Research teams from USTC have realized a high-performance single-photon source with an efficiency beyond the scalable linear optical quantum computing loss tolerance threshold for the first time. Led by Prof. Pan Jianwei, Lu Chaoyang and Hu Yongheng, the study was published in Nature Photonics on February 28.

Photons, as important carriers for quantum information processing, have the advantages of fast speed and strong resistance to environmental interference. However, for scalable linear optical quantum computing to be feasible, apart from the challenges like photons being easily lost, the efficiency of a single-photon source must exceed the tricky threshold of 2/3. Previous studies had never broken through this threshold, a key obstacle restricting the development of optical quantum computing.

To overcome this challenge, the research teams have developed a tunable open optical microcavity, achieving precise coupling of quantum dots and microcavities in both resonance frequency and spatial positioning. The microcavity solved the detuning problem of traditional fixed microcavities.