近日，北京量子信息科学研究院吴邦团队研究了基于拓扑体腔的单光子源。2025年8月28日出版的《光：科学与应用》杂志发表了这一最新研究成果。

拓扑光子学提供了发展量子光强度的潜力，具有固有的对结构紊乱的稳定性。迄今为止，人们已为此目的研究了拓扑保护边缘或角态。

研究组首次利用具有垂直方向性的拓扑体态来增强单个半导体量子点的光发射。采用不规则的“Q”形空腔建立拓扑复杂度。他们通过实验证明了拓扑体腔中单光子发射的1.6倍Purcell增强，并且对发射波长或耦合量子点的位置有一定的耐受。仿真结果表明，在8.6nm的宽光谱失谐范围或2.5μm²的覆盖面积下，这种QD腔耦合系统可以保持超过1.6的Purcell因子。

此外，与反射器集成的优化腔结构预测了高达92%的单光子提取效率。该研究结果提供了一种新的方法来开发具有高提取效率的拓扑保护量子光，并在不规则腔边界上实现量子-腔相互作用。

附：英文原文

Title: A single-photon source based on topological bulk cavity

Author: Mao, Xin-Rui, Ji, Wei-Jie, Wang, Shao-Lei, Liu, Han-Qing, Wu, Bang, Wang, Xu-Jie, Liu, Li, Zhou, Lai, Ni, Haiqiao, Niu, Zhichuan, Yuan, Zhiliang

Issue&Volume: 2025-08-28

Abstract: Topological photonics offers the potential to develop quantum light sources with inherent robustness against structural disorders. To date, topologically protected edge or corner states have been investigated for this purpose. Here, for the first time, we exploit a topological bulk state with vertical directionality to enhance the light emission from a single semiconductor quantum dot (QD). An irregular ‘Q’-shaped cavity is applied for establishing topological robustness. We experimentally demonstrate a 1.6-fold Purcell enhancement of single-photon emission in the topological bulk cavity, with tolerance to the emission wavelength or the positioning of the coupled QD. Simulations indicate that such a QD-cavity coupling system can retain a Purcell factor exceeding 1.6 under a broad spectral detuning range of 8.6nm or a coverage area of 2.5 μm2. Furthermore, the optimized cavity structure integrated with a reflector predicts a high single-photon extraction efficiency up to 92%. Our results offer a novel approach to develop topologically protected quantum light sources with high extraction efficiency and robust QD-cavity interaction against irregular cavity boundaries.

DOI: 10.1038/s41377-025-01929-4

Source: https://www.nature.com/articles/s41377-025-01929-4