光的干涉和干涉系统5.ppt

1、1,第五节 典型的双光束干涉系统及其应用 一、典型干涉系统,1、斐索 ( Fizeau ) 干涉仪：等厚干涉型的干涉仪,1）激光平面干涉仪 的组成和工作原理,2,2）主要用途 测定平板表面的平面度和局部误差 测量平行平板的平行度和小角度光楔的楔角 测量透镜的曲率半径,3, 测量平行平板的平行度和小角度光楔的楔角,4, 测量透镜的曲率半径,牛顿环,5,球面干涉仪,P,Q,6,小结： 基本特点：（1）属于等厚干涉,（2）干涉光束，一个来自标准反射面，一个来自被测面。,条纹分析：,7,2、迈克尔逊干涉仪 （The Michelson interferometer）,1）干涉仪结构 分光板和补偿板 平

2、面反射镜 干涉原理,2）干涉条纹的性质 等厚干涉 等倾干涉,8,DS,特点：M1 和M2 垂直时是等倾干涉，否则为等厚干涉。,掌握： （1）系统结构， （2）M1或M2垂直于光线移动时对条纹的影响,9,3、泰曼干涉仪（Twyman interferometer）,特点：在迈克尔逊干涉仪的一个光路中加入了被测光学器件,Contour lines Fringes of equal thickness,10,4、马赫曾德干涉仪 （Mach-Zehnder interferometer）,测量光一次通过被测域,It is preferred to measuring large transparent

3、 objects.,2）干涉仪结构,1）应用场合和测量的基本原理,3）条纹性质分析,11,二、其他干涉技术,1、数字波面干涉术,目的：产生移动的干涉条纹，用光电器件探测条纹的变化。 基本原理：利用光学拍频中干涉条纹强度随时间变化的性质。,外差干涉原理,12,t,I(x,y,t),条纹是随时间变化的量。,13,14,2、傅里叶变换光谱仪,原理：利用光源的相干长度对条纹可见度的影响，测量光源的光谱分布。,相干长度：光谱宽度为Dl的光源能够产生干涉的最大光程差,设：I0(k)为随波数而变化的谱密度函数，整个光谱分布在（-，+）之间，为两光路的光程差。则：,15,在麦克尔逊干涉仪中，通过移动M2，改变

4、D获得W(D)，再通过反傅里叶变换计算出I0(k)。,W(D),D,I(l),l,设,16,Homework (11-5),1. Using red cadmium light, =643.8nm, Michelson in his original experiment could still see interference fringes after he had moved one of the mirrors 25cm away from the coincidence position. How many fringes did he count? P244 9&16,下一节,17

5、,Armand H. L. Fizeau,Armand H. L. Fizeau (1819-1896), French physicist, was born of a wealthy French family that enabled him to be financially independent. Instead of shunning work, however, he devoted his life to diligent scientific experiment. His most important achievement was the measurement of

6、the speed of light in 1849.,18,Albert Abraham Michelson,Albert Abraham Michelson (1852-1931) was born in Strelno, Prussia. He moved to the United States with his parents when he was 2. He graduated from, and taught at, the U. S. Naval Academy and later worked at the Case School of Applied Science, C

7、lark University and the University of Chicago. In 1907 he was awarded the Nobel prize in physics, the first American scientist to be so honored.,19,Michelson is best known for his precise determination of the velocity of light, for inventing the interferometer that bears his name. He also made noteworthy contributions to astronomy, spectroscopy and geophysics, was proficient in tennis and other sports, played the violin, and liked to paint landscapes.,20,Frank Twyman,He is a manager, at Adam Hilger Ltd., astronomical and optical instrument makers in London.