发表机构
ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology; ICREA – Institució Catalana de Recerca i Estudis Avançats（光子科学研究所，巴塞罗那科学技术研究院; 加泰罗尼亚高级研究学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在掺 Pr³⁺:Y₂SiO₅ 量子存储器中，通过原子频率梳自旋波协议结合 XY4 自旋复相序列，实现了电信 herald 单光子的长寿命非经典存储，为可扩展长距离量子中继链路奠定了重要基础。
AI 中文摘要
以原子激发态形式实现单光子的长寿命存储是量子网络中长距离纠缠分发的基础。为缓解环境诱导的退相干效应，多种单发射极及基于系综的固态系统已采用微波脉冲对超精细相干性进行复相处理。然而，在包含此类自旋复相机制的吸收型量子存储器中实现单光子存储的演示仍未达成。本研究展示了在掺 Pr³⁺:Y₂SiO₅ 稀土离子晶体量子存储器中，利用原子频率梳（AFC）自旋波协议结合 XY4 自旋复相序列实现电信 herald 单光子的非经典存储。首先在经典 regime 中观测到最长约 3 ms 存储时间的长寿命 AFC 光子回波；随后利用腔增强参量光子对源产生的 herald 光子与存储信号光子间的非经典关联，在最长 180 μs 的存储时间下测得交叉关联值高达 4.6(4)。结合 Pr³⁺:Y₂SiO₅ 量子存储器（QM）支持高效多路复用存储的能力，该成果为实现可扩展的长距离量子中继链路迈出了重要一步。
英文摘要
Long-lived storage of single photons under the form of atomic excitations is at the foundation of long-distance entanglement distribution in quantum networks. To mitigate decoherence effects induced by the environment, rephasing of the hyperfine coherences using microwave pulses have been implemented in a variety of single-emitter and ensemble-based solid-state systems. However, the demonstration of storage of single photons in an absorptive quantum memory including such spin rephasing mechanism remains elusive. In this work, we show non-classical storage of telecom-heralded single photons in a Pr$^{3+}$:Y$_2$SiO$_5$ rare-earth ion doped crystal quantum memory using the atomic frequency comb (AFC) spin-wave protocol combined with a XY4 spin rephasing sequence. Long-lived AFC photon echoes are first observed in the classical regime for storage times of up to approximately 3 ms. We then demonstrate non-classical correlations between heralding photons and stored signal photons generated by a cavity-enhanced parametric photon-pair source for storage times of up to 180 $μ$s and with measured cross-correlation values as high as 4.6(4). Together with the capacity of Pr$^{3+}$:Y$_2$SiO$_5$ QMs to support highly efficient and multiplexed storage, this result represents a significant step towards scalable long-distance quantum repeater links.
Comments8 pages, 3 figures
