Université Paul Sabatier - Bat. 3R1b4 - 118 route de Narbonne 31062 Toulouse Cedex 09, France


Accueil > Événements > Séminaires 2011

Coherent control of ultrafast electron dynamics

Matthias Wollenhaupt, Universität Kassel, Institut für Physik und CINSaT, Kassel, Germany

(Salle de séminaire Bat. 3R1b4 3e étage)

The ability to generate ultrashort laser pulses of controllable shape, instantaneous frequency and polarization with sub-attosecond precision has made it possible to precisely manipulate the dynamics of quantum systems. Effective control of electron dynamics implies large population transfer rates, i.e. non-perturbative interactions, and control of three dimensional light-matter interactions. In this talk, both aspects of controlling ultrafast electron dynamics are discussed.

In the first experiment, control of three-dimensional free electron wave packets from Resonance Enhanced Multiphoton Ionization (REMPI) of potassium atoms is achieved by polarization-shaped laser pulses combined with direct 3d tomographic reconstruction based on measurements of Photoelectron Angular Distributions (PADs) [1,2].

In the second experiment we discuss strong-field control of the bound electron dynamics on molecules. In a two-color energy resolved photoelectron spectroscopy experiment, the first pulse serves to prepare an electronic wave packet. An intense second pulse, the phase of which is tailored to the electronic wave packet oscillation [3], guides the system towards a preselected target channel.

Finally, recent measurements of PADs on chiral molecules are presented. In these experiments, we investigate the Circular Dichroism in the photo-ionization of chiral molecules. Asymmetric PADs resulting from REMPI of R- and S-camphor are observed using left- and right-handed circularly polarized femtosecond laser pulses.

References

[1] M. Wollenhaupt et al., Appl.Phys. B 95, 245 (2009).

[2] M. Wollenhaupt et al., Appl.Phys. B 95, 647 (2009).

[3] T. Bayer et al., Phys.Rev.Lett. 102, 023004-1 (2009).