Collection 

Free-Electron Lasers

Photon sources, such as table-top lasers, synchrotron X-rays and free-electron lasers (FELs), can be used to explore and understand the structure of materials through photon-matter interactions.  Short wavelength and coherent photons generated, when relativistic electrons travel through undulator, from FELs are tunable and compressible to few femtosecond pulses to take snapshots of structures in order to study the time-dependent interactions and dynamics of different materials. These facilities are becoming increasingly popular in diverse research fields, because of their tunability and high spatial and temporal resolution.

In this collection, we showcase recent articles published in Nature Communications on FEL generation and characterization and their application in fundamental studies of light-matter interaction. These research papers include FEL instrumentation and techniques, investigations on photoionization and ultrafast processes in atomic and molecular physics, chemical and physical properties of condensed matter systems, and probing of structure and dynamics of biological samples. This collection highlights the increasingly significant role FELs are having on research across a diverse range of subject areas and Nature Communications’ role as a suitable platform in publishing such multidisciplinary works.