GaAs Linear Polarizer with a High Extinction Ratio for Extended Short-Wave Infrared Detection

Metasurfaces have shown an unprecedented ability to modulate electromagnetic waves at subwavelength scales, especially polarized optical metasurfaces, applied for imaging, navigation and detection. In this work, a kind of efficient all-dielectric diatomic metasurface for polarization and phase changing, consisting of a pair of GaAs nanopillar and nanocube, is proposed. By adjusting the unit cell structural parameters, the polarization state can be controlled and adjusted at the short-wave infrared (SWIR) band (1~3 μm). At the wavelength of 2125 nm, the maximum transmission efficiency, the extinction ratio and the linear polarization degree can reach 93.76%, 40.99 dB and 0.99, respectively. Overall, this all-dielectric diatomic metasurface has broad application potential in extended SWIR polarization detection.