Abstract

In noble-metal nanoparticles, collective oscillations of the conduction electrons known as surface plasmons (SP’s) show themselves as large optical resonances [1]. The dephasing time of the SP, T₂ (or the homogeneous linewidth, Γ_hom=2ħ/T₂), is controlled by intrinsic electronic processes [2], by surface effects, and by the dielectric properties of the embedding material. It has so far been inaccessible to measurement due to the inhomogeneous broadening of the SP line. In the present contribution, we present the results of experiments which use a near-field optical antenna effect to measure the homogeneous lineshape of the SP resonance in single gold nanoparticles.

© 1998 IEEE