Optical Device Based on a Nanopillar Array by the Pattern Transfer of an Anodic Aluminum Oxide Membrane.

A simple and convenient nanofabrication method is proposed to achieve nanopillar arrays by the pattern transfer of an anodic aluminum oxide membrane, profiting from the rapid and efficient preparation process and regular hexagonal lattice patterns of the anodic aluminum oxide template. The taper angle of the nanopillar is affected by the distribution of the vapor particles during the deposition process, which is highly dependent on the material and deposition power. Based on this method, a novel scheme employing aluminum nanopillar arrays is demonstrated to realize the color tuning feature by simply varying the thickness of the top dielectric layer within a large range. The nanopillar arrays are completely covered by the thick dielectric layer atop due to the great conformality of the atomic layer deposition method that is used for the dielectric deposition. In addition, the color devices present good angular insensitivity up to 45°, resulting from the excited localized surface plasmon resonance within the metallic patches. The simple fabrication method is of great advantage to produce periodic nanostructures over large areas, which are widely used in designs and verifications of optical metasurfaces for various applications, including optical communication, imaging, sensing, and so forth.