光滑样片镜反射率谱建模

Mirror Reflectance Spectrum Modeling of Smooth Samples

基于椭偏仪实验测量的材料表面镜反射率谱数据,分析和结合了多种常用的光滑样片模型的优点,提出了适用于光滑样片的镜反射率谱模型。分析了多种光滑样片在多个波段下的参数值和均方根误差,证明了该模型可以用于拟合光滑样片的镜反射率谱数据。比较了该模型与五参数双向反射分布函数(BRDF)模型,通过对该函数模型的上半空间积分,与实验测量的材料表面半球反射率比较,验证了该反射率模型的正确性。结果表明,该模型不仅能满足能量守恒定律和互易性,而且对光滑样片,该模型是BRDF模型的理想替代。

Based on the reflectance spectrum measured data obtained by ellipsometer, we analyse and combine the advantages of different models of smooth samples. A reflectance spectrum model for smooth samples is proposed. The different samples in various of bands are fitted, and the parameter values and the root mean square error correspondingly are analyzed. It proves that this model may fit the spectral data of smooth samples. To explore the correctness of the model, it is compared with the five-parameter bidirectional reflectance distribution function （BRDF） model. The model integration in the upper half space is compared with the measured hemispheric anti-rate data of the samples. The results show that the model satisfies both reciprocity and energy conservation law, and it could ideally replace BRDF model for smooth samples.