State of the Art of Low-Energy Electron Holography

A point source for electrons and ions has been employed to devise new high-resolution microscopy schemes. The key to this novel tool is an atomic-sized electron source that directly provides a beam of coherent electrons with low kinetic energy. Thus, in contrast to classical electron microscopy, lenses and their intrinsic aberrations become obsolete. We describe the properties of this electron and ion source as well as its applications, ranging from Gabor-type electron holography to ion projection microscopy to the mechanical and electronic manipulation of nanometer-sized objects.