AMO science at the FLASH and European XFEL free-electron laser facilities

Present performance and future development of the free-electron lasers (FELs) in Hamburg—FLASH for the extreme ultraviolet and the European XFEL for the soft and hard x-ray regimes—are presented. As an illustration of the unprecedented characteristics of these sources a few recent examples of experiments performed in the area of atomic, molecular and optical (AMO) physics are described. The results highlight in particular the available high photon intensities, the short pulse durations and the coherence of the FEL beam. Nonlinear processes involving for the first time inner-shell electrons, time-resolved experiments on the few femtosecond timescales, and imaging experiments on small particles have been the focus of these studies, demonstrating the unique potential of short-wavelength FELs and pointing to numerous exciting future opportunities. (invited paper)