点衍射波前位相的测评

提出一种检测点衍射干涉仪关键部件针孔所产生的衍射光学波前的方法。介绍了点衍射波前的产生原理,分析了小孔质量状态、照明光路调整状态与波前各个像差分量之间的关系。基于信息光学基础理论,采用傅里叶变换和迭代算法,采集针孔衍射图像并进行计算分析,实现对衍射波前的位相复原以获得波前信息。阐述了测试方法的理论依据和计算公式,应用研制的位相复原分析计算软件测试并分析了实际采集的点衍射图像,通过15次的迭代,输出的位相值逐渐收敛,图像误差因子下降到0.12。目前,该方法已用于对针孔的筛选和针孔照明系统的装调中,实验结果证明了该测试方法的可行性。

Test and evaluation of wavefront phase of point diffraction

A testing method was proposed for the diffraction wavefront produced by a pinhole mounted in a point-diffraction interferometer. The producing principle of the point diffraction wavefront was presented, and the relation among the pinhole states, illumination adjustment and the wavefront aberration was analyzed. On the basis of the fundamental theory of information optics, the Fourier transform and an iterative algorithm were used to calculate and analyze the pinhole diffuse image, retrieve the phase of diffraction wavefront and then to obtain the wavefront information. The related theory was discussed and the measured point diffraction image was analyzed through a computing software of phase retrieval. Results indicate that the output phase tends to a convergence after about 15 iterations, and the image error factor has dropped to 0.12. The testing method has been applied to the selection of pinholes and the assembly of pinhole illumination systems, and experimental results prove that the testing method is valid.