (1) Multi-electron recollision-free strong-field ionization dynamics, and (2) attosecond time-space-energy mapping of recollision induced impact ionization dynamics. The first route focuses on time-resolving the process of detachment of several electrons in strong circularly polarized laser pulses. By temporally restricting the process of multi-electron ionization to a single laser oscillation period we can map the direction of electron emission to their instant of emission and at the same time investigate the transition from uncorrelated (sequential) emission to a possibly correlated manner. The second route is dedicated to the temporally resolved measurement of strongly correlated double ionization dynamics initiated by the impact of an electron that was driven back to the parent ion by the strong laser field. By temporally and spatially shaping the trajectories of the recolliding wave packets in two spatial dimensions we can in addition to the well known time-energy mapping inherent to electron recollision establish a mapping between time and space and thus extract significantly more information about the process.

Personen

Projektleiter_in

Projektmitarbeiter_innen

Institut

Grant funds

  • FWF - Österr. Wissenschaftsfonds (National) Stand-Alone Project Austrian Science Fund (FWF)

Forschungsschwerpunkte

  • Photonics: 80%
  • Quantum many-body systems: 20%

Schlagwörter

DeutschEnglisch
Attosekunden Zeitauflösungattosecond time resolution
Ultrakurze Laserpulseultrafast lasers
Ionisation in starken Laserfeldernstrong-field ionization
Impulsspektroskopiemomentum spectroscopy
Interatomare/-molekulare Elektronendynamikintra-atomic/molecular electron dynamics

Publikationen