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by Herb Hanko Along with the computer chip, no other technological advance has contributed so much to change in our society as the laser. It is almost beyond believe that light can perform so many different tasks and produce so much power. Laser light, on the other hand, is all of one frequency and all the waves are lined up equally in phase with each other. It is said to be coherent light, and its waves can be amplified and focused in a tight beam. Such a coherent beam hitting any surface can produce indeed considerable physical effects. You may wonder how one goes about making light to be in phase and in one frequency. Actually its quite simple, and the word laser gives away the answer. The word laser is an acronym of: Light Amplified by Stimulated Emissions of Radiation. When an atom absorbs energy, such as light, it does so by propelling its electrons to a higher energy orbit. Once the energy inflow ceases, the atom dissipates its excess energy by pulling its electrons back to their normal orbits. In some atoms this causes the emission of a quantum of light, or photon. This is the principle at work in neon lights. A neon light is a vacuum tube, charged with a high DC voltage, containing a gas whose atoms emit light upon energy release. A laser is just a very sophisticated neon tube, with its light collected, amplified and focused by mirrors. Isn't nature grand?
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