针对目前尚无高精度通用倍率测量方法与装置的问题,提出了基于双光纤点衍射干涉仪的成像系统倍率高精度测量方法。通过分析双点光源间距、CCD相机空间位置与点衍射干涉场相位Zernike多项式系数之间的定量关系,得到物面光纤间距和像面光纤像点间距的纳米级精度测量值,进而完成对倍率的高精度测量。分别进行仿真分析和实验验证,证明了所提测量方法的可行性和稳定性。结果表明,倍率测量的扩展不确定度为2.64×10 ^-6。所提出的成像系统倍率高精度测量方法具有测量精度高和测量效率高的特点,且具备高可靠性,可以用于显微物镜、光刻投影物镜等高精度成像系统倍率的超高精度测量。

In the view of the problem that there is no high precision universal magnification measurement methods and apparatus at present, a high precision magnification measuring method for imaging system based on double fiber point-diffraction interferometer is proposed. The separation distance between two fibers in object plane and the separation distance between the fibers’ imaging points in image plane are measured with nanometer accuracy by analyzing the quantitative relationship among the separation distance between double point source, spatial location of CCD camera and the Zernike polynomial coefficients of the phase distribution of the point-diffraction interference field. And then, high precision magnification measurement is achieved. Simulation and experimental verification have been carried out to demonstrate the feasibility and stability of the proposed measuring method. The results show that the expanded uncertainty of the magnification measurement is 2.64×10 -6. The proposed method has the merits of high accuracy, high efficiency and high reliability. It can be used to measure the magnification of high accuracy imaging system with ultra-high precision, such as microscope objectives and lithographic projection lens.