Flexible-type ultrathin holographic endoscope for microscopic imaging of unstained biological tissues

Wonjun Choi, Munkyu Kang, Jin Hee Hong, Ori Katz, Byunghak Lee, Guang Hoon Kim, Youngwoon Choi*, Wonshik Choi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Ultrathin lensless fibre endoscopes offer minimally invasive investigation, but they mostly operate as a rigid type due to the need for prior calibration of a fibre probe. Furthermore, most implementations work in fluorescence mode rather than label-free imaging mode, making them unsuitable for general medical diagnosis. Herein, we report a fully flexible ultrathin fibre endoscope taking 3D holographic images of unstained tissues with 0.85-μm spatial resolution. Using a bare fibre bundle as thin as 200-μm diameter, we design a lensless Fourier holographic imaging configuration to selectively detect weak reflections from biological tissues, a critical step for label-free endoscopic reflectance imaging. A unique algorithm is developed for calibration-free holographic image reconstruction, allowing us to image through a narrow and curved passage regardless of fibre bending. We demonstrate endoscopic reflectance imaging of unstained rat intestine tissues that are completely invisible to conventional endoscopes. The proposed endoscope will expedite a more accurate and earlier diagnosis than before with minimal complications.

Original languageAmerican English
Article number4469
JournalNature Communications
Issue number1
StatePublished - Dec 2022

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© 2022, The Author(s).


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