The Physics department colloquia are usually on Friday afternoons at 3:30 pm in Lapham Hall Room 160. Coffee and cookies are served at 3:15 pm in the same room. Anyone is welcome.

Research with Free-Electron Lasers: New horizons for ultrafast X-ray sciences
Dr. Christoph Bostedt Argonne National Laboratory, Dept. of Physics & Astronomy/Northwestern Univ.

Free electron lasers are a new class of X-ray sources that deliver extremely intense, coherent X-ray flashes with femtosecond pulse length. The unprecedented brightness of these X-ray lasers opens the door for imaging transient states of matter and non-linear spectroscopy approaches for core-level states.

After an introduction to free-electron lasers, I will present selected science examples enabled by these sources. Imaging of individual superfluid helium nanodroplets allows the unambiguous identification of quantum vortices. Ultrafast scattering of highly excited nanoplasmas carries information about their transient electronic states. The combination of optical with X-ray lasers allows the investigation of dynamically evolving systems with femtosecond time and nanometer spatial resolution.

I will end my talk with an outlook on where I see the field heading in the next years and what exciting opportunities can be envisioned.