Liu Chao, Zhu Tian-Xiang, Su Ming-Xu, Ma You-Zhi, Zhou Zong-Quan, Li Chuan-Feng, Guo Guang-Can
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China and CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
Phys Rev Lett. 2020 Dec 31;125(26):260504. doi: 10.1103/PhysRevLett.125.260504.
Photonic quantum memory is the core element in quantum information processing (QIP). For the scalable and convenient practical applications, great efforts have been devoted to the integrated quantum memory based on various waveguides fabricated in solids. However, on-demand storage of qubits, which is an essential requirement for QIP, is still challenging to be implemented using such integrated quantum memory. Here we report the on-demand storage of time-bin qubits in an on-chip waveguide memory fabricated on the surface of a ^{151}Eu^{3+}:Y_{2}SiO_{5} crystal, utilizing the Stark-modulated atomic frequency comb protocol. A qubit storage fidelity of 99.3%±0.2% is obtained with single-photon-level coherent pulses, far beyond the highest fidelity achievable using the classical measure-and-prepare strategy. The developed integrated quantum memory with the on-demand retrieval capability represents an important step toward practical applications of integrated quantum nodes in quantum networks.
光子量子存储器是量子信息处理（QIP）中的核心元件。为了实现可扩展且便捷的实际应用，人们付出了巨大努力来研发基于在固体中制造的各种波导的集成量子存储器。然而，量子比特的按需存储作为量子信息处理的一项基本要求，使用这种集成量子存储器来实现仍然具有挑战性。在此，我们报告利用斯塔克调制原子频率梳协议，在一块¹⁵¹Eu³⁺:Y₂SiO₅晶体表面制造的片上波导存储器中实现时间-bin量子比特的按需存储。使用单光子级相干脉冲获得了99.3%±0.2%的量子比特存储保真度，远远超过使用经典测量与制备策略所能达到的最高保真度。所开发的具有按需检索能力的集成量子存储器代表着朝着量子网络中集成量子节点的实际应用迈出了重要一步。
