Lasers 3
Lasers 3The idea for the laser started as long ago as 1905 when Albert Einstein suggested the simulated emission of light. Light sources ie. candles, florescent substances, torches, and light bulbs give of packets of energy, called photons, when their atoms are excited by energy. Einstein suggested that these atoms could be artificially stimulated to emit photons, where the light produced would be highly concentrated, bright and powerful and could be used for many tasks. Even though Einstein new the principals for building a laser, it was not attempted until later because it would be to expensive and difficult at that time since the advanced machinery that was needed did not exist yet.
It was not until the 1950's where the stage was set to build a laser. Charles Townes,
a scientist, wanted to see if microwaves, which are very similar to light, might be stimulated to produce an amplified beam by the process that Albert Einstein described. Townes was successful in 1954 when he constructed what he called the maser (microwave amplification by stimulated emission of radiation). The maser amplifies the number of photons that cause microwaves.
After the invention of the maser many scientists became interested in the idea of building an optical maser, which soon received the name laser (light amplification by stimulated emission of radiation). Townes paired with Arthur Schawlow, two Soviets, Nikolai Basov and Aleksander Prokhorov, as well as Gordon Gould were all interested in developing a light-amplifying device. All of them knew that there were three essential ingredients in making a laser; a florescent material that would emit light when stimulated by radiation from an external energy source, two facing mirrors on the sides of the florescent material, and external energy source.
Theodore Maiman was the first to successfully assemble an optical laser. In 1960 Maiman produced the ruby laser. In it a strobe lamp is coiled around the core, a rod of ruby that has mirrors at its ends, one of which is only partially solid. As the strobe light flashes it excites the ruby atoms that in turn emit photons. The photons are reflected back and forth by the mirrors until they pass through the partially solid mirror. This results in brief bursts of pure red laser light that was millions of times brighter than the sun.
Maiman published his successful experiment but its importance was not realized immediately. Slowly other scientists began to build their own lasers and they quickly found out that materials other than ruby could...
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