基于U形纳米天线阵列的多焦点透镜的研究

发布时间：2018-01-19 03:27

本文关键词： 超表面光学分束折射率传感偏振检测多焦点透镜　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：传统光学器件对光束波前的调制是通过光束经过器件时的连续相位延迟积累实现的，而超表面（metasurface）对光束的相位调制是不连续的。超表面是由一系列具有纳米尺寸的等离子体天线单元组成的超薄金属平板，或单层，或多层，尺寸很小，对光束波前可以实现2π范围的灵活调制。组成超表面的天线形状不同，其性能也大不相同。U形孔径天线超表面是在单层金板上刻蚀一系列U形槽，相对于其它超表面，U形孔径天线超表面结构更加简单，厚度仅有几十纳米。本论文基于U形孔径天线超表面进行了多种基础光学元件的研究，包括光学分束，折射率传感，单焦点聚焦，偏振态检测及多焦点透镜。本文首先进行了基于超表面的广义Snell定律的推导，利用U形孔径天线超表面实现了反常折射现象，验证了广义Snell定律的准确性。进而利用超表面分区设计的方法设计实现了多光路分束。推导出了反常折射角与环境折射率的理论关系，模拟仿真得到了反常折射角与环境折射率的响应曲线，验证了超表面的折射率传感功能。根据传统柱透镜的相位调制曲线，设计实现了基于U形孔径天线超表面的单焦点透镜，得到了很好的聚焦仿真结果。接着探究了入射光偏振态对相应功能的影响，，发现U形孔径天线超表面对入射光的不同偏振态（左旋圆偏振或右旋圆偏振）表现出完全相反的现象，即利用U形孔径天线超表面可以实现偏振态检测功能。本文最重要的一部分工作是多焦点聚焦透镜的设计仿真。多焦点透镜一般采用透镜阵列方法，这种方法设计的透镜之间的干涉现象比较严重，影响成像质量。本文介绍了一种新型简单的类光学全息方法。分别用透镜阵列法和类光学全息法设计了相同焦距和不同焦距两类多焦点聚焦透镜，并对两种方法的结果进行了分析比较。根据类光学全息方法理论，本文提出了焦点强度可控的多焦点透镜的设计方法，并得到了与理论吻合的数值模拟结果，验证了类光学全息法设计可控焦点强度的多焦点透镜的可行性。
[Abstract]:The modulation of beam wavefront by traditional optical devices is realized by the accumulation of continuous phase delay as the beam passes through the device. The supersurface is composed of a series of nanometer-sized plasma antenna elements, or monolayer. Or multilayer, very small size, the beam wavefront can be flexibly modulated in the range of 2 蟺. The shape of the supersurface antenna is different. Its performance is also very different. U-shaped aperture antenna supersurface is etched a series of U-shaped slots on the monolayer gold plate, which is simpler than other super-surface U-shaped aperture antenna supersurface structure. The thickness is only tens of nanometers. In this paper, a variety of basic optical elements are studied based on the supersurface of the U-shaped aperture antenna, including optical beam splitting, refractive index sensing, single focus focusing, polarization state detection and multi-focus lens. In this paper, the generalized Snell's law based on the supersurface is deduced, and the abnormal refraction is realized by using the U-shaped aperture antenna supersurface. The accuracy of the generalized Snell law is verified, and the multi-path beam splitting is realized by using the method of supersurface zoning design, and the theoretical relationship between the anomalous refraction angle and the ambient refractive index is deduced. The response curves of anomalous refraction angle and ambient refractive index are obtained by simulation, and the refractive index sensing function of supersurface is verified. According to the phase modulation curve of traditional cylindrical lens. A single focus lens based on the supersurface of the U-shaped aperture antenna is designed and realized, and the simulation results are obtained. Then, the influence of the polarization state of the incident light on the corresponding function is investigated. It is found that the supersurface of the U-shaped aperture antenna exhibits completely opposite phenomena to the different polarization states (left circular polarization or right circular polarization) of the incident light, that is, the function of polarization state detection can be realized by using the U-shaped aperture antenna supersurface. The most important part of this paper is the design and simulation of the multi-focus lens, which generally adopts the lens array method, and the interference between the lenses designed by this method is serious. In this paper, a new and simple optical holography method is introduced. Two kinds of multi-focus focusing lenses with the same focal length and different focal lengths are designed by using the lens array method and the optical holography method respectively. According to the theory of quasi-optical holography, the design method of multi-focal lens with controllable focal strength is proposed, and the numerical simulation results are obtained. The feasibility of designing multi-focal lens with controllable focal intensity by optical holographic method is verified.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820

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