多层膜体折射率弱不均匀度反演计算的近似模型及性能分析  

Approximation model for refractive index slight inhomogeneity reverse determination of multilayers

作　　者：简钰东 汤建勋[1] 吴素勇[1] 江奇渊[1] 谭中奇[1] 

机构地区：[1]国防科学技术大学光电科学与工程学院,湖南长沙410073

出　　处：《应用光学》2016年第1期124-130,共7页Journal of Applied Optics

基　　金：国家自然科学基金(61405250;61205157)

摘　　要：实际应用中的薄膜或多或少存在体折射率不均匀缺陷,其准确表征对于镀膜工艺参数调校、低损耗薄膜设计与制备分析等具有影响。从Schrder近似出发,推导了体折射率弱不均匀薄膜的膜系特征矩阵,通过特征矩阵法推广,建立了体折射率弱不均匀多层膜光谱特性计算的近似模型。利用基于有效介质理论的多层均匀膜近似方法,讨论了上述近似模型的有效性、计算精度和时间消耗特性。结果表明,上述模型矩阵计算中引入体折射不均匀度这一参数,为多层膜体折射率不均匀缺陷反演提供了一种有效的手段,为基于宽带光谱测量数据拟合的膜层缺陷数值反演应用奠定了基础。Thin film coatings in actual application are always characterized by some kind of, slight or large, refractive index inhomogeneity. Its accurate characterization can be vital to the process parameters calibration of coating machine, and to the design and manufacture of ultra low loss coatings. According to Schroder approximation, the characteristic matrix of a slightly inhomogeneous thin film was derived, and an approximation model for the spectral characteristics calculation of slightly inhomogeneous multilayer coatings was presented by the matrix method. Based on the effective medium approximation theory and infinite division into large homogeneous sublayers, the effectiveness, calculation accuracy and time consumption of the approximation model were discussed in details. It shows that this model presents a fast and effective tool for the reverse determination of the refractive index inhomogeneity defect of multilayer system, and lays a foundation for the numerical optimization algorithm application into the data fitting based on the measured broadband spectral characteristics of actual multilayer coatings.

关 键 词：薄膜光学 缺陷反演模型 Schroder近似 不均匀薄膜 

分 类 号：TN305.8[电子电信—物理电子学] O439[机械工程—光学工程]