光学薄膜的分层界面散射模型

Stratified-Interface Scattering Model for Multilayer Optical Coatings

提出了一种计算光学介质膜系表面总积分散射(TIS)的理论模型。该模型认为,介质膜系粗糙的膜层界面和表面为微观结构不均匀的微薄过渡区;过渡区可用折射率为不同常量的层数足够多的均匀子层来代替,同时这些均匀子层的折射率变化满足指数函数的分布规律。利用矩阵法对积分散射的表达式进行了推导。对于电子束蒸发方法在K9玻璃上沉积的ZrO2单层膜,分层界面散射模型对积分散射的理论计算值要比非相关表面散射模型的计算值更加符合总积分散射仪的实验测量结果。

A theoretical model calculating the surface total integrated scattering （TIS） of multilayer optical coatings is presented. The new model assumes that the rough interface and surface of the coatings are very thin zones with inhomogeneous micro constructure, which can be substituted by adequate number of homogeneous sub-layers, refractive indexes of which are constant and meet the exponential distribution. The formula of TIS is deduced by using the matrix method. For ZrO2 coatings deposited on K9 glasses by the electronic beam evaporation method, the TIS result calculated by the new model is in better conformity with the measured value by the scatterometer than that by the uncorrelated surface roughness model.