The generation of high-quality entangled photon pairs has been a long-sought goal in modern quantum communication and computation. So far, the most widely used entangled photon pairs have been generated from spontaneous parametric down-conversion (SPDC), a process that is intrinsically probabilistic and thus relegated to a regime of low rates of pair generation. In contrast, semiconductor quantum dots can generate triggered entangled photon pairs through a cascaded radiative decay process and do not suffer from any fundamental trade-off between source brightness and multi-pair generation. However, a source featuring simultaneously high photon extraction efficiency, high degree of entanglement fidelity and photon indistinguishability has been lacking. Here, we present an entangled photon pair source with high brightness and indistinguishability by deterministically embedding GaAs quantum dots in broadband photonic nanostructures that enable Purcell-enhanced emission. Our source produces entangled photon pairs with a pair collection probability of up to 0.65(4) (single-photon extraction efficiency of 0.85(3)), entanglement fidelity of 0.88(2), and indistinguishabilities of 0.901(3) and 0.903(3) (brackets indicate uncertainty on last digit). This immediately creates opportunities for advancing quantum photonic technologies.

高质量纠缠光子对的生成一直是现代量子通信和计算领域长期追求的目标。到目前为止，最广泛使用的纠缠光子对是通过自发参数下转换（SPDC）生成的，该过程本质上是概率性的，因此属于低对生成率的状态。相比之下，半导体量子点可以通过级联辐射衰减过程生成触发的纠缠光子对，并且不会受到源亮度和多对生成之间的任何基本权衡的影响。然而，一直缺乏同时具有高光子提取效率、高纠缠保真度和光子不可区分性的源。在这里，我们通过将砷化镓量子点确定性地嵌入宽带光子纳米结构中，实现了珀塞尔增强发射，从而呈现出一种具有高亮度和不可区分性的纠缠光子对源。我们的源产生纠缠光子对，其对收集概率高达 0.65(4)（单光子提取效率为 0.85(3)），纠缠保真度为 0.88(2)，不可区分性为 0.901(3) 和 0.903(3) )（括号表示最后一位数字的不确定性）。这立即为推进量子光子技术创造了机会。