物理学进展

物理学进展 ›› 2026, Vol. 46 ›› Issue (5): 217-224.doi: 10.13725/j.cnki.pip.2026.05.001

所属专题： 2026年, 第46卷

• •    下一篇

基于PPKTP晶体的高纯度高预示效率单光子源研制

杨婷妤1，李丰沛1，陈建兰2，张涵1
  

  1. 1. 南京大学物理学院，固体微结构物理全国重点实验室，南京210093; 2. 安徽大学物理学院，合肥230601
  • 收稿日期:2026-04-24 修回日期:2026-05-08 接受日期:2026-05-18 出版日期:2026-10-20 发布日期:2026-10-22
  • 基金资助:
    国家自然科学基金(No. U25A6008)

Development of high purity and high heralding efficiencysingle-photon source based on PPKTP crystal

YANG Tingyu 1, LI Fengpei 1, CHEN Jianlan 2, ZHANG Han 1   

  1. 1. National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China; 2. School of Physics, Anhui University, Hefei 230601, China
  • Received:2026-04-24 Revised:2026-05-08 Accepted:2026-05-18 Online:2026-10-20 Published:2026-10-22

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摘要：

单光子源对光学量子信息处理与安全通信等领域至关重要。当前基于非线性品体自发参量下转换过程的预示单光子源通常难以兼顾高预示效率与高纯度，这直接限制了量子密钥分发的安全码率与传输距离。本文基于周期极化磷酸氧钛钾(periodically poled KTiOPO4,PPKTP)非线性晶体，利用连续光泵浦的自发参量下转换过程，研制了一种高纯度、高预示效率的单光子源。通过采用长品体并优化系浦光束腰，显著提升光子预示效率和收集效率。在系浦光功率1mW，光源亮度6.3x104 pairs/(s.mW)，预示效率57.3%的实验状态下，单光子源获得了 0.9946的单光子纯度，同时还表现出良好的稳定性和对多光子噪声的抑制能力。研究结果为制备低成本、高质量的预报单光子源提供了可行方案。

关键词: 单光子源, PPKTP 晶体, 自发参量下转换, 条件二阶关联函数

Abstract:

Single-photon sources are crucial for fields such as optical quantum informa-tion processing and secure communication. Current heralded single-photon sources based onspontaneous parametric down-conversion in nonlinear crystals often struggle to simultaneouslyachieve high heralding efficiency and high purity, which directly limits the secure key rateand transmission distance of quantum key distribution. In this paper, we develop a high-purity, high-heralding-efficiency single-photon source based on a PPKTP nonlinear crystal using continuous-wave pumped spontaneous parametric down-conversion. By employing a longcrystal and optimizing the pump beam waist, the photon heralding efficiency and collectionefficiency are significantly improved. Under an experimental condition with a pump powerof 1 mW, source brightness of 6.3 x 104 pairs/(s-mW) and heralding efficiency of 57.3%, asingle-photon purity of 0.994 6 is achieved. Additionally, the source exhibits good stability andstrong suppression of multiphoton noise. The results provide a feasible solution for fabricatinglow-cost, high-quality heralded single-photon sources.

Key words: single-photon source, PPKTP crystal, spontaneous parametric down-conversion, conditional second-order correlation function

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