The field ion microscope is a remarkably powerful optical device. It represents several generations of scientific evolution of the electron microscope and is probably the most powerful magnifying instrument yet invented.

Before German electrical engineer Ernst Ruska (1906-1988) and Max Knoll invented the electron microscope in 1932, the science of microscopy had reached a standstill. Though scientists were theorizing about the structure and composition of the atom, no microscope yet invented had the ability to resolve an image smaller than a wavelength of light; thus, there was no way to actually observe atomic and subatomic particles. Ruska and Knoll overcame this barrier by substituting a beam of electrons for the microscope's light source. With wavelengths far shorter than those of visible light, electrons could be used to view specimens at magnification levels thousands of times higher than those possible with simple microscopes. The electron microscope...