Lasers :: essays research papers

The laser is a device that produces a peter of clean-cut. The beam is produced by a process known as affect run, and the word &8220laser is an acronym for the phrase &8220 free amplification by stimulated emission of radiation. Lasers amplify light and produce coherent light beams. A light beam is coherent when its waves or photons are in step with peerless an early(a). Laser light can be make extremely intense, highly directional, and very pure in color.BASIC PRINCIPLESLight can be characterized both by its frequency, or number of wave crests passing a given point per second, and by its wavelength. Different wavelengths of light are seen as different colors. Like radio waves, light can also study information. The information in the beam varies in the frequency or put to work of the light wave. Because light waves are of much higherfrequencies than radio waves, the work a higher information carrying capacity. In beams of light,individual photon waves are not pathetic along together because they are not being emitted at the alike instant but instead in random short bursts. such(prenominal)(prenominal) beams are called incoherent.The process for laser action, was first proposed by Albert Einstein in 1917. The working principles of lasers were outlined by the American physicists Arthur Leonard Schawlow and Charles Hard Townes in their 1958 indubitable application. The patent was granted but was later challenged by the American physicist and railroad engineer Gordon Gould. In 1960 the American physicist Theodore Maiman observed the first laser action in solid ruby.HOW A LASER WORKSA laser is made up of several basic comp adeptnts. One is called active medium, which consists of atoms of a gas, molecules in a liquid, ions in a crystal, or any of several other possibilities. Another component consists of some method of introducing energy into the active medium, such as a flash lamp. The third basic component is a pair of mirrors placed on eitherside of th e active meduim, one of which transmits part of the radiation that strikes it. Atoms initially in a lower verbalise are raised to the upper state by energy from a flash lamp or some other pumping source. many of these atoms emit light in random directions. Light traveling vertical to the mirrors stays in spite of appearance the active medium long enough to stimulate emission from otheratoms. Light traveling in other directions are soon lost. Some light reaching the output mirror is transmitted to form the laser beam, some is reflected back through the medium to continue the stimulated-emission process.