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A double-tapered fibre array for pixel-dense gamma-ray imaging

Nature Photonics volume 17, pages 494–500 (2023)Cite this article

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Abstract

Luminescence intensity in photodetectors, radiation imagers and light-emitting diodes is proportional to the thickness of the light-emitting layer. However, a thick emitting layer reduces light output because of incoherent photon scattering and attenuation. Here we present the design of double-tapered optical-fibre arrays that can drastically increase the light output of thick light-emitting layers by progressively filling more propagation modes along the fibre’s depth. To enhance the light-collection efficiency and imaging resolution, the upper taper angle of each fibre is greater than the lower angle. By filling the fibre substrate with perovskite nanocrystals from a scale of micrometres thick to centimetres thick, large-scale pixel-dense X-ray or gamma-ray detector arrays can be fabricated. We demonstrate X-ray imaging with a spatial resolution of 22 lp mm−1. Pixelated gamma-ray imaging is also demonstrated using a nanocrystal scintillator film with a thickness of 4 mm and ~10,000 pixels under focused 6-MeV irradiation. Dynamic changes in the energy spectrum (5 keV to 10 MeV) and dose rate (3.5 nGy s−1 to 96 mGy s−1) can be conveniently monitored using a hemispherical fibre array dosimeter with a field of view of 150°. This study presents a high-throughput approach for fabricating thick emitter layers that could be applied to biomolecular or mechanical force sensing, medical imaging and ion beam therapy.

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Fig. 1: Structural properties of transparent double-tapered optical-fibre arrays for directional light collection.
Fig. 2: Optical characterizations of the double-tapered optical-fibre array for photon recycling and high-resolution X-ray imaging.
Fig. 3: Gamma-ray imaging using a fibre-embedded perovskite scintillator film.
Fig. 4: Hemispherical dosimeters for X-ray and gamma-ray detection with improved sensitivity and a wider field of view.
Fig. 5: Stability tests of scintillator films with embedded optical-fibre arrays.

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Data availability

The data that support the findings of this study are available from the corresponding authors upon reasonable request.

Code availability

The codes are available from the corresponding authors upon reasonable request.

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Acknowledgements

This work was supported by the NUS NANONASH Program (NUHSRO/2020/002/413 NanoNash/LOA; R143000B43114) and National Research Foundation, Prime 225 Minister’s Office, Singapore under its Competitive Research Program (award no. NRF-CRP23-2019-0002) and under its NRF Investigatorship Programme (award no. NRF-NRFI05-2019-0003) and the RIE2025 Manufacturing, Trade and Connectivity (MTC) Programmatic Fund (award no. M21J9b0085).

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Author notes

  1. These authors contributed equally: Luying Yi, Bo Hou.

Authors and Affiliations

  1. Department of Chemistry, National University of Singapore, Singapore, Singapore

    Luying Yi, Bo Hou, He Zhao & Xiaogang Liu

  2. Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, China

    He Zhao & Xiaogang Liu

  3. Division of Radiation Oncology National Cancer Centre Singapore, Singapore, Singapore

    Hong Qi Tan

  4. Center for Functional Materials, National University of Singapore Suzhou Research Institute, Suzhou, China

    Xiaogang Liu

  5. Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore

    Xiaogang Liu

Authors
  1. Luying Yi
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Contributions

L.Y., B.H. and X.L. conceived and designed the project. X.L. supervised the project. H.Z. characterized the materials. L.Y. conducted the numerical simulations. B.H. performed device fabrication. B.H., L.Y. and H.Q.T. performed gamma-ray experiments. L.Y. and B.H. wrote the manuscript. X.L. edited the manuscript. All authors participated in the discussion and analysis of the manuscript.

Corresponding author

Correspondence to Xiaogang Liu.

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Nature Photonics thanks Jiang Tang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary figs. 1–12 and table 1.

Supplementary Video 1

Comparison of pixel-dense gamma-ray imaging with and without double-tapered fibre array.

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Yi, L., Hou, B., Zhao, H. et al. A double-tapered fibre array for pixel-dense gamma-ray imaging. Nat. Photon. 17, 494–500 (2023). https://doi.org/10.1038/s41566-023-01204-1

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