Ultra-Thin Absorber based on Phase Change Metamaterial Superlattice

TL;DR

This paper presents a design for a tunable, ultra-thin infrared absorber using a VO2/SiO2 superlattice metamaterial, overcoming limitations of single-material VO2 absorbers through composite structuring.

Contribution

The study introduces a novel VO2/SiO2 superlattice metamaterial that achieves high infrared absorption with tunability, expanding the applicability of ultra-thin absorbers.

Findings

Achieves near-perfect infrared absorption with ultra-thin layers.

Demonstrates tunability of absorption across the infrared spectrum.

Overcomes limitations of single-material VO2 absorbers.

Abstract

In this paper, a superlattice VO2/SiO2 metamaterial on a lossy substrate is designed to create a near perfect absorber with tunability across the infrared spectrum. We selected VO2 as it presents a dielectric to metal-like phase change slightly above room temperature. Additionally, the slightly lossy nature of high-temperature VO2 presents comparable and small components (real and imaginary) of the complex refractive index across portions of the visible and infrared. Coupled with a limited conductivity substrate, VO2 has been employed to create highly absorbing/emitting structures where the thickness of the VO2 is ultra-thin (t << lambda/4n). Nevertheless, metal-like VO2 does not possess comparable and small components of the complex refractive index across the entire infrared spectrum, which limits the universality of this ultra-thin VO2 absorber design. Here we employ an ultra-thin superlattice of VO2/SiO2 to create a composite metamaterial that is readily designed for high absorbance across the infrared spectrum.