X射线激光全息的理论研究

在对实验室Ｘ射线激光空间相干性理论研究的基础上，提出了Ｘ射线激光全息的一种可行的原理性光路设计，对无透镜产叶变换全息的记录和再现过程进行了理论模拟。     

部分相干X射线相位成像研究

研究了基于同轴伽柏（Ｇａｂｏｒ）Ｘ射线全息方法的Ｘ射线相位成像。应用部分相干光的轴ＧａｂｏｒＸ射线全息理论,分析了射光的部分相干性对直接Ｘ射线相位成像的影响,指出相干性直接成像的影响不是很大,并研究了Ｘ射线相位全息。讨论了入射光的部分相干性、记录介质的有限分辨、物体与记录介质的准直程度和腹复原的位置等因素对成像质量的影响。证明了物体与记录介质的不准直是影响相位成像质量的最重要因素,给出了纵向记录长     

数字重现无透镜傅里叶变换X射线全息的实验模拟研究

参照无透镜傅里叶变换（ＬＬＦＴ）Ｘ射线全息图的记录光路，采用可见光源模拟研究了无透镜傅里叶变换Ｘ射线全息从记录到数字重现的全过程，给出了实验结果，并对光学重现和数字重现结果作了比较，分析了该记录方式存在的一些问题，指出实际Ｘ射线全息记录中可直接使用波带板＋１级衍射而不必在物面加一滤波小孔。分析了利用数字重现消除记录过程中非线性效应的可行性。并着重指出波带板的多级衍射的互干涉对重现象的干扰，应设法消除。     

X射线全息记录过程中影响分辨率的主要因素分析

分析了Ｘ射线全息记录过程中影响分辨率的一些主要因素。在完全相干的条件下，Ｘ射线无透镜傅里叶变换全息图的最小分辨距离不可能小于记录时用的Ｘ射线聚束器的焦斑或滤波小孔的半径，而Ｘ射线同轴全息图不可能获得比记录介质的截止频率更高的分辨率。在部分相干的条件下，Ｘ射线无透镜傅里叶变换全息所要求的相干长度和分辨率与样品半径成二次线型关系。Ｙ射线同轴全息所要求的相干长度和分辨率的平方以及样品到全息图的距离成正比，而与样品尺寸无关。随着Ｘ射线全息图分辨率的提高，其所要求的相干长度将大幅度增长。 关键词：     

用全息透镜记录多重分数傅里叶变换全息图

提出一种全息透镜记录多重分数傅里叶变换全息图的新方法，它能在三维空间不同位置和不同方向上分别再现所记录的多个物体的图象，分析了利用全息透镜记录多重分数傅里叶变换全息图的原理及特点，制作了多重分数傅里叶变换全息图，并获得了满意的再现结果。     

全息透镜用于彩色胶片全息高密度存储

本文提出一种利用全息透镜实现彩色胶片全息高密度存储的方法。用红、绿、蓝三基色激光分别记录三个焦距相同的全息透镜,用三个全息透镜依次用三基色波长记录胶片的傅氏全息图,用原参考光照明再现,可合成彩色像。     

可见光再现X射线无透镜傅里叶变换全息图的可行性研究

本文探讨了可见光再现Ｘ射线无透镜傅里叶变换全息图的可行性问题，结论是，可见光再现Ｘ射线无透镜傅里叶变换全息图，可以做到不但没有球差，而且在一定条件下慧差也可完全消除，其余像差也可校正最小，以臻忽略不计。     

用变形全息透镜实现变形分数傅里叶变换

利用一发散点光源和一束倾斜平行光制作出在两个垂直方向上具有不同焦距的变形全息透镜,且用此全息元件实现了变形分数傅里叶变换。变形全息透镜两个方向上的焦距随全息记录条件和再现条件而变化,分析了用这种全息透镜实现变形分数傅里叶变换的条件。实验表明,用该元件能够方便地实现任意级次的变形分数傅里叶变换。     

