电子束干涉和电子干涉仪

本文描述了在JEM-200CX电子显微镜上装入M(?)llenstedt电子双棱镜构成的电子干涉仪和电子干涉实验结果,详细叙述了双棱镜的结构和干涉仪光路设计,讨论了可得到的干涉条纹数目与束源亮度的关系.     

信息光学视角下菲涅耳双棱镜干涉的研究

菲涅耳双棱镜干涉在相衬成像和全息显微术中有重要应用。为了促进其应用,本文从信息光学角度研究双棱镜干涉,首先利用光场与脉冲响应函数之间的关系,理论导出了菲涅耳双棱镜干涉条纹强度公式,分析并讨论了狭缝缝宽及狭缝到双棱镜距离对菲涅耳双棱镜干涉条纹的影响,狭缝宽度大于0. 1 mm时,干涉条纹分辨率变差。接着给出了改变狭缝宽度(变化量为0. 08 mm)和改变狭缝到双棱镜的距离(从8 cm变化到12 cm)的实验结果,理论分析和实验结果一致。该结果有助于促进菲涅耳双棱镜干涉在相衬成像等领域的应用。     

双棱镜干涉实验中干涉光场的调控

针对双棱镜干涉实验存在的问题,在分析双棱镜分波前干涉原理和讨论双棱镜干涉光场的结构及其相干性的基础上,探讨了怎样通过优化实验参数调控干涉光场获得适于观测的干涉条纹.使学生更好地领略物理思想和学会实验方法,培养研究能力和启迪创新意识,促进光学教学的改革.     

二次电位分布静电双棱镜

本文提出了一种新的静电双棱镜——二次电位分布静电双棱镜,用此棱镜可增强干涉电子的强度,并扩大等间距干涉条纹的区域.     

棱镜透镜干涉仪总体设计中的一些考虑

<正> 一、总体参数的确定及总体方案的选择棱镜透镜干涉仪(又称泰曼-格林干涉仪)是棱镜干涉仪和透镜干涉仪的总称,是一种高精度、多功能的光学测试仪器。棱镜干涉仪用于检测具有平面性质的光学零件或光学系统的质量,如平板玻璃、各种棱镜以及望远系统等。透镜干涉仪主要用于测定望远物镜、照相物镜的波象差。棱镜透镜干涉仪采用的是分振幅双光束相干光路,其中测试光路的标准平面波经被检测的光学零件或光学系统后变成了由被检测件质量所决定的变形波面,该波面与参考光路的标准平面波汇合而产生干涉图形,根据干涉图形     

用半导体激光器代替纳光灯进行双棱镜实验的研究

本文对双棱镜干涉实验装置进行了改进,采用新的半导体激光器和光缝代替钠光灯和原光缝,使双棱镜干涉实验具有光路调节方便、干涉图样清晰等优点,并对人视激光替代钠光做双棱镜干涉实验的科学性作了实验验证。     

消除菲涅尔双棱镜棱脊直边衍射对干涉花样影响的简单方法

菲涅尔双棱镜产生的干涉花样,对单色光而言,根据光的干涉理论,干涉条纹应该是明暗相间的、间距相等的,光强度也是相同的。在做《用菲涅尔双棱镜测定光波波长》的实验时,在干涉场中看到的情况并不与上述结论完全一致。各个亮条纹之宽度不相等,其光强度也发生变化,如图1。这是因为双棱镜的棱脊产生的直边衍射花样与双棱镜的产生的干涉花样,相互间叠加在一起产生的     

菲涅尔双棱镜干涉实验中双棱镜两种放置方法的讨论

在菲涅尔双棱镜干涉实验中,双棱镜有两种不同的放置方法,分析了这两种放置方法中两虚光源的距离、干涉区域范围、干涉条纹间距、干涉条纹数目应相同,因而得到双棱镜的两种放置方法是等价的结论。     

利用菲涅耳双棱镜研究光的干涉现象

简要地给出了菲涅耳双棱镜干涉实验的基本光学原理和实验过程;重点对在实际教学中常见的观察不到干涉条纹、测量误差较大、凸透镜的选择、干涉条纹不均匀等情况进行了详细地讨论,并给出了解决问题的方法.     

激光双棱镜干涉实验的改进方法

提出了一种新的光路进行激光双棱镜干涉实验,作为经典激光双棱镜干涉实验的改进实验.解决了经典激光双棱镜干涉实验存在的观测视场小(这里的视场指的是眼睛能看到干涉条纹的观察范围)、观测不方便、不易演示等问题.     

