Polarization-Tuned Fano Resonances in All-Dielectric Short-Wave Infrared Metasurface

TL;DR

This paper presents a silicon-based metasurface operating in the SWIR range that uses polarization control to tune Fano resonances, enabling advanced sensing and light manipulation.

Contribution

It introduces a novel all-dielectric silicon metasurface platform for polarization-induced Fano resonance control at SWIR frequencies.

Findings

Reflectance can be engineered via polarization tuning due to Fano resonances.

The metasurface enables sharp, polarization-modulated resonances.

Nanosensors demonstrate detection of 1% refractive index changes.

Abstract

The short-wave infrared (SWIR) is an underexploited portion of the electromagnetic spectrum in metasurface-based nanophotonics despite its strategic importance in sensing and imaging applications. This is mainly attributed to the lack of material systems to tailor light-matter interactions in this range. Herein, we address this limitation and demonstrate an all-dielectric silicon-integrated metasurface enabling polarization-induced Fano resonance control at SWIR frequencies. The platform consists of a two-dimensional Si/GeSn core/shell nanowire array on a silicon wafer. By tuning the light polarization, we show that the metasurface reflectance can be efficiently engineered due to Fano resonances emerging from the electric and magnetic dipoles competition. The interference of optically induced dipoles in high-index nanowire arrays offers additional degrees of freedom to tailor the directional scattering and the flow of light while enabling sharp polarization-modulated resonances. This tunability is harnessed in nanosensors yielding an efficient detection of 10^{-2} changes in the refractive index of the surrounding medium.