Diffractive coupling in gold nanoparticle arrays and the effect of disorder

Copyright © 2009 Optical Society of America. This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-34-4-401 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Two-dimensional arrays of gold nanoparticles with a periodicity commensurate with the wavelength of resonant excitation of localized plasmons have been shown to exhibit a strong long-range interaction between particles. We investigate experimentally the effect of varying the degree of disorder in the geometrical arrangement from a periodic to a disordered lattice with constant occupancy. We also investigate the effect of disorder arising from variations in particle size for a regular lattice, and the effect this has on the broadening of the spectral line shape is discussed. A coupled dipole model is used to describe the observed spectral features