Obliquely deposited metal films for polarizers

The performance of obliquely deposited metal films as polarizers, which can be used for normally incident light, was improved. The relation between microscopic columnar structures and dichroism of the films was investigated by depositing various kinds of metals with changing deposition angles. The influence of substrate materials was also examined. It was revealed that enlargement of the spacing between the neighboring columns is the most significant to attain a good extinction ratio and a low insertion loss. For the best performance, transmittances for p-polarization and s-polarization of 50% and 1%, respectively, at a wavelength of 681 nm were attained by depositing Al on poly(methyl-methacrylate) substrates at a deposition angle of 87°.