Monolithic CMOS-compatible zero-index metamaterials

TL;DR

This paper presents a CMOS-compatible zero-index metamaterial made of silicon with a simple fabrication process, enabling practical integrated photonic devices with exotic optical properties.

Contribution

The authors demonstrate a novel zero-index metamaterial using a silicon-based design compatible with standard CMOS fabrication processes.

Findings

Achieved a zero-index metamaterial with Dirac-cone dispersion in silicon-on-insulator wafers.

Designed a low-aspect-ratio structure suitable for mass production.

Enabled potential for low-cost, high-fidelity zero-index photonic devices.

Abstract

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.