Reutilization of dead-zone photons in SiPM via gradient refractive index encapsulation media

IF 1.5 4区物理与天体物理 Q3 OPTICS

The European Physical Journal D Pub Date : 2026-05-08 DOI:10.1140/epjd/s10053-026-01172-5

Chaoqian Guo, Chao Han, Haotong Zhang, Yun Wu, Jun Wang, Yanfei Yang, Lu Liu, Lina Liu, Lianbi Li, Xiaoxiang Han, Zebin Li, Guoqing Zhang

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引用次数: 0

Abstract

Silicon photomultipliers (SiPMs) enable high-gain (> 10⁵) and magnetically robust detection in nuclear medicine and high-energy physics but suffer from geometric fill factor (GFF) loss due to dead zones between Geiger-mode avalanche photodiode (G-APD) microcells. Conventional nanolithography-based encapsulation (e.g., microlens/metasurface arrays) incurs high costs and narrow spectral response. This work proposes a gradient refractive index (GRIN) encapsulation medium with TiO2 nanoparticle concentration gradients to redirect dead-zone photons to SiPM photosensitive regions. Theoretical derivation of curved ray trajectories in radial GRIN media, COMSOL ray-tracing validation, and coupled multiphysics simulations demonstrates that GRIN encapsulation boosts photocurrent by up to 87% (10 μm G-APDs) and 52% (25 μm G-APDs). By eliminating nanofabrication and leveraging photocurable resin/nanoparticle self-assembly, this approach ensures CMOS compatibility, extends photon detection efficiency (PDE) to 300–1100 nm, and offers a cost-effective solution for high-sensitivity SiPM detection.

Graphic abstract

The alternative text for this image may have been generated using AI.

查看原文本刊更多论文

梯度折射率封装介质对SiPM死区光子的再利用

硅光电倍增管（SiPMs）在核医学和高能物理中实现高增益（> 105）和磁鲁棒检测，但由于盖格模式雪崩光电二极管（G-APD）微单元之间的死区而遭受几何填充因子（GFF）损失。传统的纳米光刻封装（如微透镜/超表面阵列）成本高，光谱响应窄。本研究提出了一种梯度折射率（GRIN）封装介质，具有TiO2纳米颗粒浓度梯度，可将死区光子重定向到SiPM光敏区。径向GRIN介质中弯曲射线轨迹的理论推导、COMSOL射线追踪验证和耦合多物理场模拟表明，GRIN封装可使光电流提高87% （10 μm g - apd）和52% （25 μm g - apd）。通过消除纳米加工和利用光固化树脂/纳米颗粒自组装，该方法确保了CMOS兼容性，将光子检测效率（PDE）扩展到300-1100 nm，并为高灵敏度SiPM检测提供了一种经济高效的解决方案。图形摘要此图像的替代文本可能是使用AI生成的。

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来源期刊

The European Physical Journal D 物理-物理：原子、分子和化学物理

CiteScore

3.10

自引率

11.10%

发文量

213

审稿时长

3 months

期刊介绍： The European Physical Journal D (EPJ D) presents new and original research results in: Atomic Physics; Molecular Physics and Chemical Physics; Atomic and Molecular Collisions; Clusters and Nanostructures; Plasma Physics; Laser Cooling and Quantum Gas; Nonlinear Dynamics; Optical Physics; Quantum Optics and Quantum Information; Ultraintense and Ultrashort Laser Fields. The range of topics covered in these areas is extensive, from Molecular Interaction and Reactivity to Spectroscopy and Thermodynamics of Clusters, from Atomic Optics to Bose-Einstein Condensation to Femtochemistry.