物理英語論文.doc

Physics and its applicationWangyuXian University of Posts and TelecommunicationsAbstract: From 1916 to now, laser got a very good development, it can also be used in every field, today, lets review the development history of the laser, and illustrates the application of laser in some industries.Pacs：0432.1+2Key words: Laser;history;applicationLaser originated in a physicists Einstein ,in 1916 Einstein put forward a series of new technology theory,called the Goaded Radiation. The theory of matter is that ,in the atom, a number of particles （ electronic ） distributed at various levels and in high energy particles by a certain level of photons, will drop from the level to the smallest （lambdatransition ） to changeling, then will the and stimulate its just the same nature, and in a state, can be a faint light of the phenomenon. This is called goaded radiation the light of the enlargement of the laser for short.In 1958, the American scientists Shawalow and Townes find a singular phenomenon ： when they will be launched in the light bulb light in a rare earth elements , crystal the molecules of a bright and always get together again. According to this phenomenon, theycame up with the Laser Principle, by its elements in the oscillating same frequency as the energy and motivation will produce the skin of light - the laster. They delivered important for this paper.After Schawlow and Towns research, scientists have made the countries of the proposed scheme, but without success.In May 15, 1960, california hughes laboratory scientists announced that the wavelength memain for 0.6943 micron laser, this is the first ever of the laser, which may become united in the world will be introduced for the first light of the areas of scientists. In July 7, 1960 , the development of the world united a success of the laser, the first united, the use of the scheme is a powerful beacon, to stimulate the ruby crystal the Cr atoms, which results in a rather focus on the thin red ray, and when it to a certain point, but to achieve even higher than the suns surface temperature.As the scientists of the research and more better laser by scientists developed rapidly, the laster also been applied to various trades and the peoples lives and social development played an alternative function.Laser welding ： car body nowadays thick cardboard, vehicle spare parts, of lithium battery, the heart performs a result, airtightness etc sealing device relay, all are not allowed to welding pollution and deformity of the device. the use of lasers is yag laser, the semiconductor laser and pump CO2 - laser.Laser a mark of various materials and ： in almost all industries are widely used, the use of lasers is yag laser, the semiconductor laser and pump co2 - laser.Laser cutting ： cars, computers, electrical, or wood by the speaker of the industry, all metal parts and special material is cut, acrylic, spring of some metals, and net plate, steel, hiding andrevealing its members and determined, hiding andrevealing its lead plate and phosphoric bronze and the boards of aluminium, quartz, glass and space industries use of titanium in alloy and so on. the use of lasers is yag laser and CO2 laser.Laser weapons is a use of laser beams are directly damaged by injury or voided of directed energy weapons. according to operational purposes, the laser weapons can be classified as strategic and tactical laser weapons laser weapons two categories. Weapons systems of laser and tracking, aimed, fired device and etc., are generally composed of the laser is a chemical laser, solid laser, CO2 laser,and so on . Laser weapons have to attack speed and flexibility, can achieve the precision and electromagnetic interference by other advantages, but there is also vulnerable to the weather and environmental impact and weaknesses. laser weapons is 30 years of history, the key technology has made the united states, russia, france, israel, all successful every laser target practice experiment. The buffer has been put into use laser weapons, mainly used in relatively close distance from the photo electric sensors, and average attack and some observation equipment ； enough laser weapons mainly adopt the chemical laser, in accordance with the existing level. the next five or ten years are expected to deploy ground and air platforms used in civil air defense against the tactics, the report and satellite operations, etc.Laser cooling ： laser is the cooling and laser the interaction of atoms are extremely slow down the movement to the atom of technology. this important technical the main purpose is to the precise measurements of atoms, in the high resolution laser spectrum and has high precision clock is a quantum frequency (atomic clock). Laser surgery: laser surgery is a traditional incomparable superiority of the operation. First, laser surgery not need to be hospitalized, surgical incision. the wound oozes blood. no hurts, no keloids. Such as ：Eye puffiness for the treatment of the traditional method of divesting surgery a broader coverage, the bleeding, was slow t