A Computational Maxwell Solver for Nonlocal Feibelman Parameters in Plasmonics

Feibelman parameters provide a convenient means to account for quantum surface effects in classical Maxwell descriptions. Recent work has shown that for incoming fields with spatial variations in the nanometer range, for instance those produced by quantum emitters in the vicinity of metallic nanoparticles, nonlocality in the directions parallel to the interface must be considered. Here we develop the methodology for mesoscopic boundary conditions incorporating nonlocal Feibelman parameters, and show how to implement them in a computational Maxwell solver based on the boundary element method. We compare our results with Mie solutions for single and coupled spheres, and find very good agreement throughout.