Compact Stereo Waveguide Display Based on a Unidirectional Polarization-Multiplexed Metagrating In-Coupler

Abstract

Three-dimensional (3D) vision in augmented reality (AR) displays can enable highly immersive and realistic viewer experience, hence, attracts much attention. Most current approaches create 3D vision by projecting stereoscopic images to different eyes using two separate projection systems, which are inevitably bulky for wearable devices. Here, we propose a compact stereo waveguide AR display system using a single piece of thin flat glass integrated with a polarization-multiplexed metagrating in-coupler and two diffractive grating out-couplers. Incident light of opposite circular polarization states carrying stereoscopic images are first steered by the metagrating in-coupler to opposite propagation directions in the flat glass waveguide, subsequently extracted by the diffractive grating out-couplers, and finally received by different eyes, forming 3D stereo vision. Experimentally, we fabricated a display prototype and demonstrated independent projection of two polarization-multiplexed stereoscopic images. This work paves a novel path toward the implementation of high-performance stereo displays with compact size, lightweight, and multicolor compatibility.