无透镜傅里叶变换型全息瞄准具研究

基于无透镜傅里叶变换全息术制作了一种新型激光全息瞄准具。瞄准具的核心部件是由一块无透镜傅里叶变换位相全息图和一块全息光束变换器组成的全息光学元件。其突出优点是大视场,大出瞳距离,适合双眼瞄准。此外,瞄准线为明亮的虚像,不会暴露目标,结构简单,对射击近距离运动目标效果突出。介绍了全息瞄准具组件的原理和制作方法,并对其性能进行了分析。     

数字全息成像系统的景深和焦深分析

根据全息理论,分析了数字全息成像系统的景深和焦深.针对数字全息不同的记录光路结构,分别给出了焦深的近似表达式.结果表明：数字全息系统的景深和焦深不仅与记录波长以及记录时的数值孔径有关,还与记录时参考光波的偏置情况有关;在记录距离和CCD参量一定的条件下,离轴无透镜傅里叶变换全息对称偏置下的焦深比非对称偏置下的稍小;显微成像情况下离轴无透镜傅里叶变换全息系统的焦深大于同轴菲涅耳数字全息系统的焦深,计算机模拟表明了结果的正确性.     

位相恢复法与X射线激光等离子体密度诊断

 详细介绍了XUV波段Gabor全息及位相恢复法去除Gabor全息孪生像的全部过程,分析了X射线激光Gabor全息术对等离子体和实验条件的要求,编程对全息图的制作、反演以及位相恢复法的全过程进行了模拟,并对三个模型进行了计算比较。     

THEORETICAL STUDY ON THE DIRECT RECONSTRUCTION OF LLFT X-RAY HOLOGRAM WITH VISIBLE LIGHT

Reconstructing X-ray hologram with visible light, without enlargement of it, can sim-plify the process of its reconstrution greatly. For lensless Fourier transform (LLFT) X-ray holography, there is no spherical aberration in it and the spacing of its interference fringes is relatively large. Therefore, it is possible to reconstruct hologram of this type directly with visible light. The effects of aberrations and emulsion shrinkage on the resolution of LLFT X-ray hologram, the conditions for perfect reconstructing of the recorded information are analyzed, and the results of corresponding numerical analyses are also given. As a result, the legibility for direct reconstructing of LLFT X-ray hologram with visible light is verified theoretically, In addition, the longitudinal resolution in X-ray holography is analyzed, and the conditione for longitudinal resolving in X-ray holography are given from the relationship between longitudinal and transverse resolution.     

X-ray interferometric Fresnel holography

The X-ray interferometric Fresnel holography was proposed and theoretically investigated. It was shown that under definite conditions the recorded interference pattern formed at the output surface ofthe analyzer crystal (the third block of interferometer) is the X-ray interferometric hologram (generally the Fresnel one) of the object under investigation. Further reconstruction of an image is performed with the help of visible light or a numerical method. As an example the recording of a Fresnel hologram of the simplest case of one-dimensional object, a narrow slit, and the reconstruction of an image by means of visible light were considered. This method may be used in X-ray microscopy and realized using synchrotron sources ofX-ray radiation, as well as X-ray free electron lasers.     

X光Gabor波带片编码成像技术实验研究

 基于星光II实验装置进行了Gabor波带片编码成像探索性实验研究。采用束匀滑光斑三倍频激光打靶，辐照专门设计的ＣＨ埋金属条靶（共两种），产生了有明确形状、边缘清晰的等离子体。研制了专门的Gabor波带片编码相机，并利用该相机采用单张胶片对不同的靶目标在不同的深度层次上曝光的技术，获得了具有深度层次信息的三维激光等离子体编码像。利用数值重建技术对实验所获得的图像解码，最终获得了在不同深度层次上的激光等离子体信息。     

Aberration analysis and elimination in image reconstruction from X-ray holograms

Aberrations in the reconstruction of images are analysed, aberration elimination methods are discussed and the feasibility of direct image reconstruction from a lensless Fourier transform X-ray hologram with visible light is investigated.     

