Chang K S, Chou C, Lin C H
Appl Opt. 1993 Jun 1;32(16):2957-62. doi: 10.1364/AO.32.002957.
The conventional algorithm for obtaining the p-ray reflectance (R) of a metal in an attenuated total-reflection (ATR) experiment is to normalize the p-ray reflecting power of the metal (I(p)) with its s-ray reflecting power (I(s)). We found that for these ATR experiments in Kretschmann's configuration, two conditions will make I(s) less than I(p). In the first condition the film itself is absorptive; in the second the film is weakly absorptive but has thin thickness. When I(p) < I(p), the conventional algorithm is not applicable anymore; otherwise, the measured reflectance will be greater than one. With a modified focused-beam ATR experiment, we demonstrated that the above hindrance can be overcome by taking the intensity distribution of the incident p ray as the normalizing signal. The reflectance of the bare prism at incident angles greater than the critical angle is also suggested to be taken as a proper normalization factor.
在衰减全反射（ATR）实验中，获取金属p光反射率（R）的传统算法是用金属的s光反射功率（I(s)）对其p光反射功率（I(p)）进行归一化处理。我们发现，对于采用克雷奇曼配置的这些ATR实验，有两种情况会使I(s)小于I(p)。第一种情况是薄膜本身具有吸收性；第二种情况是薄膜吸收性较弱但厚度较薄。当I(s) < I(p)时，传统算法不再适用；否则，测量得到的反射率将大于1。通过改进的聚焦光束ATR实验，我们证明可以通过将入射p光的强度分布作为归一化信号来克服上述障碍。还建议将入射角大于临界角时裸棱镜的反射率作为合适的归一化因子。
