MASER/LASER

Daydreaming Townes

In spring 1951 Charles H. Townes was in Washington, D.C., to attend a conference at the Office of Naval Research. He was trying to develop ways to produce extremely high frequency radio waves. The applicable technology of the day was vacuum tubes, and there was simply no way to make them so that they could produce waves high enough in frequency to satisfy Townes. While sitting on a park bench Townes realized how he could produce the radio waves he wanted using atoms and molecules instead of vacuum tubes.

Quantum Theory

Townes's concept used Einstein's theory of "stimulated emission of radiation." Einstein suggested that forcing radiation (light or microwave, for example) past a group of atoms stimulates them to release energy. This energy will travel in the direction of the stimulating source and be of the same frequency as the source. Einstein theorized that energy is released in what he called quanta—certain specific amounts, not randomly. Townes returned home to Columbia University to work on the idea after the conference.

Maser

Townes worked with J. Weber to find just the right stimulating force for his microwaves. Then they had to couple it with an atomic structure that would respond with the correct wavelength of energy. In 1954 they developed a device using ammonia gas to amplify micro-wave energy. The point was that they showed that waves could be amplified to produce a powerful tool, which they called a maser. The real discovery, however, was that light energy could be amplified as well. They called this phenomenon a laser. The race was on to produce a laser device.

Laser

Townes and his brother-in-law, Arthur Schawlow of Bell Laboratories, published a paper in 1958 describing the "optical maser," and Bell Labs filed a patent application. When he saw Townes and Schawlow's paper, physicist Gordon Gould of Columbia University claimed he had the idea for a laser in 1957 did not file a patent. His proof was an affidavit he prepared in November 1957 and had notarized in a candy store. Gould fought the legitimacy of Bell Labs' patent in the courts. In October 1977, after the Bell Labs patent had expired, the court ruled in his favor. In 1982 Gould's legal victory was upheld on appeal, and he collected a small fortune from Bell. Neither Townes and Schawlow nor Gould ever made a working laser, though. The first one was made in 1960 by Theodore Maiman.