Self-Assembly Revolutionizes Metamaterial Manufacture� - Technology Review: "The technique is surprisingly simple. These guys take a handful of polystyrene balls just a few hundred nanometers in diameter and spread them onto a flat gold surface where they naturally self assemble into a hexagonal array with few, if any, defects.
This array then serves as a template for the metamaterial. Using a series of steps in which the surface is covered in masks and then etched, the team create a thin slab consisting of a gold-silicon oxide-gold sandwich. However, this slab is punctured by a hexagonal array of holes that correspond to the position of the polystyrene beads.
This slab, say Lodewijks and co, is a negative refractive index material that operates in the near infrared region. And the operating wavelength is simple to change by altering the diameter of the beads, which in turn changes the size of the holes."