Seki Takehito, Sánchez-Santolino Gabriel, Ishikawa Ryo, Findlay Scott D, Ikuhara Yuichi, Shibata Naoya
Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-8656, Japan.
School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia.
Ultramicroscopy. 2017 Nov;182:258-263. doi: 10.1016/j.ultramic.2017.07.013. Epub 2017 Jul 26.
Differential phase contrast in scanning transmission electron microscopy can visualize local electromagnetic fields inside specimens. The contrast derived from first moments, the so-called center of mass, of the diffraction patterns for each probe position can be quantitatively related to the local electromagnetic field under the phase object approximation. While only approximate first moments can be obtained with a segmented detector, in weak phase objects the fields can be accurately quantified on the basis of a phase contrast transfer function. Through systematic image simulations we further show that the quantification based on the approximated first moment is a good approximation also for strong phase objects.
扫描透射电子显微镜中的微分相衬可以可视化样品内部的局部电磁场。在相位物体近似下，从每个探针位置的衍射图案的一阶矩（即所谓的质心）得出的对比度可以与局部电磁场定量相关。虽然使用分段探测器只能获得近似的一阶矩，但在弱相位物体中，可以基于相衬传递函数准确地量化场。通过系统的图像模拟，我们进一步表明，基于近似一阶矩的量化对于强相位物体也是一个很好的近似。
