How it began
Theodore Maiman made the first laser operate on May 16, 1960, at the Hughes Research Laboratory in California, by shining a high-power flash lamp on a ruby rod with silver-coated surfaces. Hughes announced it to the news media on July 7, 1960. Charles Townes, who had co-written the theoretical paper on such devices, recalled that several groups were then trying to make the earliest lasers.
Before it existed
Ruby had been widely used for masers, which produce waves at microwave frequencies, and had been considered for devices producing infrared or visible light. Townes wrote that Maiman's laser had features not considered in the theoretical paper or discussed by others before the demonstration, and that a different transition in ruby had been recommended, which was made to work only after Maiman's success.
How it works
Maiman used a pulsed light source lasting only a few milliseconds to excite, or pump, a synthetic ruby crystal. Having studied the relaxation times of the excited states of ruby, he concluded that a flash lamp could empty the lowest-energy state enough for stimulated emission to occur. His experiment was not set up to let a simple beam emerge, but the spectrum showed a marked narrowing of the range of frequencies, which was proof of laser action.
How it spread
Other lasers followed quickly. Still in 1960, Peter Sorokin and Mirek Stevenson at IBM in Yorktown Heights demonstrated lasers using calcium fluoride, and Ali Javan, William Bennett and Donald Herriott at Bell Laboratories built the helium-neon laser. Semiconductor lasers were first operated in 1962 by Robert Hall and colleagues at General Electric in Schenectady. Maiman founded his own company in 1962.
Who pushed back
An editor of Physical Review Letters turned down Maiman's paper, believing it was more of the same after an article Maiman had published in June 1960 on exciting ruby with light. The paper appeared in Nature instead. Some doubted the result because Maiman had not reported seeing a bright beam. Townes recalled that when the first working laser was reported it was described as "a solution looking for a problem."
