工程光学11-12.pptVIP

Interference fringes Key words 1. Path difference 2. Phase difference 3. The order of interference 4. The light distribution 5. A maximum amount of light (maxima) 6. A minimum amount of light (minima) Homework (11-12) Light passes through two narrow slits of d=0.8mm. On screen 1.6m away the distance between the two second-order maxima is 5mm. What is the wavelength of the light? P243 12 干涉现象（Interference） 在两个（或多个）光波叠加的区域形成强弱稳定的光强分布的现象，称为光的干涉现象。 Thomas Young (1773-1829) A British physician and physicist. He could read at age 2, at 6 began studying Latin, and at 13 had also mastered Greek, Hebrew, Italian and French. At 19 he entered medical school, correctly explained the accommodation of the eye and was elected Fellow of the Royal Society. In 1796, he graduated from the University of Gottingen Medical School, opened a practice in London, and 5 years later became professor of Natural Philosophy at the Royal Institution. That same year,1801, he read the first of several papers presenting the wave theory of light and the principle of interference, much to the opposition of Newton’s followers. Young made noteworthy contributions also to acoustics, atmospheric refraction, elasticity, fluid dynamics and color vision. Interference fringes The light of distribution resulting from a superposition of waves will consist of alternately bright and dark bands called interference fringes. Such fringes can be observed visually, projected on a screen, or recorded photoelectrically. * 第十一章 光的干涉和干涉系统 干涉现象是光波波动性的重要特征 1801年杨氏干涉实验—波动理论—部分相干理论 应用：测量光谱线的细微结构、测量长度 多种干涉装置：杨氏双缝干涉、迈克尔逊干涉仪等 本章内容：干涉现象、干涉理论和干涉装置 第一节 光波的干涉条件 一、干涉现象 1、什么是干涉现象（Interference） 2、相干光波（Coherent wave）和相干光源 （Coherent light source） 能够产生干涉的光波，叫相干光波； 其光源称为相干光源。 二、干涉条件 一般情况下， 对于两个平面简谐波 干涉条件（必要条件）： 补充条件： 叠加光波的光程差不超过波列的长度 第二节 杨氏干涉实验 （Young’s double-slit experiment） 一、干涉图样的计算 1、P点的干涉条纹强度 光强 I 的强弱取决于光程差 2、光程差D的计算 光程差： O x y z P(x,y,D) d S 1 r 2 r 1 S 2 S y x D w 3、干涉条纹（Interference fringes） 及其意义 x 对于接