小孔衍射和近场散射数值计算的格林函数方法

从简谐光波满足的亥姆霍兹方程出发,将由格林定理得到的介质分界面上的积分方程转化为以表面上的光波及其导数为未知量的线性方程组,并对其进行数值求解,实现了光场的数值计算。然后将这一方法应用于亚波长尺度的小孔衍射的光波以及自仿射分形表面产生的随机光场及其在近场区域范围内的传播的计算。在随机表面产生的光场计算中．提出了类比推导夫琅禾费面上散斑场自相关函数的方法产生随机表面,以及计算其导数的傅里叶变换方法。对光场的计算结果表明,在近场范围内,光场随离开表面的距离的增加而迅速变化,其传播特性完全不同于光场在远场范围内的传播特性。     

点衍射干涉检测技术

本文介绍了点衍射干涉仪不同发展阶段的特点和应用。点衍射干涉仪由波长量级的针孔产生高质量的球面波作为参考波前,能够得到衍射极限性能的分辨率。按照不同的光路特点,点衍射干涉仪可分为点衍射共路干涉和点衍射非共路干涉两种结构,主要应用于高精度波前检测和面形检测。共路干涉结构简单紧凑,对环境振动不敏感,对光源相干度要求不高,可利用光束偏振态及光栅衍射分束的特性对传统点衍射板进行改造,在全共路点衍射干涉仪中引入时间相位调制技术和干涉对比度可调技术,可进一步提高波前检测精度。采用反射式针孔和各种光纤结构发展了非共路点衍射干涉仪,实现了大口径、高精度球面反射镜面形的测量。本文重点阐述了用于极紫外光刻投影物镜中高精度球面反射镜面形检测的反射式针孔点衍射干涉仪,并展望了点衍射检测技术在生物检测等领域的应用前景和发展趋势。     

激光等离子体堵口效应的理论模拟

采用较为简化的理论模型,根据离子运动方程的自相似解,模拟了激光辐照腔靶时产生的妨碍能量继续注入的堵口效应,获得了注入腔靶的能量份额随小孔初始半径及激光参数的变化曲线。理论与实验结果相符。     

超声波扩散角的测量方法改进

为了提高利用小孔反射法测量超声波扩散角的准确度,采用多点测量获得小孔反射波强度分布曲线,通过数据处理软件得到此分布曲线的半峰全宽,在此基础上校正小孔尺寸对测量结果的影响.     

Detailed characterization of polycapillary focusing x-ray lenses by a charge-coupled device detector and a pinhole

A method to measure the detailed performance of polycapillary x-ray optics by a pinhole and charge coupled device (CCD) detector was proposed in this study. The pinhole was located between the x-ray source and the polycapillary x-ray optics to determine the illuminating region of the incident x-ray beam on the input side of the optics. The CCD detector placed downstream of the polycapillary x-ray optics ensured that the incident x-ray beam controlled by the pinhole irradiated a specific region of the input surface of the optics. The intensity of the output beam of the polycapillary x-ray optics was obtained from the far-field image of the output beam of the optics captured by CCD detector. As an application example, the focal spot size, gain in power density, transmission efficiency, and beam divergence of different parts of a polycapillary focusing x-ray lenses (PFXRL) were measured by a pinhole and CCD detector. Three pinholes with diameters of 500, 1000, and 2000 μm were used to adjust the diameter of the incident x-ray beam illuminating the PFXRL from 500 μm to the entire surface of the input side of the PFXRL. The focal spot size of the PFXRL, gain in power density, transmission efficiency, and beam divergence ranged from 27.1 μm to 34.6 μm, 400 to 3460, 26.70% to 5.38%, and 16.8 mrad to 84.86 mrad, respectively.     

六通道掠入射软X射线针孔照相技术

在对平面反射镜高能X射线截止原理分析研究的基础上,为传统的针孔照相系统配置了光学滤片加平面反射镜组成的滤波系统,消除了大部分的高能尾部的影响。介绍了六通道掠入射软X射线针孔相机的结构设计、工作原理及性能。将光源按光子能量切割成6个能段分别进行记录,滤波后各通道的出射光为窄带软X射线。在阳加速器上对六通道掠入射软X射线针孔相机系统进行考核,加速器输出电流为779 kA,电流上升时间为75 ns,使用的负载为16根环形W丝阵,成功获取了6个通道的针孔照相图像,并结合Dante谱仪相应通道测得的功率时间谱进行了对比分析,确定了部分Z箍缩辐射热点的图像与功率发射谱的对应关系。