成像模式对电子全息图空间分辨率的影响  

Effect of imaging modes of transmission electron microscope on spacial resolution of electron holography

作　　者：王岩国[1] 

机构地区：[1]中国科学院物理研究所,北京100190

出　　处：《分析仪器》2013年第3期34-40,共7页Analytical Instrumentation

基　　金：国家自然科学基金资助项目(项目批准号11274365)

摘　　要：与普通电子显微像的分辨率不同,电子全息图的分辨率并不仅仅由电子干涉条纹间距本身决定,而是取决于样品相对全息图的放大倍数,即全息图的实际空间分辨率等于干涉条纹间距除以样品相对全息图的放大倍数。因此电子全息图的分辨率可以通过两种方式而改变,(1)改变电子显微镜的成像模式,不同成像模式间的转换可以改变样品相对于全息图的放大数倍。(2)改变电子全息附件在电子光路中的位置,样品相对于全息图的放大倍数与它们的相对位置有关。将电子全息附件安装在样品前面时,样品相对于全息图并没有被放大,反而是全息图在物镜的物面处被放大了,出现在全息图中的样品多,尽管电子全息图分辨率低,但全息图具有分析样品区域大的优点。电子全息附件放在样品之后,样品相对于全息图被放大了,出现在全息图中的样品少了,尽管提高了电子全息图的分辨率,但是减小了可分析样品区域。It is different from the general transmission electron microscopic images with the resolution directly decided by the revealed microstructural details such as lattice fringes that the resolution of electron hologram equals to distance of the interference fringes divided by magnification of the sample with respect to the hologram. Thus, the resolution of the hologram not only depends on distance of interference fringes, but also on magnification of the sample. Consequently, the resolution of hologram can be modified via （1） change between high and low magnification imaging modes of electron microscope and （2） changing positions for the biprism in the column of transmission electron microscope. Image of the sample will be magnified with respect to the hologram when the biprism installed ahead the objective lens. In this case, resolution of the hologram is low and large area of the sample appears in the hologram. However, small area of the sample appears in the hologram with high resolution if the biprism installed behind the objective lens, which leads to image of the sample magnified with respect to the hologram.

关 键 词：子显微镜 电子全息 空间分辨率 

分 类 号：TN16[电子电信—物理电子学]