Theoretical Research On Plasmonic Slow-light Waveguides

High energy confinement, sub-wavelength constraint and beyond the diffraction limitetc, which are distinctive features of surface Plasmon Plaritons(SPPs), make SPPs play anincreasingly important role in the development of nano-photonic and integrated optics. Asan important application of SPPs, SPPs-based slow light waveguide supports slow groupvelocity over large frequency bandwidths, processes optical signals within sub-wavelengthand highly confines electromagnetic energy at interface between metal and dielectric.This dissertation starts from Maxwell equations, using metal Drude dispersion model,rationales of surface plasmonics at signal metal-dielectric interface, which concludedispersion relationship, length scales and excitation ways are analyzed. We studySPPs-based three layer planner optical waveguide, with an analysis of its field distributionsand give simulation results between structure parameters, electromagnetic parameters andtransmission characteristics that conclude mode effective refraction, propagation loss,propagation length. Next, the dissertation introduces finite-difference time-domain method(FDTD) in metal dispersion dielectric using in the study.In the following part, on account of FDTD, the dissertation studies SPPs-based opticalwaveguide. Under addition excitation, slow light property of this waveguide is studied witha detailed analysis of dispersion relation, group velocity cure and time-domain transmissionfields. It is shown that the MDM structure waveguide can support slow light propagationand obtain slower group velocity dispersion when setting the frequency in an appropriateregion. In addition, one conclusion can be drawn from above analysis that by changing thethickness of dielectric layer, frequency range of slow light modes can be altered.For the sake of increasing SPPs propagation length and decreasing propagation loss,dielectric-metal-dielectric (DMD) structure, long-range SPPs-based waveguide is alsostudied in the dissertation, with a detailed analysis of dispersion cures of symmetric modesand ant-symmetric modes of this waveguide. It is shown that under ant-symmetric modes,by setting the structural parameters at an appropriate value, a desirable slow light propertycan be achieved, and having long-range modes simultaneously.