Circular Polarizer Realized by a Single Layer of Planar Chiral Metallic Nanostructure

TL;DR

This paper introduces a novel, high-efficiency circular polarizer made from a single layer of planar chiral metallic nanostructure, enabling easier fabrication and integration for optical and electromagnetic applications.

Contribution

It demonstrates, for the first time, that a single-layer 2D chiral structure can function as an effective circular polarizer through unidirectional polarization conversion.

Findings

Achieved high-efficiency circular polarization with a planar 2D chiral nanostructure.

Validated the concept experimentally and theoretically.

Applicable to visible, Terahertz, and microwave regimes.

Abstract

As a basic optical element, circular polarizer plays significant roles in signal transmission, measurements and life science microscopy. Three-dimensional (3D) chiral structures have been thought to be necessary to realize circular polarizers. Here we demonstrate theoretically and experimentally for the first time that a high-efficiency circular polarizer could be realized by a single layer of planar 2D chiral structure. Our proposed circular polarizer is based on unidirectional polarization conversion instead of circular polarization stop bands. Since two-dimensional planar structures present obvious advantage for fabrication and integration on chip, the proposed circular polarizer is of great interest in integrated optics and microscopy. It provides a novel scheme to manipulate polarizations of light wave, as well as Terahertz wave and microwave.