Surface Plasmonic For Nonlinear Optical Conversion

Surface plasmonics is one of an important branch of nanophotonics. In this paper, we based two classic surface plasmon phenomenons as the surface plasmon polarization(SPPs) and localized surface plasmon(LSPs) to investigate the properties of surface plasmonic waveguide and its second harmonic conversion, then we also introduce the optical antenna and second-order nonlinear of metal.In this paper, the basic principles and main parameters of SPPs were introduced firstly, as well as the metal dielectric function model:Drude model and the Lorentz-Drude model, then introduce the basic principles and second-order nonlinear optical polarization factor of nonlinear optics. After that, the simulation environment Comsol Multiphysics, be referred through an example, we give every step of the simulation process. All of the above provide a basis to support the work of the article.We study three major surface plasmonic waveguides:hybrid waveguides, silicon waveguide, MIM waveguide, IMI waveguide. The basic properties were investigated such as geometry, mode distribution, the effective refractive index and the propagation length. And compare the ability of energy confinement and energy loss of these three guides. Thus prove that is important to give a tradeoff of energy confinement and energy loss during design surface plasmonic waveguides.In this paper, we designed a new type of surface plasmonic waveguide called hybrid slot waveguide in order to improved second harmonic conversion efficiency. In the first, study basic properties of its fundamental frequency (FF) and second harmonic (SH) including geometry, mode distribution, the effective refractive index, propagation length, the ratio of the energy of each part, and normalization mode area, for learning the nature of the waveguide. Then, we introduce a numerical methods for second harmonic conversion, including the coupling coefficient, normalized electric field and phase matching conditions, substitute all the parameters into the coupling equations we can acquire the evolution of second harmonic conversion, coupling efficiency (maximum conversion efficiency) and a peak position (position of the coupling efficiency of the spread appears). By introducing tapered structure, utilize compensation effects and the properties of different structures to achieve higher second harmonic conversion efficiency in a shorter propagation distance, so that, in the secondary propagation distance of3mm harmonic conversion efficiency reach to about10%.We have also introduced nano-optical antenna theory which based on localized surface plasmonic (LSPs), including the origin of nano-optical antennas, current research, the main structure and parameters. Then study derivation of the second harmonic field equations of metalby giving an example of two-dimensional metalby dividing the bulk and surface part of metal and using Green’s tensor approach.In general, this paper is mainly based on the Comsol Multiphysics simulation platform which on account of finite element method (FEM) to study the effect of the surface plasmonic, including those based on the theory of SPP waveguide and the second harmonic conversion, also LSPs-based nano-optics theory antenna and metal second-order nonlinear conversion, the purpose is to study and research on second-order nonlinear effect of surface plasmon effects, and strive to improve their corresponding transition effects.