Optical extinction Spectroscopy of oblate, prolate and ellipsoid shaped gold nanoparticles: Experiments and theory

Localized Surface Plasmons (LSP) on metallic nanoparticles of different shapes are investigated by extinction spectroscopy. Experimental results are compared to simulations by a Finite-Difference Time-Domain (FDTD) method. Three different shapes of nanoparticles are compared, oblates, prolates and ellipsoids, in terms of spectral tunability of the LSP resonance (LSPR). It is found that the complete geometry of the nanoparticle must be given to truly define the LSP resonance and that ellipsoids offer the widest spectral tunability.