高效、偏振不敏感超导纳米线单光子探测器  

High-efficiency polarization-insensitive superconducting nanowire single photon detector

作　　者：张文英 胡鹏 肖游[1,2,3] 李浩 尤立星[1,2] Zhang Wen-Ying;Hu Peng;Xiao You;Li Hao;You Li-Xing(State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China;Center for Excellence in Superconducting Electronics,Chinese Academy of Sciences,Shanghai 200050,China;University of Chinese Academy of Sciences,Beijing 100039,China;Key Laboratory of Space Active Opto-electronics Technology,Chinese Academy of Sciences,Shanghai 200050,China)

机构地区：[1]中国科学院上海微系统与信息技术研究所,信息功能材料国家重点实验室,上海200050 [2]中国科学院超导电子学卓越创新中心,上海200050 [3]中国科学院大学,北京100039 [4]中国科学院空间主动光电技术重点实验室,上海200050

出　　处：《物理学报》2021年第18期346-352,共7页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFA0304000);国家自然科学基金(批准号:61971408,61827823);上海市市级科技重大专项(批准号:2019SHZDZX01);上海市青年科技启明星项目(批准号:20QA1410900);中国科学院青年创新促进会项目(批准号:2020241);中国科学院空间主动光电技术重点实验室开放课题资助的课题.

摘　　要：超导纳米线单光子探测器(SNSPD)因其优异的综合性能被广泛应用于量子通信等众多领域,然而其独特的线性结构会导致SNSPD的探测效率对入射光的偏振态具有依赖性,从而限制了SNSPD在非常规光纤链路或其他非相干光探测环境中的应用.本文基于传统的回形纳米线结构设计制备了一种新型偏振不敏感SNSPD,在纳米线周围引入一层高折射率Si薄膜作为介质补偿层来提高纳米线对垂直偏振态入射光的吸收效率,并将补偿层的上表面设计为光栅结构以减小不同波长下纳米线对不同偏振态入射光的吸收差异从而实现在特定波长范围内的偏振不敏感.除此之外,还采用介质镜和双层纳米线结构来提高器件的光吸收效率,测试结果表明该器件在1605 nm波长处最大探测效率为87%,对应的偏振消光比为1.06.该工作为未来实现高探测效率的偏振不敏感SNSPD提供了参考依据.Superconducting nanowire single photon detector(SNSPD)has been widely used in many fields such as quantum communication due to its extremely high detection efficiency,low dark count rate,high count rate,and low timing jitter.Compared with conventional single-photon detectors with planar structure,SNSPD is typically made a periodical meandering structure consisting of parallel straight nanowires.However,owing to its unique linear structure,the detection efficiency of SNSPD is dependent on the polarization state of incident light,thus limiting SNSPD’s applications in unconventional fiber links or other incoherent light detection.In this paper,a polarization-insensitive SNSPD with high detection efficiency is proposed based on the traditional meandering nanowire structure.A thin silicon film with a high refractive index is introduced as a cladding layer of nanowires to reduce the dielectric mismatch between the nanowire and its surroundings,thereby improving the optical absorption efficiency of nanowires to the transverse-magnetic(TM)polarized incident light.The cladding layer is designed as a sinusoidal-shaped grating structure to minimize the difference in optical absorption efficiency between the transverse electric(TE)polarized incident light and the TM polarized incident light in a wide wavelength range.In addition,the twin-layer nanowire structure and the dielectric mirror are used to improve the optical absorption efficiency of the device.Our simulation results show that with the optimal parameters,the optical absorption efficiency of nanowires to both of the TE polarized incident light and TM polarized incident light has a maximum of over 90%at 1550 nm,and the corresponding polarization extinction ratio is less than 1.22.The fabricated device possesses a maximum detection efficiency of 87%at 1605 nm and a polarization extinction ratio of 1.06.The measured detection efficiency exceeds 50%with a polarization extinction ratio less than 1.2 in a wavelength range from 1505 nm to 1630 nm.This work provides a ref

关 键 词：超导纳米线单光子探测器 探测效率 偏振不敏感 

分 类 号：O572.212[理学—粒子物理与原子核物理]