| This dissertation describes experimental and computational studies of the effects of ordered arrangement on the linear and nonlinear optical properties of metal nanoparticles. The principal result is that second-harmonic light may be generated and observed from nanoparticle gratings having maximum in-plane symmetry, provided that one looks at non-normal observation angles. These measurements are made possible by a custom-built variable-angle microscope, and enable a variety of studies of the second-order nonlinear response of nanoparticles that were not previously feasible. In addition, the surface plasmon resonance of metal nanoparticles is studied by linear spectroscopy. A comparison of experimental data with computational modeling shows that under normal ambient conditions, Ag nanoparticles tarnish by a sulfidation reaction more readily than bulk silver, and that even a very thin surface layer of corroded material (Ag2S) considerably redshifts and weakens the localized surface plasmon resonance of a nanoparticle. |
