X-ray microscope sees twice as clearly express
An X-ray image of a battery looks like a photo taken through frosted glass: fine details blur into a gray smudge. The culprit is the detector itself, which cannot distinguish features smaller than its pixel size. Engineers proposed getting around this barrier by illuminating the sample not with a uniform beam but with a striped pattern.
The stripes act like a stencil: they transfer information about the tiniest structures onto parts of the image that the detector sees well. By shifting the pattern several times and taking images, the computer decodes this data and assembles a picture with details twice as small as the previous limit.
The same principle applies not only to standard X-rays but also to phase contrast and dark-field imaging, which reveal details invisible to conventional methods. This paves the way for materials testing and medical imaging with details that were previously out of reach without bulky setups.
Original abstract
as written by the authors arXiv:2602.18343
X-ray microscopy has become an important tool for non-destructive testing, e.g., in battery research. However, imaging a cm-scale battery cell at the desired (sub-)micrometer resolution has been challenging. State-of-the-art X-ray microscopy techniques with a suited field-of-view provide (sub-) $$10\,\mu m$$ resolution, typically limited by the detector point-spread function and the (effective) detector pixel size. This work presents a super-resolution X-ray microscopy approach overcoming both limitations. It requires a structured X-ray illumination to encode high-frequency sample information that is natively unresolved within the resolved region of support. A mathematical framework is developed that decodes this information and generates a super-resolved image from multiple acquisitions with different phase shifts of the structured X-ray illumination. The presence of this encoded high-frequency information is first experimentally demonstrated, followed by quantification and validation using a resolution test chart. A resolution improvement by a factor of 2.2 is shown. Finally, we extend the proposed super-resolution technique to X-ray microtomography. Since the image acquisition scheme is inherently multimodal, phase-contrast and dark-field X-ray images can be computed additionally. These results showcase the direct impact of the proposed technique across both non-destructive testing and biomedical imaging, alleviating pixel-size limitations in detectors and sample-size restrictions.
A 2.2-fold improvement in resolution means that on the same detector you can now see details that previously merged into a single pixel.