A new artificial material approach for flat THz frequency lenses

TL;DR

This paper introduces a novel method for creating flat THz lenses using spatially graded metal mesh layers embedded in dielectric substrates, enabling the fabrication of thin, flat, and tunable optical devices.

Contribution

It demonstrates a new approach to manufacturing graded index lenses at THz frequencies by spatially grading metal mesh geometries within a dielectric substrate.

Findings

Prototype lens achieved a Woods type parabolic profile.

The technique allows for the creation of flat, tunable THz lenses.

Potential to realize other exotic optical devices.

Abstract

Stacked layers of metal meshes embedded in a dielectric substrate are routinely used for providing spectral selection at THz frequencies. Recent work has shown that particular geometries allow the refractive index to be tuned to produce practical artificial materials. Here we show that by spatially grading in the plane of the mesh we can manufacture a Graded Index (GrIn) thin flat lens optimized for use at THz frequencies. Measurements on a prototype lens show we are able to obtain the parabolic profile of a Woods type lens which is dependent only on the mesh parameters. This technique could realize other exotic optical devices.