Biprismainterferenzen mit langsamen Elektronen

Diffraction patterns of low energy electrons (150 eV) were observed with an electron interferometer. An interferometer of special design was developed for this purpose. The electron source is reduced in size by a retardation lens, which simultaneously decelerates the electrons down to about 150 eV. The electron beam is split up by an electrostatic biprism (filament diameter 10 μ ¦) in two coherent waves, which recombine behind the biprism giving a Fresnel diffraction pattern. Then the electrons are accelerated and the interference fringes are electron optically magnified. In comparison with an interferometer for high energy electrons the intensity on the viewing screen is higher.     

Mean inner potential of bismuth

The interference electron microscopy was applied to investigate the mean inner potential of Bi spheres. With an electric biprism a system of equidistant and parallel interference lines was produced. The Bi spheres were evaporated on carbon foils in the electron microscope. From shift of the interference lines in the image plane the mean inner potential was calculated. The method allows to measure the mean inner potential at different temperatures. The results offer the possibility to measure the mean potential at the surface of an object.     

Visibility spectroscopy with electron waves using a Wien filter: higher order corrections

Fourier spectroscopy, one of the most precise spectrometry methods in light optics, has been realized in the past years with electron waves by including a crossed-field analyzer (Wien filter) as a wave packet shifting device into a biprism interferometer. To fully exploit the high precision of this method of determining the energy spectrum, higher order corrections stemming from the Wien filter's focusing action are necessary in the evaluation of the measurement. We show that these can be taken into account by using a transformation variable being proportional to the quotient of electric field strength of the Wien capacitor over fringe spacing. Finally, we make some remarks about the possibility of interference of inelastically scattered electrons.     

电子干涉和全息的实验方法

本文对于迄今为止用来进行电子干涉和电子全息实验的五种光路设计作了简明的比较。介绍了使用Mollenstedt电子双棱镜作为分束器,在JEM-200CX型电子显微镜上成功地进行电子干涉与电子全息实验的两种操作模式。并且给出了有关实验参数及计算结果。最后,根据我们的经验提出了操作中应当加以重视的事项。 关键词：     

基于电子束剪切干涉的PIE成像技术研究

提出了基于M?llenstedt电子双棱镜的电压扫描剪切干涉全场ptychographic iterative engine(PIE)显微成像技术.从低到高逐步改变电子双棱镜的电压,并同时记录所形成的剪切干涉条纹,待测样品透射电子束的强度和相位分布就可以用PIE算法得以快速重建,而且双棱镜的方向、位置和实际电场强度分布等诸多实验中不可避免地偏差都可以在迭代过程中自动得以更正.所提技术能够克服现阶段用电子束进行PIE成像的诸多技术困扰,从而有望推动PIE技术在电子显微成像领域的发展和应用.     

Elektronen-Zweistrahlinterferenzen mit hohem Gangunterschied

On a photograph of an electron interference pattern produced in an electrostatic biprism arrangement 2200 fringes could be counted. Though this number is still far below the theoretical limit following from the chromatic inhomogeneousness of the electron source, it exceeds the highest hitherto measured number of electron interfrence fringes by the factor of 7.     

激光笔干涉仪的研制

介绍所研制的激光笔干涉仪．由激光笔发出的激光束在反射镜组间不断反射,使光传播距离增大,从而可以清楚地展现具有一定宽度和高度的干涉条纹,故适合于教学以及演讲中对干涉现象的演示和讲解．     

狭缝离双棱镜多远干涉条纹清晰易辨

计算狭缝和双棱镜之间的距离对折射光束单心性的影响，发现只有间距合理，干涉条纹才清晰易辨。     

The application of Fresnel fringes to the determination of the local filament diameter in an electron biprism

Intensity distribution in a diffraction pattern of the electron diffraction at a filament depends to a great extent on its diameter. This is used for the determination of the filament diameter with an accuracy better than 2%. The described method is suitable e.g. for the determination of the local filament diameter in an electron biprism. Therefore the non-uniform diameter of filaments used in an electron biprism presents no difficulties in the interpretation of diffraction and interference patterns.The authors present their thanks to Dr. M. ernohorský CSc. from the Institute of Metallurgy for his helpful comments and to Dr. Ing. O. Hlínka from the Technical University, Brno, for his suggestion concerning the design of the plot in Fig. 2. They also thank Mrs V. Gregorová for her help with numerical calculations and drawing the diagrams.