Influence of titanium on the light transmittance through a nano-aperture

The Al-coated-oxide pyramids have been fabricated with and without Ti wetting layer. The nano-size aperture surrounded by the periodic structure on the fabricated oxide pyramid has been fabricated using focused ion beam milling system. The significantly reduced light transmittance from the Al metal aperture with Ti wetting layer have been measured, and compared it with the sample without Ti layer. This can be the evidence for surface plasmon polariton contribution to the enhancement of light transmittance through the metallic subwavelength size aperture in the visible range.