Modeling and imprint fabrication of an infrared wire-grid polarizer with an antireflection grating structure

•We fabricated an infrared wire-grid polarizer with an antireflection grating structure using direct imprint lithography on a chalcogenide glass.•We formed the Al grating (0.7 fill factor, 100 nm thickness, and 500 nm period) by depositing Al obliquely on the grating.•The transverse magnetic transmittance of the fabricated polarizer was over 70% in the 8.5–10.5 μm wavelength range.•The TE transmittance of the fabricated element was around 1% in the 2.5−12 μm wavelength range.

An infrared wire-grid polarizer with an antireflection (AR) grating structure was fabricated using direct imprint lithography on both sides of a low toxicity chalcogenide glass (Sb–Ge–Sn–S system) simultaneously. The AR grating structure was designed using rigorous coupled-wave analysis theory. Silicon carbide with a grating period of 500 nm and glassy carbon with a grating period of 3 μm were employed as molds. After imprinting, a wire-grid polarizer was made by depositing Al obliquely on the grating. The transverse magnetic (TM) transmittance of the fabricated polarizer was over 70% at 8.5–10.5 μm wavelength, although the transmittance of the glass substrate is 62–66%, and the extinction ratio was over 20 dB at 11 μm wavelength. The polarizer has a high TM transmittance and is cheaper and simpler to fabricate as compared with conventional infrared polarizers.