We propose a modified method for thickness measurement of a dielectric coating layer on metal based on Otto optical configuration (O-configuration). This method enables us to estimate the coating thickness that typically ranges from several tens of nanometers to more than one micrometer with precision less than a few nanometers. The common method to measure the thickness of dielectric coating layer is to utilize the frustrated total-internal reflection. In order to measure the thickness of several tens of nanometers, one can apply the surface-plasmon-resonance (SPR) phenomenon generated by the p-polarized light. For thickness larger than one hundred nanometers, a metal-clad leaky-waveguide (MCLW) mode generated by the p- or the s-polarized light can be employed without significant changes to the optical setup. The numerical and experimental verifications of the modified O-configuration reveals its effectiveness for precise measurement of moderately-thick dielectric coating layer on the metal.

我们提出了一种改进的方法，用于基于Otto光学配置（O-配置）的金属上介电涂层的厚度测量。这种方法使我们能够估计涂层厚度，通常范围从几十纳米到大于一微米，而精度小于几纳米。测量介电涂层厚度的常用方法是利用受挫的全内反射。为了测量几十纳米的厚度，可以应用由p偏振光产生的表面等离子体共振（SPR）现象。对于大于一百纳米的厚度，可以使用由p或s偏振光产生的金属包覆的泄漏波导（MCLW）模式，而无需对光学设置进行重大更改。