《光电类专业英语》课堂讲义文献.doc

光电类专业英语 任基 陈敏 胡晓飞 编著 成都信息工程学院光电技术系 二〇〇五年九月 CONTENT Total 119 Unit 1 1 1-1 The Function of Laser 1 1-2 Optical Fiber Communications 9 1-3 Organic Light Emitting Diodes 15 1-4 Holography 25 1-5 Photoelectron Spectroscopy 31 1-6 Photonics Unlocks Chip Bandwidth Bottleneck 35 Unit 2 40 2-1 History of Physics 40 2-2 Stephen Hawking and Black Holes 45 2-3 Electronics - Aerospace Synergy 49 2-4 Nanotechnology 55 Unit 3 62 3-1 Computer Security 62 3-2 Supercomputers on the Cheap 66 3-3 Bluetooth Technology 70 3-4 Teaching and Learning in the Wireless Classroom 79 3-5 What Is the Future of Telecommunications Networking 84 3-6 Introduction to 3G 94 Unit 4 98 4-1 Thinking Boldly, Acting Wisely 98 4-2 Income Tax 104 4-3 B2B E-commerce 109 4-4 WTO Basic Principles of the Trading System 115 Unit 1 1-1 The Function of Laser The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation. A laser is a device that produces a beam of monochromatic light in which all the waves are in phase or are coherent. In 1917, in the course of calculations on the equilibrium of a gas, Einstein discovered that there must be two possible types of emission. Atoms tend to gravitate toward their ground states. So the electrons drop down spontaneously and emit photons. This process is called spontaneous emission. Einstein wondered what would happen if an electron were already in an excited state when it encountered a photon of the proper energy. A natural conclusion would be that the electron would move to still higher orbit. Natural, but wrong. Einstein predicted instead that the electron would drop to a lower orbit and emit a photon, as by spontaneous emission, except that in this case the stimulating photon would not be absorbed but would simply continue on its way. We’d then end up with two photons of identical energy, or wavelength. Einstein called this stimulated emission. This concept, formulated by Einstein in 1916, was the germ of the idea that even