European XFEL: attosecond X-ray flashes reach record intensity
X-ray pulses of around 300 attoseconds, focused onto a spot of 180 by 330 nanometres: a team at the European XFEL reached a peak intensity above 10²⁰ watts per square centimetre.
Archive image · Photo: Dirtsc / Wikimedia Commons, CC BY-SA 3.0 (cropped and resized)
Researchers at the European XFEL X-ray laser in Schenefeld near Hamburg have produced hard X-ray attosecond pulses lasting an estimated 300 attoseconds with record intensity and fluence – an attosecond is a billionth of a billionth of a second. Two precision mirrors of a so-called advanced Kirkpatrick-Baez system focused the flashes onto a spot of about 180 by 330 nanometres. The peak intensity exceeded 10²⁰ watts per square centimetre. The results appeared in the journal Optica (DOI 10.1364/OPTICA.613284).
The measurements were made in April 2026 at the MID instrument. To verify the intensity independently, the team aimed the pulses at a copper foil and observed amplified spontaneous emission there. "This is a world record in intensity and fluence for a hard-X-ray attosecond pulse," said first author Ichiro Inoue of the University of Tokyo.
Such pulses could in future allow detailed studies of how electrons behave in atoms and molecules. The mirror system used was brought in from Japan. European XFEL expects its own system in early 2027, funded through a collaboration with the University of Hamburg and Germany's Federal Research Ministry (BMFTR).