Press release: Double-slit experiment reveals hidden details between light and matter
No. 46 - 20.04.2026
Researchers build world’s smallest interferometer to measure how X-rays and atomic nuclei interact
(pug) A rainbow reveals with colours what otherwise remains hidden: light is “refracted” by transparent matter, in this case water droplets. This same physical effect underlies many everyday technologies, like LCD screens and broadband connections based on fibre-optic cables. Light refraction is caused by an interaction between light and the atoms of matter. This brings the light waves slightly out of sync, so to speak. “X-ray light” is “refracted”, too. But the effect is difficult to measure here. A miniature device now offers a novel approach: Researchers from the Universities of Göttingen and Hamburg, together with partners, have built the world's smallest X-ray interferometer, to their knowledge. It has enabled them to precisely measure, for the first time, the refraction of X-rays confined to a few nanometres, and to deduce how they interact with atomic nuclei. The study was published in the journal Nature Photonics.
The new X-ray interferometer is based on the famous double-slit experiment, which Nobel laureate Richard Feynman said “has in it the heart of quantum mechanics”. “Our X-ray interferometer is probably the smallest interferometer in the world: The two slits are only 50 nanometres apart; that is roughly one-thousandth of the thickness of a human hair”, says lead author Dr Leon M. Lohse, who conducted the study at the University of Hamburg and works as a researcher at Göttingen University now. The researchers carried out experiments at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France.
They placed atoms of the iron isotope 57Fe into one of the two slits. “The fascinating thing is that we carried out our experiment largely using single X-ray photons,” explains Lohse. Each of these “light particles” passes through both slits at the same time. In one slit, the photon interacts with the atomic nuclei of the iron isotope. It then produces characteristic patterns behind the slits, revealing how much the light is refracted. From the strength of light refraction, the researchers were able to draw conclusions about the interaction between the X-ray photons and iron atoms.
Building interferometers for X-rays is challenging. They must be exceptionally precise because “X-ray light waves” are refracted only slightly and they are extremely short – about a thousand times shorter than those of visible light and even shorter than the typical distance between atoms in matter. At the same time, their refraction is highly relevant. For example, it is used in X-ray phase-contrast imaging to generate detailed 3D images of biological samples without damaging them. It also provides information about the atoms contained in matter and how they are arranged – details that have been difficult for researchers to access until now.
“Our experiment opens up numerous avenues of research,” explains Professor Tim Salditt of Göttingen University. “It demonstrates how light refraction provides information that doesn’t emerge from the usually measured attenuation of light – particularly in connection with atomic resonances.” It also lays a foundation to measure the refractive index of different elements for X-rays systematically and precisely. “Integrated optical circuits” for X-rays could be possible in the future, too, the team envisions.
Original publication: Lohse, L. M. et al. Interferometric measurement of nuclear resonant phase shift with a nanoscale Young double waveguide. Nature Photonics. DOI: 10.1038/s41566-026-01892-5
Contact:
Dr Leon M. Lohse
University of Göttingen
Institute for X-ray Physics
Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
Email: llohse@uni-goettingen.de
Professor Tim Salditt
University of Göttingen
Institute for X-ray Physics
Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
Phone: +49 (0)551 39-25556
Email: tsaldit@gwdg.de
https://www.uni-goettingen.de/en/563229.html