Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots

• Published in: Nature communications 2017-05, Vol.8 (1), p.15506-15506, Article 15506
• Main Authors: Huber, Daniel, Reindl, Marcus, Huo, Yongheng, Huang, Huiying, Wildmann, Johannes S., Schmidt, Oliver G., Rastelli, Armando, Trotta, Rinaldo
• Format: Article
• Language: English
• Subjects: 639/624/399/1017; 639/766/400/482; 639/766/483/3925; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms15506

The development of scalable sources of non-classical light is fundamental to unlocking the technological potential of quantum photonics. Semiconductor quantum dots are emerging as near-optimal sources of indistinguishable single photons. However, their performance as sources of entangled-photon pairs are still modest compared to parametric down converters. Photons emitted from conventional Stranski–Krastanov InGaAs quantum dots have shown non-optimal levels of entanglement and indistinguishability. For quantum networks, both criteria must be met simultaneously. Here, we show that this is possible with a system that has received limited attention so far: GaAs quantum dots. They can emit triggered polarization-entangled photons with high purity (g (2) (0) = 0.002±0.002), high indistinguishability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity (0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dot entanglement sources in future quantum technologies. Scalable and integratable sources of entangled-photon pairs are an important building block for quantum photonic applications. Here, Huber et al . demonstrate that droplet-etched gallium arsenide quantum dots can emit highly indistinguishable photon pairs with a high degree of entanglement.