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RUBY LASER | |
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The first
laser (which is the abbreviation of the words Light Amplification by Stimulated
Emission of Radiation) was created in 1961 by Theodore Maiman (b.1927) at the Hughes Research Laboratories.
He used a rod of synthetic ruby as the lasing medium. The crystalline structure
of ruby is similar to the one of corundum, i.e. a crystal of aluminum oxide (Al2O3),
in which the small part of atoms of aluminum (about 0,05 %) is replaced with
ions Cr +++. Ruby rod is illuminated by intense impulse of
light, which is generated by helical xenon discharge lamp as shown in animation.
The ends of ruby rod are highly polished and silvered to serve as laser mirrors.
The impulse of light creates the inverse population of electrons in ruby rod and
due to the presence of mirrors the laser generation is excited. The duration of
the laser impulse is a little bit shorter than the pump impulse of the flash
lamp.