《2013光的干涉1学生.ppt

(三)、增透膜和增反膜 增透膜----- 利用薄膜上、下表面反射光的光程差符合相消干涉条件来减少反射，从而使透射增强。 增反膜----- 利用薄膜上、下表面反射光的光程差满足相长干涉，因此反射光加强。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. = λ A 5500 例4 增透膜 在玻璃表面镀上一层 薄膜，使波 MgF 2 长为 0 的绿光全部通过。 求：膜的厚度。 解：使反射绿光干涉相消 d 2 n 2 ? = λ 2 = + ( ) k 1 2 = λ + ( ) 1 2 4 n 2 × 1.38 3 4 A 0 = 5500 × = 2989 A 0 λ d = + ( ) k 1 2 4 n 2 取 k = 1 MgF 2 玻璃 1.38 = n 2 1.50 = n 3 e 1 2 半波损失? n1 = 1 n1 n2 n3,没有 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 例 5、 P119。已知 ∶海上油膜 ， n1=1.20，海水 n2=1.30油膜厚度 d=460nm。 (1)从直升飞机上看 ，油膜呈什么颜色 ？ (2)潜水员从水下看 ，油膜呈什么颜色 ？ 解 ∶ (1) 1.20 = n 1 1.30 = n 2 d 1 2 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 1.20 = n 1 1.30 = n 2 d 1 2 (2) 油膜呈紫红色 。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 一 、劈尖 11-4 劈尖 牛顿环—等厚条纹 1、实验装置 干涉条纹示意图 厚度不均匀薄膜表面 D Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2、定量计算 明条纹 暗条纹 L D n1 n1 n Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. L D n1 n 相邻等厚条纹对应的厚度差为 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 3. 劈尖的应用： （1）测波长，折射率： （2）测细小厚度、 （3）测表面不平度 等厚条纹 待测工件 平晶 依据公式 微小变化： 思考题 17-12 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 等厚干涉条纹 劈尖 不规则表面 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 二 、牛顿环 1、实验装置 装置示意图 ① ② S 显微镜 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. * 第十一章 波 动 光 学 Evaluation only. Crea