KENBIKYO Vol.52▶No.1 2017
■Feature Articles: Current Status of Electron Phase Imaging

Phase Mapping Obtained by Transport of Intensity Equation

Yoshifumi Oshima and Xiaobin Zhang

Abstract: Transmission electron microscope (TEM) has attracted much interest due to not only very high spatial resolution but also retrieving the phase information of the transmitted electron wave, which is helpful to understand the electrostatic potential and local electric or magnetic field around the specimen. Recently, the spatial resolution of TEM has been improved by the development of spherical aberration corrector. While, it has been still studied how to retrieve the phase information. In this paper, we introduce “transport of intensity equation (TIE)”, which enables us to retrieve the phase information from only three TEM images. We will discuss about the spatial resolution in TIE retrieved phase map, show the atomic resolved phase map of a MoS2 atomic sheet. Moreover, We will show that TIE method can be applied to retrieving the phase distribution at the interface between amorphous Ge layer and vacuum.

Key words: Transport of intensity equation, phase mapping, electrostatic potential, spherical aberration corrector