2019/07/16 by Hui Wang, Yu-Ming He, Tung Hsun Chung +21 · 1 citation
Physics and Astronomy · #quant-ph #cond-mat.mes-hall #physics.app-ph
paper · pdf · doi:10.1038/s41566-019-0494-3
published as Nature Photonics 13, 770-775 (2019) · 28 pages, 16 figures. partial overlap with arXiv:1809.10992 which was unpublished
arxiv created 2019/07/16 · arxiv updated 2019/12/17
An optimal single-photon source should deterministically deliver one and only one photon at a time, with no trade-off between the source's efficiency and the photon indistinguishability. However, all reported solid-state sources of indistinguishable single photons had to rely on polarization filtering which reduced the efficiency by 50%, which fundamentally limited the scaling of photonic quantum technologies. Here, we overcome this final long-standing challenge by coherently driving quantum dots deterministically coupled to polarization-selective Purcell microcavities--two examples are narrowband, elliptical micropillars and broadband, elliptical Bragg gratings. A polarization-orthogonal excitation-collection scheme is designed to minimize the polarization-filtering loss under resonant excitation. We demonstrate a polarized single-photon efficiency of 0.60+/-0.02 (0.56+/-0.02), a single-photon purity of 0.975+/-0.005 (0.991+/-0.003), and an indistinguishability of 0.975+/-0.006 (0.951+/-0.005) for the micropillar (Bragg grating) device. Our work provides promising solutions for truly optimal single-photon sources combining near-unity indistinguishability and near-unity system efficiency simultaneously.