World’s Most Powerful Beam

Press, Volume CIX, Issue 32303, 22 May 1970, Page 9

World’s Most Powerful Beam

(By

RICHARD D. LYONS)

American scientists reported on April 29 the development of the world’s most powerful continuous-beam laser whose output energy could, theoretically, drive a sports car.

The new laser can produce 30 kilowatts of power in a very narrow beam and 60 kilowatts in a more divergent beam. These values are about triple those of the most powerful continuous-beam lasers in operation. Dr Edward T. Gerry of the Aveo Research Laboratory in Everett, Massachusetts, which developed the new device, described the laser at .the annual meeting of the American Physical Society. Scientists attending the meeting heard more reports of newer and lighter-powered lasers of various types from other groups of American re-1 seai'ch teams. The laser, only a decade old, is a device that generates an extremely powerful and concentrated beam of. light.. The acronym stands for light , amplification by stimulation! of emitted radiation. Lasers are increasingly being used for a number of purposes from cutting the hardest metals to drilling wholes in the nipples of baby bottles. They are also used! |to make maps and detect tur-j bulent air in the atmosphere..

“Death Ray” Denied

Scientists appearing at a news conference on laser developments emphatically denied that lasers were being built'to be used as "death rays," about which there has been much speculation. Yet it is known that the Department of Defence is spending at least 810 m a year to underwrite laser research. During the news conference, scientists, some of whom receive money from the Pentagon to conduct laser research.

repeatedly shied away from discussing why the miltary services are so interested in

the devices. Dr Gerry, whose company receives funds for laser research from the Air Force and Advanced Research Projects Agency, the Pentagon’s research arm, commented that “you had probably better direct questions about the military applications of this laser to the military itself."

ti| Attempts to obtain answers; y from the Pentagon were un-j r availing.

Dr Gerry described the Avco laser as resembling a rocket engine composed of two chambers the size of breadboxes separated by a nozzle. A gas composed of nitrogen and carbon dioxide is heated in one chamber to about 3000 degrees Farenheit. The gas is shot through the nozzle into the. second chamber at supersonic speed. The carbon dioxide molecules become extremely “excited” and some of them “last,” or emit photons. Mirrors focus them into a beam of light that is emitted from the chamber.

Specialised Applicant Dr Gerry amphasised that lasers, at least at, present can only be used' for specialised applications such as the drilling of very small holes. Wider applications, such as power sources for cars, arc not possible because lasers are so inefficient. Only about 1 per cent of the energy put into the Avco Everett laser emerges as light. Mr Anthony J. De Maria of the united Aircraft Research Laboratories in East Hartford. Connecticut, described a new type of electrically powered laser that develops less power than the Avco Everett model. 11.5 kilowatts, but is far more efficient. About 14.5 per cent of the power that goes into this type is emitted as light. He said his company was experimenting with the laser to determine if it could be used as an atmospheric optical scanner to detect the jet stream and turbulence caused naturally by winds and artificially by large jet aircraft. Dr Alexander .1. Glass of Wayne State University said scientists in the United States, the Soviet Union and France were developing increasingly larger lasers that produce enormous bursts of light energy, such as 100 trillion kilowatts, in extremely short periods of time, such as a few trillionths of a second.—Copyright. “New York Times” News Service