Open geometry Fourier modal method: Modeling nanophotonic structures in infinite domains

TL;DR

This paper introduces an open geometry Fourier modal method that combines open boundary conditions with a novel k-space discretization, significantly improving the accuracy and efficiency of modeling nanophotonic structures in infinite domains.

Contribution

The paper presents a new Fourier modal method with open boundaries and a non-uniform k-space sampling technique, enhancing convergence and modeling of open nanophotonic structures.

Findings

Improved convergence with fewer degrees of freedom.

Effective handling of radiation modes in open domains.

Applicable to various photonic structures.

Abstract

We present an open geometry Fourier modal method based on a new combination of open boundary conditions and an efficient $k$-space discretization. The open boundary of the computational domain is obtained using basis functions that expand the whole space, and the integrals subsequently appearing due to the continuous nature of the radiation modes are handled using a discretization based on non-uniform sampling of the $k$-space. We apply the method to a variety of photonic structures and demonstrate that our method leads to significantly improved convergence with respect to the number of degrees of freedom, which may pave the way for more accurate and efficient modeling of open nanophotonic structures.