Absorbing boundary condition for Bloch-Floquet eigenmodes

TL;DR

This paper introduces a novel absorbing boundary condition for electromagnetic simulations that effectively absorbs multiple Bloch-Floquet eigenmodes in complex photonic structures, improving accuracy in modeling photonic crystals and metamaterials.

Contribution

It proposes a new boundary condition based on an orthogonality condition for Bloch-Floquet eigenmodes, applicable to complex and lossy photonic materials.

Findings

Successfully absorbs multiple eigenmodes in simulations

Works with lossy, active, and anisotropic materials

Numerical tests confirm effectiveness

Abstract

We present an absorbing boundary condition for electromagnetic frequency domain simulations of photonic crystals and metamaterials. This boundary condition can simultaneously absorb multiple Bloch-Floquet eigenmodes of a periodic crystal, including both propagating and evanescent modes. The photonic crystal or metamaterial in question can include lossy, active, anisotropic and even bi-anisotropic inclusions. The absorbing boundary condition is dependent on an orthogonality condition for Bloch-Floquet eigenmodes, a generalized version of which is presented here. We test this absorbing boundary condition numerically and present the results.