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From Science Fiction to Scientific Reality.
In the nineteenth century H. G. Wells, in his War of the Worlds (1898), wrote of Martians invading with weapons that fired deadly light beams. In the 1930s comic-book hero Buck Rogers used a ray gun. In the 1980s laser therapy came into use for a wide variety of medical problems. Lasers repaired detached retinas in the eye, vaporized abnormal growths and tumors, halted internal bleeding, and erased port-wine birthmarks without scarring.
How It Works.
Since the laser's invention in 1960, many different types were created — gas, solid-state, diode, and others. Basically, a laser is a glass rod or tube filled with a gas. When it is stimulated with energy, electrons in the gas are excited into higher energy states. These high-energy electrons are unstable and must return to a lower energy level, but as they lose their energy...
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This section contains 665 words (approx. 3 pages at 300 words per page) |
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