Single-Layer Full-Color Waveguide Display Based on a Broadband Efficient Meta-Grating

TL;DR

This paper introduces a new AR display using meta-gratings to achieve high efficiency and full-color performance in a single-layer design.

Contribution

A monolithic, full-color AR display with high efficiency using meta-grating in-coupler and out-coupler on a single substrate.

Findings

Meta-gratings achieved over 60% coupling efficiency for red, green, and blue wavelengths.

Prototype demonstrated high efficiency and color-enhanced imaging in a large field of view.

System enables monolithic trichromatic operation with a single-layer optical waveguide.

Abstract

Augmented reality (AR) displays are pivotal for delivering immersive experiences in the metaverse, thus driving significant research interest. Current AR systems, predominantly relying on diffraction principles, often suffer from low efficiency and face challenges in realizing monolithic full-color operation. Herein, we propose an AR system that integrates a broadband and highly efficient meta-grating in-coupler and an elliptical meta-grating out-coupler onto a single thin glass substrate. The meta-gratings, with unique nanostructures, enable coupling efficiency exceeding 60% for red (R), green (G), and blue (B) wavelengths across the entire field of view (FOV). Image-bearing light is first coupled into a single-layer optical waveguide via the meta-grating, then undergoes two-dimensional expansion through the elliptical meta-grating, and is ultimately coupled into the human eye to form a large AR FOV. Experimentally, we fabricated an optical waveguide prototype and validated the system’s high efficiency and color-enhanced imaging capabilities. This work advances the development of monolithic, trichromatic, highly efficient, and large FOV AR displays based on meta-grating technology.

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