Thickness control of porous alumina membranes and observation of their optical transmittance

Porous alumina with a uniform nanopore array has attracted much attention because of its versatile applications in nanowire growth templates, plasmon pattern formation, and nano-filter membranes. In this study, through two anodization processes we generated porous alumina membranes having a uniform channel ngth and a uniform hole diameter. The thicknesses of the porous alumina membranes were controlled by using different anodization times. The optical transmittances were measured and compared for membranes with different thicknesses. The transmittance at a specific wavelength changed with the membrane's thickness.