Amplitude recovery in Fresnel projection microscopy

Tantalising images of organic molecules have become available from Fresnel projection electron microscopes with nanoscale (and hence low energy coherent) electron sources. Initial forward calculations of the images assuming a simple opaque mask have succeeded in reproducing the major features in the images. Here a method is explored for recovering the object function from such images in order to extract useful information from the sample under the assumption of a pure amplitude object. Analogous real and complex specimen function recovery in electron microscopy has been studied for decades with varying degrees of success. From diverse approaches, a similar algorithm to the Gerchberg-Saxton method has been implemented. Simulations showing the sensitivity and effectiveness of this method are presented.