DAST超材料的设计及特性研究

发布时间：2018-03-25 22:12

本文选题：太赫兹　切入点：超材料　出处：《电子科技大学》2016年硕士论文

【摘要】：近年来,超材料的研究覆盖了众多领域,从微波波段到可见光波段,从基础研究到应用研究。最近,超材料在非线性、可增益、动态可调、光转换以及量子等方面取得的新进展,使超材料成为研究一些特殊物理现象的一个丰富多彩的媒介,并为光子学器件的突破性发展奠定了基础。另一方面,4-(4-二甲基氨基苯乙烯基)甲基吡啶对甲基苯磺酸盐(简称DAST)是一种非常重要的有机材料,具有显著的双折射效应、横向光学声子、电光效应以及二阶非线性效应,在太赫兹发射、探测领域,以及高速电光调制、电光采样、集成光波导等光学集成器件领域具有广阔的应用前景。本论文中,通过将DAST晶体与超材料结构相结合,作为超材料的介电层,得到以下结果:(1)将DAST晶体作为超材料的介电层,利用DAST晶体的双折射效应,实现了响应频率随入射光偏振方向变化的超材料。仿真结果表明:本论文设计的超材料结构,其响应频率可在1.54THz到2.07THz范围内变化,变化范围达到29%。(2)利用DAST晶体在1.1THz处的横向光学声子,将DAST的分子振动与超材料的结构振动集成到一个系统中。仿真结果表明:DAST超材料耦合系统属于光与物质的强耦合,系统的真空Rabi分裂频率为0.37THz,是本征振动频率1.1THz的31%。仿真得到的随超材料结构尺寸变化的分裂峰,其分布曲线与理论计算预测结果吻合得很好。(3)首次成功地制作出DAST多晶超材料,并进行了太赫兹响应测试。结果表明,在响应频率1.04THz处,超材料的吸收率达50%。此外,在原有的Al/Si衬底基础上,引入图形化SiO2层后,DAST薄膜的平整度获得明显改善,DAST多晶超材料的响应得到增强,吸收率达到60%。(4)在DAST多晶超材料中,发现了DAST分子振动与超材料上下金属层之间的F-P腔共振耦合,从实验上观测到了分子振动引入透过现象。(5)首次成功地制作出DAST单晶超材料,并从实验上观测到DAST分子振动与超材料结构之间的强耦合,以及DAST晶体的各向异性对超材料响应的影响。这些研究成果,在一定程度上,发掘了DAST晶体的应用潜力,拓展了超材料的研究范围;同时,为光与物质的耦合相关基础物理学理论的研究,提供了一个可行的实验方案及证明。
[Abstract]:In recent years, the research of metamaterials has covered many fields, from microwave band to visible wave band, from basic research to application research. New advances in optical conversion and quantum have made metamaterials a colorful medium for the study of specific physical phenomena. It also lays a foundation for the breakthrough development of photonics devices. On the other hand, 4-dimethylaminophenylvinyl) pyridine p-methylbenzene sulfonate (DAST) is a very important organic material with remarkable birefringence effect. Transverse optical phonons, electro-optic effects and second-order nonlinear effects have broad application prospects in the field of terahertz emission, detection, high-speed electro-optic modulation, electro-optic sampling, integrated optical waveguide and other optical integrated devices. By combining DAST crystal with metamaterial structure as the dielectric layer of supermaterial, the following results are obtained: 1) the DAST crystal is used as the dielectric layer of metamaterial, and the birefringence effect of DAST crystal is utilized. The supermaterial whose response frequency varies with the polarization direction of incident light is realized. The simulation results show that the response frequency of the metamaterial structure designed in this paper can vary from 1.54THz to 2.07THz. Using the transverse optical phonon of DAST crystal at 1.1THz, the molecular vibration of DAST and the structural vibration of metamaterials are integrated into a system. The simulation results show that the coupling system of DAST supermaterial belongs to the strong coupling of light and matter. The vacuum Rabi splitting frequency of the system is 0.37 THZ, which is the 31th peak of the intrinsic vibration frequency 1.1THz. The distribution curve of DAST polycrystalline supermaterial obtained by simulation is in good agreement with the predicted results of theoretical calculation. The terahertz response test was carried out. The results show that the absorptivity of the supermaterial reaches 50% at the response frequency 1.04THz. In addition, on the basis of the original Al/Si substrate, The flatness of Dast film was improved by introducing graphical SiO2 layer. The response of Dast polycrystalline supermaterial was enhanced, and the absorptivity reached 60%. In DAST polycrystalline supermaterial, the resonance coupling between DAST molecular vibration and the upper and lower metal layers of the supermaterial was found. In this paper, we have observed experimentally the phenomenon of molecular vibration introducing transmission. (5) the DAST single crystal supermaterial has been successfully prepared for the first time, and the strong coupling between the molecular vibration of DAST and the structure of the supermaterial has been observed experimentally. And the effect of anisotropy of DAST crystal on the response of metamaterials. To some extent, these results have explored the application potential of DAST crystals and expanded the research scope of metamaterials. It provides a feasible experimental scheme and proof for the fundamental physics theory of the coupling of light and matter.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB34

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