[英语学习]专业英语6_Laser.ppt

Laser Adventure What is a Laser 1. How Does Laser Light Differ from Other Light ？ 2. What is Stimulated Emission ？ Applications of Laser 1. Everyday Use of Laser 2. Military 3. Communications 4. Medicine 5. Industry 6. Research 课堂要点 Appendix I: LASER HISTORY Large number of ‘projects on lasers were done in secret laboratories, and we shall ‘concentrate on some of the simplest and most known appli’cations, such as: Laser range-finder(测距仪), Target designation[,dezig’nei??n](指示), Laser weapons (Star Wars), Laser blinding for man and sensitive equipment. A laser range-finder is a device consisting of a pulsed laser and a light detector. By measuring the time taken for light to reflect off a far object, and knowing the speed of light, the range to the object can be found. A laser rangefinder is thus a simple form of LIDAR[‘laid?]激光雷达(laser radar). The distance to the target can then be used to aim a weapon such as a tanks main gun. Another military use of lasers is as a laser target designator. This is a low-power laser pointer used to indicate a target, typically launched from an aircraft. The laser is used to mark targets for attack by smart artillery [?:’til?ri](炮兵的总称) and guided missiles[‘misail](导弹). A lot was written on the ‘project named “Star Wars” of the US government. The idea was to build high power devices that can send beams over very big distances in a very high ‘accuracy and very high speed. These high power devices were supposed to destroy the USSR missiles above their lounching sites right after this launch. A simple and very ‘promising(有前途的) project, which is being developed at many sites all over the world, is laser system for blinding enemy soldiers and their optical equipment. The power required is not specially high, because of the high ‘sensi’tivity of our sight system, and the high sensitivity of the optical detection systems in use at the battlefield. Optical power density higher than the safe level can cause blindne