Control and single-shot readout of an ion embedded in a nanophotonic cavity
Control and single-shot readout of an ion embedded in a nanophotonic cavity
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DOI：
10.1038/s41586-020-2160-9
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发表时间：
2020-03-30
期刊：
影响因子：
64.8
通讯作者：
Faraon, Andrei
中科院分区：
文献类型：
--
作者：
Kindem, Jonathan M.;Ruskuc, Andrei;Faraon, Andrei
使用光网络在长距离上分布纠缠是一种有趣的宏观量子现象，在量子系统中应用于高级计算和安全通信（1，2）。构建量子网络需要基于原子（3）、离子（4）或其他光学可寻址量子位的可扩展量子光物质接口（1）。固态发射体（5），例如量子点和金刚石或碳化硅中的缺陷（6-10），已经成为这种界面的有希望的候选者。到目前为止，还不可能扩大这些系统的规模，从而推动了替代平台的开发。一个核心的挑战是确定发射器，表现出相干的光学和自旋跃迁，同时耦合到光子腔，增强光-物质相互作用和通道发射到光纤。已知晶体中的稀土离子具有适合于量子存储和转换的高度相干的4f-4f光学和自旋跃迁（11-15），但直到最近才分离出单个稀土离子（16，17）并将其耦合到纳米腔（18，19）。将单一稀土离子用于量子网络的关键下一步是在光子谐振器中实现长自旋相干和单次读出。在这里，我们展示了自旋初始化，相干光学和自旋操纵，高保真单次光学读出的超精细自旋状态的单个Yb-171（3+）离子耦合到一个纳米光子腔中制作的钇原钒酸盐主晶体。这些离子具有对磁场波动一阶不敏感的光学和自旋跃迁，即使在大于1开尔文的温度下，腔耦合离子的光学线宽也小于1兆赫，自旋相干时间超过30毫秒。腔增强的光发射率有助于有效的自旋初始化和单次读出，条件保真度大于95%。这些结果展示了未来量子互联网的基于单个相干稀土离子的固态平台。纳米光子腔中的单个镱离子量子比特具有较长的相干时间，可以在单次读出中进行光学读取，使它们成为光量子网络的优秀候选者。
Distributing entanglement over long distances using optical networks is an intriguing macroscopic quantum phenomenon with applications in quantum systems for advanced computing and secure communication(1,2). Building quantum networks requires scalable quantum light-matter interfaces(1) based on atoms(3), ions(4) or other optically addressable qubits. Solid-state emitters(5), such as quantum dots and defects in diamond or silicon carbide(6-10), have emerged as promising candidates for such interfaces. So far, it has not been possible to scale up these systems, motivating the development of alternative platforms. A central challenge is identifying emitters that exhibit coherent optical and spin transitions while coupled to photonic cavities that enhance the light-matter interaction and channel emission into optical fibres. Rare-earth ions in crystals are known to have highly coherent 4f-4f optical and spin transitions suited to quantum storage and transduction(11-15), but only recently have single rare-earth ions been isolated(16,17) and coupled to nanocavities(18,19). The crucial next steps towards using single rare-earth ions for quantum networks are realizing long spin coherence and single-shot readout in photonic resonators. Here we demonstrate spin initialization, coherent optical and spin manipulation, and high-fidelity single-shot optical readout of the hyperfine spin state of single Yb-171(3+) ions coupled to a nanophotonic cavity fabricated in an yttrium orthovanadate host crystal. These ions have optical and spin transitions that are first-order insensitive to magnetic field fluctuations, enabling optical linewidths of less than one megahertz and spin coherence times exceeding thirty milliseconds for cavity-coupled ions, even at temperatures greater than one kelvin. The cavity-enhanced optical emission rate facilitates efficient spin initialization and single-shot readout with conditional fidelity greater than 95 per cent. These results showcase a solid-state platform based on single coherent rare-earth ions for the future quantum internet.Single ytterbium ion qubits in nanophotonic cavities have long coherence times and can be optically read out in a single shot, establishing them as excellent candidates for optical quantum networks.