Ruska, Ernst August Friedrich (1906–1988)

German physicist who was awarded the Nobel Prize for Physics in 1986 for his work in opto-electronics and on the construction of the first electron microscope (called the transmission electron microscope). He shared the award with Gerd Binnig and Heinrich Rohrer.

By the 1920s it was known that electrons could, in appropriate circumstances, behave like waves. In 1926 Hans Busch in Berlin showed how a magnetic coil could be used to focus electron waves. In 1931 Max Knoll and Ernst Ruska, also in Berlin, combined these phenomena to make the first electron microscope, which was capable of magnifying 17 times. Knoll left the team soon after and Ruska, working alone as a doctoral student, produced the first electron microscope which surpassed the optical microscope. By 1933 he had made an instrument which magnified 12,000 times (the best optical microscopes magnify around 2,000 times).

Ruska was born in Heidelberg and studied electrical engineering in Munich and Berlin. He worked on the development of commercial electron microscopes from December 1933. In 1938 he completed the first prototype of a commercial electron microscope for the German firm of Siemens. During World War II, he worked in a disused bakery until it was destroyed by Soviet troops. After the war, he continued development work with Siemens. From 1949 to 1971 he was a professor at the Free University in Berlin.