Formulation of the finite-difference time-domain method for the analysis of axially symmetric metal nanodevices

摘要

A systematic finite-difference time-domain method, established in the cylindrical coordinate and integrated with the six-pole Lorentz-Drude model using the auxiliary differential equation method, is formulated. The model is appropriate for analyzing metal photonic devices with an axially symmetric nanostructure, such as metal nanowires, metal particles, and plasmonic lenses. As an example, an experimentally demonstrated plasmonic lens is analyzed based on the Drude model, the Lorentz-Drude model, and the Lorentz model. Depending on the different dispersion models, distinct electric field distributions for the plasmonic lens are obtained. The interesting numerical results, which are explained in this paper, show the high efficiency and accuracy of the simulation model.