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Free-electron lasers create coherent light by constantly accelerating a beam of electrons. Free-electron lasers are particularly useful because they can produce radiation with a short-wavelength, down to just a few tenths of a nanometre. Thus, it is hoped they will become an important tool for atom-level material characterization.
Researchers have demonstrated the generation and control of subfemtosecond pulse pairs from a two-colour X-ray free-electron laser and conducted pump–probe experiments in core-ionized molecules.
Researchers focused hard X-rays from a free-electron laser down to transverse dimensions of ~7 nm × 7 nm, enabling a two-order increase in intensity of photons and yielding access to the elusive 1022 W cm−2 regime. Such intense, short-wavelength electromagnetic radiation may probe atomic, molecular and optical physics with extremely high resolution.
While MHz repetition rates at modern X-ray free-electron laser (XFEL) facilities achieve remarkable capabilities for imaging, the high repetition rates may also lead to new stability problems. The authors experimentally demonstrate that thermoelastic displacements between successive pulses can be detrimental to the performance of cavity-based XFEL
The demonstration of a low-loss diamond mirror cavity that can temporally store X-ray pulses brings hope for a future generation of X-ray free electron lasers.
Exacerbated by the impacts of climate change and the recent energy crisis, concentrated efforts towards more sustainable research have become matters of urgency, in particular for large-scale accelerator complexes and light sources.
Over the past decade, several X-ray free-electron laser (XFEL) facilities have been constructed and started operation worldwide. New, high-repetition XFELs are expected to open to users in the next 5 years.
This month in a dedicated Focus issue, we look back at the first decade of X-ray free-electron lasers (XFELs) and forward to the challenges and opportunities lying ahead.
