SNSPD的物理模型与研究进展

Physical Model and Research Progress of the SNSPD

基于超导原理的超导纳米线单光子探测器(superconducting nanowire single photon detector,SNSPD)以其在高量子效率、高计数率、低暗计数和低时间抖动等方面的优势引起广泛的研究。综述了SNSPD的物理模型和研究进展。首先从第一次在实验上发现超导铅薄膜的电热效应出发讲述了SNSPD的起源。然后从SNSPD进行单光子探测的物理过程出发详细分析了SNSPD的单光子探测机制,并分别根据电热模型和唯象模型对探测机制进行了详细的物理解释。紧接着,详细阐述了量子效率分析模型,指出SNSPD的系统量子效率由本征量子效率、耦合效率和光吸收效率三部分组成。最后,从如何提高入射光子与SNSPD的耦合效率、如何提高光子吸收效率、如何提高SNSPD本征量子效率、研究基于新型材料的SNSPD、如何实现光子数分辨和对光子偏振态不敏感的SNSPD、以及研究SNSPD的噪声机制以减小暗计数和时间抖动等方面详细列举了目前各小组研究SNSPD所取得的最新进展。

Based on the superconducting theory, superconducting nanowire single photon detector （SNSPD） is widely researched because of its inherent advantages such as high quantum efficien- cy, high counting rate, low dark count and low time jitter. The physical model and the research progress of SNSPD are reviewed. Firstly, the origin process of the SNSPD, which is dated from the first found of the electro-thermal effect in superconducting lead film, is elaborated. Then, the detection mechanism of SNSPD is analyzed in detail with the electron-thermal model and pheno- menological model. Following that, the quantum efficiency analysis model is expounded in detail, and it is pointed that the system detection efficiency （SDE） consists of the intrinsic quantum efficiency, the coupling efficiency and the absorption efficiency. Finally, the latest evolutions ofSNSPD are presented on the following aspects： the improvements of the coupling efficiency be- tween the SNSPD and the fiber, the increase of the photon absorption efficiency and intrinsic quantum efficiency of SNSPD, the study of a new kind of SNSPD based on new superconducting materials, the realization of ability to resolve photon number and to be polarization-independent for SNSPD, and the research of noise mechanism for SNSPD to reduce the dark count rate and time jitter, etc.