ПоәК 042-18-38-92/03-2013 №1 басылым
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- Lesson № 4 Theme: Lasers
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Discussion, short composition Methodical recommendations to carrying out of SIWT 1. Read the text and try to translate without dictionary 2. Do the exercises belong the text in writing 3 Form dialogue and monologue speech Distributing materials: text, lexical exercises The list of literatures: 1. Е.И.Курашвили. Английский язык для студентов – физиков. Москва Астрель. АСТ 2005 2. Е.В. Хомутова. Интенсивный курс английского языка для физиков. Издательство Московского университета 1983 Lesson № 4 Theme: Lasers 1. to acquire the special text with the aim learning the necessary information. 2. to learn lexical minimum and to use it in practice. 3. to communicate in English with partner on this subject Text LASERS 1. The term laser derives its name from the description, Light Amplification by Stimulated Emission and Radiation. In principle the laser is a device that produces an intense, concentrated, and highly parallel bеam of light. So parallel would be the beam from a visible light laser 1 ft in diameter that at the m0on the beam would be no more than a mile wide. ч^в^э~«^-;с 2. Lasers are of three general kinds, those using solids, those using liquids, and those using gases. For the case of liquid or gas lasers, a Fabry—Perot interferometer, with silvered end plates is filled with a fluid. In the solid laser, the ends of a crystal are polished and silvered. Since the first successful laser was made with a large single crystal of ruby, this' device will be explained as representative of solid state lasers. 3. The atomic lattice structure of (a ruby crystal has the properties of absorbing light of certain frequencies u0 and, of holding this absorbed energy for a period of time. Then by bouncing light of a different frequency vi back and forth between the silvered ends, the excited atoms may be stimulated to emit their stored energy as light of the same frequency v\ and in exact phase with the original light waves. As these intensified waves bounce back and forth, they stimulate others, thus amplifying the original beam intensity. жүктеу/скачать 1,54 Mb. Достарыңызбен бөлісу:
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