Scalable Wafer-Level Fabrication of Slanted TiO2 Gratings for Directional Visible Light Control

Abstract

Slanted TiO₂ gratings serve as key couplers enabling high-efficiency, large-angle diffraction in augmented reality (AR) diffractive optical waveguide systems, thereby supporting compact and transparent display integration. However, fabrication challenges and high production costs have hindered their scalability. Here, we demonstrate a streamlined and high-fidelity pattern transfer framework, integrating interference lithography, nanoimprint lithography, inductively coupled plasma etching, and reactive ion beam etching. This framework enables one-step pattern replication and precise angular control across wafer-scale areas. An experimental demonstration of the slanted TiO₂ grating confirms high structural fidelity and effective phase modulation, enabling efficient directional light steering toward desired diffraction orders. Our work offers a practical and scalable fabrication strategy for implementing slanted TiO₂ gratings in AR systems, advancing their feasibility for large-scale integration and commercial deployment.