A spin-photon interface using charge-tunable quantum dots strongly coupled to a cavity.
A spin-photon interface using charge-tunable quantum dots strongly coupled to a cavity.
复制标题
使用电荷可调量子点与腔体强耦合的自旋光子界面。
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
E. Waks
中科院分区：
文献类型：
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作者：
Zhouchen Luo;Shuo Sun;A. Karasahin;A. Bracker;S. Carter;M. Yakes;D. Gammon;E. Waks
含有电子或空穴自旋的带电量子点是一种明亮的固态量子比特，适用于量子网络和分布式量子计算。将这样的量子点自旋引入光子晶体腔中，产生了一个强大的自旋-光子界面，在这个界面中，自旋可以通过调制腔反射系数来控制光子。然而，之前对这种自旋-光子界面的演示依赖于被附近杂质随机带电的量子点，导致荷电状态不稳定，从而导致腔反射率的对比度较差。在这里，我们演示了一个强大的自旋-光子界面，它使用的是一个带有二极管结构的确定电荷的量子点。通过在光子晶体腔中引入这种带电的量子点，我们实现了腔模和量子点的负电荷态之间的强耦合。此外，通过光抽运来初始化自旋，我们显示了腔反射率与自旋相关的强调制，对应的合作系数为12。这种与自旋相关的反射率对于利用光子来调节自旋之间的纠缠以及在量子网络和分布式量子计算中产生强的光子-光子相互作用是重要的。
Charged quantum dots containing an electron or hole spin are bright solid-state qubits suitable for quantum networks and distributed quantum computing. Incorporating such quantum dot spin into a photonic crystal cavity creates a strong spin-photon interface, in which the spin can control a photon by modulating the cavity reflection coefficient. However, previous demonstrations of such spin-photon interfaces have relied on quantum dots that are charged randomly by nearby impurities, leading to instability in the charge state, which causes poor contrast in the cavity reflectivity. Here we demonstrate a strong spin-photon interface using a quantum dot that is charged deterministically with a diode structure. By incorporating this actively charged quantum dot in a photonic crystal cavity, we achieve strong coupling between the cavity mode and the negatively charged state of the dot. Furthermore, by initializing the spin through optical pumping, we show strong spin-dependent modulation of the cavity reflectivity, corresponding to a cooperativity of 12. This spin-dependent reflectivity is important for mediating entanglement between spins using photons, as well as generating strong photon-photon interactions for applications in quantum networking and distributed quantum computing.