Simulation of large-area metasurfaces with a distributed transition matrix method

TL;DR

This paper introduces a scalable, accurate simulation method for large-area metasurfaces using a distributed transition-matrix approach, enabling efficient gradient-based design optimization of complex flat optical devices.

Contribution

The authors develop a distributed T-matrix simulation technique that reduces computation time and accurately models scatterer interactions in large-area metasurfaces.

Findings

Distributed simulation reduces computation time linearly with compute nodes.

Accurately models scatterer interactions beyond local periodicity.

Enables efficient gradient computation for metasurface optimization.

Abstract

Inverse design of large-area metasurfaces can potentially exploit the full parameter space that such devices offer and achieve highly efficient multifunctional flat optical elements. However, since practically useful flat optics elements are large in the linear dimension, an accurate simulation of their scattering properties is challenging. Here, we demonstrate a method to compute accurate simulations and gradients of large-area metasurfaces. Our approach relies on two key ingredients - a simulation distribution strategy that allows a linear reduction in the simulation time with number of compute (GPU) nodes and an efficient single-node computation using the Transition-matrix (T-matrix) method. We demonstrate ability to perform a distributed simulation of large-area, while accurately accounting for scatterer-scatterer interactions significantly beyond the locally periodic approximation, and efficiently compute gradients with respect to the metasurface design parameters. This scalable and accurate metasurface simulation method opens the door to gradient-based optimization of full large-area metasurfaces.