This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers used the European XFEL to create X-ray flashes that were not only extremely short but also reached record intensity for this type of pulse. The researchers focused the X-rays to an area roughly 100,000 times smaller than the cross section of a typical human hair.
This concentrated the X-ray light into a tiny but extremely powerful spot. The method could enable detailed studies of how electrons behave in atoms and molecules and, in the long term, could even allow researchers to control electrons during chemical reactions. The team has now published the results of the experiment, carried out in April 2026, in the journal Optica.
"This is a world record in intensity and fluence for a hard-X-ray attosecond pulse," says Ichiro Inoue from the University of Tokyo, first author of the publication. Hard X-rays are light waves with a particularly short wavelength. Fluence measures how much energy this light delivers to a certain area.
Intensity also takes into account how quickly that energy arrives. The pulses used in the experiment lasted an estimated 300 attoseconds (an attosecond is a billionth of a billionth of a second). They passed through a set of two extremely precise mirrors, known as an advanced Kirkpatrick–Baez, or AKB, optical system.
Each X-ray flash reflected four times in total: one mirror focused the pulse vertically and the other horizontally. This resulted in a focal spot of just 180 × 330 nanometers (a nanometer is a billionth of a meter). "A few years ago, we demonstrated terawatt-scale hard X-ray attosecond pulses at the European XFEL," says DESY scientist Jiawei Yan, one of the corresponding authors of the study.
"But generating powerful pulses is only the first step. For experiments, what really matters is what we can deliver to the sample. With this advance, we can now use attosecond X-rays to explore highly nonlinear interactions between X-rays and matter." The researchers independently verified that they reached a peak intensity of more than 10²⁰ watts per square centimeter by shining the pulses onto a copper foil.
Extract — continue reading at the source.
