Lasers :: essays research papers

The laser is a device that produces a beam of light. The beam is produced by a process cognise as stimulated emission, and the word &8220laser is an acronym for the phrase &8220light amplification by stimulated emission of radiation therapy. Lasers amplify light and produce coherent light beams. A light beam is coherent when its waves or photons are in step with one another. Laser light can be made extremely intense, super directional, and very pure in color.BASIC PRINCIPLESLight can be characterized both by its frequency, or number of wave crests passing a apt(p) point per second, and by its wavelength. Different wavelengths of light are seen as different colors. Like radio waves, light can also carry data. The information in the beam varies in the frequency or shape of the light wave. Because light waves are of much higherfrequencies than radio waves, the have a higher information carrying capacity. In beams of light,individual photon waves are not moving along together becau se they are not being emitted at the same instant but instead in random short bursts. Such beams are called incoherent.The process for laser bodily process, was first proposed by Albert Einstein in 1917. The working principles of lasers were outlined by the American physicists Arthur Leonard Schawlow and Charles sternly Townes in their 1958 patent application. The patent was granted but was later challenged by the American physicist and 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 components. 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(a) 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 the active meduim, one of which transmits par t of the radiation that strikes it. Atoms initially in a lower state are raised to the upper state by energy from a flash lamp or some other pumping source. Some of these atoms emit light in random directions. Light traveling vertical to the mirrors stays within the active medium long plenteous to stimulate emission from otheratoms. Light traveling in other directions are soon lost. Some light reaching the output mirror is contagious to form the laser beam, some is reflected back through the medium to continue the stimulated-emission process.