Versteegh Marijn A M, Reimer Michael E, Jöns Klaus D, Dalacu Dan, Poole Philip J, Gulinatti Angelo, Giudice Andrea, Zwiller Val
Quantum Transport, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, The Netherlands.
National Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6.
Nat Commun. 2014 Oct 31;5:5298. doi: 10.1038/ncomms6298.
A bright photon source that combines high-fidelity entanglement, on-demand generation, high extraction efficiency, directional and coherent emission, as well as position control at the nanoscale is required for implementing ambitious schemes in quantum information processing, such as that of a quantum repeater. Still, all of these properties have not yet been achieved in a single device. Semiconductor quantum dots embedded in nanowire waveguides potentially satisfy all of these requirements; however, although theoretically predicted, entanglement has not yet been demonstrated for a nanowire quantum dot. Here, we demonstrate a bright and coherent source of strongly entangled photon pairs from a position-controlled nanowire quantum dot with a fidelity as high as 0.859±0.006 and concurrence of 0.80±0.02. The two-photon quantum state is modified via the nanowire shape. Our new nanoscale entangled photon source can be integrated at desired positions in a quantum photonic circuit, single-electron devices and light-emitting diodes.
要在量子信息处理中实现诸如量子中继器这样的宏伟方案，需要一个明亮的光子源，它要兼具高保真纠缠、按需生成、高提取效率、定向且相干发射以及纳米级位置控制等特性。然而，目前尚未有单个器件能同时具备所有这些特性。嵌入纳米线波导中的半导体量子点有可能满足所有这些要求；不过，尽管有理论预测，但纳米线量子点的纠缠尚未得到证实。在此，我们展示了一个来自位置可控的纳米线量子点的明亮且相干的强纠缠光子对源，其保真度高达0.859±0.006，并发度为0.80±0.02。双光子量子态可通过纳米线形状进行调控。我们新的纳米级纠缠光子源可集成到量子光子电路、单电子器件和发光二极管中的所需位置。
