Freely-suspended matrix-free metamaterials showing THz left-handed pass bands

TL;DR

This paper presents the development of large-area, freely-suspended matrix-free THz metamaterials with left-handed passbands, overcoming previous limitations of embedding in matrices and enabling easier handling and tunability.

Contribution

The authors introduce the first freely-suspended, matrix-free metallic metamaterials with large areas and THz passbands, fabricated via UV/X-ray lithography, enhancing practicality and tunability.

Findings

Left-handed passbands from 1.6 to 2.2 THz identified

Metamaterials are easily handled due to their size

Devices are tunable and two-dimensionally isotropic

Abstract

Featuring dense spatial distributions of engineered metallic particles, electromagnetic metamaterials exhibit simultaneously negative values of both, dielectric permittivity and magnetic permeability, within a resonance frequency band called left-handed passband. Unusual electromagnetic properties are found resulting in promising applications such as sub-wavelength resolution imaging. State-of-the-art micro/nanomanufacturing has led to resonance frequencies reaching the visible red. The common embedding of the metal particles in plastic matrices or deposition on dielectric substrates within a small area severely limits the usefulness of the materials. Here, we use UV or X-ray lithography to build comparably large areas and quantities of the first freely-suspended matrix-free metamaterials in which the metallic structures are S-string-like with their ends held by a window-frame. In vacuo spectral characterization combined with simulation reveals left-handed passbands from 1.6 to 2.2 THz. Owing to their size, the devices can be easily handled. They offer a straightforward way of making them tunable and two-dimensionally isotropic.