Rytov approximation in electron scattering

Abstract

In this work we introduce the Rytov approximation in the scope of high-energy electron scattering with the motivation of developing better linear models for electron scattering. Such linear models play an important role in tomography and similar reconstruction techniques. Conventional linear models, such as the Phase Grating Approximation, have reached their limits in current and forseeable applications, most importantly in achieving three-dimensional atomic resolution using electron holographic tomography. The Rytov approximation incorporates propagation effects which are the most pressing limitation of conventional models. While predominately used in the weak-scattering regime of light microscopy we show that the Rytov approximation can give reasonable results in the inherently strong-scattering regime of transmission electron microscopy.

Real-Time Imaging With Simultaneous Use of Born and Rytov Approximations in Quantitative Microwave Holography

“…It indicates that the benefits of using Rytov's data approximation are significant in transmission (forward-scattered) measurements. This result reinforces the extensive comparisons of the two approximations in diffraction tomography [15], [18], [39] and in transmission electron microscopy [40], [41], which considers applications with transmission measurements only. In contrast, the majority of the microwave and millimeter-wave imaging radars employ reflection responses (e.g., [2], [4], [42]), where the benefits of Rytov's approximation are insignificant.…”