Chip-Integrated Metasurface-GaAsSb Nanowire Array Photodetectors for Single-Pixel Polarimetric Imaging

Polarization-sensitive photodetectors can enhance the capability of target recognition in intelligent driving, security monitoring, and biomedical diagnostics. However, miniaturizing such devices to subwavelength scales introduces a fundamental trade-off between light absorption efficiency and polarization extinction ratio. To address this, we integrate ultrathin metasurface polarization filter arrays (MPFAs) onto GaAsSb nanowire (NW) array photodetectors. The GaAsSb NW array geometry was designed and optimized for 93.5% average absorption across a broad wavelength range from 660 to 840 nm, to exhibit a high photodetector peak responsivity of 2.0 A W⁻¹ and a specific detectivity of 4.3×10¹⁰ cm•√Hz W⁻¹ under a low bias voltage of 1 V. The L-shaped silver nanohole MPFA was designed and fabricated via focused ion beam, generating strong polarization-selective plasmonic resonance in the near-infrared region. This leads to the demonstration of an integrated device with a linear polarization extinction ratio of 3.5 and good device performance (peak responsivity of 1.5 A W⁻¹ and detectivity of 2.3×10¹⁰ cm•√Hz W⁻¹), enabling high-resolution single-pixel polarimetric imaging. The direct metasurface/III-V semiconductor NW array integration strategy provides a new route toward next-generation ultra-compact, high-performance polarimetric infrared imaging systems covering a broad spectrum from the near- to mid-wave infrared for diverse applications.