Extraordinary optical transmission and vortex excitation by periodic arrays of Fresnel zone plates

TL;DR

This paper demonstrates how a periodic array of Fresnel zone plates can achieve extraordinary optical transmission, focus light effectively, and generate optical vortices, with potential applications in nanoparticle manipulation.

Contribution

It introduces a novel two-dimensional structure of Fresnel zone plates arranged periodically, enabling enhanced optical transmission, focusing, and vortex excitation.

Findings

High field concentration at the focal plane

Effective optical vortex excitation observed

Potential for nanoparticle manipulation

Abstract

Extraordinary optical transmission and good focusing properties of a two-dimensional scattering structure is presented. The structure is made of Fresnel zone plates periodically arranged along two orthogonal directions. Each plate consists of two ring-shaped waveguides supporting modes that match the symmetry of a circularly polarized incident plane wave. High field concentration at the focal plane is obtained with short transverse and long longitudinal foci diameters. Optical vortex excitation in a paraxial region of the transmitted field is also observed and analysed in terms of cross-polarisation coupling. The structure presented may appear useful in visualization, trapping and precise manipulations of nanoparticles.