The Investigation On Propagation Properties Of Typical Structure Of Hybrid Plasmonic Waveguide

In recent years,with the continuous progress of science and technology,surface plasmon has been widely used in photonics research,and captures great concern of many researchers.Surface plasmon is an electromagnetic surface wave,which has the strongest field strength at the surface and can be excited by electrons or photon waves.Surface plasmon,whose distribution depth can be less than the wavelength is easy to be introduced in sub-wavelength optoelectronic integrated device.However,there is large loss in surface plasmon transfer,which limits it's application.Surface plasmon can be used to realize nanometer-scaled optical information transmission and processing.In addition,the unique characteristics of the surface plasmon make it widely used in the fields of high sensitive biological detection,sensing and new light source.In this thesis,the propagation characteristics of nanometer light in metal are analyzed based on the characteristics of surface plasmon.as follows:(1)The propagation characteristics of surface plasmon in metal cylinder waveguide.The effects of the geometrical parameters of the waveguide and the metal material(Ag and Au)on the propagation characteristics are analyzed at wavelength 1550nm.The results show that the energy density along the longitudinal direction is mainly distributed on the circumference of the metal column,and the closer to the metal cylinder,the greater the energy density is.Silver rods have better propagation characteristics than Au.(2)Next,the propagation characteristics of the surface plasmonic waveguide of the metal cylinder waveguide with substrate.By changing the diameter of the metal cylinder and the distance between the cylinder and the substrate,the energy density,effective refractive index,propagation length and mode area are analyzed.The effect of different substrate materials(silicon and germanium)on propagation characteristics,is analyzed and compared which show that the germanium substrate has more advantages.(3)A new of surface plasmonic waveguide with the metalic double elliptical and high refractive index substrate is designed.The dependence of the distribution of longitudinal energy flux density,the effective refractive index,the propagation length and the effective area of the fundamental mode of the waveguide,on the geometrical parameters and the structure are analyzed by the finite element method.The energy is mainly distributed in the central area,which is formed by two metallic ellipses,and there is also energy between the metal and the germanium substrate and between the substrate and the substrate.The transmission characteristics of this waveguide mode can be adjusted by tuning the center distance of two ellipses and the size of the two semiaxes.(4)A new type of slit-type surface plasmon waveguide is proposed,and the surface plasmon waveguide has been further studied.This structure consists of two media blocks embedded in the metal ring.By adjusting the gap width and contacting area the transmission characteristics are analyzed.The structure can be widely used in photonic integrated circuits and sensors.In summary,the surface plasmonic waveguide can be analyzed by changing the geometric parameters,communication wavelength,etc.In this paper,we study the surface plasmon waveguides with different structures at fixed wavelength.By adjusting the parameters of the geometry structure,we analyze the propagation properties such as the effective refractive index,the propagation length and the effective mode area.These studies provide the theoretical basis for future research on optical communication and optical sensing.