Manipulating the optical properties of individual and arrays of gold nanopyramids

This chapter describes the fabrication and optical characterization of a new type of metal nanoparticle: gold nanopyramids. Individual pyramids exhibit orientation-dependent scattering under unpolarized white light, which can be used to determine their relative orientation on a substrate without direct imaging tools. Arrays of gold pyramids encapsulated within a polymer film exhibit polarization and wavevector-dependent optical properties that match well with calculations. The scattering peaks observed at visible wavelengths can be assigned to multi-polar surface plasmon resonances, which originate from the large size and anisotropic shape of the pyramids. Unique prospects of these three-dimensional metal particles will also be discussed.