Scientists achieve high efficiency single photon sources above loss tolerance thresholds
Schematic diagrams of single-photon source systems and the efficiency of single-photon sources above the loss tolerance threshold. (Images by Pan et al.). Credit: USTC
The USTC research team is the first to recognize a high-performance single-photon source with efficiency exceeding the scalable linear optical quantum computing loss tolerance threshold. The study, led by Professors Pan Jiangvai, Lu Chaoyang and Hu Yonggen, was published in Nature Photonics on February 28th.
Photons as important carriers in quantum information processing have the advantages of high speed and strong resistance to environmental interference. However, for scalable linear optical quantum computing to be feasible, the efficiency of a single photon source must exceed a 2/3 tricky threshold, except for challenges such as the easy loss of photons. Previous studies have not broken this threshold. This is an important obstacle limiting the development of optical quantum computing.
To overcome this challenge, the researchers developed an adjustable open optical microsphericity, achieving accurate coupling of quantum dots and microattacks in both resonance frequency and spatial positioning. Microlocals solved the conventional ejection problem of fixed microlocals.
Additionally, the team adopted tailor-type laser pulsed excitation with high-rise efficiency single quantum dots. Excitation significantly improves the overall performance of the single-photon source.
Specifically, the single photon properties of the single photon source exceeded 98.0%, the photon distinction probability exceeded 98.5%, and the system efficiency reached 71.2%.
Furthermore, extraction efficiency exceeded 80.6%, with the 2/3 loss tolerance threshold being breached for the first time.
With the development of this source, the researchers reported a further 40-photon event with a 1.89 db intensity aperture and a counting rate of 1.67 MHz.
This study shows another important step towards an ideal single photon source, achieving the efficiency of the source system above the threshold required to compensate for photon losses in photonic quantum computing.
More information: Xing Ding et al, efficient linear optical quantum computing, a highly efficient single-photon source exceeding the loss tolerance threshold of Nature Photonics (2025). doi: 10.1038/s41566-025-01639-8. on arxiv: doi: 10.48550/arxiv.2311.08347
Provided by the Chinese University of Science and Technology
Citation: Scientists have achieved a highly efficient single-photon source beyond the loss resistance threshold recovered on April 8, 2025 from https://news/2025-04-scientists-scientists-source-photon-source.html from April 8, 2025 (April 7, 2025)
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