Quantum correlations of spontaneous two-photon emission from a quantum dot
成果类型：
Article
署名作者：
Liu, Shunfa; Wang, Yangpeng; Saleem, Yasser; Li, Xueshi; Liu, Hanqing; Yang, Cheng-Ao; Yang, Jiawei; Ni, Haiqiao; Niu, Zhichuan; Meng, Yun; Hu, Xiaolong; Yu, Ying; Wang, Xuehua; Cygorek, Moritz; Liu, Jin
署名单位：
Sun Yat Sen University; Dortmund University of Technology; Chinese Academy of Sciences; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Tianjin University
刊物名称：
Nature
ISSN/ISSBN：
0028-1505
DOI：
10.1038/s41586-025-09267-6
发表日期：
2025-07-31
关键词：
摘要：
Spontaneous two-photon emission (STPE) is a second-order quantum radiation process with implications in astrophysics1, atomic physics2 and quantum technology3. In particular, on-demand STPE from single quantum emitters has long been predicted to revolutionize photonic quantum science and technology4,5. Here we report STPE with brightness comparable to that of competing single-photon radiation from a single semiconductor quantum dot deterministically coupled to a high-quality micropillar cavity. This is because of strong vacuum fluctuations in the microcavity, which drive a biexciton directly to the ground state. We show the quantum nature associated with STPE in the cavity quantum electrodynamics regime using photon statistics measurements. Furthermore, STPE is exploited to build unconventional entangled quantum light sources that can simultaneously achieve near-unity entanglement fidelity for spontaneous parametric down-conversion sources and on-demand photon emission for atomic quantum emitters. Our work provides insights into the two-photon process in the quantum regime, which could empower photonic quantum technology with nonlinear quantum radiation.