Modal Propagation in Periodic Chains of Circular Rods: Real and Complex Solutions

A full-wave numerical approach for the analysis of bounded and leaky modes in periodic chain composed of both lossless and lossy 2-D cylindrical inclusions is proposed. An effective method based on the lattice sums technique is adapted to the analysis of modes with complex propagation wavenumbers, thus allowing for the appropriate choice of the spectral determination for each spatial harmonic. Periodic chains of both dielectric and silver nanocylinders are studied and the relevant modal phase and attenuation constants are rigorously calculated in all the different propagation regimes, including bound and radiative regions as well as plasmonic behaviors.