vendredi 16 juillet 2010

Lasers – etymology, history, future progress

Le présent article a été rédigé par Jonathan Goldberg, que je remercie. Une traduction en français suivra.

The laser was invented in July 1960 and is celebrating its 50th anniversary. It is a machine that amplifies light waves of atoms that have been stimulated to radiate, then shoots them out as narrow, intense beams of light.

LASER is an acronym of Light Amplification by Stimulated Emission of Radiation. It superseded the word maser, coined in 1950, meaning Microwave Amplification by Stimulated Emission of Radiation. In 1962 the verb to lase was coined. The American Heritage Dictionary of the English Language contains a definition of its transitive and intransitive forms:

Intransitive verb:
To function as a laser; emit coherent radiation by the action of a laser.

Transitive verb:
1. To subject to laser light: e.g. he lased the tissue during surgery.
2. To direct a laser used to guide munitions at (a target).

The first laser was demonstrated by Theodor H. Maiman, an American physicist and engineer, using a device that fitted into his hand. While working for Hughes Aircraft Company, he had requested to make a laser. His employers initially preferred him to work on "computers or something useful.” Eventually he helped Hughes win the race to develop the first laser beam. This development built on research conducted by Albert Einstein, who wrote about it in 1917, and by others.

Dr Maiman used pulses of light to excite atoms in the ruby. The laser thus produced only a short flash of light, rather than a continuous wave. But because so much energy was released so fast, it provided considerably more power than in past experiments.

This first laser, tiny in power compared with later versions, shone with the brilliance of a million suns. Its beam spread less in one mile than a flashlight beam spreads when directed across the room. Scientists call laser light “coherent light”.

The History of Laser Light - http://www.youtube.com/watch?v=XRLRSdgvLg0&feature=related

Dr. Maiman was twice nominated for the Nobel Prize and won many other awards. He was inducted into the National Inventors Hall of Fame in 1984,

In 2000 he described his invention in “The Laser Odyssey”.

http://www.amazon.com/Laser-Odyssey-Theodore-Maiman/dp/0970292708/ref=sr_1_1?ie=UTF8&s=books&qid=1269781060&sr=1-1-spell

Today lasers are used to read CDs and bar codes, guide missiles, remove ulcers, fabricate steel, precisely measure the distance from Earth to the Moon, record ultra-defined images of brain tissue, entertain people in light shows and do thousands of other things. One such show was given by Jason Latimer, the “world champion of magic.”

http://www.youtube.com/watch?v=T-XoN1Ts6Wg

The laser offers potential for exciting, new applications in many fields, such as that of biomedics and DNA sequencing.

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