Cathode lens electron microscopy is a method for imaging surfaces and thin films with reflected or emitted low energy electrons. This talk will discuss the principles, possibilities and limitations of the various operation modes. They include the reflection modes low energy electron microscopy (LEEM) and mirror electron microscopy (MEM), the emission modes photo emission electron microscopy (PEEM) with UV, laser and synchrotron X-ray light excitation and Auger electron emission microscopy. Some of these operation modes give not only structural information but also magnetic information, making use of the spin dependence of the reflectivity or the circular dichroism in emission. Chemical information can be obtained with X-ray PEEM (XPEEM) and Auger electron emission microscopy (AEEM) via energy filtering. In addition to imaging most instruments allow also diffraction and spectroscopy. Combining several of these techniques a rather comprehensive characterization of surface and thin films on the 1 to 10 nm resolution level is possible, depending upon operation mode and instrument design. The ultimate resolution is limited by the long wavelength of low energy electrons to about 2 nm in aberration-corrected instruments.
The talk assumes familiarity with the basic physical processes involved in these imaging modes, such as electron diffraction, UV and X-ray photoelectron emission and Auger electron emission, in order to allow enough time for the illustration of their application with examples.

General reference: E. Bauer: Surface Electron Microscopy with Slow Electrons, Springer, New York, 2014