柔性太赫兹波超材料吸收器的研究

发布时间：2018-08-24 08:37

【摘要】：随着太赫兹(Terahertz,THz)科学的发展,太赫兹吸收器、滤波器等能改善传输过程和性能的功能器件引起了人们研究的热潮。但是由于自然界中缺少对太赫兹波响应和探测的材料,严重制约了其发展,超材料(Metamaterials,MMs)的出现为研究和设计太赫兹器件提供了极大的便利。超材料可以通过改变单元周期结构的几何参数,使它的介电常数和磁导率在特定频率范围内一个或者两个同时为负值,从而改变它的电磁共振响应,因此它在电磁隐身、光电探测等方面都有极大的应用前景。相比传统的吸波材料,超材料吸收器存在厚度薄、质量轻、吸收强、频率可控性和设计灵活性等诸多优点,在微波段、光波段特别是在太赫兹波段引起了人们的研究热潮。本文设计了不同类型的超材料吸收器并对其吸收特性进行研究,主要工作和创新点如下:1.在太赫兹波段设计一种光激励可调谐超材料吸收器。在开口谐振环(split-ring resonators,SRRs)的关键区域开口处植入光敏半导体硅,通过改变外部泵浦光的光照能量,改变半导体硅的电导率,实现共振频率由0.684THz到1.414THz的蓝移调谐。在此基础上研究了两个共振频率产生的机理,并着重分析了单元结构尺寸b、线宽ω、电介质层聚酰亚胺(PI)的厚度、硅的电导率σ、材料PI的介电常数ε以及开口长度c等参数对此可调谐超材料吸收性能的影响。2.基于十字型结构,在太赫兹波段构造出单频带、双频带以及多频带超材料吸收器。首先,在太赫兹波段设计出基于十字型结构的完美超材料吸收器,在1.74THz处产生了强的共振频点,同时基于谐振电路理论,研究了十字型吸波器谐振频率与其几何参数的依赖关系。其次,在十字型结构的基础上,上下左右各加一条金属线条,设计出双频带超材料吸收器,共振频点分别位于0.89THz和2.18THz;最后,设计出多频带超材料吸收器,共振频点分别为0.996THz、1.194THz、1.870THz、1.990THz和2.298THz。这些超材料吸收器结构简单性能优良,具有一定的借鉴意义和研究价值。
[Abstract]:With the development of Terahertz,THz science, terahertz absorbers, filters and other functional devices that can improve the transmission process and performance have aroused a lot of research. However, the development of terahertz (THz) devices is greatly facilitated by the appearance of metamaterials (Metamaterials,MMs) due to the lack of materials to respond and detect terahertz waves in nature. Metamaterials can change their electromagnetic resonance response by changing the geometric parameters of their periodic structures so that their permittivity and permeability are negative at the same time in a given frequency range, so that they become electromagnetic invisibility. Photoelectric detection and other aspects have great application prospects. Compared with traditional absorbing materials, metamaterial absorbers have many advantages, such as thin thickness, light weight, strong absorption, frequency controllability and design flexibility. In this paper, different types of metamaterial absorbers are designed and their absorption characteristics are studied. The main work and innovations are as follows: 1. An optically excited tunable super material absorber is designed at terahertz. The semiconductor silicon is implanted into the opening of the key region of the open resonant ring (split-ring resonators,SRRs). By changing the illumination energy of the external pump light and changing the conductivity of the semiconductor silicon, the blue shift tuning of the resonance frequency from 0.684THz to 1.414THz is realized. On this basis, the mechanism of two resonant frequencies is studied, and the structure size b, linewidth 蠅, thickness of dielectric layer polyimide (PI) are analyzed emphatically. The influence of Si conductivity 蟽, dielectric constant 蔚 of PI and opening length c on the absorption properties of the tunable metamaterials. Based on cross structure, single band, double band and multi band super material absorbers are constructed in terahertz band. First of all, a perfect supermaterial absorber based on cross structure is designed in terahertz band, which produces strong resonance frequency at 1.74THz, and based on resonant circuit theory. The dependence of resonant frequency of cross-type absorber on its geometric parameters is studied. Secondly, on the basis of cross-type structure, a metal line is added to each side, and a dual-band supermaterial absorber is designed. The resonance frequency points are located at 0.89THz and 2.18 THZ, respectively. Finally, a multi-band supermaterial absorber is designed, the resonance frequency points are 0.996 THZ 1.194 THz1. 870 THz1. 990 THz and 2. 298 THZ, respectively. These metamaterial absorbers have simple structure and excellent properties, which have some reference significance and research value.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O441.4

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