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The Research Of Waveguide Based On Graphene

Posted on:2015-03-27Degree:MasterType:Thesis
Country:ChinaCandidate:X Z ZhangFull Text:PDF
GTID:2268330428484608Subject:Optical engineering
Abstract/Summary:PDF Full Text Request
Since graphene been found in2004, it has been widely attention for its unique electronics, mechanical and other properties. The noble metals, such as silver and gold, have been popular materials for constructing optical metamaterials for surface plasmon. However, the difficulty in controlling and varying permittivity functions of noble metals and the existence of material losses degrade the quality of the plasmon resonance and limit the relative propagation lengths of SPP waves along the interface. Now, grphene has been graphene as a one-atom-thick platform for infrared and THz metamaterials can play an important role in optical science and engineering. This paper research content is as follows:1) We study the free-standing graphene waveguide. The guided modes are tightly confined in both the lateral direction and the propagation direction. A single mode operation region has been found in the free-standing graphene waveguide. Due to the tight confinement, a record small mode area (an order smaller than the smallest mode area of any waveguide that has ever been reported in the literature) and extremely high effective refractive index can be achieved.2) We study the waveguide properties of graphene nanoribbon with medium structure. The low-loss waveguide structure with an embedded low index silica layer between the graphene layer and the silicon substrate has been proposed to reduce the propagation loss and increase the FOM of the plasmonic waveguide.3) We study the waveguide properties of two graphene nanoribbons. The coupled configurations with two identical graphene ribbons also exhibit interesting properties. In particular, the side-side-coupling can further reduce the waveguide mode area, while the top-bottom-coupling can result in much larger effective indices than an isolated graphene ribbon.4) A nano-ring cavity of extremely small size based on a graphene ribbon waveguide has been shown to support a cavity resonance at far infrared range.
Keywords/Search Tags:graphene, nanoribbon, waveguide modes, ultra-small mode area, large effective refractive index
PDF Full Text Request
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