Fast analysis of electrically large plasmonic arrays with aperiodic spiral order

This work presents a fast analysis of electromagnetic scattering from arrays of metallic nano-particles with aperiodic spiral order. The reported method extends the integral equation fast Fourier transform (IE-FFT) algorithm to the method of moments solution of PMCHWT integral equation for aperiodic homogenous dielectric arrays. The algorithm relies on the interpolation of Greens function by Lagrangian polynomials on a uniform Cartesian grid. Hence, the matrix-vector product in the iterative solver can be computed via the fast Fourier transform. The memory requirement and the computational complexity of the algorithm tend to stay close to O(N) and O(NlogN), respectively, where N is the number of unknowns. Some numerical examples are included, which illustrate the accuracy and capability of the present method.