Zhai Liang, Löbl Matthias C, Nguyen Giang N, Ritzmann Julian, Javadi Alisa, Spinnler Clemens, Wieck Andreas D, Ludwig Arne, Warburton Richard J
Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, DE-44780, Bochum, Germany.
Nat Commun. 2020 Sep 21;11(1):4745. doi: 10.1038/s41467-020-18625-z.
Quantum dots are both excellent single-photon sources and hosts for single spins. This combination enables the deterministic generation of Raman-photons-bandwidth-matched to an atomic quantum-memory-and the generation of photon cluster states, a resource in quantum communication and measurement-based quantum computing. GaAs quantum dots in AlGaAs can be matched in frequency to a rubidium-based photon memory, and have potentially improved electron spin coherence compared to the widely used InGaAs quantum dots. However, their charge stability and optical linewidths are typically much worse than for their InGaAs counterparts. Here, we embed GaAs quantum dots into an n-i-p-diode specially designed for low-temperature operation. We demonstrate ultra-low noise behaviour: charge control via Coulomb blockade, close-to lifetime-limited linewidths, and no blinking. We observe high-fidelity optical electron-spin initialisation and long electron-spin lifetimes for these quantum dots. Our work establishes a materials platform for low-noise quantum photonics close to the red part of the spectrum.
量子点既是优秀的单光子源，也是单自旋的宿主。这种组合能够确定性地产生与原子量子存储器带宽匹配的拉曼光子，并产生光子簇态，这是量子通信和基于测量的量子计算中的一种资源。AlGaAs中的GaAs量子点在频率上可以与基于铷的光子存储器匹配，并且与广泛使用的InGaAs量子点相比，其电子自旋相干性可能得到改善。然而，它们的电荷稳定性和光学线宽通常比InGaAs量子点差得多。在这里，我们将GaAs量子点嵌入到专门为低温操作设计的n-i-p二极管中。我们展示了超低噪声行为：通过库仑阻塞进行电荷控制、接近寿命限制的线宽以及无闪烁。我们观察到这些量子点具有高保真光学电子自旋初始化和长电子自旋寿命。我们的工作建立了一个接近光谱红色部分的低噪声量子光子学材料平台。
