Study On The Propagating Properties Of Two Novel Hybrid Surface Plasmonic Waveguide

Compared with electronic devices,photonic devices have the ad-vantages of miniaturization,high speed,wide band and high stability,so it is attractive for us to achieve the application of integrating optics.However,due to the limitation of the diffraction limit,the sizes of the traditional optical de-vices are in the scale of several micrometers or more,and it is difficult to re-alize the high compact integrating of optoelectronic devices to nano scale.So,in recent years,people try to break this limitation to achieve the purpose of the miniaturization of more compact photonic devices.As a result,the re-searchers have found that the surface plasmon waveguide(SPW)can confine the electromagnetic field to sub-wavelength scale and guide it propagating along the interface of dielectric and metal to the length of tens or hundreds micrometers.In recent years,the study of the design and the propagating properties of SPW gradually becomes one of the research hotspots.It has important significance for the development of nano optics and high speed in-tegrated optical devices.In this paper,we firstly give the basic knowledge of surface plasmon polaritons(SPPs),surface plasmon waveguide(SPW)and the classification and characteristics of the reported surface plasmon waveguide in the litera-ture.Secondly,the numerical methods used in this paper including the finite element method(FEM)and the use of FEM based COMSOL Multiphysics software are introduced.Thirdly,we propose two kinds of novel hybrid SPWs structures,and then the distribution and propagating characteristics of the supported fundamental modes are investigated.The main research con-tents of the thesis are organized as follows:(1)We design a novel coaxial multi-layer hybrid plasmonic waveguide structure.Through the exchange of high and low refractive index medium,the proposed waveguide can show different properties of field distribution and mode propagating.We have carried out the detailed investigation of the waveguide,and theoretical results reveal that the fundamental mode field can be strongly localized in the low-index dielectric media region.It can be found that the significant dependences of the effective index,propagation length,mode area and the confinement factor on the working wavelength and geo-metrical parameters of waveguides are discussed.Numerical analysis results show that the proposed waveguide structures can achieve very good mode properties and the long propagation length,with potential laboratory test and application prospect.By using of gain material,moreover,the compensation of mode loss is realized to obtain much longer propagating distance.(2)Another novel hybrid plasmonic waveguide composed of two iden-tical dielectric nanotubes symmetrically placed on both sides of a thin metal film is proposed.The properties of field distribution and mode propagating of the supported antisymmetric and symmetric electromagnetic field modes are numerically analyzed.Simulation results show that the strong coupling be-tween the dielectric waveguide mode and the plasmon mode makes the elec-tromagnetic mode tightly confined in the low index gaps between the nano-tubes and the metal film.At the same time,sub-wavelength mode confine-ment and long-range propagation length can be achieved simultaneously.At last,through comparison,we have proved that the proposed waveguide structure has the advantages of simplicity in structure and easiness in labora-tory manufacture.By adjusting the geometrical parameters,one can control the propagating properties of the proposed SPW which makes it have poten-tial values in future applications.