Efficient multiband and broadband cross polarization converters based on slotted L-shaped nanoantennas.

Jun Ding,Jin Shao,Han Ren,Mi Zhou,Bayaner Arigong,Yuankun Lin,Hualiang Zhang

doi:10.1364/oe.22.029143

Abstract

In this paper, we presented highly efficient reflective cross polarization converters based on metamaterials operating in the infrared regime, which are composed of a dielectric spacer sandwiched between slotted L-shaped metallic nanoantennas and a ground plane. The proposed polarization converters can convert a linearly polarized wave to its cross polarized wave with high polarization conversion ratio (> 0.95) over multiple / broad frequency bands. The resulting multi-band and broadband operations are induced by the localized mode hybridizations between the slot and the original metallic nanoantenna. Furthermore, the performance of the proposed converters under different incident angles is also explored. It is found that the first broad band (or the first two resonant frequencies) of the proposed broadband (or multi-band) converters appears to be independent of the incident angle (up to 47°).

Highlights

Manipulation of the polarization state of electromagnetic (EM) waves and light is of practical importance in many optical systems as many phenomena are polarization sensitive in optics
Various designs of polarizers and wave plates have been achieved through anisotropic and chiral metamaterials structural simplicity and easy fabrication
These results show that the proposed cross polarization converters (CPC) with L-shaped slots appears to be independent of the incidence angle at the first two resonant frequencies of the triple-band CPC and the first broad band of the broadband CPC, which could be the result of the hybridization of the localized resonant modes from the slot and the metallic nanoantenna

Summary

Introduction

Manipulation of the polarization state of electromagnetic (EM) waves and light is of practical importance in many optical systems as many phenomena are polarization sensitive in optics. Researchers have found that the strong polarization dependence working from microwave and terahertz to optical frequency regimes, such as metallic nanoparticles [6,7,8,9,10,11,12,13], subwavelength metallic apertures [14,15,16], and threedimensional chiral metamaterials [17,18]. Among these designs, L-shaped and V-shaped metallic nanoparticles and apertures are widely adopted due to the structural simplicity and easy fabrication. The proposed CPCs feature both flexible properties (e.g., multiband operations) and high conversion efficiency, making them attractive for practical applications

Design

Results and discussions

Conclusions