electron microscopy, a technique using an electron microscope in which a beam of electrons is focused by an electromagnetic lens and directed onto an extremely thin specimen. The electrons emerging are focused and directed by a second lens onto a fluorescent screen. The magnified image produced is 1000 times greater than that produced by an optic microscope and well resolved, but it is two-dimensional because of the thinness of the specimen. Compare scanning electron microscopy, transmission scanning electron microscopy.