探测器光电特性对叠层相干衍射成像的影响  

Effect of detector photoelectric parameters on ptychographic iterative engine

作　　者：齐乃杰 何小亮[1] 吴丽青 刘诚[1] 朱健强[1] Qi Nai-Jie;He Xiao-Liang;Wu Li-Qing;Liu Cheng;Zhu Jian-Qiang(Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]中国科学院上海光学精密机械研究所,上海201800

出　　处：《物理学报》2023年第15期50-64,共15页Acta Physica Sinica

摘　　要：从叠层相干衍射成像的解析求解模型出发,通过在频域中将叠层相干衍射成像描述为待测样品与照明光空间频谱的线性方程组,将探测器的光电参数和线性方程组的个数以及每个方程的未知数个数直接关联.根据方程组存在唯一解的条件,从理论上定量分析叠层相干衍射成像对探测器采样间隔、靶面宽度、像元尺寸、灵敏度和动态范围等关键光电参数的要求以及图像重建所受影响.通过数值模拟,对理论分析和预测的正确性进行了数值验证,得出了参数不理想情况下叠层相干衍射成像仍能获得高质量重建像的物理机制,对于提高重建质量和改进实验装置具有直接促进意义.An analytical solution model for ptychographic iterative engine(PIE)is proposed.In this model,PIE can be described as a system of linear equations between the sample and the illumination in the frequency domain.This system of linear equations(AX=B)is derived with the spectrum of the illumination as the coefficient(A),the spectrum of the sample as the unknown(X),and the intensity of the diffraction pattern as the vector(B).Hence,the sample can be recovered by solving this linear system.In PIE,the detector(such as Pike F-100,AVT)has a large resolution,meaning that 1000×1000 linear equations can be generated by recording a single pattern.It is still the case,however,that the number of obtained equations is smaller than the number of unknowns,leading to the inability to obtain a unique solution about the sample.Relative motions of sample and illumination,can generate more diffraction patterns to construct a sufficient number of linear independent equations.For coefficient(A),since the initial illumination is known,the illumination after shifting can still be obtained by recording its shifting distance.Hence the unique solution for the sample can be directly obtained by solving this linear independent system of equations.Simultaneously,the photoelectric parameters of the detector have a significant influence on the imaging quality of PIE.Using this linear system,the photoelectric parameters of the detector can be characterized by the number of linear equations and unknowns in each equation.According to the conditions that there is a unique solution in the system of equations and the requirements of the photoelectric parameters(such as pixel sampling interval,width of target surface,pixel size,sensitivity and dynamic range),the influence of the reconstruction for PIE is quantified theoretically.Obviously,the numerical simulation results based on this theory not only verify the correctness of the theoretical analysis and predictions,but also reveal the physical mechanism of recovering high-quality results in imperfect

关 键 词：探测器光电特性 相位恢复 相干衍射成像 叠层相干衍射成像 

分 类 号：O436.1[机械工程—光学工程] TP391.41[理学—光学]