Lasers

The word "laser" is an acronym for "light amplification by stimulated emission of radiation." What does it mean? In short, a high energy atom can be stimulated to release light that is in phase (in step, or matching) a wave that hits it, thus amplifying the stimulating wave. When billions and billions of atoms do this at once, they produce a monochromatic ray of light where all the waves are in step with each other. This is a great advantage in applications that require a focused and concentrated beam of light. In science too, the monochromatic nature of this light (being of a single wavelength) makes it easier to use in experiments.

When lasers were first invented in 1960, no one knew what to do with them. Today, you can find them almost everywhere, from the CD players, to supermarket barcode scanners, to surgery tools, to the Mars Sojourner Rover, which used laser rangefinding to avoid running into rocks. One application that promises to vastly improve the Internet you are using to view this site is fiber optics. Because of its high frequency, light can carry massive amounts of information. (Just compare what you see through your eyes with what you hear!) However, until the laser was invented, light usually spread out, diffused, and generally got blurred so that at large distances no information could be extracted. With a laser beam, the light is very bright, monochromatic, and tightly focused. This helps a laser beam carry for great distances. (Scientists bounced laser beams off the moon!) However, for earthly destinations, air, dust, and objects will often get in the way of a laser beam, preventing it from traveling too far. That is, until fiber optics were invented. Fiber optics are simply thin strands of ultra-pure glass. Due to the angle of incidence, there is total internal reflection for a laser beam traveling down this strand of glass, and thus, most of the light arrives intact at the other end, delivering vast amounts of information.

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