Townes, Charles Hard

SUBJECT AREA: Electronics and information technology

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b. 28 July 1915 Greenville, South Carolina, USA

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American physicist who developed the maser and contributed to the development of the laser.

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Charles H.Townes entered Furman University, Greenville, at the early age of 16 and in 1935 obtained a BA in modern languages and a BS in physics. After a year of postgraduate study at Duke University, he received a master's degree in physics in 1936. He then went on to the California Institute of Technology, where he obtained a PhD in 1939. From 1939 to 1947 he worked at the Bell Telephone Laboratories, mainly on airborne radar, although he also did some work on radio astronomy. In 1948 he joined Columbia University as Associate Professor of Physics and in 1950 was appointed a full professor. He was Director of the University's Radiation Laboratory from 1950 to 1952, and from 1952 to 1955 he was Chairman of the Physics Department.

To meet the need for an oscillator generating very short wavelength electromagnetic radiation, Townes in 1951 realized that use could be made of the different natural energy levels of atoms and molecules. The practical application of this idea was achieved in his laboratory in 1953 using ammonia gas to make the device known as a maser (an acronym of microwave amplification by stimulated emission of radiation). The maser was developed in the next few years and in 1958, in a joint paper with his brother-in-law Arthur L. Schawlow, Townes suggested the possibility of a further development into optical frequencies or an optical maser, later known as a laser (an acronym of light amplification by stimulated emission of radiation). Two years later the first such device was made by Theodore H. Maiman.

In 1959 Townes was given leave from Columbia University to serve as Vice-President and Director of Research at the Institute for Defense Analyses until 1961. He was then appointed Provost and Professor of Physics at the Massachusetts Institute of Technology. In 1967 he became University Professor of Physics at the University of California, where he has extended his research interests in the field of microwave and infra-red astronomy. He is a member of the National Academy of Sciences, the Institute of Electrical and Electronics Engineers and the American Astronomical Society.

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Principal Honours and Distinctions

Nobel Prize for Physics 1964. Foreign Member, Royal Society of London. President, American Physical Society 1967. Townes has received many awards from American and other scientific societies and institutions and honorary degrees from more than twenty universities.

Bibliography

Townes is the author of many scientific papers and, with Arthur L.Schawlow, of

Microwave Spectroscopy (1955).

1980, entry, McGraw-Hill Modern Scientists and Engineers, Part 3, New York, pp. 227– 8 (autobiography).

1991, entry, The Nobel Century, London, p. 106 (autobiography).

Further Reading

T.Wasson (ed.), 1987, Nobel Prize Winners, New York, pp. 1,071–3 (contains a short biography).

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