A Tunable “Ancient Coin”-Type Perfect Absorber with High Refractive Index Sensitivity and Good Angular Polarization Tolerance

Hao Luo,Yougen Yi,Shubo Cheng,Qianyi Shangguan,Zhizhong Li,Yinting Yi

doi:10.3390/coatings11070814

Abstract

In this paper, we design and present a graphene-based “ancient coin”-type dual-band perfect metamaterial absorber, which is composed of a silver layer, silicon dioxide layer, and a top “ancient coin” graphene layer. The absorption performance of the absorber is affected by the hollowed-out square in the center of the graphene layer and geometric parameters of the remaining nano disk. The optical properties of graphene can be changed by adjusting the voltage, to control the absorption performance of the absorber dynamically. In addition, the centrally symmetric pattern structure greatly eliminates the polarization angle dependence of our proposed absorber, and it exhibits good angular polarization tolerance. Furthermore, the proposed “ancient coin”-type absorber shows great application potential as a sensor or detector in biopharmaceutical, optical imaging, and other fields due to its strong tunability and high refractive index sensitivity.

Highlights

The concept of metamaterials (MMs) was first proposed by Rodger M
Compared with the single-band absorption metamaterial absorber proposed by Huang et al [62], the “ancient coin”-type absorber we proposed showed two Coatings 2021, 11, 814 absorption modes
As for the “ancient coin” structure we proposed, as shown in Figure 2c, it has two perfect absorption peaks at λ1 = 22.53 μm and λ2 = 71.98 μm, and the absorption efficiency reaches 99.74% and 99.90%, which is very close to 100%

Summary

Introduction

The concept of metamaterials (MMs) was first proposed by Rodger M. The peculiar electromagnetic properties of metamaterials have not been found in natural materials and traditional composite materials [9,10,11,12], for example, backward waves and negative refractive index [13,14,15]. Based on these excellent optical and electromagnetic properties of metamaterials, researchers have expanded many applications of metamaterials, such as perfect lenses, stealth, photovoltaic solar cells, and absorbers [16,17,18]

Methods

Results

Conclusion