Broad Ion Beam Processing for Scalable Manufacturing of Blazed Gratings for AR Waveguides

As Augmented Reality devices move toward widespread adoption, waveguide optics face increasing demands for optical efficiency, image uniformity, reduced stray light, and manufacturing scalability. Blazed Surface Relief Gratings (SRGs) have emerged as an attractive waveguide coupling technology due to their ability to direct light efficiently into selected diffraction orders. However, achieving the required profile accuracy, wafer-scale uniformity, and optical surface quality simultaneously remains a significant manufacturing challenge.

Abstract

Broad Ion Beam Processing for Scalable Manufacturing of Blazed Gratings for AR Waveguides

Dr Paulo Lima, Oxford Instruments Plasma Technology

In this presentation, you will discover a Broad Ion Beam processing approach for the fabrication and finishing of blazed gratings for AR waveguides. The process combines controlled profile formation with precision ion beam surface finishing to address two critical requirements for next-generation waveguide manufacturing: accurate diffraction geometry and optical quality surfaces. Blazed gratings fabricated on 200 mm SiO₂ wafers demonstrated blaze angle uniformity within ±1.5° across the wafer and etch depth uniformity of 4%. A subsequent ion beam finishing step reduced facet roughness from 2.66 nm Ra to 0.54 nm Ra while preserving the blaze profile and apex geometry. The results demonstrate a practical route to wafer scale fabrication of high-performance blazed gratings and highlight the role of Broad Ion Beam technology as an enabling process for both research and development and high-volume manufacturing of Augmented Reality optics.