What is Electron Microscopy & How does it work?
(EM – 101) Here we compare two basic types of microscopes – optical and electron microscopes. The electron microscope uses a beam of electrons or the wave-like characteristics of electrons to magnify an object’s image unlike the optical microscope that uses visible light to magnify images. The optical microscopes can magnify between 40 to 2000 times but the electron microscope can resolve features that are more than 1 million times smaller. Electron Microscopes(EMs) function like their optical counterparts except that they use a focused beam of electrons instead of light to “image” the specimen and gain information as to its structure and composition. The basic steps involved in all EMs: A stream of electrons is formed (by the Electron Source) and accelerated toward the specimen using a positive electrical potential. This stream is confined and focused using metal apertures and magnetic lenses into a thin, focused, monochromatic beam. This beam is focused onto the sample using a magnet
