研究相关光子光场的光谱分布对基于自发参量下转换的光电探测器的宽波段辐射定标具有重要意义。建立了相关光子宽光谱分布测量实验系统。利用355 nm 连续波(CW)激光抽运BBO 晶体产生I 类非共线自发参量下转换，使用光子计数系统测量了相关光子在晶体后端的光谱分布，测量的相关光子光谱分布带宽为259 nm(550~808 nm)。相关光子的光谱角分布测量结果与理论模拟结果近似，相对误差小于2%。实验结果表明相关光子存在着可见-近红外宽波段光谱分布，有望应用于光电探测器的宽光谱定标。

Research on spectrum distribution of correlated photon optics-field has great significance in terms of the calibration for photoelectric detector in broadband spectrum based on spontaneous parametric down-conversion. An experiment is set up to measure the distribution of correlated photon broadband spectrum. A continuous wave 355 nm laser and a photon counting system are used to pump the β -barium borate (BBO) crystal to product type I spontaneous parametric down-conversion in the regime of nonlinear and the spectrum distribution of correlated photon outside the BBO crystal is measured, respectively. The bandwidth of correlated photon spectrum in experiment is 259 nm (550~808 nm). The angle distribution result in experiment is in accordance with the theory prediction, with the angle distribution difference less than 2%. It is turned out that a broad band spectrum distribution from visible to near infrared exists with respect to correlated photon. It is promising to be applied to calibration for photoelectric detector in broadband spectrum.