Experimental measurement of the dispersion relations of the surface plasmon modes of metal nanoparticle chains

The dispersion relations of the surface plasmon modes of metal nanoparticle chains are measured, and compared with theory. The theoretical model includes the effects of retardation, radiative damping and dynamic depolarization due to the finite size of the nanoparticles. The results reveal that, in addition to one longitudinal and one transverse mode, there is a third mode, which has not been previously reported. (C) 2007 Optical Society of America.