We report on chemically prepared silver nanowires (diameters around 100 nm) sustaining surface plasmon modes with wavelengths shortened to about half the value of the exciting light. As we find by scattered light spectroscopy and near-field optical microscopy, the nonradiating character of these modes together with minimized damping due to the well developed wire crystal structure gives rise to large values of surface plasmon propagation length and nanowire end face reflectivity of about 10 microm and 25%, respectively. We demonstrate that these properties allow us to apply the nanowires as efficient surface plasmon Fabry-Perot resonators.

We probe the influence of grating effects on plasmon excitations in gold nanoparticles arranged in regular two-dimensional patterns. Samples produced by electron-beam lithography are investigated by femtosecond time-resolved and spectroscopic methods. We find a strong dependence of the plasmon lifetime and resonance wavelength on the grating constant.

We report the experimental realization of highly efficient optical elements built up from metal nanostructures to manipulate surface plasmon polaritons propagating along a silver/polymer interface. Mirrors, beamsplitters, and interferometers produced by electron-beam lithography are investigated. The plasmon fields are imaged by detecting the fluorescence of molecules dispersed in the polymer.

We have developed a simple, fast, and flexible technique to measure optical scattering spectra of individual metallic nanoparticles. The particles are placed in an evanescent field produced by total internal reflection of light from a halogen lamp in a glass prism. The light scattered by individual particles is collected using a conventional microscope and is spectrally analyzed by a nitrogen-cooled charge-coupled-device array coupled to a spectrometer. This technique is employed to measure the effect of particle diameter on the dephasing time of the particle plasmon resonance in gold nanoparticles. We also demonstrate the use of this technique for measurements in liquids, which is important for the potential application of particle plasmons in chemical or biological nanosensors

We map the complete plasmonic spectrum of silver nanodisks by electron energy loss spectroscopy and show that the mode which couples strongest to the electron beam has radial symmetry with no net dipole moment. Therefore, this mode does not couple to light and has escaped from observation in optical experiments. This radial breathing mode has the character of an extended two-dimensional surface plasmon with a wavenumber determined by the circular disk confinement. Its strong near fields can impact the hybridization in coupled plasmonic nanoparticles as well as couplings with nearby quantum emitters.