Design and Fabrication of Bilayer Wire Grid Polarizer Using Ultraviolet Replicated Nanograting against Nickel Electroformed Nanostamp

A bilayer wire grid polarizer (B-WGP) composed of UV-replicated nanograting and deposited aluminum layer was designed, fabricated, and evaluated as a simpler and less costly reflective polarizer. To design the B-WGP structure, a parametric study of structural design factors on the simulated performance was conducted using rigorous coupled wave analysis. A durable electroformed nickel stamp was fabricated using a lithographed photo resist master pattern having a nanograting with a pitch of 110 nm, a line width of 65 nm, and a height of 80 nm. A polymer grating was fabricated by the UV replication process, and an aluminum layer with a thickness of 50 nm was deposited by electron-beam evaporation. To examine the performance of the fabricated bilayer wire-grid polarizer, the transmission spectra of p- and s-polarized light, and the extinction ratio spectra were measured and compared with the simulated values. The measured transmittance of p-polarized light and the extinction ratio of the fabricated bilayer wire grid polarizer were ${\sim}40$% and ${\sim}10^{3}$ in whole visible ranges, respectively.