Sandfuchs Oliver, Pätz Daniel, Sinzinger Stefan, Pesch Alexander, Brunner Robert
Microstructured Optics, Corporate Research and Technology, Carl Zeiss AG, Jena, Germany.
J Opt Soc Am A Opt Image Sci Vis. 2008 Aug;25(8):1885-93. doi: 10.1364/josaa.25.001885.
Blazed diffraction gratings are of enormous practical importance for imaging and analyzing hybrid optical systems. The intermediate diffraction regime is characterized by the transition from the scalar to the rigorous electromagnetic theory. An effect known as shadowing occurs and reduces the diffraction efficiency. Based on rigorous calculations for optimized sawtooth-shaped and binary-multilevel blaze profiles, we deduce a semianalytical model describing the shadowing phenomenon for the general case of oblique incidence. We discuss illumination both from air and from the substrate. Though a multilevel blaze possesses a discrete substructure, our shadowing model remains valid, if substructural effects are neglected. We find that electromagnetic effects due to the passive blaze facet lead to the efficiency reduction, and the blazing efficiency shows a linear dependence on the ratio of blaze wavelength to grating period. Our shadowing model is applied to predict the performance of a Littrow-like blazing condition in transmission geometry as, e.g., for a diffractive solid immersion lens.
闪耀衍射光栅对于混合光学系统的成像和分析具有极其重要的实际意义。中间衍射区域的特征是从标量电磁理论向严格电磁理论的转变。一种称为阴影效应的现象会出现并降低衍射效率。基于对优化锯齿形和二元多级闪耀轮廓的严格计算，我们推导了一个半解析模型，用于描述斜入射一般情况下的阴影现象。我们讨论了从空气和从衬底的照明情况。尽管多级闪耀具有离散子结构，但如果忽略子结构效应，我们的阴影模型仍然有效。我们发现，无源闪耀面的电磁效应会导致效率降低，并且闪耀效率与闪耀波长与光栅周期的比值呈线性关系。我们的阴影模型被应用于预测透射几何结构中类似利特罗闪耀条件的性能，例如用于衍射固体浸没透镜。
