水窗波段附近激光等离子体X光辐射产生的途径

讨论了利用激光等离子体产生水窗波段Ｘ光辐射的可能途径。靶材，即原子序数的选取是决定产生这一波段辐射的基本因素，利用激光等离子体的平衡态和非平衡态特性都可在水窗波段产生亮度Ｘ光辐射，提出利用黑体辐射来实现水窗波段Ｘ光显微成像研究的方案。     

同轴软X射线全息成像及其数字重视

用光刻胶记录了水窗波段同轴Ｘ射线全息图，并以数字方法再现了原物像。所用光源为彘线怀单色仪单色化的８００ＭｅＶ电子储存环弯铁辐射（３．２０ｎｍ），再现物体的分辨率为２μｍ并有较大提高的可能性。     

实现水窗波段X射线激光的途径

研究了类氢、类氦、类锂和类钠离子等四种实现复合机制Ｘ射线激光的方案，对可能实现水窗波段Ｘ射线激光的几种方案比较，分析了其各种的优缺点，并讨论了可能的具体实验方法。     

软X射线显微术活体材料成像的实验研究

软Ｘ射线显微术活体材料成像的实验研究蒋诗平张新夷阚娅付绍军徐向东单晓斌（中国科学技术大学国家同步辐射实验室，合肥２３００２９）陈建文徐至展陈敏（中国科学院上海光学精密机械研究所，上海２０１８００）软Ｘ射线显微术可以研究完整的不染色的活体细胞显微结构，...     

同轴软X射线全息成像及其数字重现

用光刻胶记录了水窗波段同轴Ｘ射线全息图,并以数字方法再现了原物像。所用光源为经线性单色仪单色化的８００ＭｅＶ电子储存环弯铁辐射（３．２０ｎｍ）。再现物体的分辨率为２μｍ,并有较大提高的可能性     

“水窗”波段类Li离子各电离态的电离能

用相对论多组成Ｄｉｒａｃ－Ｆｏｃｋ方法计算了“水窗”波段类Ｌｉ离子各电离态的电离能，这些能量对于优化复合泵浦软Ｘ射线激光机制具有重要意义。     

短密度梯度尺度等离子体中的软X射线激光

通过数值求解等离子体流体力学方程组，研究了短脉冲激光打靶结束后形成的短密度梯度尺度等离子体的冷降温过程，讨论了热传导，膨胀作功，辐射损失三种冷却机制对降温过程的贡献，并用解流体力学方程组得到的等离子参数计算ＭｇＸＩ等离子体中波长小于２０ｎｍ的所有可能跃迁的自发辐射放大增益系数，分析了它们与环境条件的关系，指出了在ＭｇＸＩ等离子体中获取水窗附近乃至水窗波段软Ｘ射线激光的可能性。     

水窗波段反射式偏振光学元件的设计和制作

水窗波段是软X射线进行生物活细胞显微成像的最佳波段,因此对于水窗波段偏振光学元件的研究有着非常重要的意义。用菲涅耳公式计算出在水窗波段内不同材料组合对应不同波长的最大反射率,模拟分析了多层膜周期和表界面粗糙度对多层膜偏振光学元件性能的影响。用超高真空磁控溅射镀膜设备,制作出2．40nm、3．00nm和4．30nm波长处W／B4C多层膜偏振元件,并用X射线衍射仪对元件的周期厚度进行了测量,得到的测量结果与设计值偏差很小,可以进行实际应用。为水窗波段反射式偏振光学元件的研究提供了理论依据,同时也为相应偏振光学元件的制备确定了合适的工艺参量。     

X射线波带片的制作及其应用

波带片的低衍射效率限制其在可见光波段的使用,可是在Ｘ射线波段,波带片是唯一达到衍射极限的光学元件,因而引起人们的极大兴趣。本文介绍了当前国际上Ｘ射线波带片的主要制作方法及其应用,同时回顾了用于Ｘ射线聚焦、成像的光学元件——Ｘ射线菲涅耳波带片及近几年才出现的布拉格－菲涅耳波带片的历史背景、基本概念和主要类型。     

上海软X射线自由电子激光外种子运行模式的模拟研究

上海软X射线自由电子激光用户装置（SXFEL）是我国首台可以运行在水窗波段的自由电子激光装置,未来可以为5个实验线站供光,其主要运行模式为自放大自发辐射模式以及外种子模式。本文就SXFEL的外种子模式进行了从头到尾的模拟研究,主要包括EEHG-HGHG混合级联与单级EEHG两种方案。模拟结果表明,虽然EEHG-HGHG混合级联模式较为复杂,但能够产生更高功率的高次谐波辐射。除此之外,我们还研究了各种三维效应对EEHG的影响。模拟和分析结果表明,通过上述两种方案,采用紫外波段的种子激光,用户可以得到全相干、窄带宽、短脉冲的水窗波段自由电子激光。     

Improvement of 1D off-axis computer-generated holograms

Creation of Fresnel off-axis computer-generated holograms and improvement of images reconstructed from the holograms are described. To improve the reconstructed images, we have created the holograms with high construct diffraction patterns by using a histogram method. From reconstruction experiments of the holograms, clear images have been obtained and 3D images have been seen directly with eyes.     

