Linear accelerator-based free-electron lasers (FELs) are the leading source of fully coherent
X-rays with ultra-high peak powers and ultra-short pulse lengths. Current X-ray FEL facilities …

Free-electron lasers and high-harmonic-generation table-top systems are new sources of
extreme-ultraviolet to hard X-ray photons, providing ultrashort pulses that are intense …

The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-
energy superconducting linear accelerator. The superconducting technology allows for the …

We prepared bulk samples of supercooled liquid water under pressure by isochoric heating
of high-density amorphous ice to temperatures of 205±10 kelvin, using an infrared …

We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that
recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very …

The quantum-mechanical motion of electrons in molecules and solids occurs on the sub-
femtosecond timescale. Consequently, the study of ultrafast electronic phenomena requires …

Recent experiments continue to find evidence for a liquid-liquid phase transition (LLPT) in
supercooled water, which would unify our understanding of the anomalous properties of …

High-resolution X-ray spectroscopy in the sub-nanosecond to femtosecond time range
requires ultrashort X-ray pulses and a spectral X-ray flux considerably larger than that …

X-ray free-electron lasers (FELs) are state-of-the-art scientific tools capable to study matter
on the scale of atomic processes. Since the initial operation of X-ray FELs more than a …

A self-seeded X-ray free-electron laser (XFEL) is a promising approach to realize bright, fully
coherent free-electron laser (FEL) sources in the hard X-ray domain that have been a long …