High spatial resolution spectroscopic information may be acquired by using an electron beam in a Scanning Electron Microscope (SEM), exploiting a phenomenon called Cathodoluminescence (CL). CL can be used to perform non-destructive analysis of a broad range of materials comprising insulators, semiconductors, metals as well as inorganic and organic samples. This approach offers several advantages over usual optical spectroscopy techniques. The multimode imaging capabilities of the SEM enable the correlation of optical/structural/electrical properties (via CL) with surface morphology (secondary electron – SE – mode) at the nanometer scale. In semiconductors and insulators, the CL spectrum gives local information on the electronic bandgap and defect states. 

In geological applications, trace element, composition, growth, minerals origin determination can be disclosed. For biological samples, structural mapping of the different elements constituting the samples (cell, bacteria, DNA…) can be performed.