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chi20190523上海光机所喻虹557593Intensity correlation technology originated from quantum imaging. It utilizes the high-order correlation characteristics of optical field to obtain object information. Due to its high resolution and strong resistance to atmospheric disturbance, it has prospered in the field of imaging for the past decades. X-ray Fourier-transform intensity correlated imaging combing intensity correlation techniques with x-ray imaging provides a new way in x-ray diffraction microscopy. Without necessity for high spatially coherent light source, it can be expected to achieve nanometer resolution for the internal structure examination of samples on tabletop x-ray microscopy systems. However, the monochromaticity of laboratory x-ray sources are poor, and it is difficult to obtain high-quality diffraction pattern of a sample by directly calculating intensity correlation. To solve this problem, the influence of polychromatic light on the Fourier-transform intensity correlated imaging has been investigated, and a correction method for polychromatic Fourie-transform diffraction patterns has been proposed. The results can be also applied to the pulsar measurement with x-ray intensity interferometry, which will enhance the measurement accuracy of a detector with limited energy resolution. This thesis specifically carried out the following work: Based on the basic theory of intensity correlated imaging, the polychromatic intensity correlation function has been derived, and the influence of polychromatic light on the intensity correlated imaging is clarified. The result of intensity correlation calculation of a polychromatic system is the superposition of the sample’s Fourier-transform diffraction patterns of different x-ray wavelengths. On this basis, a method to correct the sample’s diffraction pattern has been proposed. According to the scale relationship between the diffraction patterns of different x-ray wavelengths, a matrix equation between the sample’s diffraction pattern and the polychromatic intensity correlation function is established, and the diffraction pattern can be obtained by solving the equation. According to the parameters of the table-top X-ray Fourier-transform intensity correlated imaging system, a numerical simulation model is set up. The influence of polychromatic light source on the speckle field and the correlated imaging results are analyzed. The distorted diffraction pattern obtained in the simulation is corrected, and the influence of noise on the correction is discussed. The simulation results are validated by visible light experiments, and the recovered spatial distribution of the sample is significantly improved by using the corrected diffraction pattern. The influence of the detector’s energy resolution on the measurement accuracy of the pulsar angular diameter has been explored by numerical simulation. The measurement accuracy of the angular diameter can be significantly improved after the coherence curve correction. Cosmic noise influence on the correction is analyzed. Results are verified with visible light experiments.2019atalunwen2196131111828ocxIntensity Correlation; Polychromatic Light,;X-ray imaging; Pulsar InterferometryResearch on Fourier-transform Intensity Correlation Technique with Polychromatic Light非单色光傅立叶变换强度关联技术研究强度关联技术起源于量子成像,它利用光场的高阶关联特性获取物体信息,由于具有分辨率高、抗大气扰动能力强等性质,近年来在光学成像领域发展迅速。X光傅立叶变换强度关联成像将强度关联测量与X光成像相结合,提供了一种全新的X光衍射显微机制,它对光源的空间相干性要求不高,有望利用台式装置实现样品内部结构纳米分辨。但是实验室X射线源的单色性较差,难以通过强度关联计算直接获得高质量的样品衍射谱。针对这一问题,本文研究了非单色光对傅立叶变换强度关联成像的影响,提出了非单色光傅立叶变换衍射谱校正方法,并将其应用于脉冲星X射线强度关联干涉测量领域,解决了探测器能量分辨率有限造成的测量精度下降问题。 论文具体开展了以下工作: 1、基于强度关联成像基本理论,推导了非单色光强度关联函数表达式,阐明了非单色光对强度关联成像的影响,非单色光强度关联计算的结果是不同波长对应的样品傅立叶变换衍射谱的叠加。在此基础上提出了样品衍射谱校正方法,基于不同波长对应的衍射谱之间的尺度变换关系,可以建立样品衍射谱与非单色光强度关联函数之间的矩阵方程,从而解算出样品衍射谱。 2、参照台式X光傅立叶变换强度关联成像系统参数,建立数值仿真模型,分析了光源非单色性对散斑场以及关联成像结果的影响,对仿真得到的失真衍射谱进行校正,探讨了系统噪声对衍射谱校正的影响。并且通过可见光实验对仿真结果进行了验证,利用校正后的衍射谱获得了质量显著提高的样品实空间分布。 3、仿真研究了X射线强度关联干涉测量中探测器能谱分辨对脉冲星角直径测量精度的影响,相干曲线校正后角直径测量的精度可显著提高,分析了宇宙噪声对相干曲线校正的干扰,并利用可见光进行了实验验证。强度关联;非单色光;X光成像;脉冲星干涉测量中国科学院上海光学精密机械研究所杨善初光学工程硕士
中文题目: 非单色光傅立叶变换强度关联技术研究
外文题目: Research on Fourier-transform Intensity Correlation Technique with Polychromatic Light
作者: 杨善初
导师姓名: 喻虹
学位授予机构: 中国科学院上海光学精密机械研究所
答辩时间: 20190523
中文关键词:
强度关联;非单色光;X光成像;脉冲星干涉测量
英文关键词:
Intensity Correlation; Polychromatic Light,;X-ray imaging; Pulsar Interferometry
中文摘要:
英文摘要:
文献类型:学位论文
学位级别: 硕士
正文语种: chi
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