牛顿环等厚干涉条纹清晰度的探究  

Research on clarity of equal thickness interference of Newton rings

作　　者：骆敏[1] 张锡晨 余观夏[1] LUO Min;ZHANG Xichen;YU Guanxia(College of Science,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学理学院,江苏南京210037

出　　处：《实验技术与管理》2021年第7期59-62,77,共5页Experimental Technology and Management

基　　金：大学生创新训练计划项目(2020NFUSPITP0696);南京林业大学2016年高等教育研究课题(163101152)。

摘　　要：基于薄膜干涉理论和菲涅尔公式,通过理论和定量计算,分析了在利用牛顿环等厚干涉实验测量液体折射率时,其干涉视场和干涉条纹相比空气薄膜时变暗和不清楚的原因。探讨了两干涉光束的振幅、薄膜下表面的反射率与干涉条纹对比度3者之间的关系。结果表明,两干涉光束的振幅比、光强度、光强度差值以及在干涉相遇点的光程差对干涉条纹的质量起到关键的影响,可以通过在平凸透镜表面覆盖液体、镀增透膜和提高平板玻璃上表面一定的反射率来增大干涉光束的振幅,以及增大透镜的曲率半径来降低两干涉光束的光程差等方法来获得明暗清晰可观察的干涉条纹,有助于降低测量误差和加深学生对光干涉以及干涉条纹对比度等相关知识的理解。Based on the theory of thin film interference and Fresnel formula,through theoretical and quantitative calculation,this paper analyzes the reason why the field of view and fringes of Newton’s ring equal thickness interference experiment are darkened and unclear when compared with air film.The relationship between the amplitude of the two interference beams,the reflectivity of the lower surface of the film and the contrast of the interference fringe is discussed.The relationship between the amplitude of the two interference beams,reflectivity of the lower surface of the film and contrast of the interference fringes are discussed.The results show that the amplitude ratio,light intensity,light intensity difference and optical path difference of two interference beams play a key role in the quality of interference fringes.The interference fringes can be observed clearly by covering the convex lens with liquid,coating antireflection film,increasing the reflectivity of the upper surface of the flat glass to increase the amplitude of the interference beam,and increasing the curvature radius of the lens to reduce the optical path difference between the two interference beams,which is helpful to reduce measurement error and deepen students’understanding of light interference and interference fringe contrast.

关 键 词：牛顿环 条纹对比度 等厚干涉 反射率 

分 类 号：O436.1[机械工程—光学工程]