In 1958, Bell Labs researchers Charles Townes and Arthur Schawlow, having not yet made a laser, applied for a patent based on a paper they'd written on the subject. They had written in the December 1958 issue of the journal Physical Review that it was possible to extend the principles of the "maser" to the optical regions of the spectrum. They received U.S. patent number 2,929,922 in 1960, the same year that Theodore Maiman at Hughes Aircraft built the world's first actual laser.
The laser turns 50 on May 16.
In this image, likely from 1958, Schawlow works on a ruby optical maser during an experiment. At the same time, C.G.B. Garrett gets ready to photograph the flash of the maser.
A maser stands for "microwave amplification by stimulation emission of radiation," according to Stanford's Gravity Probe B program. "A laser is a maser that works with higher frequency photons in the ultraviolet or visible light spectrum."
