Dual-band dichroic asymmetric transmission of linearly polarized waves in terahertz chiral metamaterial

Tingting Lv,Jinhui Shi,Zheng Zhu,Chunmei Ouyang,Jiaguang Han,Dongming Liu,Weili Zhang,Xieyu Chen,Shuang Zhang,Guohua Dong,Chunying Guan,Meng Liu,Yuxiang Li

doi:10.1515/nanoph-2019-0507

Abstract

Abstract Polarization conversion dichroism is of particular interest in manipulating the polarization state of light, whereas high-performance asymmetric transmission (AT) of linearly polarized waves is still inaccessible in the terahertz range. Here, a bilayer chiral metamaterial consisting of orthogonally chained S-shaped patterns with broken symmetry along the light propagation direction is proposed and demonstrated experimentally to realize a dual-band dichroic AT effect for linearly polarized terahertz waves. The AT effects are robust across a wide range of incident angles. The observed strong AT can be theoretically explained by a multiple reflection and transmission interference model and the transfer matrix method. The proposed bilayer chiral metamaterial may have broad applications in polarization manipulation, chiral biosensing and direction-dependent information processing.

Highlights

Over the past decades, many attempts have been devoted to manipulating the polarization, phase, amplitude and propagation direction of electromagnetic waves using metamaterials [1,2,3,4,5,6,7,8,9], exploiting their flexible structural designs and potential for compact integrated optical components
Various intriguing phenomena have been reported in metamaterials, including anomalous refraction [4, 5], invisibility [6], ideal Weyl point and surface state [7], optical activity [8, 9], and asymmetric transmission (AT) [10, 11]
Most of them are composed of multilayer coupled resonators with a few exceptions of single layer structures [17, 20]. These findings show that multilayer chiral m etamaterials can greatly increase the polarization conversion and enhance the AT effects

Summary

Introduction

Many attempts have been devoted to manipulating the polarization, phase, amplitude and propagation direction of electromagnetic waves using metamaterials [1,2,3,4,5,6,7,8,9], exploiting their flexible structural designs and potential for compact integrated optical components. The AT phenomenon in a lossy metamaterial refers to the difference in the total transmission intensity between forward and backward propagation directions for linearly or circularly polarized waves. T. Lv et al.: Dual-band dichroic asymmetric transmission of linearly polarized waves nanostructures [14], achiral metamaterial showing extrinsic 2D chirality at oblique incidence [15] and multilayer structures [16].

Results

Conclusion