Preparation and optical properties of porous anodic alumina films with different branched structure

Using a two-step anodization process, the porous anodic alumina (PAA) templates are prepared. During the course of the second-step anodization, the anodization voltage is decreased as 1/(√n)V0, where V0 is the initial voltage. Then PAA with n branches pores is obtained. UV-3101 spectral photometer is used to measure the transmitted spectrum and polarized spectrum of the PAA. The result shows that the PAA with linear pores (n = 1) behaves better transmittance ratio and extinction ratio in the visible and near-infrared waveband than others (n>1). It found that the AAO with linear spectral photometer is a good reference as a kind of template material of wire grid polarizer.