Metamaterial Perfect Absorber Analyzed by a Meta-cavity Model Consisting of Multilayer Metasurfaces

TL;DR

This paper models metamaterial perfect absorbers as meta-cavities formed by multilayer metasurfaces, explaining their angle independence, ultra-thinness, and field localization, and suggesting new applications.

Contribution

Introduces a meta-cavity model for metamaterial perfect absorbers, providing a unified explanation for their key features and potential for advanced photonic applications.

Findings

Absorbers behave as Fabry-Perot cavities with high Q-factor

Model explains angle independence and field localization

Suggests applications in sensors and quantum devices

Abstract

We demonstrate that the metamaterial perfect absorber behaves as a meta-cavity bounded between a resonant metasurface and a metallic thin-film reflector. The perfect absorption is achieved by the Fabry-Perot cavity resonance via multiple reflections between the "quasi-open" boundary of resonator and the "closed" boundary of reflector. The characteristic features including angle independence, ultra-thin thickness and strong field localization can be well explained by this model. With this model, metamaterial perfect absorber can be redefined as a meta-cavity exhibiting high Q-factor, strong field enhancement and extremely high photonic density of states, thereby promising novel applications for high performance sensor, infrared photodetector and cavity quantum electrodynamics devices.