The interaction between metal nanoparticle resonances and optical-frequency surface waves

This dissertation investigates the optical properties of metallic, dipole-like scatterers in planar geometries. The treatment begins with a general description of the optical properties of particles that are small compared to an optical wavelength. The localized plasma oscillation of the conduction electrons in a metallic nanoparticle is investigated and a new method by which to tune the natural frequency of that oscillation is introduced.; A discussion of the optical properties of metallic nanoparticles near planar structures begins with a mathematical description of how a local structure can modify the lifetime of an oscillating electric-dipole. It is shown that a point dipole situated in the cover region of a planar waveguide can emit a substantial fraction of light into the bound modes of the underlying surfaces. The mathematical description of point dipoles is extended to cover nanoscopic particles of finite size by use of a coupled-dipole formalism.; A general theory is developed, in the dipole limit, for light-scattering from a random, two-dimensional array of nanoparticles spaced much less than an optical wavelength from a layered-surface or waveguide. It is shown that coherent inter actions between particles near a waveguide cause dramatic, qualitative changes to the particle susceptibilities. Hence, the scattering spectrum from a collection of such particles shows strong, surface induced peaks that are associated with the onset of leaky guided waves of the layered substrate. It is also shown that two-dimensional arrays of metallic nanoparticles supported on a dielectric substrate can support their own set of propagating surface waves that resemble leaky planar-waveguide modes.; The application of a layer of silver nanoparticles to the surface of an optical detector built into the silicon-on-insulator (SOI) material system is shown to result in nearly 30x photocurrent enhancement in the device. The model of light-scattering from random overlayers developed in this dissertation is applied to and found to be in good agreement with measured photocurrent enhancement in an SO] structure.