Seeing fine tissue structures deep inside the body has always involved compromise. High-resolution images usually fade quickly with depth, while deeper views often lose sharpness. Researchers now report a miniature side-viewing fiber probe that breaks this trade-off. The new probe keeps images sharp over a much longer distance, allowing clinicians to see deeper without sacrificing detail. It achieves this while remaining extremely small, making it suitable for narrow and sensitive anatomical spaces. By combining extended imaging depth with micrometer-scale resolution, the probe offers a clearer and more reliable view of internal structures. This advance could significantly improve how early-stage tissue abnormalities are detected during minimally invasive procedures.
Endoscopic optical coherence tomography is widely used to visualize tissue microstructures in real time, but current probes face clear limitations. Conventional designs struggle in narrow lumens, where space is limited and tissue damage must be avoided. More importantly, probe designers have long faced a physical trade-off: increasing image sharpness reduces imaging depth, while extending depth blurs fine details. These constraints restrict the clinical value of endoscopic imaging, especially for early diagnosis in confined organs. Manufacturing challenges further limit probe miniaturization and robustness. Based on these challenges, there is a strong need to develop new side-viewing probes that deliver deep, sharp imaging without increasing size or complexity.
Writing (DOI: 10.1038/s41378-025-01034-x) in Microsystems & Nanoengineering in 2025, a research team led by scientists at Beijing Institute of Technology presents a new side-viewing fiber probe for optical coherence tomography. The probe introduces a redesigned light-delivery strategy that dramatically extends imaging depth while preserving high lateral resolution. Tested using both linear and rotational scanning, the probe produced clear images in biological tissues and narrow-lumen samples. The results suggest a practical path toward safer, more informative endoscopic imaging in clinical and industrial settings.
At the core of the advance is how the probe controls light. Instead of focusing light into a single tight spot that quickly spreads, the new probe maintains a narrow beam over a long distance. This allows the system to capture clear images across a much larger depth range.
Experiments showed that the probe achieves an imaging depth of roughly 350 micrometers—more than ten times deeper than many conventional fiber probes—while keeping lateral resolution around 1.4 micrometers. In practical terms, this means fine structures remain visible even as the probe scans deeper into tissue.
Crucially, this performance comes in a probe with a diameter close to one millimeter, small enough for narrow anatomical passages. The researchers also demonstrated that imaging quality remains stable during rotational scanning, a key requirement for three-dimensional endoscopic imaging.
The probe successfully resolved internal features in layered materials, plant tissues, and animal tissues. These demonstrations show that extended depth and high resolution no longer need to be traded against each other. Instead, both can be achieved in a compact, fiber-based design suitable for real-world use.
"This work shows that we can rethink the limits of miniature endoscopic imaging," said the study's corresponding author. "By keeping the beam focused over a longer range, we can see deeper while preserving fine detail. Just as importantly, the probe is built using standard fiber-processing techniques, which makes it realistic to scale and deploy. We believe this approach can help bring more reliable, less invasive imaging tools into clinical practice."
The new fiber probe could broaden the use of endoscopic OCT in areas where imaging has been difficult or risky. In medicine, it may enable clearer visualization of airways, gastrointestinal tracts, and pediatric organs, supporting earlier diagnosis with less tissue disturbance. Beyond healthcare, the probe could be adapted for non-destructive inspection of industrial components, layered materials, or micro-scale defects. Because the design is compact, low-cost, and compatible with existing manufacturing methods, it offers a realistic route from laboratory research to practical devices. More broadly, the study highlights how smarter light control can redefine what miniature imaging systems can achieve.
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References
DOI
Original Source URL
https://doi.org/10.1038/s41378-025-01034-x
Funding information
The authors acknowledge the support from National Key Research and Development Program of China (2024YFC3015204, 2022YFB4702902), National Natural Science Foundation of China Program (62105020, 62275023), Beijing Municipal Natural Science Foundation (4232077), Shenzhen Science and Technology Program (KJZD20230923114310021), Office of New Economy and S&T at Chengdu Economy Development District (LQXKJ-KJXM-2022-01), Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities) (FRF-IDRY-22-013), Fundamental Research Funds for the Central Universities (00007753), and Open funding of Guangxi Key Laboratory of Optoelectronic Information Processing (GD21201).
About Microsystems & Nanoengineering
Microsystems & Nanoengineering is an online-only, open access international journal devoted to publishing original research results and reviews on all aspects of Micro and Nano Electro Mechanical Systems from fundamental to applied research. The journal is published by Springer Nature in partnership with the Aerospace Information Research Institute, Chinese Academy of Sciences, supported by the State Key Laboratory of Transducer Technology.
Microsystems & Nanoengineering
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Side-viewing axicon-integrated miniature fiber probe for extended depth of focus and ultrahigh lateral resolution endoscopic imaging
28-Nov-2025
The authors declare that they have no competing interests.