Abstract
In this paper, we formulate an analytical theory that quantifies the first-order effect of a small random uncontrollable disorder that is due to limitations in the realization of periodic arrays of plasmonic nanoparticles. In particular, we show how the effect of a small disorder may be quantitatively taken into account when evaluating the guidance properties of these otherwise periodic chains, and how the main effect of the small disorder consists of additional radiation losses for the guided mode. Similar quantitative analyses may be extended to the general class of periodic metamaterials, providing an idea of how disorder affects their electromagnetic response, and which types of disorder have the most effect.