摘要
高灵敏度的红外探测系统对于远距离探测有巨大的潜力,但光学系统内部的噪声会抑制探测系统的信噪比,从而降低探测灵敏度与探测距离.本文基于红外超导纳米线单光子探测器,设计了一个工作在中红外波段的光学系统,构建了红外光学系统自发辐射计算模型,理论分析了红外光学系统的信噪比和噪声特性.首次提出了利用高性能超导单光子探测器精确表征红外光学系统的微弱背景辐射光信号,为优化设计红外系统提供了依据.并且基于超导单光子探测器的光子计数能力,研究了光学系统的背景辐射对红外探测系统性能的影响,并优化了光学系统的性能.实验结果表明,超导单光子探测器对于分析红外光学系统具有较高的灵敏度,最小可分辨移动距离为2.74×10-2 mm,在黑体温度为100℃时,光子计数率提高了6.4×104 cps(1 cps = 1 cycle per second),光学系统的耦合效率提升了 97%;在黑体温度为 102℃时,光子计数率提高了9.1×104 cps,光学系统的耦合效率提升了 114%,降低了杂散辐射对探测系统的影响,同等条件下系统信噪比提升2.7倍,对于超导红外探测系统的应用研究具有重要意义.
Abstract
Superconducting nanowire single-photon detector is a kind of refrigerated photon-counting detector with high performance,which can detect extremely weak signals.The noise of optical system is an important factor limiting the sensitivity of infrared superconducting nanowire single-photon detector.In order to improve the sensitivity of infrared detection system,the calculation model of signal-to-noise ratio and background radiation of infrared optical system based on superconducting single photon detector is established and the source of noise in optical system and the radiation emission of black body are analyzed theoretically.The noise characteristics of infrared optical system are quantitatively analyzed by photon counting capability of superconducting nanowire single-photon detector,and the relationship between the photon count rate and temperature under a small temperature difference is explored.An optical system based on infrared superconducting single photon detector is designed.The designed optical system improves the infrared photon coupling efficiency and the signal-to-noise ratio of the superconducting detection system,which are verified theoretically and experimentally,thus reducing the influence of background radiation on the detection system.The results show that the super-conducting single-photon detector has high sensitivity to the analysis of the infrared optical system,and the mini-mum resolved movement distance is 2.74×10-2 mm.The physical coupling efficiency of the optical system and the photon count rate of the detection system are improved by optimizing the optical system,and the signal-to-noise ratio of the system increases by 2.7 times under the same conditions.It is expected that this infrared superconducting nanowire single-photon detector can be used in finer and higher precision detection field.
基金项目
国家自然科学基金(12033002)
国家自然科学基金(62101240)
国家自然科学基金(62071218)
国家自然科学基金(6207121461801206)
国家自然科学基金(11227904)
国家重点研发计划(2017YFA0304002)
江苏省自然科学基金(BK202010177)
维普
万方数据