Measuring thin films using quantitative frustrated total internal reflection (FTIR)
Measuring thin films using quantitative frustrated total internal reflection (FTIR)
复制标题
使用定量受抑全内反射 (FTIR) 测量薄膜
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Chao Sun
中科院分区：
文献类型：
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作者：
Minori Shirota;M. A. J. van Limbeek;D. Lohse;Chao Sun
在液体和固体之间相互作用的研究中，精确测量两种介质之间的膜厚度对于研究动力学至关重要。由于干涉测量法受到所用光源波长的限制，最近对薄膜的研究促使使用受抑全内反射 (FTIR)。在许多研究中，使用了强度随膜厚度的简单指数衰减的假设。在本研究中，我们强调该模型不满足菲涅尔方程，因此低估了薄膜。我们表明，必须考虑薄膜上下界面的多次反射和透射，才能准确描述测量的强度。为了定量验证 FTIR 技术，我们测量了已知几何形状的凸透镜与平坦表面之间的气隙薄膜厚度，并获得了极好的一致性。此外，我们还发现，通过与赫兹理论的结果进行比较，我们可以准确地测量透镜在负载下的弹性变形。
In the study of interactions between liquids and solids, an accurate measurement of the film thickness between the two media is essential to study the dynamics. As interferometry is restricted by the wavelength of the light source used, recent studies of thinner films have prompted the use of frustrated total internal reflection (FTIR). In many studies the assumption of a simple exponential decay of the intensity with film thickness was used. In the present study we highlight that this model does not satisfy the Fresnel equations and thus gives an underestimation of the films. We show that the multiple reflections and transmissions at both the upper and the lower interfaces of the film must be taken into account to accurately describe the measured intensity. In order to quantitatively validate the FTIR technique, we measured the film thickness of the air gap between a convex lens of known geometry and a flat surface and obtain excellent agreement. Furthermore, we also found that we can accurately measure the elastic deformations of the lens under loads by comparing them with the results of the Herzian theory.