Coherent population trapping of an electron spin in a single negatively charged quantum dot
Coherent population trapping of an electron spin in a single negatively charged quantum dot
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DOI：
10.1038/nphys1054
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发表时间：
2008-09-01
期刊：
影响因子：
19.6
通讯作者：
Sham, L. J.
中科院分区：
文献类型：
--
作者：
Xu, Xiaodong;Sun, Bo;Sham, L. J.
相干布居俘获（CPT）是指三能级原子系统中，两个基态通过相干光场耦合到中间态，在相干叠加态中布居的稳态俘获（1）。最近，利用荧光技术在GaAs中施主束缚自旋系综（参考文献2）和金刚石中单个氮空位中心（参考文献3）中观察到CPT。在这里，我们报告的CPT演示的电子自旋在一个单一的量子点。观测结果表明，电子自旋的CPT和电子的两个自旋基态之间的拉曼相干性的成功产生（4-6）。这种技术可以用来初始化，在约千兆赫的速率，通过改变驱动和探测场之间的拉比频率的比率，在任意叠加的电子自旋状态。结果表明，带电量子点对于实现电磁感应透明（7，8）、慢光（9）、量子信息存储（10）和量子中继器（11，12）的固态方法的潜在重要性。
Coherent population trapping (CPT) refers to the steady-state trapping of population in a coherent superposition of two ground states that are coupled by coherent optical fields to an intermediate state in a three-level atomic system(1). Recently, CPT has been observed in an ensemble of donor-bound spins in GaAs (ref.2) and in single nitrogen-vacancy centres in diamond(3) by using a fluorescence technique. Here, we report the demonstration of CPT of an electron spin in a single quantum dot. The observation demonstrates both the CPT of an electron spin and the successful generation of Raman coherence between the two spin ground states of the electron(4-6). This technique can be used to initialize, at about a gigahertz rate, an electron spin state in an arbitrary superposition by varying the ratio of the Rabi frequencies between the driving and probe fields. The results show the potential importance of charged quantum dots for a solid-state approach to the implementation of electromagnetically induced transparency(7,8), slow light(9), quantum information storage(10) and quantum repeaters(11,12).