An electron microscope is a type of microscope that uses a beam of electron particles to illuminate a sample and create a highly magnified image. Electron microscopes have greater resolving power than optical microscopes that use electromagnetic radiation. They can achieve much higher magnifications up to 2 million times. This resolution and magnification comes from the fact that the wavelength of an electron (de Broglie wavelength) is much smaller than that of a photon of visible light.

The electron microscope uses electrostatic and electromagnetic lenses to form the image by controlling the electron beam to converge on a particular plane relative to the sample. This mode is similar to the way an optical microscope uses glass lenses to converge light onto or through the sample to form an image.