  Zero-index materials exhibit exotic optical properties that can be utilized
for integrated-optics applications. However, practical implementation requires
compatibility with complementary metallic-oxide-semiconductor (CMOS)
technologies. We demonstrate a CMOS-compatible zero-index metamaterial
consisting of a square array of air holes in a 220-nm-thick
silicon-on-insulator (SOI) wafer. This design is achieved through a Dirac-cone
dispersion. The metamaterial is entirely composed of silicon and offers
compatibility through low-aspect-ratio structures that can be simply fabricated
in a standard device layer. This platform enables mass adoption and exploration
of zero-index-based photonic devices at low cost and high fidelity.

Optics