大物实验lj逊干涉仪测5.pdfVIP

实验四 用迈克尔逊 仪空气的折射率 一、实验目的 用分离的光学元件构建一个迈克尔逊 仪。 通过降低空气的压强测量其折射率。 二、仪器和光学元件 光学平台；HeNe 激光；调整架，35x35mm；平面镜，30x30mm ；磁性基座；分束器50:50；透镜，f=+20mm ； 白屏； 容器，手持气压泵，组合夹具，T 形连接，适配器，软管，硅管 三、实验原理 借助迈克尔逊 仪装置中的两个镜，光线被引进 仪。通过改变光路中容器内气体的压强，推算出空气的 折射率。 If two Waves having the same frequency  , but different amplitudes and different phases are coincident at one location , they superimpose to Y =a • ( ) ( ) sin wt − +a •sin wt − 1 1 2 2 The resulting can be described by the followlng : = ( ) Y A •sin wt − 2 2 2 w ith the amplitude A = a +a +2a a •cos (1) 1 2 1 2 and the phase difference = − 1 2 In a Michelson interferometer , the light beam is split by a half-silvered glass plate into two partial beams ( amplitude splitting ) , reflected by two mirrors , and again brought to interference behind the glass plate . Since only large luminous spots can exhibit circular interference fringes , the Iight beam is expanded between the laser and the glass plate by a lens L . / If one replaces the real mirror M3 with its virtual image M3 , , Which is formed by reflection by the glass plate , a point P of / the real light source appears as the points P , and P of the virtual light sources L and L ·Due to the different light l 2 paths , using the designations in Fig . 2 ,