We report our study of detection efficiency (DE) saturation in wavelength range 400–1550 nm for the NbN superconducting microstrip single-photon detectors (SMSPDs) featuring the strip width up to 3 m. We observe an expected decrease of the DE saturation plateau with the increase of photon wavelength and decrease of film sheet resistance. At 1.7 K temperature DE saturation can be clearly observed at 1550 nm wavelength in strip with the width up to 2 m when sheet resistance of the film is above 630 Ω sq⁻¹. In such strips the length of the saturation plateau almost does not depend on the strip width. We used these films to make meander-shaped detectors with the light sensitive area from 20 20 m² to a circle 50 m in diameter. In the latter case, the detector with the strip width of 0.49 m demonstrates saturation of DE up to 1064 nm wavelength. Although DE at 1310 and 1550 nm is not saturated, it is as high as 60%. The response time is limited by the kinetic inductance and equals to 20 ns (by 1/e decay), timing jitter is 44 ps. When coupled to multi-mode fibre large-area meanders demonstrate significantly higher dark count rate which we attribute to thermal background photons, thus advanced filtering technique would be required for practical applications.

我们报告了我们对 NbN 超导微带单光子探测器 (SMSPD) 在 400-1550 nm 波长范围内的探测效率 (DE) 饱和度的研究，该探测器的条带宽度高达 3 米。我们观察到随着光子波长的增加和薄膜薄层电阻的降低，DE 饱和平台预期减少。在 1.7 K 温度下，在 1550 nm 波长处可以清楚地观察到 DE 饱和，条带宽度可达 2m 当薄膜的薄层电阻高于 630 Ω sq ^{-1 时}。在这种带钢中，饱和平台的长度几乎不取决于带钢宽度。我们用这些薄膜制作了光敏面积从 20 20m ²到一个圆 50米直径。在后一种情况下，检测器的条宽为 0.49m 表明 DE 达到 1064 nm 波长的饱和度。虽然 1310 和 1550 nm 处的 DE 未饱和，但高达 60%。响应时间受动态电感限制，等于 20 ns（按 1/ e衰减），时序抖动为 44 ps。当与多模光纤耦合时，大面积弯曲表现出显着更高的暗计数率，我们将其归因于热背景光子，因此实际应用需要先进的过滤技术。