Broadband telecom transparency of semiconductor-coated metal nanowires: more transparent than glass

TL;DR

This paper demonstrates that semiconductor-coated metallic nanowires can be made highly transparent in the infrared telecommunications range, outperforming glass, with robustness against fabrication imperfections and various incident angles.

Contribution

It introduces a universal electrostatic law for designing transparent metal-dielectric nanowires, achieving significantly reduced scattering and broad bandwidth in the IR telecom range.

Findings

Scattering efficiency reduced by up to three orders of magnitude.

Transparency robust against polarization and incidence angle variations.

Effective in dense nanowire arrangements.

Abstract

Metallic nanowires (NW) coated with a high permittivity dielectric are proposed as means to strongly reduce the light scattering of the conducting NW, rendering them transparent at infrared wavelengths of interest in telecommunications. Based on a simple, universal law derived from electrostatics arguments, we find appropriate parameters to reduce the scattering efficiency of hybrid metal-dielectric NW by up to three orders of magnitude as compared with the scattering efficiency of the homogeneous metallic NW. We show that metal@dielectric structures are much more robust against fabrication imperfections than analogous dielectric@metal ones. The bandwidth of the transparent region entirely covers the near IR telecommunications range. Although this effect is optimum at normal incidence and for a given polarization, rigorous theoretical and numerical calculations reveal that transparency is robust against changes in polarization and angle of incidence, and also holds for relatively dense periodic or random arrangements. A wealth of applications based on metal-NWs may benefit from such invisibility.