Improvement of reconstruction in 3D computer-generated holograms using 1D Fourier transform operations

Improvement of images reconstructed from 3D computer-generated holograms using 1D Fourier transform operations is presented. Required computing time for making 3D holograms is decreased when 1D Fourier transform method is used instead of 2D Fourier transform method, but reconstructed images from the holograms created by the 1D Fourier transform method are somewhat inferior in quality to the images by 2D Fourier transform method. In this paper, we propose a method that the disadvantageous properties of the holograms made by 1D Fourier transform are improved. We have performed two step improvements in this experiment. From the numerical experiments, the images that are reconstructed from the holograms created from 1D Fourier transform method show marked improvement.     

Soft X-ray Holographic Microscopy with Sub-micrometer Resolution

Gabor X-ray in-line holograms are recorded with a photoresist at Hefei National Synchrotron Radiation Laboratory. An Atomic Force Microscope (AFM) is used to read the X-ray holograms of minute granules recorded on photoresist PMMA. Digitized hologram is reconstructed by numerical method. The granules with a size less than 0.3 μm can be resolved in the reconstructed image. So the eatimated resolution reaches the level of suibmicrometer.     

Soft X-ray Holographic Microscopy with Sub-micrometer Resolution

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无透镜傅里叶变换全息图在欠采样条件下的数值再现分析

在理论分析无透镜傅里叶变换全息图记录的基础上，结合CCD的结构特点，用傅里叶频谱方法具体研究了无透镜傅里叶变换全息图在欠采样条件下的再现问题.指出在无透镜傅里叶变换全息术中，对有限尺寸物体而言，在记录过程不满足申农（Shannon）采样定理的条件下，仍能完整再现出物体的像.同时对再现像的变化特点进行了理论说明.所得的实验结果与理论分析一致.     

Reconstruction from computer-generated holograms displayed by a line printer

Experimental results are shown of optically reconstructed images from computer-generated holograms made with only binary-quantized levels in the real parts of the Fourier-transform complex disturbance of a signal and displayed by a line printer. Relatively good images having no distortion due to the high-pass filtering effect are reconstructed from computer generated holograms multiplied by the random phase factor. Reconstruction is also possible from the present holograms for signals having various degrees of light intensity.     

Simple computer-generated holograms displayed by an x-y plotter

New simple computer-generated holograms displayed by an x-y plotter are proposed and investigated. In the construction of holograms by computer, phase coding methods are used in order to distribute the Fourier-transform values of an original object over the whole of the receiving plane where the hologram is to be constructed. It is found that relatively good images are reconstructed from the computer-generated holograms proposed here.     

彩色全息图的计算机产生和数字再现

提出了一种基于色彩合成以及菲涅尔衍射原理,用计算机产生全息图并用数字方法再现彩色全息图的方法。该方法的第一步是将物体的彩色RGB图像分离为三基色强度图,再利用博奇编码的方法制成修正离轴参考光分色计算机全息图;第二步是分别对分色全息图在频域进行调制以实现用原参考光真实再现原始物光波。通过滤波消除零级衍射及共轭像的影响,获得了所需要的实像并提高了像质。提供的实验是选用一幅RGB图像作为原始物体,给出了用博奇编码法制成的全息图以及最后经色彩合成获得的再现像。结果表明,该方法能使各分色全息图的再现像准确重合,解决了在色彩合成时容易出现的色串扰问题。     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Wave front reconstruction of Fresnel off-axis holograms with compensation of aberrations by means of phase-shifting digital holography

Off-axis holograms recorded with a CCD camera are numerically reconstructed in amplitude by calculating through the Fresnel–Kirchhoff integral. A phase-shifting Mach–Zehnder interferometer is used for recording four-quadrature phase-shifted off-axis holograms. The basic principle of this technique and its experimental verification are described. We show that the application of this algorithm allows for the suppression of the zero order of diffraction and of the twin image and that the contrast of the reconstructed images can be further enhanced by digital compensation of the aberrations introduced by the holographic recording system