Tunable mid-infrared coherent perfect absorption in a graphene meta-surface

Yuancheng Fan,Hongqiang Li,Fuli Zhang,Quanhong Fu,Junjie Li,Zhe Liu,Changzhi Gu,Qian Zhao,Zeyong Wei

doi:10.1038/srep13956

Abstract

Graphene has drawn considerable attention due to its intriguing properties in photonics and optoelectronics. However, its interaction with light is normally rather weak. Meta-surfaces, artificial structures with single planar function-layers, have demonstrated exotic performances in boosting light-matter interactions, e.g., for absorption enhancement. Graphene based high efficiency absorber is desirable for its potential applications in optical detections and signal modulations. Here we exploit graphene nanoribbons based meta-surface to realize coherent perfect absorption (CPA) in the mid-infrared regime. It was shown that quasi-CPA frequencies, at which CPA can be demonstrated with proper phase modulations, exist for the grapheme meta-surface with strong resonant behaviors. The CPA can be tuned substantially by merging the geometric design of the meta-surface and the electrical tunability of graphene. Furthermore, we found that the graphene nanoribbon meta-surface based CPA is realizable with experimentally achievable graphene sample.

Highlights

Mode of the nanodisks together with multi-reflection from the assistants of total internal reflection and metal reflection can result in a complete optical absorption[28]
A comparative study[37] found that the fundamental electric dipolar mode provides stronger light-graphene interaction at terahertz frequencies than the magnetic and higher-order electric modes, it is found that the maximum absorption in a monolayer graphene is 50%, which is associated with a real number effective surface conductivity 2/η0 where η0 represents the characteristic impedance of vacuum[42]
We propose a tunable mid-infrared coherent perfect absorber with a graphene nanoribbon based meta-surface

Summary

Introduction

Mode of the nanodisks together with multi-reflection from the assistants of total internal reflection and metal reflection can result in a complete optical absorption[28]. We propose a tunable mid-infrared coherent perfect absorber with a graphene nanoribbon based meta-surface.

Results

Conclusion