Fabrication of a bilayer wire grid polarizer in the near infrared wavelength region by using a UV curing nanoimprinting method

Abstract

In this study, we have designed and fabricated an Al bilayer wire grid polarizer (B-WGP) in the near-infrared wavelength region. A finite difference time domain method was employed to design and analyze the subwavelength B-WGP with a period of 450 nm, a grating height of 150 nm, and a duty cycle of 0.5. The high polarization extinction ratio of 1200 indicates that the B-WGP may be used as a normal incidence polarization beam splitter. A subwavelength polymer pattern was fabricated by using an UV curing nanoimprinting method, and an Al thin film was deposited by using a thermal evaporation method. The experimental results show that the transmittance of the TM-wave of the B-WGP is over 50% at wavelengths in the range 1000 similar to 2000 nm wavelength while the transmittance of the TE-wave is less than 1%, and that the polarization extinction ratio 250. The discrepancies between the simulated and the experimental results are discussed.