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Laser (light amplication by stimulated emission of radiation)

English Essay on "Laser"

The word laser stands for light amplification by stimulated emission of radiation. Laser light differs from light from an incandescent lamp in many respects. Firstly the laser light is monochromatic. It consists of only one wave length and one colour while the light from an incandescent lamp has a number of wave lengths and colors. Secondly the laser light is emitted in only one direction while ordinary light from an incandescent lamp is not limited to one direction. Thirdly the laser light-is coherent and all parts of a laser beam are in the same phase. Fourthly the laser light is far more intense than ordinary light.

Laser action has been achieved in gaseous, solid and liquid media. The ruby laser consists of a cylinder of ruby about 5 cms long and 1 cm. in diameter, the ends being polished flat and parallel, one end having a silvered reflecting surface and the other a semi—silvered surface. Chromium ions in the ruby lattice are excited by an intense flash of light to produce laser.

Lasers are very useful and have so far been employed o do many service in many fields. In industrial field lasers are used for cutting metals, for drilling small holes and for welding. These things are made possible by two characteristics of lasers. The first characteristic is that it can be produced in high intensity and the second is that a large amount of energy can be concentrated in a small region. Laser beam can also be used to induce nuclear fusion reactions.

In medical field, lasers have proved very useful. Lasers are now used to break stones in human kidneys and gall bladders. This saves unnecessary cost and labour in performing operations. The broken stones are got rid of through urine. Eye surgeons also use lasers in reattaching detached retina. In other fields also lasers have proved to be useful. They are used to produce three dimensional images called holograms.(9essay.com) To do this a beam of coherent light from a laser is split into two by a semi transparent mirror so that one beam can be detracted by the object to be reproduced onto a photographic film or plate and the other beam falls directly on the film. The two beams form interference pattern on the plate, thus forming hologram. Lasers are also used in research to study non linear optical properties of materials. Lasers are also used as range tinder over large distances and as such are used in guided missiles.

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