基于石墨烯的超材料电磁诱导透明现象的调控研究

发布时间：2018-02-03 03:47

本文关键词： 超材料石墨烯电磁诱导透明群折射率　出处：《上海师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：超材料(metamaterials)是人工设计的亚波长结构,可以展现许多新奇的光学现象,比如负折射率,超分辨,光学隐身,类电磁诱导透明等。其中,类电磁诱导透明现象是源于一种由量子相干效应产生的光学类比现象。就电磁诱导透明现象而言,因其具有慢光、强非线性等特点和在无粒子数反转激光器中的应用,受到了广泛的关注。相比量子的电磁诱导透明现象,由超材料调制的类电磁诱导透明具有结构可调的优点,对这类现象的的深入研究,不仅可以不断创新有关光与材料相互作用的科学理论;而且还可以发掘其丰富的潜在应用。超材料电磁诱导透明发展至今,通过改变结构尺寸来调节EIT(Electromagnetically Induced Transparency)的透射峰位,调节群速度,实现慢光效应的固定式调节已经被研究的比较透彻。下一步,人们考虑的方向是一种主动式的调节,即根据需求来主动调节透射窗口和峰位。本文中,基于石墨烯与超材料的混合结构,通过石墨烯与超材料的电感性耦合,实现超材料EIT透明窗口的动态可调,并实现对慢光效应的动态调制。本论文从理论和模拟仿真上来研究基于石墨烯的超材料电磁诱导透明现象的调控。主要内容:一,利用微扰理论研究了石墨烯与金属结构耦合后对峰位的影响,研究结果表明透射峰的移动正比于石墨烯电导率的虚部。并通过耦合模理论得到了电磁诱导透明透射公式;二,研究了在不同模式间距下超材料EIT峰位和群速度的变化以及不同费米能级的石墨烯对EIT透射谱和群速度的影响。结果表明,在无石墨烯的情况下,间距30 nm,透射窗口的群速度可以降低到2.862%光速。附加不同费米能级的石墨烯后,既可以动态调制峰位的蓝移或红移也可以调控群速度;三,利用不同费米能级的石墨烯调制EIT现象,实现峰位,群速度的动态调控。最后利用推导的公式拟合EIT透射谱,确定结构参数和石墨烯在超材料电磁诱导透明现象中所扮演的角色,并通过石墨烯对明暗模式的单独调制,发现暗模式对EIT的峰位起主要作用。
[Abstract]:Metamaterials) is an artificially designed subwavelength structure that displays many novel optical phenomena, such as negative refractive index, superresolution, optical stealth, electromagnetically induced transparency, etc. Electromagnetic induced transparency is a kind of optical analogies produced by quantum coherence effect. As far as electromagnetic induced transparency is concerned, it has the characteristics of slow light, strong nonlinearity and its application in non-inversion of population lasers. Compared with the quantum electromagnetically induced transparency, the quasi-electromagnetic induced transparency modulated by metamaterials has the advantage of adjustable structure. Not only can the scientific theory of the interaction between light and material be innovated continuously, but also its rich potential applications can be explored. The transmission peak position of EIT(Electromagnetically Induced transparent can be adjusted by changing the structural dimension of the supermaterial electromagnetically induced transparency. Adjusting group velocity and realizing fixed regulation of slow light effect have been studied thoroughly. The next step is to actively adjust the transmission window and peak position according to the demand, the next step is to adjust the transmission window and peak position according to the demand. Based on the mixed structure of graphene and metamaterial, the dynamic tunable of EIT transparent window is realized by the inductive coupling of graphene and metamaterial. In this thesis, the modulation of electromagnetically induced transparency in graphene based supermaterials is studied theoretically and simulated. The main contents are as follows: 1. The effect of graphene coupled with metal structure on the peak position is studied by using perturbation theory. The results show that the shift of transmission peak is proportional to the imaginary part of the conductivity of graphene. The electromagnetically induced transparent transmission formula is obtained by coupling mode theory. The variation of EIT peak position and group velocity of metamaterials at different mode spacing and the influence of graphene with different Fermi levels on EIT transmission spectra and group velocities are studied. The results show that the EIT transmission spectra and group velocities are affected by graphene without graphene. The group velocity of transmission window can be reduced to 2.862% speed of light when the distance is 30 nm. When graphene with different Fermi energy levels is added, the group velocity can be dynamically modulated either by blue shift or red shift of peak position. The EIT phenomenon is modulated by graphene with different Fermi levels to realize the dynamic regulation of peak position and group velocity. Finally, the EIT transmission spectrum is fitted by the derived formula. The structure parameters and the role of graphene in the electromagnetically induced transparency of metamaterials are determined. It is found that the dark mode plays a major role in the peak position of EIT by the alone modulation of the light and dark modes by graphene.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O441;TB34

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