Reducing current crowding in meander superconducting strip single-photon detectors by thickening bends
Reducing current crowding in meander superconducting strip single-photon detectors by thickening bends
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DOI：
10.1088/1361-6668/ac5fe4
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发表时间：
2021-12
影响因子：
3.6
通讯作者：
J. Xiong;Weijun Zhang;Guangzhao Xu;L. You;Xingyu Zhang;Lu Zhang;Cheng-Jun Zhang;D-H Fan;Yu-Ze Wang;Hao Li;Zhen Wang
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文献类型：
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作者：
J. Xiong;Weijun Zhang;Guangzhao Xu;L. You;Xingyu Zhang;Lu Zhang;Cheng-Jun Zhang;D-H Fan;Yu-Ze Wang;Hao Li;Zhen Wang
超导纳米/微带单光子探测器（SNSPD/SMSPD）的有源区通常被设计成具有高填充因子（例如0.5）的曲折结构，以实现高的光耦合效率和吸收率。然而，SNSPD/SMSPD的切换电流（I sw）（检测器切换到正常状态时）受到几何形状引起的“电流拥挤效应”的显著抑制，其中条带中存在急剧弯曲。在这里，我们提出并实验验证了一种替代方法，以减少电流拥挤SNSPD和SMSPD通过直接增加弯曲的厚度，通过沉积和剥离的次级超导膜。我们测量和比较SNSPD和SMSPD的性能与不同的填充因子和弯曲配置，有或没有加厚弯曲。改进的检测器中观察到的检测效率，固有的暗计数率，和时间抖动，由于增强的I SW。我们的方法提供了一个很有前途的方式优化SNSPD/SMSPD检测性能。
To facilitate high optical coupling efficiency and absorptance, the active area of a superconducting nano/microstrip single-photon detector (SNSPD/SMSPD) is often designed as a meander configuration with a high filling factor (e.g. ⩾0.5). However, the switching current (I sw) of SNSPD/SMSPD, at which the detector switches into the normal state, is significantly suppressed by a geometry-induced ‘current crowding effect’, where there are sharp bends in the strip. Here, we propose and experimentally verify an alternative method to reduce current crowding both in SNSPD and SMSPD by directly increasing the thickness of the bends through the deposition and lift-off of a secondary superconducting film. We measure and compare the performance of SNSPDs and SMSPDs with different filling factors and bend configurations, with or without thickened bends. Improvements for detectors were observed in detection efficiency, intrinsic dark count rate, and time jitter, owing to the enhanced I sw. Our method provides a promising way of optimizing SNSPD/SMSPD detection performance.