Hybrid Surface Plasma Waveguides And Ultra-lens Simulation

Plasmonic wave is a kind of wave that propagation along the metal surface. And it is due to the interaction of the electromagnetic with electronic resonance at the interface of metal and dielectric. It can propagate severalμm in lateral direction and decay exponentially in longitudinal direction. Its special characteristics attract much attention to the plasmonic lasers, nanophotonic circuit, and superlens. And many papers about this were published.We do many simulation works on plasmonic laser and superlens by using the characteristics of surface plasmon polaritons. And also we constructed the model of a hybrid plasma waveguide model, and plasmonic lens model. Then we showed the result of the simulation and given the detailed discussion and analysis of the result.At first this thesis analyzes the principle of surface Plasmon and superlens, and gives a brief introduction of the finite-difference time-domain (FDTD) method and the simulation software.Then we explored the characteristics of surface Plasmon and its advance application. We simulated several hybrid nanometer scale waveguide models which were constructed by CdS-MgF2-Si,CdS-MgF2-Au,CdS-Si and CdS-Au multilayer structure. We analyzed the working wavelength of this type of waveguide by using beam whose wavelength from 450nm to 800nm as the source of the model. And we find that the CdS-MgF2-Au multilayer structure has a strong overall confinement effect in the gap region between the CdS wire and metal surface when the wavelength was about 650 nm. And it could be used in plasmonic laser devices.At last we present the elliptical pinholes-based plasmonic lens. Tuning effect of different polarization states was presented. It can be realized by a plasmonic lens constructed with elliptical pinholes ranging from submicron to nanoscales distributed in variant period along radial direction. Propagation properties of the lens illuminated under four different polarization states: linear, elliptical, radial, and cylindrical vector bean, were calculated and analyzed combining with finite-difference time-domain algorithm. Different focusing performances of the lens were illustrated while the polarized light passes through the pinholes. Our calculation results demonstrate that polarization effect of the plasmonic lens can generate high transmission intensity and sharp focusing for our proposed specific structure. Beam focal region, position, and transmission intensity distribution can be tailored by the four polarization states. The tuning effect of different parameterδwas also presented when the source is linear polarization. And hereδis defined asδ=a /b, where b is the length of long axis of the elliptical pinholes, and a is the short axis.