Manipulation of polarization and spatial properties of light beams with chiral metafilms

TL;DR

This paper demonstrates how chiral nanohole lattices in plasmonic films can effectively manipulate light's polarization and spatial properties, enabling advanced optical device functionalities.

Contribution

It introduces a novel design of chiral metafilms that achieve polarization conversion and circular dichroism through electromagnetic simulations, revealing tunable optical effects.

Findings

Effective polarization conversion demonstrated

Strong circular dichroism in diffraction orders

Manipulation of effects via wavelength and structural parameters

Abstract

Two-dimensional lattices of chiral nanoholes in a plasmonic film with lattice constants being slightly larger than light wavelength are proposed for effective control of polarization and spatial properties of light beams. Effective polarization conversion and strong circular dichroism in non-zero diffraction orders in these chiral metafilms are demonstrated by electromagnetic simulations. These interesting effects are found to result from interplay between radiation pattern of single chiral nanohole and diffraction pattern of the planar lattice, and can be manipulated by varying wavelength and polarization of incoming light as well as period of metastructure and refractive indexes of substrate and overlayer. Therefore, this work offers a novel paradigm for developing planar chiral metafilm-based optical devices with controllable polarization state, spatial orientation and intensity of outgoing light.