RESUMO
We present rigorous optimization and design of three-dimensional photonic-crystal (PhC) structures involving finite dielectric rods. These types of PhCs are known to be useful in diverse applications, such as imaging, power focusing, filtering, and pattern shaping at optical frequencies. Without resorting to their two-dimensional models, which are commonly used in the literature, we consider PhCs as three-dimensional structures, whose electromagnetic characteristics are optimized via genetic algorithms integrated with an efficient and accurate solver based on the multilevel fast multipole algorithm. In addition to the designs of PhCs that can provide desired output patterns, we present sensitivity tests to understand the critical geometric parameters, as well as to test and evaluate the tolerance of the proposed designs to possible fabrication errors.
RESUMO
We consider computational analysis of deformed nanowires and their arrays using a full-wave simulation environment based on integral-equation formulations and the multilevel fast multipole algorithm (MLFMA). Without requiring any periodicity assumptions, MLFMA allows for fast and accurate simulations of complex nanowire structures with three-dimensional geometries and random deformations. We present the results of hundreds of simulations, where deformed nanowires are considered as isolated, as well as in array configurations, and their scattering characteristics are compared to those of non-deformed ones. Based on the simulation results, we rigorously investigate common effects of deformations on scattering properties of nanowires and identify strong field enhancements in forward-scattering directions.
