  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.
