Graphene-Based THz Absorber with a Broad Band for Tuning the Absorption Rate and a Narrow Band for Tuning the Absorbing Frequency.

Qihui Zhou,Song Zha,Yuandong Zhou,Peiguo Liu,Chenxi Liu

doi:10.3390/nano9081138

Qihui Zhou, Song Zha + Show 3 more

Open Access

https://doi.org/10.3390/nano9081138

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Journal: Nanomaterials	Publication Date: Aug 8, 2019
Citations: 23	License type: CC BY 4.0

Affiliation: National University of Defense Technology

Abstract

In this paper, we propose a broadband absorption-controllable absorber based on nested nanostructure graphene and a narrowband frequency-tunable absorber utilizing gold-graphene hybrid structure in the terahertz regime. The numerical simulation results showed that the absorption of the broadband absorber can be changed from 27% to more than 90% over 0.75 to 1.7 THz by regulating the chemical potential of graphene. With the same regulation mechanism, the absorbing peak of the narrowband absorber can be moved from 2.29 to 2.48 THz continuously with absorption of 90%. Furthermore, via the cascade of the two types of absorbers, an independently tunable dual-band absorber is constituted. Its absorption spectrum is the superposition of absorption-controllable absorber and frequency-tunable absorber. The absorptivity and operating frequency of the two absorbing bands can be tuned independently without mutual inference. Moreover, it is insensitive to the polarization and it maintains high absorption over a wide range of incident angle. For the flexibility, tunability as well as the independence of polarization and angle, this design has wide prospects in various applications.

Highlights

In recent years, terahertz (THz) wave, lying between the microwaves and infrared light in the electromagnetic spectrum, has attracted great attention of researchers for its potential applications in communication, imaging, sensing, spectroscopy, etc. [1,2,3,4]
A monolayer of carbon atoms arranged in a honeycomb lattice, is an ideal candidate to design absorbers due to its remarkable mechanical properties, high carrier mobility, flexibility, and the ability to support localized surface plasmon resonance [9,10,11]
The surface conductivity of graphene can be continuously tuned by regulating the chemical potential via electrostatic doping [12,13]

Summary

Introduction

Terahertz (THz) wave, lying between the microwaves and infrared light in the electromagnetic spectrum, has attracted great attention of researchers for its potential applications in communication, imaging, sensing, spectroscopy, etc. [1,2,3,4]. The surface conductivity of graphene can be continuously tuned by regulating the chemical potential via electrostatic doping [12,13]. We propose a dual-band THz graphene absorber with a broad absorption-controllable band and a narrow frequency-tunable band using the cascade method.

Results

Conclusion