Study on the reduction of speckle noise in the reconstructed image of digital hologram

As one of the most important 3-D display technique, reduction of speckle noise in the reconstructed image of digital holography should be grounded on the digital hologram itself. Based on the whole process of the recording and reconstruction of digital holography, the optical distributions of recorded object and reconstructed image of digital holography have been studied. It has been proposed that the root formation cause of speckle noise in its reconstructed image is the speckle noise formed on the recorded object surface when illuminated by coherent light because of its optical roughness. A novel approach has been presented to reduce speckle noise in digital holography by changing the interference structure of hologram itself. First, by reducing the speckle noise in the reconstructed image, the distribution of ideal reconstruction light with reduced speckle noise is acquired. Then in turn, taking the ideal reconstruction light with reduced speckle noise as ideal object light, a new hologram can be rebuilt, which can reconstruct the ideal object light. The experimental results are given to confirm the proposed method. Therefore, it offers a brand-new thought and practical way to reduce the speckle noise in the reconstructed image of digital holography.     

基于Hilbert变换实现数字全息高精度相位重建

为了提高数字全息相位重建精度,研究了基于Hilbert变换重建相位的理论和方法,并通过像面数字全息实验对该方法的有效性进行了验证,同时与数字全息常规重建方法得到的结果进行了比较.结果表明:Hilbert变换本身具有消除直流项的作用,对利用频域滤波滤除零级谱后的全息图进行Hilbert变换,能够彻底消除零级衍射项的干扰,从而提高相位重建精度.与常规重建结果相比,基于Hilbert变换的相位重建结果的标准偏差降低了14.0%.本文结果对提高数字全息相位重建精度具有重要的指导意义.     

X-ray interferometric Fourier holography

An X-ray interferometric Fourier holography was proposed and theoretically investigated. X-ray Interferometric Young fringes and the reconstruction of an object image were investigated by the Fourier transform method. It was shown that on the output surface of the analyzer crystal (the third plate of the interferometer) the interference pattern of two slits gives X-ray interferometric Young fringes. An expression for the period of X-ray interferometric Young fringes was obtained. The subsequent reconstruction of the slit image as an object is conducted by means of the Fourier transform method of intensity distribution on the hologram. Three methods for reconstruction of the function of complex transmission of the object are presented: an analytical one–the approximate method, the iteration method and the step-by-step approach. As examples a recording of X-ray interferometric Fourier hologram and the reconstruction of the function of complex amplitude transmission of a beryllium circular cylinder are given.     

一种三维全息图的数字化实现方法

提出一种实现三维显示的新方法,从两步法彩虹全息基本原理出发,通过分区域分幅的方式对多视角图形的波前进行数字化编码,获得夫琅和费光场分布,在位相型硅基液晶空间光调制器上按视角顺序输入该信息,利用透镜的傅里叶变换特性再现多视角子图像,干涉法逐区域拼接获得完整三维图像.最后通过实验获得了三维图像样品,验证了该方法.本方法可成为三维显示的重要技术手段.     

数字无透镜傅里叶变换全息术中非傍轴及离焦像差的校正

对数字无透镜傅里叶变换全息图直接采用逆傅里叶变换进行物场的数值重建时.需要满足两个条件:第一,全息图的记录过程必须满足傍轴近似条件,否则再现过程中会产生非傍轴像差;第二,记录全息图时物平面与参考点光源到全息图记录平面的距离必须相等,否则再现过程中会产生离焦像差.理论分析了非傍轴及离焦记录条件下数字无透镜傅里叶变换全息图的灰度分布特点,并提出了相应的非傍轴及离焦像差的数值校正方法.根据实际的非傍轴或离焦记录情况.分别给所记录的数字全息图灰度分布矩阵乘以适当的非傍轴或离焦校正因子,以消除灰度矩阵中非傍轴或离焦因素的影响.然后再对校正后的伞息图灰度矩阵做逆傅里叶变换处理.即可得到准确的数字再现像.实验结果表明.该数值重建方法能够有效地消除无透镜傅里叶变换全息术中数字再现像的非傍轴像差及离焦像差,提高再现像的质量.