An electron microscope captures the geometry of a sample not with visible light, but with an electron beam. Since fast electrons have a much shorter wavelength than visible light and the maximum resolution of a microscope depends directly on the wavelength, an electron microscope can resolve much smaller structures. The resolution limit for an electron microscope is approximately 0.1 nm and for a light microscope 200 nm. Samples for electron microscopy are often ultra-cleaned by means of plasma. feinstgereinigt. Diener electronic offers special plasma systems for electron microscopy (see ⇒ Plasma systems).
Due to the different recording techniques, electron microscopes can be divided into transmission electron microscopes and secondary electron microscopes.