Linear optical properties of gold nanoshells

A metal nanoshell consists of a nanometer-scale dielectric core surrounded by a thin metallic shell. The plasmon resonance of metal nanoshells displays a geometric tunability controlled by the ratio of the core radius to the total radius. For gold-coated Au2S this ratio varies from 0.6 to 0.9, yielding a plasmon resonance tunable from 600 to greater than 1000 nm. Mie scattering theory for the nanoshell geometry quantitatively accounts for the observed plasmon resonance shifts and linewidths. In addition, the plasmon linewidth is shown to be dominated by electron surface scattering. (C) 1999 Optical Society of America [S0740-3224(99)02910-0].