【作者】 杨亮亮；

【导师】 崔庆丰；

【作者基本信息】 长春理工大学 ， 光学工程， 2013， 博士

【摘要】 多层衍射光学技术是衍射光学领域的前沿课题之一。多层衍射光学元件能够在很宽的光谱波段范围内获得很高的衍射效率,解决了传统单层衍射光学元件存在的偏离设计波长后衍射效率显著下降的问题。本文首先基于光波的标量衍射理论和位相光栅方程,对衍射光学元件的衍射效率问题进行了深入的研究。通过对单层衍射光学元件表面微结构、基底材料的选择等相关参数的讨论,分析了斜入射状态下单层衍射光学元件的衍射效率特性。讨论了衍射光学元件的消色差和消热差特性,以及衍射光学元件产生冷反射的计算分析方法。分析了衍射光学元件的初级像差特性。分析了谐衍射光学元件的设计方法,讨论了谐衍射光学元件的色散特性,以及谐衍射光学元件不同于传统单层衍射光学元件的衍射效率特性。基于单层衍射光学元件斜入射衍射效率的分析,研究了斜入射状态下多层衍射光学元件衍射效率与入射角的变化关系,并建立了描述这种关系的数学模型。分析了在不同方向斜入射时,衍射效率随入射角度的变化关系,不仅分析了双层衍射光学元件斜入射时的衍射效率特性,同时,也讨论了三层衍射光学元件斜入射的衍射效率和入射方向、基底材料的选择以及中间介质材料选择的关系。衍射光学元件的微结构高度、周期宽度等参数的加工误差会对衍射效率产生直接的影响。本文基于衍射光学元件的微结构高度、周期宽度等参数与衍射效率的关系,在对单层衍射光学元件的加工误差对衍射效率影响的分析基础上,研究了多层衍射光学元件的加工误差对其衍射效率影响的分析方法。针对多层衍射光学元件的微结构高度误差变化一致和相反的两种情况,给出了多层衍射光学元件的微结构高度误差对衍射效率的影响,当微结构高度误差变化趋于一致时,对应的衍射效率下降比较缓慢。这个结论可以用来指导衍射光学元件的加工,以及存在加工误差时如何实现衍射效率的最大化设计。本文讨论了衍射光学元件衍射效率的实验测量方法。以衍射光学元件衍射效率的定义为基础,分析了衍射效率的测量原理,进一步搭建了衍射效率的实验测量装置。通过合理地选择测量装置中针孔光阑的大小,能够精确地得到一级衍射的能量,并滤掉次级衍射对测量结果的影响,保证了测量结果的准确性。用这个测量装置对一个已经研制出的折衍射混合成像光学系统中的单层衍射光学元件进行了衍射效率的测量,分别选择了三个激光波长,测量了单层衍射光学元件的衍射效率,通过将衍射效率测量结果的拟合曲线与理论曲线进行对比可知,双光路测量装置能够以较高的精度测量衍射光学元件的衍射效率。为了验证多层衍射光学元件的衍射效率随入射角度的变化关系,设计并研制了一个含有多层衍射光学元件的光学系统,在O。-30.6。范围内对该多层衍射光学元件进行了衍射效率的测量,获得了多层衍射光学元件的衍射效率与入射角度对应关系的实验测量结果。该测量结果验证了通过理论计算得到的多层衍射光学元件衍射效率与入射角的变化关系,实际测量得到的多层衍射光学元件的衍射效率与入射角度关系的变化趋势与理论分析得到的变化趋势是一致的。更多还原

【Abstract】 The technology of multilayer diffractive optical elements (MLDOEs) is one of the frontier subjects in the field of diffractive optics. MLDOEs can achieve very high diffraction efficiency within a wide spectrum, which can solve the problem of the traditional single layer diffractive optical elements with the diffraction efficiency decreases significantly when the wavelength deviates from the design wavelength. In this paper, based on the scalar diffraction theory and the phase grating equation, the diffraction efficiency of diffractive optical elements is analyzed. By discussing the relevant parameters such as the microstructure height, the choise of the substrate materials and so on, the diffraction efficiency of single layer diffractive optical elements with oblique incidence is analyzed. The achromatic and athermal properties of diffractive optical elements, the narcissus intensity evaluation for diffractive optical elements are analyzed. The third-order aberration theory of diffractive optical elements is discussed.The design method of harmonic diffractive optical elements is analyzed. The special dispersion property of harmonic diffractive optical elements and the diffraction efficiency of harmonic diffractive optical elements which is different from tradional single layer diffractive optical elements are discussed. Based on the diffraction efficiency with oblique incidence of single layer diffractive optical elements, the relationship and the mathematics model of the diffraction efficiency and incidence angle for MLDOEs are built up. The relationship of diffraction efficiency with different incident direction is also analyzed. The diffraction efficiency of MLDOEs, not only the doulble layer diffractive optical elements, but also the three layer diffractive optical elements is systematically studied with different incident directions, different substrate materials and different selection of the third materials with oblique incidence angle.The manufacturing errors of depth-scaling, periodic width and so on have a direct influence on diffraction efficiency of diffractive optical elements. Based on the analysis of single layer diffractive optical elements, the effect of the manufacturing errors on diffraction efficiency for MLDOEs is analyzed. The relationship of diffraction efficiency and depth-scaling errors are presented for two different cases, with the two relative depth-scaling errors change in the same sign and in the opposite sign. As the depth-scaling errors change consistently, the corresponding diffraction efficiency declines relatively slow. This conclusion can be used to guide the manufacturing of diffractive optical elements, realize the maximization of diffraction efficiency with the effect of manufacturing errors.The experiment method of measuring diffraction efficiency of diffractive optical element is studied. Based on the definition of the diffraction efficiency of diffractive optical elements, the measuring principle of diffraction efficiency is discussed, and the double path measurement device of diffraction efficiency is set up. The diffraction light of the main order can be obtained by the reasonable choice of the pinhole aperture of the measuring device, and the subprime diffraction light will be filtered out, ensuring the accuracy of the measuring results. The diffraction efficiency of the single layer diffractive optical elements in the designed hybrid refractive-diffractive optical system is measured at three laser wavelengths over the visible waveband. By comparing the measuring results with the theoretical calculating results, the double path measurement device can be used to measure the diffraction efficiency of diffractive optical elements with high accuracy.In order to verify the relationship of the diffraction efficiency and the incidence angle for MLDOEs, a MLDOEs and an optical system contained this MLDOEs are designed and manufactured. This optical system is used to measure the diffraction efficiency within the incidence angles in the ranges of0°to30.6°, and the measured diffraction efficiency of MLDOEs under different incidence angles are obtained which can be used to verify the theoretical diffraction efficiency. The relationship of the measured diffraction efficiency and the incidence angle is in correspondence with the relationship of the theoretical diffraction efficiency and incidence angle.更多还原