High Resolution Imaging in Bright and Dark Field at High Voltages

Abstract

The weak beam dark field and high order bright field imaging(2) methods are powerful means for improving the resolution of images detected by diffraction contrast. However, at high voltages, many beam interactions become important as more interband transitions occur between different Bloch waves. At the exact Bragg condition, for any order reflection, usually more than two interband transitions are important for both weak beam and bright field images, and complicated images result.