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

Area of Science:

• Nanophotonics and Metasurface Engineering
• Computational Electromagnetics
• Optical Simulation Techniques

Background:

• Metasurface design is often slow due to parameter sweeping and computationally intensive simulations.
• Existing numerical methods like FDTD struggle with large-scale, high-resolution, or 3D metasurface simulations.
• The discrete dipole approximation (DDA) offers potential speedups but lacks comprehensive benchmarking in metasurface design.

Purpose of the Study:

• To compare the accuracy and speed of three DDA methods against the FDTD method for metasurface simulations.
• To identify the most efficient DDA approach for metasurface design.
• To evaluate different polarizability models within the DDA framework.

Main Methods:

• Comparison of three DDA techniques: substrate discretization, 2D Cartesian Green's functions, and 1D cylindrical Green's functions.
• Benchmarking against the finite difference time domain (FDTD) method.
• Evaluation of four polarizability models: Clausius-Mossotti, radiation reaction, lattice dispersion relation, and digitized Green's function.

Main Results:

• The 1D cylindrical DDA method demonstrated superior performance, achieving high accuracy with significantly reduced computation time (6x faster than FDTD for a sample case).
• The radiation reaction dipole model yielded the best pattern accuracy, while the digitized Green's function model showed the lowest power error.
• The 1D cylindrical DDA approach supports parallel processing and provides transmitted field solutions, a feature not commonly found in existing tools.

Conclusions:

• The 1D cylindrical DDA method is a highly accurate and efficient alternative for metasurface design simulations.
• This DDA approach accelerates optical device design by overcoming the speed limitations of traditional methods.
• The findings provide valuable insights for selecting appropriate DDA methods and polarizability models for specific metasurface simulation needs.