Negative-index bi-anisotropic photonic metamaterial fabricated by direct laser writing and silver shadow evaporation

TL;DR

This paper introduces a new negative-index bi-anisotropic photonic metamaterial fabricated using advanced laser writing and silver evaporation, demonstrating negative refractive index at mid-infrared wavelengths with good experimental-theoretical agreement.

Contribution

The work presents a novel fabrication method for a negative-index bi-anisotropic metamaterial with experimental validation of its optical properties.

Findings

Negative real part of refractive index at 3.85 micrometers

Good agreement between measured spectra and theoretical predictions

Successful fabrication of a bi-anisotropic negative-index metamaterial

Abstract

We present the blueprint for a novel negative-index metamaterial. This structure is fabricated via three-dimensional two-photon direct laser writing and silver shadow evaporation. The comparison of measured linear optical spectra with theory shows good agreement and reveals a negative real part of the refractive index at around 3.85 micrometer wavelength - despite the fact that the metamaterial structure is bi-anisotropic due to the lack of inversion symmetry along its surface normal.