基于Kramers-Kronig关系对薄膜材料光学特征的数值反演

Numerical inversion of the optical characteristics of film material based on Kramers-Kronig relations

依据试验测量得到特殊镀金聚酯薄膜反射率谱及光学常数,利用Kramers-Kronig(K-K)关系,数值反演了镀金聚酯薄膜反射系数、相位反射率和光学常数。在近红外波段,将理论反演与试验测量值进行比较。结果表明:利用K-K方法反演薄膜材料表面的光学特征光谱反射率和光学常数实部误差较小,其中相位反射率的绝对误差小于0.96°,相对误差平均值为0.0831,但消光系数试验和反演数据误差较大。在缺乏试验测量条件或已知部分材料光学特征的条件下,开展具有薄膜、涂层目标光谱散射和辐射特性的研究工作,该反演方法是行之有效的。

According to the measured spectral reflectivity and the optical constants of a special kind of gilded polyster film,the reflection coefficients,phases reflectivity and optical constants of the gilded polyster film were numerically inversed using the Kramers-Kronig（K-K） relations in this paper.In near infrared wave band,the experimental measurement data was compared with the theoretical inversion value.It is shown that the error of the spectral reflectivity and the real part of the optical constants of the inversed optical characteristics of film with K-K method is little,among them,the absolute error of the phase reflectivity of the film is less than 0.96° and its average relative error is 0.083 1 .However,a big error exists between the experimental and the K-K inversed data of the extinction coefficient.The inversion method introduced in this paper is feasible for the research on the light spectra scattering or radiation characteristics of the targets with the rough dielectric film and coat in case of the lack of necessary experimental condition or the partially known optical characteristics of used materials.