Anisotropic optical loss and birefringence of anodized alumina film

Anodicallyoxidized alumina has been investigated theoretically and experimentally concerning the anisotropy of its optical loss and refractive index. When the pores in the alumina film are filled with metallic materials, the film yields anisotropy of the optical loss and consequently acts as a polarizer. However, the film acts as a retardation plate when the pores are filled with suitable dielectric materials. It has been demonstrated that the anodized alumina offers efficient optical elements throughout the wide spectral range from the visible to the infrared.