Charles Townes

Born on 28 July 1915 in Greenville, South Carolina, Charles Townes was a Nobel Prize–winning physicist who invented the maser and laser. After earning his PhD in physics at Caltech in 1939, Townes joined Bell Labs in Murray Hill, New Jersey. During World War II, he developed radar bombing and navigational systems before moving on to research in microwave physics. He continued that research after joining the faculty at Columbia University in 1948. It was in the early 1950s that Townes began working to amplify microwave radiation. He claimed his invention of the maser, an acronym for “microwave amplification by stimulated emission of radiation,” resulted from a eureka moment that he experienced one day in 1951 as he sat on a park bench in Washington, DC. By 1958 Townes and his brother-in-law, Arthur Schawlow, expanded the concept by showing that masers could operate in the optical range, which led to the invention of the laser. Since the first laser was built in 1960, the technology has become ubiquitous, finding uses in bloodless surgeries, missile defense, spectroscopy, laser printers, barcode scanners, and more. For his part in the development of the maser and laser, Townes shared the 1964 Nobel Prize in Physics with Nicolay Basov and Aleksandr Prokhorov. In 1967 he was appointed University Professor at the University of California, Berkeley, where he remained for almost 50 years. After a career that spanned nearly eight decades, Townes died at the age of 99 in 2015; you can read his obituary in Physics Today. (Photo credit: AIP Emilio Segrè Visual Archives, Physics Today Collection)

Date in History: 28 July 1915