Modal analysis of chains of metallic nanowires partially buried in a half-space substrate with the Source-Model Technique

Chains of metallic nanowires are of growing interest for their ability to guide surface-plasmon type waves at optical frequencies, thus rendering them feasible as nanometric-scale optical circuit interconnects. A technique for computing the modes that can be guided along chains of 2D wires with arbitrary, smooth cross-section is presented. The wires are assumed to be partially-buried in a supporting dielectric half-space substrate, as may be found in such fabricated structures. The method of solution is based on the rigorous, full-wave frequency-domain Source-Model Technique (SMT). With the SMT, instead of formulating the fields in terms of displacement currents, they are formulated in terms of fictitious sources located on mathematical surfaces inside and outside the media boundaries. The solution scheme allows efficient determination of the modal fields and their complex modal propagation constants. The method and the respective software tool are robust to the choice of material or geometric parameters.