2. 外语
  3. The word laser was coined as an acronym for Light Amplification by the Stimulated Emission of Radiation. Ordinary light, from th

The word laser was coined as an acronym for Light Amplification by the Stimulated Emission of Radiation. Ordinary light, from th

admin2010-01-10  51
问题    The word laser was coined as an acronym for Light Amplification by the Stimulated Emission of Radiation. Ordinary light, from the Sun or a light bulb, is emitted spontaneously, when atoms or molecules get rid of excess energy by them-selves, without any outside intervention. Stimulated emission is different because it occurs when an atom or molecule holding onto excess energy has been stimulated to emit it as light.
   Albert Einstein was the first to suggest the existence of stimulated emission in a paper published in 1917. However, for many years physicists thought that atoms and molecules always were much more likely to emit light spontaneously and that stimulated emission thus always would be much weaker. It was not until after the Second World War that physicists began trying to make stimulated emission dominate. They sought ways by which one atom or molecule could stimulate many others to emit light, amplifying it to much higher powers.
   The first to succeed was Charles H. Townes, then at Columbia University in New York. Instead of working with light, however, he worked with microwaves, which have a much longer wavelength, and built a device he called a "maser," for Microwave Amplification by the Stimulated Emission of Radiation. Although he thought of the key idea in 1951, the first maser was not completed until a couple of years later. Before long, many other physicists were building masers and trying to discover how to produce stimulated mission at even shorter wavelengths.
   The key concepts emerged about 1957. Townes and Arthur Schawlow, then at Bell Telephone Laboratories, wrote a long paper outlining the conditions needed to amplify stimulated emission of visible light waves. At about the same time, similar ideas crystallized in the mind of Gordon Gould, then a 37-year-old graduate student at Columbia, who wrote them down in a series of notebooks. Townes and Schawlow published their ideas in a scientific journal, Physical Review Letters, but Gould filed a patent application. Three decades later, people still argue about who deserves the credit for the concept of the laser.
Why do people still argue about who deserves the credit for the concept of the laser?
选项 A、The researchers’ notebooks were lost.
B、Several people were developing the idea at the same time.
C、No one claimed credit for the development until recently.
D、The work is still incomplete.
答案B
解析 为什么人们还在争论谁应该获得提出激光概念的荣誉：A研究人员丢失了笔记本；B几个人同时发展了想法；C直到最近才有人为发展要求信用；D工作还不完全。前面我们说道，汤尼斯和阿瑟Sehawlow，然而几乎同时，类似的想法在戈登古尔德的头脑中结晶了。汤尼斯和Schawlow在科学报刊上发表了他们的想法，但是古尔德把理论归档了。所以，应该选B。
转载请注明原文地址:https://kaotiyun.com/show/xr6K777K
0

专业英语四级

相关试题推荐
随机试题
最新回复(0)