We build and test a single-photon detector based on a Si avalanche photodiode Excelitas 30902SH thermoelectrically cooled to −100∘C. Our detector has dark count rate below 1 Hz, $500\ \mu\mathrm{m}$ diameter photosensitive area, photon detection efficiency around 50%, afterpulsing less than 0.35%, and timing jitter under 1 ns. These characteristics make it suitable for long-distance free-space quantum communication links, which we briefly discuss. We also report an improved method that we call long-time afterpulsing analysis, used to determine and visualise long trap lifetimes at different temperatures.

中文翻译：

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一种用于长距离自由空间量子通信的低噪声单光子探测器

我们构建并测试了基于 Si 雪崩光电二极管 Excelitas 30902SH 热电冷却至 -100∘C 的单光子探测器。我们的探测器具有低于 1 Hz 的暗计数率、$500\ \mu\mathrm{m}$ 直径光敏面积、约 50% 的光子检测效率、小于 0.35% 的后脉冲和低于 1 ns 的定时抖动。这些特性使其适用于长距离自由空间量子通信链路，我们将对其进行简要讨论。我们还报告了一种改进的方法，我们称之为长时间后脉冲分析，用于确定和可视化不同温度下的长陷阱寿命。