The metamaterial consists of an array of silicon pillars embedded in a polymer matrix and clad in gold film. It can couple to silicon waveguides to interface with standard integrated photonic components and chips.
Professor Eric Mazur said: “Light doesn’t typically like to be squeezed or manipulated, but this metamaterial permits you to manipulate light from one chip to another, to squeeze, bend, twist and reduce the diameter of a beam from the macroscale to the nanoscale. It’s a remarkable new way to manipulate light.”
While nothing travels faster than light, its phase velocity – how quickly the crests of the wave move – increases or decreases, depending on the material it’s moving through. When light passes through water, its phase velocity is reduced. Once it exits the water, its phase velocity increases again. The higher the refraction index, the more the material interferes with the propagation of the wave crests of light. When the refraction index is reduced to zero, ‘really weird and interesting things start to happen’, said the team.
A zero-index material that fits on a chip could have exciting applications, the team noted, especially in the world of quantum computing. Postdoctoral fellow Yang Li added: “This zero-index metamaterial offers a solution for the confinement of electromagnetic energy in different waveguide configurations because its high internal phase velocity produces full transmission, regardless of how the material is configured.”
