Superconducting nanowire single photon detector is a new type of single-photon detection technology that appeared at the beginning of this century. Its detection efficiency, dark counting, time jitter and other performance indicators are obviously superior to the traditional semiconductor single-photon detector, It has been widely used in quantum communication, quantum computing and other fields, and strongly promoted the development of quantum information technology.
At the operating wavelength of 1550 nm for optical fiber communication, the SNSPD manufactured by the US National Institute of Standards and Technology Marsili et al. Using WSi, a cryogenic superconducting material, achieves a maximum probing efficiency of 93%. However, the WSi-SNSPD typically operates at operating temperatures below 1 K , Expensive and complicated deep cryogenic refrigerators (such as dilution refrigerators) must be used, which greatly limits the application of such high-performance single photon detectors.
Many researchers at home and abroad are trying to develop SNSPD using NbN material with higher superconducting transition temperature in order to achieve high detection efficiency at a working temperature above 2K. The miniaturized, user-friendly, closed cycle refrigerator can work, thereby greatly reducing the operating cost After more than 10 years of hard work, the detection efficiency of NbN-SNSPD is up to 80%, which is obviously different from the efficiency of WSi-SNSPD detection.In order to achieve more than 90% detection efficiency, several different parameters, such as light Coupling efficiency, light absorption efficiency, detection efficiency and other intrinsically optimized, so far has not been successfully reported.
Youlixing, a researcher at the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences (superconducting electronics excellence innovation center of the Chinese Academy of Sciences), conducted superconducting single photon detection research for nearly 10 years and made many international achievements in the research and application of detectors , Has been widely concerned at home and abroad with the Pan Jianwei team of the University of Science and Technology of China, has repeatedly created a world record of experiments in the field of quantum information, and keep the world record of 404 km optical fiber communication.
The team's latest results reveal that the detection efficiency (1550 nm operating wavelength) of the NbN-SNSPD system can exceed 90% at a working temperature of 2.1 K, based on a small, closed cycle refrigerator, as the temperature decreases to 1.8 K, the detection efficiency can be further enhanced To 92% .This article is covered in the cover article. Shigehito Miki, a well-known scholar at SNSPD, a research institute of Japanese intelligence and communication, gave a lecture on Quest towards ultimate performance in superconducting nanowire single photon The first author of the dissertation is assistant researcher Zhang Weijun and the writer of communication is You Lising.
After the publication of the dissertation, it received widespread attention, many foreign media reported or reproduced the results.This work won the national key R & D project 'high-performance single-photon detection technology', the Chinese Academy of Sciences Class B strategic pilot science and technology 'superconducting electronic devices Basic research ', the National Natural Science Foundation and the Shanghai Municipal Science and Technology Commission and other funding.
