基于曲线图解法的额外光程差分析

Analysis on Extra Range Differences of Film Interference Based on Graphic Illustration

根据菲涅耳公式推导了薄膜干涉模型中两光线不同分量的反射系数,并表示成直观的曲线图;利用曲线图分析了薄膜反射干涉时的额外光程差问题,讨论了不同折射率分布对干涉条纹对比度的影响.该方法有利于学生对额外光程差现象及产生额外光程差的条件的理解.

The reflectances from different interfaces of film are deduced from Fresnel formula, and they are expressed as graphs. The extra range differences of film interference are analyzed by the graphs. And the influence of visibility of fringe pattern on different distributions of refractive index is discussed. It is a very clear and distinct illustration for extra range differences of film interference by the graphic charts. The method is beneficial for students’understanding.