From 1951 to 1953, John Coleman served as a Physicist for the National Bureau of Standards. He was an Instructor in Physics at Howard University from 1957-58, later becoming an Engineer for RCA beginning in 1958. His research involved the physics of electrons. The electron microscope uses streams of electrons which have a wave nature instead of light. It uses electromagnets to focus the beams of electrons on the specimen.
Some electrons pass through the material others are scattered producing a visible image.
Electrons have a shorter wavelength than light and so can magnify up to one million times. The high magnification of the microscope and the high vacuum required for the flow of the electron beam requires that the specimens must be dead, specially prepared and very thinly sliced. 1965 - The scanning electron microscope was introduced. It has lower magnification but more detailed surface features can be seen. 1969 - The scanning electron microscope is built.