Joel Venzke

Coherent control with a short-wavelength free-electron laser

Researchers demonstrate correlation of two colours (63.0 and 31.5 nm wavelengths) in a free-electron laser and control photoelectron angular distribution by adjusting phase with 3 attosecond resolution.

Photoelectron angular distribution in bichromatic atomic ionization

Theoretical aspects of photoelectron angular distributions are discussed with reference to bichromatic ionization by an FEL beam. Specifically, we consider an asymmetry in the angular distribution due to interference between the ionization paths from the fundamental and the second harmonic. The case of circularly polarized radiation is analyzed in detail in the vicinity of an intermediate resonance in the two-photon ionization paths. Similarities and differences to interference phenomena due to non-dipole effects are also discussed.

Pulse-shape effects in strong-field atomic ionization by an XUV pulse

Achieving a significant displacement, defined as a time integral of the vector potential taken over the pulse duration, in strong-field atomic ionization critically depends on the envelope function used for the electric field. Due to the sensitivity of theoretical predictions to the pulse details, an experimental realization of the effect appears to be a major challenge.