Ernst Ruska

Ernst Ruska (1906-1988), German physicist, electrical engineer, and Nobel Prize winner. For his design of the first electron microscope, and subsequent improvements to the instrument, Ruska shared the 1986 Nobel Prize in physics with physicists Gerd Karl Binnig of Germany and Heinrich Rohrer of Switzerland, who designed the scanning tunneling microscope (STM).

Born in Heidelberg, Ernst August Friedrich Ruska earned an engineering degree from the University of Berlin in 1931 and a Ph.D. degree in 1933. In 1937 Ruska accepted a research position at Siemens-Reiniger-Werke. He remained there until 1955, when he became director of the Institute for Electron Microscopy of the Fritz Haber Institute. Concurrently, Ruska served at the institute and as professor at the Technical University of Berlin, from 1957 until his retirement in 1972.

Before leaving the University of Berlin in the 1930s, Ruska had already made the contribution to science that would bring him fame. He knew that electrons possess a wave aspect, so he believed he could treat them in a fashion similar to light waves. Ruska was also aware that magnetic fields could manipulate electrons, possibly focusing them as optical lenses do light. After confirming these principles through research, he set out to design an electron microscope. Ruska had deduced that an electron microscope would be much more powerful than an ordinary optical microscope, because he knew that magnification increased with shorter reflective waves. Since electron waves were shorter than ordinary light waves, it followed that they would allow for greater magnification. In 1932 Ruska and a collaborator, German physicist Max Knoll, under whom he obtained his doctorate, built the first crude electron microscope. Despite the fact that it was primitive and not fit for practical use, the instrument was still capable of magnifying objects 400 times.

Although modern electron microscopes can magnify an object 2 million times, they are still based upon Ruska's prototype and his correlation between wavelength and magnification. The electron microscope is an integral part of many laboratories. Researchers use it to examine biological materials (such as microorganisms and cells), a variety of large molecules, medical biopsy samples, metals and crystalline structures, and the characteristics of various surfaces.