Three-tiered Au nano-disk array for broadband interaction with light.

We demonstrate a straightforward method to enlarge the spectral window for broadband interaction with light, by creating a plasmonic nanostructure composed of closely spaced multiple Au nano-disks. The vertically stacked, Au nano-disks of three different sizes make it possible to merge the individual spectral windows of the internal nano-disks into one broadband window, and can be simply generated by a single-step electron-beam lithography step with subsequent sputter deposition.