Pan Jianwei’s team at the University of Science and Technology of China realizes a single-photon source with the best performance in the world
University of Science and Technology of China Pan Jianwei, Lu Chaoyang and others realized the first semiconductor-based semiconductor in the world The high efficiency and highly isotropic single photon source of quantum dots has achieved the best comprehensive performance in the world, laying a scientific foundation for the realization of large-scale photon entanglement and quantum information technology based on solid-state systems.
The internationally authoritative academic journal "Physical Review Letters" recently published this research result in the form of "Editor's Recommendation" and wrote a special article on the Physics website of the American Physical Society.
Quantum dots are semiconductor quantum devices prepared by molecular beam epitaxy. They are also known as "artificial atoms". In principle, they can provide ideal single devices for quantum information technology. photon source.
In order to be truly used in scalable and practical quantum information technology, single-photon devices must simultaneously meet three core performance indicators: single-photon properties, high isotacticity and high extraction efficiency.
Although many international research institutions (including the University of California, Stanford University, Cambridge University, etc.) have conducted long-term and extensive exploration of quantum dot optical control since 2000, these three core indicators have always been cannot be satisfied at the same time, thus becoming a major unresolved challenge in the field of solid-state quantum optics in the past 15 years.
In 2013, Pan Jianwei, Lu Chaoyang and others pioneered the pulse resonance excitation of quantum dots, achieving what was thenThe best isotropic single photon source in the world.
However, due to the limitations of the quantum dot planar cavity structure, the fluorescence collection efficiency was low in previous experiments.
In order to greatly improve the fluorescence extraction efficiency, the researchers used a combination of high-precision molecular beam epitaxial growth and nano-etching processes to obtain a high-quality factor optical resonant cavity that resonates with the single-photon frequency of quantum dots at low temperatures.
As a result, the extraction efficiency of the single-photon source produced by the experiment reached 66%, the single-photon property was better than 99.1%, and the isotacticity was better than 98.6%. It was the first time in the world that the three key issues of single-photon sources were simultaneously solved. problem, becoming the single-photon source with the best comprehensive performance in the world.
The brightness of the experimentally realized quantum dot single photon source is 10 times higher than the world's best triggered single photon based on parametric down conversion. It also has near-perfect isomorphism and the required laser pump power consumption is reduced by 10 million times. (on the nanowatt scale), such quantum dot single-photon sources can be used in large-scale photon entanglement in the future, further promoting the development of multi-photon entanglement and interferometry.
The reviewer evaluated this research result as an "experimental masterpiece" (tour-de-force) and "has important influence in the field."
"Nature" magazine made a special report in the latest issue of "Research Highlights" column under the title "Practical Single Photon Source".
