基于石墨烯的介质波导研究

发布时间：2018-07-18 13:35

【摘要】：自从2004年石墨烯发现以来,石墨烯以其独特的电子、机械等特性而广受关注。曾经,贵金属(金、银等)被广泛地认为是现存最好的表面波材料。但是,这些材料存在着巨大的欧姆损耗和一旦结构固定则不可调制的缺点。而石墨烯则被认为是可以作为表面波导在红外波段新的平台和THZ波段的超材料。本论文研究的内容如下： 1)我们研究了单层独立存在的石墨烯波导。在石墨烯波导中,导模可以被紧紧的约束在横向和波导的传播方向上。而且我们发现了在单层独立存在的石墨烯纳米带波导中,存在着单模区间。并且,由于模式被紧紧地约束起来,我们得到了一个可以打破记录的极小的模式面积(比其他以发表的波导模式面积的最小值还小了一个数量级),并且同时得到了一个极高的等效折射率。 2)我们研究了介质结构的石墨烯纳米带波导。我们得到了一个低损耗的波导结构,石墨烯-氧化硅-硅结构,它同时降低了传播的损耗和增加了波导质量因数FOM。 3)我们研究了由两条石墨烯纳米带所组成的结构的波导特性。在对这些结构的研究当中,对于两个不同的结构,我们发现了一些独特的,吸引人的特性。在左右结构的石墨烯波导当中,通过对带隙d的控制,可以做到对波导模式面积的控制,当带隙减小时,模式面积能有效地减小。在上下结构中,我们通过对带隙的控制我们可以得到一个远超过独立存在的石墨烯纳米带的等效折射率数值。 4)本论文通过一个极小的纳米尺寸的环形腔的设计,来证明石墨烯纳米带在远红外波段领域具有极大的潜能。
[Abstract]:Since the discovery of graphene in 2004, graphene has been widely concerned with its unique electronic and mechanical properties. Once, precious metals (gold, silver, etc.) were widely considered to be the best existing surface wave materials. However, these materials have huge ohmic losses and the shortcomings of non modulation once the structure is fixed. And graphene is considered to be the case. It can be used as a new platform and THZ band metamaterial for the surface waveguide in the infrared band.
1) we studied the monolayer independent graphene waveguides. In the graphene waveguides, the guide modes can be tightly confined in the direction of transverse and waveguide propagation. Moreover, we found the existence of a single mode range in the monolayer independent graphene nanoscale waveguide. And, as the mode is tightly constrained, we get it. A minimal mode area that can break the record is one order of magnitude smaller than the smallest value of the published waveguide mode area, and a very high equivalent refractive index is obtained at the same time.
2) we studied the dielectric structure of the graphene nanoribbon waveguide. We have obtained a low loss waveguide structure, the graphene oxide silicon silicon structure, which simultaneously reduces the propagation loss and increases the waveguide mass factor FOM..
3) we studied the waveguide characteristics of a structure consisting of two graphene nanoribbons. In the study of these structures, we found some unique and attractive characteristics for two different structures. In the graphene waveguides of the left and right structures, the mode area of the waveguide can be controlled by the control of the band gap D. When the band gap is reduced, the mode area can be effectively reduced. In the upper and lower structures, we can obtain an equivalent index value of the graphene nanoribbons that are far beyond the independent existence by controlling the band gap.
4) in this paper, the design of a nanoscale ring cavity is used to prove that graphene nanoribbons have great potential in the far infrared band.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN814

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