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 …

Intense attosecond X-ray pulses are key for ultrafast nonlinear spectroscopy and diffractive
imaging. Here we demonstrate the generation of terawatt-scale isolated attosecond pulses …

Pump–probe experiments with subfemtosecond resolution are the key to understanding
electronic dynamics in quantum systems. Here we demonstrate the generation and control …

We demonstrate the generation of coherent soft x-ray free-electron laser (FEL) pulses with a
duration below 1 fs using nonlinear compression with a low-charge electron beam (10 pC) …

X-ray free-electron lasers (FELs) are modern research tools with applications in multiple
scientific fields. Standard x-ray FEL pulses are produced by the self-amplified spontaneous …

We present the generation of x-ray pulses with average pulse energies up to one millijoule
and rms pulse durations down to the femtosecond level. We have produced these intense …

The identification of the decay pathway of the nucleobase uracil after being photoexcited by
ultraviolet light has been a long-standing problem. Various theoretical models have been …

We investigate entangled x-ray photon pair emissions in a free-electron laser (FEL) and
establish a quantum electrodynamical theory for coherently amplified entangled photon pair …

Time-resolved diagnostics are fundamental for x-ray free-electron lasers (FELs). Radio-
frequency (RF) transverse deflector structures (TDSs) are typically employed to characterize …

Photoinjectors and Free Electron Lasers (FEL) are amongst the most advanced systems in
accelerator physics and have consistently pushed the boundaries of emittance and x-ray …