超导纳米线单光子探测器光子响应机制研究进展

Research progress of photon response mechanism of superconducting nanowire single photon detector

超导纳米线单光子探测器(SNSPD)已在量子信息、深空激光通信、激光雷达等众多领域发挥了重要的作用.虽然SNSPD经过二十年的研究,但其光子响应本征机制还有待完善.深入理解与厘清其光子响应过程是研发高性能探测器的前提与关键.现在较为成熟的超导纳米线单光子探测器响应理论有热点模型和涡旋模型.但是这两种理论都存在一定的缺陷,前者存在截止波长,后者存在尺寸效应,都需要进一步完善.超导相位滑移是超导体的内禀性耗散,有望用于解释超导纳米线单光子探测器的光子响应过程,形成统一完备的理论.这三种模型是对SNSPD光子检测理解的不断深入:热点模型是一种唯象模型,研究电子-声子等准粒子体系的相互作用;涡旋模型由Ginzburg-Landau方程和电磁学方程出发,研究涡旋在超导体中的运动及其带来的超导态耗散;相位滑移模型是基于量子力学的解释,研究热扰动和宏观量子隧穿引发的超导态耗散.本文综述了热点模型、涡旋模型和超导相位滑移的基本概念、发展历史和研究进展,讨论和对比了这三种理论的特点和发展前景,为超导纳米线单光子探测器光子检测理论研究提供参考和借鉴.

Superconducting nanowire single photon detector(SNSPD) plays a significant role in plenty of fields such as quantum information,deep space laser communication and lidar,while the mechanism of the photon response process still lacks a recognized theory.It is prerequisite and essential for fabricating high-performance SNSPD to understand in depth and clarify the photon response mechanism of the SNSPD.As mature theories on the SNSPD response progress,hot-spot model and vortex-based model both have their disadvantages:in the former there exists the cut-off wavelength and in the later there is the size effect,so they both need further improving.The Cut-off wavelength means that the detection efficiency of the SNSPD drops to zero with the increase of light wavelength,which is indicated by the hot-spot model but not yet observed in experiment.The size effect implies that the vortex does not exist in the weak link with the width less than 4.41ζ,where ζ is the GL coherence length.Phase slip is responsible for the intrinsic dissipation of superconductors,which promises to expound the SNSPD photon response progress and to establish a complete theory.This paper reviews and discusses the fundamental conception,the development history and the research progress of the hot-spot models,i.e.the vortex-based model and the superconductor phase slips,providing a reference for studying the SNSPD photon response mechanism.