High-Performance Asymmetric Optical Transmission Based on a Dielectric-Metal Metasurface.

Wenbing Liu,Wei Hong,Chenkai Xie,Jifei Ding,Yi Luo,Lirong Huang

doi:10.3390/nano11092410

Abstract

Asymmetric optical transmission plays a key role in many optical systems. In this work, we propose and numerically demonstrate a dielectric–metal metasurface that can achieve high-performance asymmetric transmission for linearly polarized light in the near-infrared region. Most notably, it supports a forward transmittance peak (with a transmittance of 0.70) and a backward transmittance dip (with a transmittance of 0.07) at the same wavelength of 922 nm, which significantly enhances operation bandwidth and the contrast ratio between forward and backward transmittances. Mechanism analyses reveal that the forward transmittance peak is caused by the unidirectional excitation of surface plasmon polaritons and the first Kerker condition, whereas the backward transmittance dip is due to reflection from the metal film and a strong toroidal dipole response. Our work provides an alternative and simple way to obtain high-performance asymmetric transmission devices.

Highlights

Asymmetric optical transmission refers to different transmittance responses when a beam of light passes through a medium in forward and backward directions
Periodic boundary conditions are applied in the x- and tions, and a perfectly matched layer condition is applied in the z-direction
The thin metal layer is gold, and constants are taken from Johnson and Christy data, which can be obtained in the its dielectric constants are taken from Johnson and Christy data, which can be obtained material database from the simulation software

Summary

Introduction

Asymmetric optical transmission refers to different transmittance responses when a beam of light passes through a medium in forward and backward directions. Various AT devices based on artificial structures have been proposed which use photonic crystals [19,20], subwavelength asymmetric gratings [21,22,23,24], chiral metamaterials [25,26,27] and metasurfaces [28,29,30], and the operation wavelengths have been covered from microwave to visible light [31,32,33]. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

Methods

Results

Conclusion