Study On The Transmission Properties Of Nano-scale Optical Device Based On Graphene

In the past few decades,science and technology have greatly changed the life of people.The demand of high quality,intelligent product is increasing.Whether it is household,transportation,communication,or entertainment,people want to be able to live in a more convenient and efficient environment.Communication,as an important branch of social life,plays a decisive role to the development of society.In the field of communication,the development of various optoelectronic devices directly determines the quality of communication.However,the traditional electronics and photonic devices became difficult to meet the needs of compact integration and high-speed processing.The emergence of Surface Plasmon Polaritons?SPPs?,can not only solve the problem of optical diffraction limit,but can also provide a promising way for micro-nano devices design and high density integration.Surface Plasmon Polaritons?SPPs?are electromagnetic modes propagating along metal-dielectric interfaces with amplitude decaying exponentially in the direction vertical to the interface.Traditional noble metal is always thought as the material which can support the SPPs,but its development is restricted due to the internal losses and unmodifiable characteristics.Graphene,a kind of novel 2D material,has become a research hotspot because of its unique optical and electrical characteristics since it has been made in 2004.In a particular frequency band,it is similar to the noble metal,and can support SPPs.Moreover,its characteristics can be tuned without changing the structure.Therefore,the optical device based on graphene is broadly researched.The main research contents of the thesis are organized as follows:?1?We designed a novel type of all-optical logic device based on graphene surface plasmon polaritons?GSP?which can realize six different basic logic gates including OR,XOR,NOT,AND,NOR,and NAND without modify the structure.?2?The propagating and mode characteristics of a type of plasmonic waveguide composed of a bow-tie type graphene-coated nanowire pair with a high-index dielectric slab in-between is investigated.We find that the designed waveguide has better mode confinement and higher figure of merit.The propagation length is greater than 2?m and the normalized mode area is closer to an order of magnitude of 10^-5.Moreover,the characteristics of GSP can be tuned by geometrical parameters and electromagnetic parameters.?3?We researched two novel constructions of which the transmission spectrum analogous to the Electromagnetically Induced Transparency?EIT?,and which can be named as the Plasmon Induced Transparency?PIT?phenomenon.We find the transparency window can be dynamically tuned by geometrical parameters and chemical potential of the graphene.The results prove that slow-light effect can be obtained which may apply to light storage and slow-light device.