Nanophotonic resonators in stratified media with the NANOBEM toolbox

NANOBEM is a recently developed MATLAB toolbox for the solution of Maxwell's equations using a boundary element method, which is particularly suited for nanophotonic resonators and the computation of resonance modes [Hohenester et al., CPC 276, 108337 (2022)]. In this paper we present an extension that allows simulating nanoparticles situated in stratified media, using the matrix-friendly approach of Chew. Possible simulation setups include nanoparticles on substrates or embedded in layer structures, holes in films, or void structures. We provide a detailed documentation of the various toolbox classes, and present selected showcase results and convergence studies.Program summaryProgram Title: NANOBEM CPC Library link to program files: https://doi .org /10 .17632 /f59yhhbjwx .1 Licensing provisions: GNU General Public License 3 Programming language: Matlab Nature of problem: Solve Maxwell's equations for metallic or dielectric nanoparticles embedded in stratified media. Solution method: Galerkin implementation of boundary element method approach using the matrix-friendly approach of Chew for stratified media. Additional comments including restrictions and unusual features: Toolbox has been developed and tested for small to intermediate problems with a few thousand boundary elements.