Студопедия.Орг Главная | Случайная страница | Контакты | Мы поможем в написании вашей работы!  
 

Exercise 8. Fill in the gaps with the words given above



1. It was near the _______ of City Road and Old Street. 2. This tool can be used in a ________ of ways. 3. They sell a wide range of domestic ________ – washing machines, dishwashers and so on. 4. Her unusual talent ________ her worldwide recognition. 5. The game will be broadcast ________ on TV and radio. 6. What rate will I get if I ________ my dollars into euros? 7. That comment needs some ________. 8. The town is ________ for its ancient harbour. 9. It’s not a hotel, in the ________ sense, but rather a whole village turned into a hotel. 10. The bar codes on the products are read by ________. 11. He has lived and worked in France almost ________ since 1990.

TEXT 1

Laser

The laser period opens with the achievement of the ruby laser. The acronym l.a.s.e.r. stands for light amplification by stimulated emission of radiation.

Physicist Theodore Harold Maiman invented the first operable laser. While employed at Hughes Research Laboratories as a section head in 1960, he developed, demonstrated, and patented a laser using a pink ruby medium, for which he gained worldwide recognition. Born in Los Angeles, California, Maiman, in his teens earned college money by repairing electrical appliances and radios. He attended the University of Colorado and received a B.S.* in engineering physics in 1949, then went on to do graduate work at Stanford University, where he received an M.S.* in electrical engineering in 1951 and a Ph.D.* in physics in 1955. In 1962 Maiman founded his own company, Korad Corporation, devoted to the research, development, and manufacture of lasers.

Early in 1961 the first continuously operating laser was announced by Ali Javan and coworkers at Bell Laboratories. This laser was the first to use a gas, a mixture of helium and neon, for the light emitting material. At the same years scientists from American Optical Company made the first neodymium-doped glass laser. In 1962 scientists at General Electric and International Business Machines (IBM) almost simultaneously demonstrated the first semiconductor junction laser.

In 1962 Basov and Oraevskii proposed that rapid cooling could produce population inversions in molecular systems. And in 1966, the first gas-dynamic laser was successfully operated at the Avco Everett Research Lab. Many new laser types were discovered, most notable among these are the semiconductor lasers. In these lasers electrical energy is converted directly into highly monochromatic radiation.

The 1970s years became the time of discovery of a free electron laser. Laser applications have also increased in variety. Clearly, most optical experiments can be done at least as well with lasers as with conventional light sources and many can be done much better. Experiments requiring really high intensities in narrow spectral regions can only be made with lasers. Outside the field of scientific experimentation many applications were found in medicine, communications, geophysical and space exploration, military and metals technology. The potential importance of these applications continues to stimulate new developments in the laser field.

The 1964 Nobel Prize in physics was awarded to Charles Townes and to the Russian scientists Nikolai Basov and Alexander Prokhorov for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle.





Дата публикования: 2015-01-13; Прочитано: 455 | Нарушение авторского права страницы | Мы поможем в написании вашей работы!



studopedia.org - Студопедия.Орг - 2014-2024 год. Студопедия не является автором материалов, которые размещены. Но предоставляет возможность бесплатного использования (0.006 с)...