利用基于参量下转换产生的相关光子可以实现“无溯源”的绝对定标。该定标方法推广应用于模拟探测器定标的过程中,其中获 取高通量的相关光子是一个重要的难点。介绍了一种基于自发参量下转换制备高通量相关光子的方法原理和实验装置。 采用532 nm连续激光泵浦周期性极化铌酸锂(PPLN)晶体,在满足准相位匹配(QPM)方式下产生高通量的纠缠光源,改变泵浦 光源的功率,实验结果显示具有较好的线性。叙述了准相位匹配技术原理,搭建了制备高通量相关光子的实验装置,并优化 了泵浦激光光源和各光学元器件的设计参数。该研究结果为后期进行高精度定标和模拟探测奠定了基础。

Absolute calibration can be realized by means of correlation photon which is generated by the spontaneous parametric down-conversion. The main difficulty of using correlation photons method to realize the absolute calibration of analog detectors is to acquire ultra-bright entangled photons. The calibration principle and experimental device of acquiring ultra-bright correlation photons were described based on spontaneous parametric down-conversion. A laser (532 nm) was used to pump the nonlinear crystal periodically-poled lithium niobate (PPLN), and ultra-bright entanglement source satisfing the quasi-phase matching (QPM) manner was produced. The measurement result shows good linearity when pump laser power is different. The principle of phase matching technology was described and the preparation of the experiment device of ultra-bright correlation photons was set up, the pump laser light source and the design parameters of the optical components were improved. This novel method shows great significance to high-accuracy calibration for the wavelength of correlation photons and the future researches on analog detector.