Word: lightness
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Dates: during 1960-1969
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Then for a while, optimism faded. Practical uses for the new source of light, which scientists christened laser (for light amplification by stimulated emission of radiation), proved to be both scarce and elusive. Physicist Theodore Maiman, an early laser pioneer, described the new light source as "a solution seeking a problem." He was understandably impatient, but problem after problem has since been found- in ever increasing numbers. And the versatile laser is beginning to solve those problems in a manner that more than justifies the early, expansive claims. Lasers have become a $300 million-a-year business. As they...
Welding Retinas. Taking advantage of the unerring straightness and narrow diameter of laser beams, engineers are already using them to keep bridges, tunnels and dams in line during construction. Laser light has also proved helpful in aligning jet-plane assembly operations and the two-mile-long Stanford linear accelerator. When the high energy of laser light is concentrated on a small area, it serves as a high-speed drill that can burn precision holes through materials as hard as diamonds in a small fraction of the time required by conventional methods. It can vaporize the rough edges of such microscopically...
...them entree to the operating room, where they can cut into human and animal tissue as delicately as a finely honed scalpel. Even better, the laser knife does not draw blood. Its searing but highly localized heat cauterizes capillaries and other blood vessels as they are severed. Like ordinary light, laser beams pass through transparent substances but are absorbed by darker, opaque materials. Thus they flash harmlessly through the cornea and lens of the eyeball to weld a detached retina back into place, or puncture small holes in the retina to ease the pressure of glaucoma. They also penetrate translucent...
...Einstein pointed out that an atom or molecule stimulated by an electro-magnetic wave (light, for example) would give off a basic unit of light called the photon, which would have the same wave length as the stimulating wave. A number of subsequent experiments proved Einstein correct. But not until 1958 did Physicists Arthur Schawlow and Charles Townes describe a device that they thought would be able to stimulate molecules of gas confined in a cylinder until they gave off photons in an intense and powerful stream. Their device was a variation of Townes's earlier Nobel Prizewinning invention...
Just two years later, Physicist Maiman used the Townes-Schawlow theory and built the world's first working laser, a small, hand-held instrument that shot out bursts of brilliant red light. Instead of a gas, Maiman's laser used a synthetic ruby crystal grown in a bath of molten aluminum oxide. In pure form, the aluminum oxide crystal is colorless and transparent. But a pinch of chromium added to the bath as an impurity gives the resulting crystals their characteristic ruby-red hue and supplies the chromium atoms (one for every 5,000 aluminum atoms) that cause...