An
electron microscope is a microscope that uses a beam of accelerated
electrons as a source of illumination. Because the wavelength of an electron can be up to 100,000 times shorter than that of visible light
photons, the electron microscope has a higher
resolving power than a
light microscope and can reveal the structure of smaller objects. A transmission electron microscope can achieve better than 50
pm resolution and
magnifications of up to about 10,000,000x whereas most
light microscopes are limited by
diffraction to about 200
nm resolution and useful magnifications below 2000x.