Semiconductor quantum dots (QDs) have recently emerged as a leading platform to generate highly indistinguishable photons efficiently, and this work addresses the timely question of how good these solid-state sources can ultimately be. We establish the crucial role of lattice relaxation in these systems in giving rise to trade-offs between indistinguishability and efficiency. We analyse the two source architectures most commonly employed: a QD embedded in a waveguide and a QD coupled to an optical cavity. For waveguides, we demonstrate that the broadband Purcell effect results in a simple inverse relationship, in which indistinguishability and efficiency cannot be simultaneously increased. For cavities, the frequency selectivity of the Purcell enhancement results in a more subtle trade-off, in which indistinguishability and efficiency can be increased simultaneously, although not arbitrarily, which limits a source with near-unity indistinguishability (>99%) to an efficiency of approximately 96% for realistic parameters.

中文翻译：

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声子散射抑制了半导体单光子源中同时的近统一效率和不可分辨性

半导体量子点（QD）最近已成为有效生成高度不可区分的光子的领先平台，这项工作解决了这些固态光源最终的优良性能的及时问题。我们在这些系统中建立了晶格弛豫的关键作用，以在不可分辨性和效率之间进行权衡。我们分析了两种最常用的源体系结构：嵌入在波导中的QD和耦合到光腔的QD。对于波导，我们证明宽带赛尔效应会导致简单的逆关系，其中不可分辨性和效率无法同时提高。对于腔体而言，赛尔增强的频率选择性会导致更微妙的权衡，