Polarizer Made of Anodic Alumina Film

A theoretical evaluation has been made of the optical loss of anodic alumina film with implanted metal columns. It has been shown that micro-columns arranged in the alumina film give rise to an optical loss that strongly depends on the direction of polarization, exhibit a prominent anisotropy in the optical loss near the infrared wavelength. The porous alumina film was prepared by anodizing aluminum, and then silver was electrodeposited into pores of alumina film by using alternating current. Silver nanowires are parallel to each other in the pores of the alumina film. Spectrophotometer measurements show that anodic alumina film with silver nanowire arrays has an excellent polarization property in near infrared region. An extinction ratio of 30 dB and average insertion loss of 0.8 dB in the wavelength range 1-2.2 mum were obtained. The anodic alumina film with silver nanowires can be used as a novel polarizer