Angle-resolved photoemission spectroscopy (ARPES)—an experimental technique based
on the photoelectric effect—is arguably the most powerful method for probing the electronic …

X-ray free-electron lasers (x-ray FELs) give us for the first time the possibility to explore
structures and dynamical processes of atomic and molecular systems at the angstrom …

We report the first generation of coherent, tunable, variable-polarization, soft X-ray
femtosecond pulses, generated by a seeded free-electron laser (FEL) operating in the fresh …

Four-wave mixing (FWM) processes, based on third-order nonlinear light–matter
interactions, can combine ultrafast time resolution with energy and wavevector selectivity …

FERMI is a seeded free-electron laser (FEL) facility located at the Elettra laboratory in
Trieste, Italy, and is now in user operation with its first FEL line, FEL-1, covering the …

The two single-pass, externally seeded free-electron lasers (FELs) of the FERMI user facility
are designed around Apple-II-type undulators that can operate at arbitrary polarization in the …

X-ray free-electron lasers (FELs) produce femtosecond x-ray pulses with unprecedented
intensities that are uniquely suited for studying many phenomena in atomic, molecular, and …

The significant progress in angle-resolved photoemission spectroscopy (ARPES) in last
three decades has elevated it from a traditional band mapping tool to a precise probe of …

Exploring the dynamics of matter driven to extreme non-equilibrium states by an intense
ultrashort X-ray pulse is becoming reality, thanks to the advent of free-electron laser …

The first steps in photochemical processes, such as photosynthesis or animal vision, involve
changes in electronic and geometric structure on extremely short time scales. Time-resolved …