基于参变下转换效应的光辐射定标方法

Optical Radiometric Calibration Based on Parametric Down-Conversion Effect

介绍了一种新型的基于参变下转换效应的光辐射绝对定标方法,利用固体钛宝石激光器倍频后产生的351nm的激光光源抽运非线性BBO晶体,制备了一对简并的参变下转换光子对(波长为702nm),并利用晶体的角度调谐特性,制备了另一对非简并的参变下转换光子对(波长为633nm和789nm)。定标了光电倍增管的量子效率,介绍了实验原理和定标装置,系统分析了测量过程中引入的不确定度。结果表明,参变下转换效应光辐射定标方法的相对合成不确定度小于5.5%。参变下转换定标方法与传统的基于标准探测器的辐射定标方法作了一个比对,表明两种定标方法相对误差小于10%。

A new calibration method of detectors by using correlated photons generated in spontaneous parametric down-conversion effect of nonlinear crystal is proposed. A CW ultraviolet （351 nm）, diode-pumped, frequencydoubled, solid-state laser is used to pump BBO crystal. The degenerate parametric down-conversion （PDC） photons with wavelengths of 702 nm were produced and by tuning crystal angle, nondegenerate PDC photons with wavelengths of 633nm and 789nm were also produced. The quantum efficiencies of the photomultiplier at the above wavelengths were measured respectively. An absolute calibration system of detector quantum efficiency was performed. And its principle and experimental setup were introduced. The calibration uncertainties of PDC method were analyzed systematically. The results show the total calibration relative uncertainties are less than 5.5 %. In the end, a comparison between PDC effect method and conventional method based on standard detectors was performed. The results show that the relative difference of the two methods is less than 10%.