亚波长金属光栅宽光谱、宽视角偏振特性的研究

发布时间：2018-01-09 02:08

本文关键词：亚波长金属光栅宽光谱、宽视角偏振特性的研究　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：偏振分束器是光学偏振系统中的重要光学器件,传统的偏振分束器无法满足高效性、易集成等要求。亚波长金属光栅的光栅周期小于入射波长,能对不同偏振态的偏振光产生不同的衍射效果。而由其制成的偏振分束器还可以实现高效性、宽光谱、宽视角的目的。所以,亚波长金属光栅被广泛应用于光存储、光纤通信以及偏振成像系统等领域。基于严格耦合波理论,建立了单层光栅和多层膜光栅的入射光偏振衍射模型,并采用增强透射矩阵的方法解决了多层膜光栅的数值不稳定问题。本文以金属Ag为光栅材料,设计了三种类型的亚波长金属光栅:中心波长为1550nm的亚波长多层膜金属光栅、中心波长为800nm的亚波长夹层式金属光栅、中心波长为800nm的亚波长嵌入式金属光栅。采用严格耦合波理论和遗传算法优化出三类光栅的最佳结构参数,通过讨论三类光栅偏振特性与入射波长和入射角的关系,研究金属光栅的宽光谱性和宽视角性。最后,对三类亚波长金属光栅进行了工艺容差分析。研究结果显示,所设计的三类亚波长金属光栅满足宽光谱、宽视角、高衍射效率、高消光比的设计要求,且对光栅的周期、光栅的槽深、覆盖层厚度等结构参数具有较大的工艺容差。三类光栅的结构简单、成本低廉、偏振分束效果明显,为实际制备宽光谱、宽视角、高衍射效率、高消光比的亚波长金属光栅提供理论依据。
[Abstract]:Polarization beam splitter is an important optical device in optical polarization system. The traditional polarization splitter can not meet the requirements of high efficiency and easy integration. The grating period of subwavelength metal grating is less than the incident wavelength. It can produce different diffraction effects for polarized light with different polarization states. And the polarizing beam splitter made by the polarizer can also achieve the purpose of high efficiency, wide spectrum and wide angle of view. Subwavelength metal gratings are widely used in optical storage, optical fiber communication and polarization imaging systems. Based on the strictly coupled wave theory, the incident light polarization diffraction models of single-layer gratings and multilayer gratings are established. The numerical instability of multilayer grating is solved by the method of enhanced transmission matrix. In this paper, the metal Ag is used as the grating material. Three types of subwavelength metal gratings are designed: the subwavelength multilayer metal gratings with the center wavelength of 1550nm and the interlayer metal gratings with the center wavelength of 800nm. The subwavelength embedded metal grating with the center wavelength of 800nm is used to optimize the optimal structure parameters of the three kinds of gratings by using strictly coupled wave theory and genetic algorithm. By discussing the relationship between polarization characteristics of three kinds of gratings and incident wavelength and incident angle, the wide spectrum and wide angle of view of metal gratings are studied. The results show that the three subwavelength metal gratings can meet the design requirements of wide spectrum, wide angle of view, high diffraction efficiency and high extinction ratio. For the period of grating, groove depth of grating, thickness of overlay and other structural parameters, the structure of the three kinds of gratings is simple, low cost, the effect of polarization beam splitting is obvious, for the actual preparation of wide spectrum. The subwavelength metal grating with wide angle of view, high diffraction efficiency and high extinction ratio provides theoretical basis.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O436.3;TN25

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