Electron Energy-Loss Spectroscopy Calculation in Finite-Difference Time-Domain Package

TLDR

Electron energy‑loss spectroscopy (EELS) is a unique tool extensively used to probe the plasmonic response of metallic nanostructures. We present a novel approach for EELS calculations using the finite‑difference time‑domain (FDTD) method (EELS‑FDTD). The approach is benchmarked against boundary element method results and experimental data, and EELS spectra are computed for spherical nanoparticles, dimers, nanodisks on various substrates, and a gold bowtie antenna on silicon nitride. The EELS‑FDTD method is easily extendable to complex geometries and can be exported to other Maxwell solvers.

Abstract

Electron energy-loss spectroscopy (EELS) is a unique tool that is extensively used to investigate the plasmonic response of metallic nanostructures. We present here a novel approach for EELS calculations using the finite-difference time-domain (FDTD) method (EELS-FDTD). We benchmark our approach by direct comparison with results from the well-established boundary element method (BEM) and published experimental results. In particular, we compute EELS spectra for spherical nanoparticles, nanoparticle dimers, nanodisks supported by various substrates, and a gold bowtie antenna on a silicon nitride substrate. Our EELS-FDTD method can be easily extended to more complex geometries and configurations. This implementation can also be directly exported beyond the FDTD framework and implemented in other Maxwell’s equation solvers.