In a groundbreaking advancement at the intersection of quantum mechanics and X-ray physics, researchers from the Universities of Göttingen and Hamburg have developed what is believed to be the world’s smallest X-ray interferometer. This miniature device, employing the principles of the iconic double-slit experiment, has enabled an unprecedented precise measurement of the refraction of X-rays at a nanoscale, elucidating intricate interactions between X-ray photons and atomic nuclei. This pioneering study, recently published in Nature Photonics, signifies a watershed moment in the realm of photonics and atomic-scale measurement technologies.
The phenomenon of light refraction, commonly recognized when a rainbow unfolds in the sky or when light bends through water droplets, arises due to the interaction of light waves with the atoms constituting matter. Traditional optics already harness this effect extensively—from the vivid displays of LCD screens to the high-speed data transmission enabled by fiber optics. However, the refraction of X-rays, a much higher-energy form of light, remained notoriously elusive to measure with precise accuracy, primarily because of the extremely short wavelengths involved and the subtlety of refraction effects at this scale.
Delving deeper into this challenge, the researchers ingeniously employed a device inspired by Richard Feynman’s legendary double-slit experiment, which lies at the heart of quantum mechanics. Their X-ray interferometer features two slits separated by a mere 50 nanometers, smaller than a fraction of the width of a human hair. Utilizing the synchrotron radiation source at the European Synchrotron Radiation Facility in Grenoble, the team conducted experiments where single X-ray photons simultaneously traversed both slits, thereby generating a delicately intricate interference pattern behind the slits.
What sets this experiment apart is the strategic placement of iron isotope ^57Fe atoms inside one of the two slits. These iron atoms serve not merely as passive participants but interact resonantly with the X-ray photons. As photons emerge from both slits and interfere, distinctive patterns arise, encoding the extent to which the X-rays are refracted by the iron nuclei. By analyzing these patterns, scientists could extract detailed measurements of the refractive interactions, offering insights into the underlying quantum processes governing light-matter interaction at nuclear scales.
Constructing interferometers operable with X-rays introduces unparalleled technical complexities. The challenge stems from the exceptionally short wavelength of X-rays—approximately a thousand times shorter than visible light—and their minute refraction angles. Maintaining nanoscale precision in slit separation and alignment is critical, as any deviation would obscure the subtle interference signatures vital for measurement. The success of this experiment underscores advances not only in instrumentation but also in fabrication techniques that allow manipulation at the atomic scale.
Measurement of X-ray refraction holds significant practical value, particularly in enhancing phase-contrast imaging techniques known for producing high-resolution, three-dimensional images of biological specimens without radiation damage. This imaging approach harnesses variations in refractive indices to distinguish soft tissues and microscopic structures that are otherwise invisible in conventional absorption-based imaging. By refining understanding of how X-rays refract through specific atomic species, researchers can potentially elevate the sensitivity and detail achievable in biological and medical imaging.
Beyond biological applications, this research also reveals new facets of photon-atom interactions. Unlike attenuation, which involves the absorption or scattering of photons, refraction pertains to phase shifts that photons undergo while traversing matter. By unraveling these phase shifts related to nuclear resonances, the interferometric technique opens a novel window to probe the nuclear environment and quantum electrodynamics effects within atomic nuclei—a frontier largely untapped until now.
The implications of this work stretch into the future of integrated optics as well. The ability to manipulate X-rays with optical circuits on the nanoscale could pave the way for sophisticated X-ray quantum devices, including miniature sensors, modulators, and quantum information processing elements. While integrated photonics for visible and infrared light is well established, extending these concepts to X-rays promises unprecedented precision and performance, especially beneficial in materials science, quantum computing, and fundamental physics.
The experiment’s reliance on single-photon states reinforces the quantum mechanical underpinnings of light behavior, vividly demonstrating how an individual photon can interfere with itself, a phenomenon defying classical intuition. Such quantum coherence effects, now measured in the high-energy X-ray regime, may lead the way to next-generation quantum technologies combining high spatial resolution with quantum information encoding.
Professor Tim Salditt from Göttingen University highlights how this interferometric approach to measuring nuclear resonant phase shifts transcends traditional measurements focused on intensity changes alone. By tapping into phase information, researchers can obtain richer data about the material’s internal composition and configuration. This enhanced interpretive power is crucial for advancing material characterization and could inspire new analytical methods with broader applicability.
Moreover, the research exemplifies the power of interdisciplinary collaboration. Combining expertise in quantum optics, nano-fabrication, synchrotron science, and nuclear physics has culminated in a tool capable of precisely quantifying previously inaccessible parameters. Such synergy underscores the future trajectory of scientific exploration, where convergent approaches unlock novel insights across domains.
In summary, the creation and application of the world’s smallest X-ray interferometer mark a pivotal milestone in both fundamental science and applied technology. By bridging the gap between quantum mechanics and X-ray optics, the device offers a new avenue for studying material properties with nanoscale precision and facilitates the push toward X-ray integrated photonic devices. As the field progresses, this breakthrough will likely spark innovative research directions and technological applications harnessing the quantum nature of X-rays to probe and manipulate matter at its most elemental level.
Subject of Research: Not applicable
Article Title: Interferometric measurement of nuclear resonant phase shift with a nanoscale Young double waveguide.
News Publication Date: 14-Apr-2026
Web References: https://www.nature.com/articles/s41566-026-01892-5
References: 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
Image Credits: Markus Osterhoff
Keywords
Photonics, Applied optics, Diffraction, X ray diffraction, Physics, Direct visualization, High resolution imaging, Interferometry, Medical imaging, Molecular imaging, Radiography, Image processing, Optics, Spectroscopy, Imaging
