Fast and accurate electromagnetic field calculation for substrate-supported metasurfaces using the discrete dipole approximation

Weilin Liu, Euan McLeod

Research output: Contribution to journalArticlepeer-review

Abstract

Metasurface design tends to be tedious and time-consuming based on sweeping geometric parameters. Common numerical simulation techniques are slow for large areas, ultra-fine grids, and/or three-dimensional simulations. Simulation time can be reduced by combining the principle of the discrete dipole approximation (DDA) with analytical solutions for light scattered by a dipole near a flat surface. The DDA has rarely been used in metasurface design, and comprehensive benchmarking comparisons are lacking. Here, we compare the accuracy and speed of three DDA methods - substrate discretization, two-dimensional Cartesian Green's functions, and one-dimensional (1D) cylindrical Green's functions - against the finite difference time domain (FDTD) method. We find that the 1D cylindrical approach performs best. For example, the s-polarized field scattered from a silica-substrate-supported 600 × 180 × 60 nm gold elliptic nanocylinder discretized into 642 dipoles is computed with 0.78 % pattern error and 6.54 % net power error within 294 s, which is 6 times faster than FDTD. Our 1D cylindrical approach takes advantage of parallel processing and also gives transmitted field solutions, which, to the best of our knowledge, is not found in existing tools. We also examine the differences among four polarizability models: Clausius-Mossotti, radiation reaction, lattice dispersion relation, and digitized Green's function, finding that the radiation reaction dipole model performs best in terms of pattern error, while the digitized Green's function has the lowest power error.

Original languageEnglish (US)
Pages (from-to)4167-4183
Number of pages17
JournalNanophotonics
Volume12
Issue number22
DOIs
StatePublished - Nov 1 2023

Keywords

  • Sommerfeld integral
  • cylindrical Green's function
  • discrete dipole approximation
  • finite difference time domain
  • metasurface

ASJC Scopus subject areas

  • Biotechnology
  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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