Size Dependence of the Plasmon Ruler Equation for Two-Dimensional Metal Nanosphere Arrays

Abstract

We have utilized the discrete dipole approximation to study the localized surface plasmon resonance in infinite, periodic two-dimensional arrays of gold nanospheres with the nanospheres arranged according to the {100} face of an fcc crystal. Specifically, we have performed a systematic study of the sensitivity of both the plasmon resonance wavelength shift and extinction properties considering nanosphere diameters ranging from 20 to 100 nm, and for nanosphere gap distances ranging from 0.5 to 6 times the nanosphere diameter. In doing so, we find that the same universal decay length of the plasmon resonance wavelength shift of about 0.2 units of the nanosphere size that was previously found by Jain et al.(1) for nanoparticle dimers is also operant for two-dimensional arrays. However, we also find that the universality of the plasmon ruler is only valid for arrays with nanospheres smaller than a critical nanosphere diameter of about 70 nm, whereas for larger nanosphere diameters, a decrease in the extinctio...