具有3~5μm宽带光吸收特性的超导纳米线单光子探测器设计  

Design of Superconducting Nanowire Single-Photon Detector with Broadband Light Absorption Characteristics in 3-5μm

作　　者：赵雨辰[1] 赵博洋 郑家欢 原艳宁[1] 席晓莉[1] Zhao Yuchen;Zhao Boyang;Zheng Jiahuan;Yuan Yanning;Xi Xiaoli(College of Automation and Information Engineering,Xi’an University of Technology,Xi’an,Shannxi 710048,China)

机构地区：[1]西安理工大学自动化与信息工程学院,陕西西安710048

出　　处：《激光与光电子学进展》2022年第1期90-96,共7页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(61971346);西安理工大学科研基金(103-451319009,103-451420002)。

摘　　要：与成熟的近红外波段设计相比,3~5μm波长范围内较低的光子能量对于超导纳米线单光子探测器(SNSPD)宽带光吸收特性设计提出了更高的要求。为此,提出了一种中红外波段SNSPD宽带光吸收特性设计方法。以加载SiO_(2)/Au反射腔的超窄纳米线结构SNSPD为例,在通过优化上下腔3层介质层厚度实现2个目标波长处阻抗匹配的基础上,引入介质层总厚度与谐振波长之比作为评价每个谐振波长处带宽特性的指标,更好地取得了阻抗匹配精度与带宽特性之间的平衡,从而达到了双宽带耦合谐振以拓展总体吸收带宽的目的。数值结果表明,所提SNSPD在2928~4856 nm波长范围内对电场分量平行于纳米线的入射光能够吸收至少50%。Compared with the mature design in near-infrared band,the lower photon energy in the 3-5μm wavelength range puts forward higher requirements for the design of broadband optical absorption characteristics of superconducting nanowire single-photon detector(SNSPD).Therefore,a design method of broadband optical absorption characteristics of SNSPD in mid infrared band is proposed.Taking the ultra narrow nanowire structure SNSPD loaded with SiO2/Au reflective cavity as an example,on the basis of realizing impedance matching at two target wavelengths by optimizing the thickness of three dielectric layers in the upper and lower cavities,the ratio of total dielectric layer thickness to resonant wavelength is introduced as an index to evaluate the bandwidth characteristics at each resonant wavelength,so as to better achieve the balance between impedance matching accuracy and bandwidth characteristics,thus,the purpose of double broadband coupling resonance to expand the overall absorption bandwidth is achieved.The numerical results show that the proposed SNSPD can absorb at least 50% of the incident light whose electric field component is parallel to the nanowires in the wavelength range of 2928-4856 nm.

关 键 词：探测器 超导纳米线单光子探测器 宽带光吸收 中红外 3~5μm 

分 类 号：TN215[电子电信—物理电子学]