单球面透镜产生线光束的理论分析与计算

基于几何光学定律和菲涅耳公式，建立了单块球面透镜生产线光束的数学模型，给出了光束出射角、橡距、像散、光强分布的计算公式，通过计算机仿真计算，得出了一些有益的结论。指出了大入射角产生的大像散是单球面透镜产生线光束的原因，子午面内光束各点的反射和透射系数不等。是它使入射的细高斯光束趋于均匀化的原因。理论与实验结果吻合。     

高斯光束通过非轴对称光学系统的变换

高斯光束通过非轴对称光学系统时就变成像散椭圆高斯光束。本文使用矩阵方法研究了有简单像散高斯光束的变换特性,推导出像空间中xoz和yoz面上束腰重合和相等的条件,以及一股地,像空间中光斑椭圆变成圆和等相面为球面的条件,并以数值计算例说明。     

内含柱面透镜的象散腔

本文用矩阵光学的方法研究了内含柱面透镜的象散腔，给出了其稳定图，此图清楚地显示出由于象散作而使用腔稳定工作区域大大缩小，本文还给了显示象散特征的稳定脸膜参数计算公式，并作了数值计算。     

透镜主动光学的像差补偿性能

针对透射式投影物镜中由于不均匀照明产生的像散,提出了采用平面透镜作为主动光学元件以补偿像散的方法。本文对直径为Φ140mm,通光孔径为Φ120mm的平面透镜的支撑结构进行设计和有限元分析,分析了支撑结构的各个关键参数、镜片厚度和驱动力大小对面形的影响,得到了支撑结构的关键参数和驱动力对面形的影响规律为线性曲线,镜片厚度对面形的影响规律为指数下降曲线和不同驱动力导致的面形图。结果表明,本支撑结构在补偿像散时,面形补偿分辨率约为2nm,引入的高阶像差可以忽略,设计分析结果为投影物镜中主动光学镜片的选择和支撑结构的设计及实验提供依据。     

半导体激光束的成形变换

本文利用矩阵光学方法研究像用椭圆高斯光束的变换特性，推导出正确的半导体激光束的校正像散与旋转对称化变换公式。     

氩离子激光泵浦的掺钛宝石激光器研究

本文报导用氩离子激光连续泵浦的掺钛宝石(Ti~(3+),Al_2O_3)可调谐固体激光器的实验结果。泵浦光为全谱线,基模,激光器采用消象散的折叠谐振腔结构,获得基模激光输出功率0.67W,效率大于10.8％,可调谐范围为735nm～900nm。     

像散透镜对超高斯光束的变换特性

利用广义惠更斯菲涅耳衍射积分,并考虑像散的影响,对超高斯光束通过像散透镜后的传输特性作了数值计算和讨论,得出一些新的结论.以桶中功率为参数分析了像散超高斯光束的光束质量,并以数值计算例加以说明.     

Higher-order aberration corrector for an image-forming system in a transmission electron microscope

We developed a new electron optical system with three dodecapoles to compensate for spherical aberration and six-fold astigmatism, which generally remains in a two-hexapole type corrector. In this study, we applied the corrector for image-forming system in transmission electron microscope. Compensation for higher-order aberration was demonstrated through a diffractogram tableau using a triple three-fold astigmatism field system, which was then compared with a double hexapole field system. Using this electron optical system, six-fold astigmatism was measured to be less than 0.1 mm at an acceleration voltage of 60 kV, showing that the system successfully compensated for six-fold astigmatism.     

Observation of lens aberrations for very high-resolution electron microscopy. I. Theory

Least-squares fitting methods are described, currently the most accurate known, for determining the imaging aberrations and other important parameters. The data required are either the image displacement or the image diffractogram shape (or both), as a function of injected beam tilt; the analysis is largely common to the two cases. Explicit solutions are given for some simple cases (e.g. coma-free alignment on the basis of three images only) and some promising developments are considered; the relevant aberration theory is set out in detail. Experimental work reported in a companion paper has confirmed the presence of threefold astigmatism at significant levels, but has not shown any evidence of other higher order aberrations.     

A robust focusing and astigmatism correction method for the scanning electron microscope—Part III: An improved technique

As described in a previous work, a new technique has been developed to perform automatic focusing and astigmatism correction on any general scanning electron microscope (SEM) sample ranging from gold-on-carbon to integrated circuit (IC) tracks. In this work, various improvements made to this technique are reported. They include the implementation of direct control of the SEM and the development of three new algorithms, namely the adaptive fast Fourier transform (FFT) algorithm, the coarse focusing algorithm, and the fine focusing algorithm. Direct control reduces the communication time with the SEM while the three new algorithms are integrated with the existing technique to make it even more robust to noise and to extend it to correct images with any degree of defocus and astigmatism. The enhanced focusing and astigmatism correction algorithm is able to perform the correction in a shorter time while maintaining the accuracy of the original algorithm even under noisy conditions.