新型手性负折射率材料结构设计及其性能研究

发布时间：2018-05-17 04:20

本文选题：手性负折射率材料 + 铁磁材料　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：负折射率材料是将人工设计的几何结构单元与普通材料相结合,形成具有自然界材料所不具备的电磁性能的新型材料。该材料在军事、医疗、生物科学、无线通信等领域有着巨大的应用前景。20世纪90年代末,负折射率材料的理论结构及制作方法首次被提出并在实验上成功实现,越来越多的科研工作者将注意力集中在负折射率材料的研究中。在不断的探索中,研究者们相继提出了利用传输线结构、光子晶体、手性结构等实现负折射率的方式。其中手性负折射率材料由于其不需要同时实现负介电常数与负磁导率、结构简单易于制造、品质因数高、折射率在结构中渐变等优点而成为实现负折射率的主要方法之一。近十年来所设计的负折射率结构多数存在着应用频带窄、损耗大、可调谐性能差等问题。本论文针对这些问题,基于负折射率材料的设计理念,结合手性实现负折射率的方法,自行设计了一种基于电谐振机理的圆环形金属谐振结构,通过数值模拟方法研究该结构的透射、折射及可调谐性能,利用参数反演算法(包含Kramers-Kronig色散关系)研究该材料的有效电磁参数。通过改变结构参数实现了负折射率频带的可调谐性能,通过分析负折射频带内介电常数与磁导率不同时为负来探究手性结构所起到的作用,并证明该结构具有良好的旋光性能。分析在各个谐振频带下金属内部电场及表面电流分布情况,深入探究了该结构的谐振机理。由于通过改变结构参数来调谐负折射频带在实际应用中十分不方便,因此本论文运用铁磁材料可实现负磁导率的特性,将铁磁材料与所设计的负折射率结构相结合形成复合结构,通过改变加载在铁磁材料内部的磁场强度来调节复合结构的工作频带。首先将铁磁材料匹配到已设计的简单负折射率结构上,依次改变铁磁材料的厚度、两者的匹配方式、外加磁场强度并进行数值模拟,分析各因素对复合结构透射性、谐振性、工作频带可调谐性的影响,不断优化铁磁材料的结构参数,探究铁磁材料与负折射率材料的最佳匹配方式。对匹配后的复合结构进行数值模拟,将模拟结果与未匹配铁磁材料的负折射率结构模拟结果进行对比,分析铁磁材料对复合材料旋光性、损耗、谐振强度等性能的影响。本课题对具有多频带可调谐的性能的手性负折射率材料设计有着一定的参考价值,对推进手性负折射率材料的发展具有实际意义。
[Abstract]:Negative refractive index material is a new material which combines the geometric structure unit of artificial design and ordinary material to form a new material with electromagnetic properties that natural materials do not possess. The material has a great application prospect in military, medical, biological, wireless communication and other fields. The theoretical structure and system of negative refractive index materials in the late.20 of the 90s. More and more researchers focus on the study of negative refractive index materials for the first time, and more and more researchers focus on the study of negative refractive index materials. In the continuous exploration, the researchers have put forward the ways of realizing the negative ejection rate by using the structure of the transmission line, the photonic crystal and the chiral structure. It does not need to realize negative permittivity and negative permeability at the same time, the structure is simple and easy to manufacture, the quality factor is high, and the refractive index becomes one of the main methods to realize the negative refractive index. In the last ten years, most of the negative refractive index structures have the problems of narrow application frequency band, large loss and poor tunable performance. In order to solve these problems, based on the design idea of negative refractive index material and the method of realizing the negative refractive index of the chiral, a circular ring metal resonant structure based on the mechanism of electric resonance is designed, and the transmission, refraction and tunability of the structure are studied by the numerical simulation method, and the parameter inversion algorithm (including Kramers-Kronig color) is used. The effective electromagnetic parameters of the material are studied. The tunable performance of the negative refractive index band is realized by changing the structural parameters. By analyzing the role of the dielectric constant and the permeability in the negative refraction band, it is proved that the structure has good optical properties. The internal electric field and the distribution of the surface current in the lower metal are deeply explored. Because it is very inconvenient to tune the negative refraction band in the practical application by changing the structural parameters, the ferromagnetic material can be used to realize the characteristics of the negative permeability, and the ferromagnetic material is combined with the design of the negative refractive index structure. A composite structure is formed to adjust the working frequency band of the composite structure by changing the magnetic field strength loaded in the ferromagnetic material. First, the ferromagnetic material is matched to the designed simple negative refractive index structure, and the thickness of the ferromagnetic material is changed in turn, the matching mode of the two, the magnetic field strength and numerical simulation are carried out, and the complex factors are analyzed. The structure parameters of ferromagnetic materials are continuously optimized and the optimum matching mode of ferromagnetic materials and negative refractive index materials is investigated. The simulation results are compared with the negative refractive index structure simulation results of the unmatched ferromagnetic materials. The effect of ferromagnetic materials on the properties of the composites, such as the properties of optical rotation, loss and resonant strength, has a certain reference value for the design of the chiral negative refractive index materials with multi band tunable properties, and is of practical significance for the development of the chiral negative refractive index materials.
【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】：2015
【分类号】：TB39

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