Anti-reflection coatings for highly anisotropic materials in the mid infrared

TL;DR

This paper presents the development and experimental validation of anti-reflection coatings specifically designed for highly anisotropic materials in the mid-infrared, addressing the limitations of conventional isotropic assumptions.

Contribution

It introduces novel ARC designs that fully incorporate anisotropic properties, including a bilayer structure, advancing the application of ARCs to anisotropic materials.

Findings

Planar bilayer ARC achieved broad-angle, polarization-independent anti-reflectance.

Design method fully accounts for anisotropic refractive indices.

Experimental results confirm effectiveness across mid-infrared spectrum.

Abstract

We develop and optimize thin anti-reflection coatings (ARCs) for highly anisotropic materials in the mid infrared. Unlike conventional ARCs that assume nearly isotropic refractive indices, this work fully integrates the anisotropic nature of materials into the design process. We describe two designs of thin ARCs for highly anisotropic materials: a single form-birefringent layer, and a planar bilayer. We realized the planar bilayer ARC experimentally, demonstrating excellent mid-infrared anti-reflectance across over a broad range of angles for all polarizations.