Noise characteristics analysis and suppression of optical system based on infrared superconducting single-photon detector

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 superconducting single-photon detector has high sensitivity to the analysis of the infrared optical system, and the minimum resolved movement distance is 2.74 x 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.