High-Resolution TEM Imaging
The Huygens principle of physical optics is developed qualitatively, and then quantitatively with Green’s functions. The relationship between phase and potential is developed. Phase shifts of materials and lenses are described, and combined with propagators in the Cowley–Moodie method for high resolution TEM (HRTEM) image simulation. Experimental effects of lens aberrations, specimens, and beam conditions are discussed. The chapter explains how these effects are incorporated into simulations of images, and shows examples of these effects on HRTEM images. Although direct simulations of images are an important part of the work, the chapter also presents methods for working with images directly, and discusses the risks of some types of interpretations.