Ernst Ruska came to Technische Hochschule zu Berlin as a student in 1928, searching for an interesting topic for his term paper and Diploma thesis. Four years later, in September 1932, he published a “Contribution to Geometric Electron Optics” with his tutor Dr. Max Knoll. This laid an important foundation for one of the most significant discoveries of the 20th century. In his 1933 dissertation, he described a magnetic lens that has remained the design model for lenses in electron optics. The actual birth of electron microscopy was on 23 September 1933, when the young researcher captured images with a prototype he had built, which, with 12,000x magnification, far exceeded the resolution of conventional light microscopes. Ernst Ruska jointly received the Nobel Prize in Physics in 1986 with Gerd Binnig and Heinrich Rohrer for his fundamental work in electron microscopy.
Ruska’s success resulted from his work at Technische Hochschule zu Berlin. In a state-of-the-art high voltage laboratory located in the main building’s atrium - where there is now a commemorative plaque - Ruska began his work under Professor Adolf Matthias. The institute conducted research on the actual influence of storms on overhead power lines and transformer stations for energy supply. Powerful cathode ray oscillators played an important role as measuring devices in this work. However, Ruska was entrusted with experiments beyond the lab’s field of work, working in the field of cathode ray optics. Ruska later described this segue as follows: "While we were supposed to solve technical problems as engineering students, our teacher, Professor Matthias, also understood when we pursued physical problems or got side-tracked.” It was this that led to the theory of electron optics and essentially to the electron microscope.
Before he could complete his doctorate however, Ruska left Technische Hochschule zu Berlin as he was not granted funding to continue his research on the microscope. From 1933 to 1937, he worked in development at Fernseh AG in Berlin. Beginning in 1937, he and Bodo von Borries headed the industrial development of electron microscopy at Siemens. In 1938, the first Siemens super microscope was produced, and a year later the first production model. Ruska completed his Habilitation at the Technische Hochschule in 1944. In the years following 1945, he established the Institute of Electron Optics at Siemens. Together with his brother Helmut, a microbiologist, he also made improvements to electron microscopy. Ruska left Siemens in 1955 due to the company’s unwillingness to fund the further development of the electron microscope.
He worked at the Fritz Haber Institute in Dahlem until his retirement in 1974. Technische Universität Berlin awarded him an adjunct professorship in 1959. Highly honored, he died on 27 May 1988. He was laid to rest aside his brother Helmut in the Zehlendorf forest cemetery.