A Potential-Based Boundary Element Implementation for Modeling Multiple Scattering from Local and Nonlocal Plasmonic Nanowires

A novel boundary element implementation that models multiple scattering of plasmonic nanowires is presented. The modeling is based on potentials and the materials constituting the wires can be local (described by the local response model) or nonlocal (described by the nonlocal hydrodynamic model). The nonlocal hydrodynamic model (HDM) provides an important approximation describing nonclassical effects associated with the collective motion of free electrons in metals. The modeling is challenging as different interface conditions are needed at a boundary which separates 1) a local medium from a local medium; 2) a local (nonlocal) medium from a nonlocal (local) medium; and 3) a nonlocal medium from a nonlocal medium. The algorithm can address constructs of arbitrary geometry and material composition within the HDM; thus, it becomes a complete numerical tool for exploration of nonlocal nanowires. Fictitious sources are imposed at the boundaries, linking the scattered fields to the imposed sources, and matching the interface conditions at the boundaries. This procedure yields a set of Boundary Integral Equations (BIEs). Then, the BIEs are numerically solved utilizing the Boundary Element Method (BEM). The results from the BEM solver are verified quantitatively and qualitatively showing good agreement in both the near- and the far-field regimes.

Automated summary

This study presents a novel implementation of the boundary element method for modeling multiple scattering of plasmonic nanowires. The model considers both local and nonlocal materials and the nonlocal hydrodynamic model is used to capture nonclassical effects of free electron motion in metals. The challenging aspect of the modeling lies in the different interface conditions required at the boundaries of various media. The proposed algorithm is capable of handling arbitrary geometries and material compositions, making it a comprehensive numerical tool for exploring nonlocal nanowires. The accuracy and agreement of the results obtained using the boundary element method are verified both quantitatively and qualitatively, demonstrating good performance in both near- and far-field regimes.