本文選題：雙曲超材料 + 智能流體�。� 參考：《西北工業(yè)大學(xué)》2015年碩士論文

【摘要】：超材料是一種由次波長結(jié)構(gòu)單元構(gòu)建的人工介質(zhì),它能表現(xiàn)出不同尋常的電磁、光、聲等性質(zhì)。雙曲超材料是超材料中最為奇特的一種,它的介電常數(shù)或磁導(dǎo)率張量的一個主軸分量與其他兩個主軸分量的值符號相反,導(dǎo)致它有擁有雙曲型色散曲線,這種特性使雙曲超材料擁有許多獨特的性質(zhì)。本文設(shè)計了新型的電場可調(diào)智能雙曲超材料,并通過仿真研究了其電場可調(diào)反常光學(xué)行為,主要工作和結(jié)果概括如下:1.設(shè)計了一種電場可調(diào)智能流體基雙曲超材料,這種超材料由二氧化硅包覆的金納米棒與硅油組成。在外加電場下,Au@SiO2納米棒會形成單軸取向晶格結(jié)構(gòu),由于Au在可見光區(qū)的負介電特性,會導(dǎo)致流體沿電場方向的介電常數(shù)為負,流體系統(tǒng)呈現(xiàn)等頻雙曲色散特點,因此,可以實現(xiàn)對于TM波的全角度光頻負折射。我們計算了流體系統(tǒng)的有效介電常數(shù)張量與外加電場強度的關(guān)系,并用有限元仿真證實了電場誘導(dǎo)的光頻負折射實現(xiàn)與可調(diào)變化行為,系統(tǒng)研究了納棒直徑/長度,芯殼配伍、顆粒濃度等對可調(diào)光頻負折射實現(xiàn)和行為影響。另外,我們還證實了該智能流體基雙曲超材料的聚焦行為,而當(dāng)對流體系統(tǒng)施加一個非均勻電場時能夠?qū)崿F(xiàn)梯度負折射。2.設(shè)計了一種超薄的多層石墨烯基太赫茲吸收器,這種超材料吸收器是由單層石墨烯/MgF2多層堆垛結(jié)構(gòu)單元排列在金膜平面上構(gòu)成。我們在理論上證明了這種吸收器有著雙帶全吸收效果。由于有效介電常數(shù)的各向異性,石墨烯/MgF2多層堆垛結(jié)構(gòu)單元有一個雙曲色散。結(jié)構(gòu)單元間的強電偶極子諧振和磁偶極子諧振使吸收器的阻抗和自由空間匹配,導(dǎo)致了在太赫茲范圍內(nèi)的兩個完全吸收峰。這兩個吸收峰對于入射電磁波偏振方向不敏感并隨費米能級變化展現(xiàn)可調(diào)性,但吸收峰強度和頻率取決于材料和多層結(jié)構(gòu)的幾何參數(shù)。被吸收的電磁波最終被轉(zhuǎn)化為熱量,因此這個吸收器展現(xiàn)了一個很好的納秒加熱效果。
[Abstract]:Metamaterials are artificial media constructed from subwavelength structure units, which can exhibit unusual electromagnetic, optical and acoustic properties. Hyperbolic metamaterials are the strangest of metamaterials. One of the principal axis components of its permittivity or permeability Zhang Liang is opposite to the value symbol of the other two principal axis components, which results in its having a hyperbolic dispersion curve. This property makes hyperbolic metamaterials have many unique properties. In this paper, a new type of electric field adjustable intelligent hyperbolic supermaterial is designed, and its electric field tunable anomalous optical behavior is studied by simulation. The main work and results are summarized as follows: 1. An intelligent fluid based hyperbolic supermaterial with adjustable electric field is designed, which consists of silica coated gold nanorods and silicon oil. Under the applied electric field, the Aur SiO2 nanorods form uniaxially oriented lattice structure. Due to the negative dielectric properties of au in the visible region, the dielectric constant of the fluid along the electric field is negative, and the fluid system presents the characteristics of iso-frequency hyperbolic dispersion. All angle optical negative refraction for TM wave can be realized. We calculate the relationship between the effective dielectric constant Zhang Liang of fluid system and the external electric field strength, and verify the realization of negative refraction of optical frequency induced by electric field and the adjustable variation behavior by finite element simulation. The diameter / length of nanorods and the compatibility of core and shell are systematically studied. The effect of particle concentration on the realization and behavior of negative refraction of tunable optical frequency. In addition, we also confirm the focusing behavior of the intelligent fluid based hyperbolic supermaterial, and the gradient negative refraction of the fluid system can be achieved when a non-uniform electric field is applied to the fluid system. An ultra-thin multilayer graphene THz absorber is designed. The supermaterial absorber is composed of single-layer graphene / MgF2 multilayer stacking structure units arranged on the gold film plane. We have theoretically proved that this absorber has double band full absorption effect. Because of the anisotropy of effective permittivity, the graphene / MgF2 multilayer stacking unit has a hyperbolic dispersion. The strong electric dipole resonance and magnetic dipole resonance between the structure elements make the impedance of the absorber match with the free space, resulting in two complete absorption peaks in the terahertz range. These two absorption peaks are insensitive to the polarization direction of the incident electromagnetic wave and can be adjusted with the Fermi energy level, but the intensity and frequency of the absorption peaks depend on the geometric parameters of the material and the multilayer structure. The absorbed electromagnetic wave is eventually converted into heat, so the absorber shows a good nanosecond heating effect.
【學(xué)位授予單位】：西北工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB381

【參考文獻】

相關(guān)期刊論文 前1條

1 ;Tunable left-handed metamaterial based on electrorheological fluids[J];Progress in Natural Science;2008年07期

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本文編號：1792659