Large-area flexible infrared nanowire grid polarizer fabricated using nanoimprint lithography

We fabricated a 4-in large-area flexible infrared nanowire grid polarizer using a nanoimprint and metal thermal evaporation process. To protect the Si master template, as well as to prolong the service life of it, we first fabricated a nickel template as an alternative by an electroforming process. Then, the nanowire grid structure was transferred from this template to IPS substrate by a thermal nanoimprint process. Finally, Al was deposited on the IPS nanowire structure by vertical thermal evaporation technology. The results of the infrared optical test reveal that the TM transmittance of the polarizer is greater than 60% in the 4-5.71 μm and 5.73-6.7 μm wavelength ranges, and, especially, it is greater than 70% in the wavelength ranges of 4.70-5.69 μm and 5.75-6.59 μm. The extinction ratio is more than 20 dB in the wavelength range of 3.6-6.7 μm, proving that the polarizer has good polarization characteristics. The flexible infrared nanowire grid polarizer has potential applications in the fields of curved surface monitoring equipment and polarized imaging equipment.