Excitation and propagation of surface plasmons on metallic nanowires

摘要

The comprehensive understanding of the excitation and propagation of surface plasmons (SPs) on metallic nanowires(NWs) is essential for potential applications of these materials as nanoscale optical waveguides. Combining theory anddifferent experimental methods, we did intensive study on the excitation and propagation of SP modes in crystal Agnanowires. We found the excitation of NW SP modes is strongly affected by the excitation configuration. When anoptically “thick” NW is radiated at the end of the NW, several SP modes could be excited simultaneously withappropriate incident polarization. If the NW is in the medium of uniform refractive index, the coherent superposition ofthese SP modes generates chiral SPs in single NW, and the handedness of the chiral SPs can be controlled by the inputpolarization angle. When we use a near field scanning optical fiber tip to excite the SPs on metallic nanowires from themiddle of the NW, we also found multiple SP modes in the NWs can be excited through polarization selective near fieldinteraction. The excitation mechanism of the tip-induced SP propagation is quite different from the previous wire-endlaunchingscheme. We found the input coupling efficiency is modulated by Fabry-Pérot interferences in the near fieldcoupling case.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.