Zero-index material made of silicon pillar arrays embedded in a...

Zero-index material made of silicon pillar arrays embedded in a polymer matrix and clad in gold film.

Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have designed the first on-chip metamaterial with a refractive index of zero, meaning that the phase of light can travel infinitely fast.

(You may find a quick explanation of this effect here)

Credit: Peter Allen, Harvard SEAS

Via Phys.org: To infinity and beyond: Light goes infinitely fast with new on-chip material

Paper (abstract & references), Nature Photonics: On-chip zero-index metamaterials