| A property of surface plasmonpolaritons (SPP) is to confine light far below the diffraction limit, and SPP have been widely harnessed to build efficient nanoscale integrated optical circuits.Plasmonic silver nanowires, as key components for SPP propagation, have been thoroughly investigated for different purposes, such as all light quantum logic circuits and optical nanocavities. Furthermore, plasmonic silvernanowires give rise to enhanced light-matter interactionsand provide an appealing platform for plasmon lasers. Understanding these interactions is notonly of fundamental importance for nanostructure and surface effect but also of interest forapplications ranging from novel plasmonic devices and photoelectric integration technology of nanochips, it is also significant to the interdiscipline composed of photoelectronics, information science and material science. In this thesis, we investigate the transmissions and resonators of SPP in Ag_nanowire nanostructure, and propose a QD-coupled plasmonic nanocavity system.This thesis presents theresearch works and conclusions, as following:1. According to the classical maxwell equation in cylindrical coordinate system,we investigate the propagation modes of silver nanowires.Comparing the transmission characteristic and the field distribution of dielectric coated silver nanowires,dielectric supported nanowires and GAP-SPP structuresby the FEM method. Multiple modes ofSPP can exist in silver nanowires, and chiral SPP can be generated.2. We show that the surfaceplasmon bragg mirrors fabricated in silver nanowires, in the surface of nanowires and in the gap of GAP-SPP structures can selectthe modes of SPP. For the proposed filter, the mode selection could be achieved with improved transmittance by varying the parameters of gratings, such as grating width and refractiveindex of dielectric.3. We theoretically investigate the characteristics of SPP modes and the ratio of Q factor to mode volume of three silver nanoring resonators structures with Finite Element Method (FEM). A high-Q/Veff gap-mode plasmonic Fabry-Perot nanocavity, which is composed of a silver nanowire on a flat silver substratespacedby patterned dielectric distributed Bragg gratings,is investigated both analytically and numerically. The design parameters and properties of the nanocavity are exploited with the use of generalized Fabry-Perot model. The Veff～0.0026(λ/n)3and Q/Veff～1.4×105/μum3of the nanocavity can be achieved. Furthermore, we put a quantum dot in the high-Q/Veff gap-mode plasmonic Fabry-Perot nanocavity, and analyze the phenomenon theoretically with transfer matrix method.4. We develop a spectral detection strategy based on local-excition and local-spectral measurementof SPP-FP modes achieved. This approach allows us toilluminate one end of a silver nanowire and to collect the propagation spectrum at the other end. Then, we employ this technique to investigate SPP-FP modes of nanowires with two different lengths in air or oil immersed environments, respectively.The propagation spectra aresuccessfully obtained and compared with a generalized FP model.Highlights in this thesis are as following:1. We studied the SPP mode and cavity features of Ag_nanowire nanostructure. According to the analysis of SPP modes in these nanostructures, we designed a high Q/Veff gap-mode plasmonic Fabry-Perot nanocavity, and applied a simplified generalized Fabry-Perot model to explain the transmission spectrum and the characteristics of the resonator. By using theoretical analysis and numerical simulation, the Veff～0.0026(λ/n)3and Q/Veff～1.4×105/μm3of the nanocavity can be achieved. We have put a quantum dot in the high-Q/Veff gap-mode plasmonic Fabry-Perot nanocavity, and the transport property of this structure was investigated theoretically.2. We developed a local-excitation and local-spectral measurement system to separate and the emission point from the incident light. We measured the propagation spectra of silver nanowires with different lengths atair-glass and oil-glass interfaces. The simplified generalized FP model was employed to explainthe relations between spectra and nanowire lengths and environments, and qualitative correspondence was observed between experimental and theoretical spectra. |
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