UC Berkeley's Charles Townes, Physicist and Laser Pioneer, Dies at 99

Charles H. Townes, a pioneering physicist who won a Nobel Prize in 1964 for his role in developing the laser, has died at age 99.

UC Berkeley, where Townes was still a professor emeritus, said he died Tuesday in Oakland.

In a short video made last year shortly before his 99th birthday (embedded above), Townes said that physics was a matter of ongoing exploration and pleasure.

"I've practically never worked a day in my life," Townes said. "I've just had fun doing physics."

UC Berkeley's obituary on Townes describes the moment of inspiration that led eventually to development of the laser:

Townes was 35 in the spring of 1951 when, seated on a park bench among blooming azaleas in Washington, D.C., he was struck by the solution to a longstanding problem, how to create a pure beam of short-wavelength, high-frequency light.

That revelation – not much different from a religious revelation, Townes believed – eventually led to the first laser, a now ubiquitous device common in medicine, telecommunication, entertainment and science.

Then a professor at Columbia University and a consultant for Bell Telephone Laboratories, Townes had transitioned from working on radar during World War II to using shorter wavelengths of light to study the energy states of molecules, a field called spectroscopy. The problem bedeviling him was how to create an intense beam of microwave energy to use as a probe. Albert Einstein proposed in 1917 that the right wavelength of light can stimulate an excited atom to emit light of the same wavelength, essentially amplifying it, but Townes was stymied by how to corral a gas of excited atoms without them flying apart.

His revelatory solution allowed him to separate excited from non-excited molecules and store them in a resonant cavity, so that when a microwave traveled through the gas, the molecules were stimulated to emit microwaves in step with one another: a coherent burst. He and his students built such a device using ammonia gas in 1954 and dubbed it a maser, for microwave amplification by stimulated emission of radiation.

Four years later, in 1958, he and his brother-in-law and future Nobelist Arthur Schawlow conceived the idea of doing the same thing with optical light, but using mirrors at the ends of a gas tube to amplify the light to get an “optical maser.” Bell Labs patented the laser, while Townes retained the patent on the maser, which he turned over to a nonprofit. Townes’ appointment as director of research for the U.S. government’s Institute of Defense Analysis in 1959 slowed his efforts to build an optical device, opening the door for Theodore Maiman to demonstrate the first laser – light amplification by stimulated emission of radiation – in 1960.

As the New York Times says, the scientific and practical import of Townes' and his colleagues' work is almost impossible to exaggerate:

One of the most versatile inventions of the 20th century, the laser amplifies waves of stimulated atoms that shoot out as narrow beams of light, to read CDs and bar codes, guide missiles, cut steel, perform eye surgery, make astronomical measurements and carry out myriad other tasks, from transmitting a thousand books a second over fiber optic lines to entertaining crowds with light shows.

The technological revolution spawned by lasers, laying foundations for much of the gadgetry and scientific knowledge the world now takes for granted, was given enormous momentum by the discoveries of Dr. Townes and — because almost nothing important in science is done in isolation — by the contributions of colleagues and competitors.

Thus, Dr. Townes shared his Nobel with Nikolai G. Basov and Aleksandr M. Prokhorov, of the Lebedev Institute for Physics in Moscow, whom he had never met. It was Dr. Townes and Dr. Arthur L. Schawlow who wrote the 1958 paper “Infrared and Optical Masers,” describing a device to produce laser light, and secured a patent for it. A graduate student, R. Gordon Gould, came up with insights on how to build it, and named it a laser, for light amplification by stimulated emission of radiation. And it was Dr. Theodore H. Maiman, a physicist with Hughes Aircraft in California, who built the first operational laser in 1960.

Townes was a native of South Carolina whose family, he said, had arrived before the American Revolution. His Nobel laureate's biography hints at his wide-ranging interests:

Charles Hard Townes was born in Greenville, South Carolina, on July 28, 1915, the son of Henry Keith Townes, an attorney, and Ellen (Hard) Townes. He attended the Greenville public schools and then Furman University in Greenville, where he completed the requirements for the Bachelor of Science degree in Physics and the Bachelor of Arts degree in Modern Languages, graduating summa cum laude in 1935, at the age of 19. ... He was also interested in natural history while at Furman, serving as curator of the museum, and working during the summers as collector for Furman's biology camp. In addition, he was busy with other activities, including the swimming team, the college newspaper and the football band.

In an oral history interview with the American Institute of Physics, Townes recalled his experience seeking a physics degree at Furman:

I was very entranced by physics, partly because of its logic, and because it dealt with the real world. Mathematics was logic enough, but I liked to deal with the real world, and as I saw it, physics really did that, and was a beautiful subject because things could be figured out if you worked at it. Now, that college didn't have very much physics. It graduated maybe about one physics major per year, and my last year, there were no other students than I, and so I just studied the book and worked the problems. That was the course. ...

I remember very well some of the excitement of some of the first physics. Newton's Laws themselves I found really just tremendous. That was my first exposure to physics. That was when I was a sophomore. Then when I was a junior, I studied a book. I largely studied by myself because there was only one other student in the course, and the professor didn't lecture very much. I remember very vividly, I was at my grandmother's mountain house up in the mountains one summer, and I thought, well, let's start studying the book and get ahead a little bit. I sat up in the woods overlooking a stream, and I remember very well the rock I was sitting on and the stream and the woods around, just exactly how it looked. I read for the first time about special relativity, and that was just a tremendous experience, to see what could be found out by reason, and a whole new view of what time and space were like.