Welcome to the extreme timescales group
Attosecond spectroscopy was first extended to condensed matter systems in 2007. In this demonstration, approximately 300 attosecond, isolated XUV pulses were used to achieve sub-100-attosecond time resolution, allowing the relative escape times of photo-emitted electrons through a metal surface to be measured. While these first experiments focused on the observation of the elementary photoemission process, this result also established a route to probing stimulated and controlled dynamics in condensed-matter systems on extreme timescales.
Within the MPSD, our goal is to extend these techniques to study correlated electron systems, which exhibit dynamics on the few-femtosecond to attosecond timescale. In the future, the full spectrum of electro-magnetic radiation, from THz frequencies to hard, kilovolt x-rays will be required to fully explore these complex systems through time-resolved optical pump-probe, photoemission, absorption spectroscopy, soft x-ray scattering and hard x-ray diffraction experiments. These experiments will be performed with time-resolution dictated by the bandwidth, or timescale, of the dynamics at hand, allowing us to unravel the interplay between electronic and structural dynamics. This complex behavior is the basis for such interesting physical phenomena as, for example, superconductivity or giant magnetoresistance. Ultimately, our goal is to control these phenomena in new ways and with increased precision.
Investigation of condensed matter systems across the full range of photon energies and timescales, however, is currently not feasible due to the lack of a light source that can meet these demands. To bridge the gap, our group is working to develop suitable sources along two distinct routes. On the tabletop, we are pursuing the use and advancement of attosecond XUV laser systems based on high-harmonic generation. While at large-scale user facilities, we are working to harness the temporal resolution and flexibility of accelerator-based free-electron lasers.
Independent Research Group Leader: Adrian L. Cavalieri