Since the first transmission electron microscope was sold in 1935, microscopes that use electrons--rather than light waves--to image objects have brought into focus levels of detail that were previously unimaginable. The scanning tunneling microscope (STM) is one of the more recent developments in this field, and using STM to write with atoms is one of its more innovative applications. But scientists are using electron microscopy in other new ways, as well. These include constructing three- dimensional images of minerals and some biological molecules, creating and analyzing polymers and superconductors, and even watching--on the atomic level--complex biological processes in action.
The electron microscope is essentially a light microscope that uses beams of high-energy electrons in place of light waves to illuminate the specimen. Using electrons with wavelengths as small as 0.1 nanometer, rather than longer-wavelength visible light, removes the limits on resolution imposed by diffraction in optical microscopy. The transmission electron ...
