电子出射波重构的基本原理和应用

随着场发射枪透射电子显微镜的普及，电镜的信息分辨极限和点分辨率成为表征电镜分辨本领的两个重要指标。由于电镜衬度传递函数的振荡特性，用场发射透射电镜拍摄的高分辨像在其点分辨率和信息分辨极限之间的信息很难解释。电子出射波重构就是通过拍摄系列欠焦高分辨像，计算获得电子离开样品表面的出射波函数，将电镜的分辨本领由点分辨率延伸到其信息分辨极限，井消除球差、欠焦、像散等影响，有望在中等电压电镜上获得近埃、乃至亚埃级可直接解释的高分辨像，实现C、N、O等轻元素单原子列探测，为今后定量电子显微学研究奠定基础。

Reconstruction of electron exit waves: basic theory and applications

With the popularization of field emission gun transmission electron microscopes (FEG-TEM),the information limit and the point resolution become two key important parameters to characterize the resolution ability of the microscopes.Because of the oscillation characteristic of the contrast transfer function,the information between the point resolution and information limit in the high resolution images taken from the FEG-TEM is difficult to interpret.Reconstruction of electron exit waves from focal series of lattice images extends resolution to near/sub-angstrom values,corrects for dominant aberrations of the objective lens,and allows imaging the atomic structure of crystalline materials directly.This has enabled us to directly record columns of the light elements carbon,nitrogen and oxygen with sub-angstrom resolution.This technique establishes the basis of quantitative TEM.