Microstructure Effects for Casimir Forces in Chiral Metamaterials

TL;DR

This paper investigates how microstructure details in chiral metamaterials influence Casimir forces, revealing that microstructure effects dominate at certain separations and that chirality effects are very small compared to these microstructure influences.

Contribution

The study provides the first numerical computation of Casimir forces considering exact microstructures, highlighting the dominance of microstructure effects over chirality at relevant separations.

Findings

Microstructure effects dominate Casimir forces at certain separations.

Chirality effects are at most 10^{-4} of the total force at large separations.

Exact microstructure modeling reveals significant deviations from homogeneous approximations.

Abstract

We examine a recent prediction for the chirality-dependence of the Casimir force in chiral metamaterials by numerical computation of the forces between the exact microstructures, rather than homogeneous approximations. We compute the exact force for a chiral bent-cross pattern, as well as forces for an idealized "omega"-particle medium in the dilute approximation and identify the effects of structural inhomogeneity (i.e. proximity forces and anisotropy). We find that these microstructure effects dominate the force for separations where chirality was predicted to have a strong influence. To get observations of chirality free from microstructure effects, one must go to large separations where the effect of chirality is at most $\sim10^{-4}$ of the total force.