对铌/铝超导纳米线单光子探测器(SNSPD)的光耦合结构和性能表征进行了研究。通过溅射与剥离的方法制作了超薄铌/铝SNSPD,设计了带有激光准直器的光耦合结构和封装方法,并搭建了可靠的低温测试系统。在700mK下表征了SNSPD的直流特性,得到了单光子响应脉冲和1550nm波长下的探测效率,并研究了探测效率和暗计数率与偏置电流的关系。
The authors investigated Nb/Al superconducting nanowire single photon detectors (SNSPD) , fabricated SNSPD made of Nb based on silicon substrate with Al as protecting layer. To characterize optical and electrical performance, a reliable cryogenic research system was built up. A packaging structure with collimator was proved to meet the needs for light coupling. By this way, the authors obtained single photon response as well as detection efficiency at 700inK using 1550nm infrared light. Relations between detection efficiency and biasing current were also investigated.