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Реферат: Lasers Essay Research Paper Through out the

Название: Lasers Essay Research Paper Through out the
Раздел: Топики по английскому языку
Тип: реферат Добавлен 11:14:38 16 ноября 2010 Похожие работы
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Lasers Essay, Research Paper

Through out the past few years lasers have been going through many

innovations thus having a tremendous impact on technology . What is a laser? A laser is a special kind of light .The initials stand for ( L-A-S-E-R light amplification by stimulated emission of radiation)Only the light that is commonly know to us is the type that spreads out . Laser light is in a straight beam. There are many types of lasers , some make holograms , some have special features like long coherence length or an output beam in different color (blue green ..) and helium neon lasers .Lasers serve for many purposes they can trigger thermonuclear explosions , telephone communication , photography ,printing (computers and laser printers ) drill through diamond , detect the measure of electrons , art and music , eye surgery , and fun games like laser tag .

The first person to come up with the concept of light was Albert Einstein. In 1917 he developed a theory that a special kind of light could be made , under the right conditions the light wouldn?t scatter unlike normal light, and it would be very intense. Nearly 45 years latter scientists came up with the first laser . The reason no one figured out how to make the lasers is because they lacked the basic concept and theory . ” Atoms always tend to be at their ground state . When they are stimulated , they remain at an excited state for only a split second. The chances for a photon with the same energy level striking an excited electron are very small. Therefore we never see laser light in nature .”

Lasers come in different types , the first is called Optically Pumped laser .The inventor of this laser is Theodore Maiman . In this laser atoms of a solid material crystal or glass are excited by bursts of light .In this laser is made of a rod with mirrors at the end to make the light bounce back and forth. The second laser is a Liquid Laser this laser eliminates the need for rods by replacing it with a liquid dye . “The dye is put into a glass tube and light is pumped through it to excite the atoms .” The third type is a Gas Laser.

These lasers have the most coherent beam of any type of laser . This is the primary reason they are used in communications. “Gas or mixtures of gas and other compounds are put in a tube and stimulated by a power source either chemical or electrical . Strong gas lasers which are powered by carbon dioxide can drill cut weld and do surgery. Lower powered gas lasers powered by helium or neon just make a red beam these are used in supermarkets and libraries to scan bar codes .

In 1963 lasers provided an important phenomenon . A researcher aimed a laser at two balloons. One balloon was clear , the other was blue . The blue balloon was inflated inside the clear one , the scientist were surprised that the laser went through the clear balloon . The reason the balloon performed this action was that the laser was pumped by a ruby particles. While passing the clear balloon nothing happened but as it hit the blue balloon it punctured a hole in the skin . This is because the balloons color absorbed the energy of the ruby laser . This proved that lasers can be used to repair damaged eyes. The clear part of the balloon is like to cornea and the inner part is the retina . Repairing eyes was very hard and tedious but now with the laser its routine . The laser passes harmlessly through the clear part of the eye and into the problemed area , the retina . Correcting eyes was time consuming , difficult and took several days to heal . Now patients go home the same day .

In 1898 H.G Wells published a novel called War of the Worlds . In this novel their martians who used laser rays that made things blow up . And vaporize things . Anything that they were aimed at got blown up and destroyed . It seems after reading books like this that in the future guns will be replaced by lasers. This is impossible for one thing the energy need to vaporize a cell is fairly large but to vaporize a person or tank an energy station is needed , a power plant as big as a house would be needed . In addition bullets get there destructive force by there speed and weight

( Vf=Vi+at ) or (Vf squared = Vi squared + 2ad ) and Force +mass x acceleration . Lasers beams have no weight because they travel at the speed of light . But the military has found a way to use lasers to their advantage . Since lasers travel at 186,000 miles a second they can detect how far something is in seconds . Therefore lasers can be used with anti tank weapons and flying aircraft support can locate targets . Aircraft?s are also equipped with laser guided missiles “smart bombs” . Smart bombs are made by fitting regular bombs with laser seeking heads . When dropped these bombs are guided to their targets by laser beams. The beams are fired by soldiers or other aircraft. Many theories have concluded that lasers could replace patriot missiles . Sure the cost would be lower , lasers are faster , and reusable but a missile traveling at 6 times the speed of light which is about 4,400 miles per hour couldn?t be blown out of the sky because a laser from a distance could be fired at the target in seconds thus reaching it in seconds but the effect would be inadequate. A laser works by burning a hole in something so in this case the laser would have to be focused on the missile?s cone for a while , giving it time to mess up the electrical circuits , thus burning a hole in it . But that would do nothing . The missile would fall and explode somewhere because the speed of the fall. This is dangerous because its unpredictable , what if a missile with a messed up circuit system feel on a hospital or school . This would be catastrophic. In addition this type of weapon would be fired from satellites in space. These types of satellites run off of solar cell batteries which have the power of a kitchen toaster .A laser with this type of potential needs at least 150 megawatts . Even if the adequate power was supplied hundreds of acres would be need to fit the plates. With something this big floating in space it could be easily traced and shot down.

AT&T has ventured back in time to pick up an old idea and revise it. Alexander Bell the inventor of the telephone also made a photo-phone. . This device used light beams not electrical beams to transmit voices . The problem was that this invention need mirrors and sunlight . On a cloudy day it was useless . Bells photo-phone worked by bouncing back sunlight from a reflector through a lens . Speech made the sunlight vibrate .Light is a form of electromagnetic energy therefore it can carry tremendous amounts of information . Light waves have a high frequency so they can carry more information than the telephone radio or television. The television has a transfer rate of 6 million bits per second the laser beam has 100 billion bits per second transfer rate. By far superior to anything . The problem about cloudy days is eliminated because laser beams can be sent over glass wires as thin a strand of hair .One fiberoptic line can carry about a thousand phone calls.

Lasers have also effected the music and computer industry . Everyone remembers record players . They used a thin needle to read a giant record then issue sounds. Now compact disc are engraved by lasers . They can hold up to 1000 old record songs . And the constant issue of getting a new needle for a record player is gone. Cd?s are read by lasers. Computers can read Cds also four volumes of encyclopedias thats 450 books can be stored on one 4and a half by four and a half disc .

There are lasers that can handle 40,000 telephone calls through a single fiberopic , there are lasers that can measure the distance between the sun and the moon in a fraction of a second , there are lasers that can read and print there are lasers that kill and destroy and there are lasers heal and build . These are just a few of the possible future uses of lasers . Its too early to tell if we will see them come to pass. But what is certain is that we can look forward to the future potential of lasers . When lasers first came out no one ever though that lasers would have such vital roles like correcting vision , or cutting diamonds . The potential and possibility for lasers is endless . Who knows maybe someday we will have laser cell phones, laser powered and laser powered cars!

Kasper , Joseph . The complete book of holograms . New York : John Wiley

and sons 1987.

Burroughs , William . Understanding Science : Lasers . New York : Warwick

Press , 1982

Encarta CD , Lasers Holograms Military , Microsoft Inc 1996

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