Research Of Surface Plasmon Nanostructure For Nearfield Optical Features

The Surface Plasmons are collective oscillations of conduction electrons of metal nanoparticles that are excited by the incident light. The Surface Plasmon exists in the interface between the metal and the medium that leads to increase the localized electric field rapidly. Various nano optical devices based on the surface plasmon are able to break through the diffraction limit for all optical integrated loops with nano scale. The near field features of nanostructure can produce peculiar physical phenomena. The study on surface plasmon has been a hot topic for the application such as nano sensor, light solar cells and waveguide.In this paper, we have developed and made a theoretical research on the characteristics of surface plasma physics such as the near field optical features of nano optical antenna and nano particles. The basic features of surface plasmon physics are obtained by constructing different parameters. Some special physical mechanism and phenomena of the surface plasma resonances are obtained. The details of our works are listed as following:(1) In this work, we perform the theory analysis on the near field features of the nano antenna. We make a research on a new style nano antenna with backfire. The performance of the Yagi-Uda nano antenna with backfire improves remarkably compared with the Yagi-Uda nano antenna without backfire. The directive gain increases up to1.95times than that of the Yagi-Uda nano antenna. The results indicate that the nano antenna with backfire can send and receive electromagnetic wave. The dependencies of the antenna directive gain on the geometrical structural parameters are presented effectively. The optimized parameters of the nano antenna with backfire have been displayed in the paper. In the end, the Yagi-Uda nano antenna with tapering directors and backfire is studied. The result indicates that when the numbers of directors are fixed, the Yagi-Uda nano antenna with backfire has an optimized tapering angle to get the maximum directive gain.(2) In this paper, we study the near field optical features of metal nanoparticles based on the surface plasmon. The existences of the substrate have an important influence on surface plasmon resonance wavelength. The works that we do here are different from the previous work because we use the Bragg reflector as a substrate. The Bragg reflector has a property of coherence interference that contributes to the plasmon resonances. We have developed and presented the theoretical analysis on the optical features of nanoparticles such as the scatting cross section, the absorption cross section and the field enhancement. The dependencies of the nanoparticles resonance wavelength on the geometrical structural such as the distance, the width and the periodic numbers of the substance are presented that are very import for the surface plasmon resonances.In a word, we make a theoretical research on the near field features of the nano particles based on the plasmon resonances with the finite element analysis simulation. It has a theoretical significance to explore the new type of integration, the microwave optical device.