42.4: Compact Stereo Waveguide Display Using a Polarization‐Multiplexed In‐coupling Metagrating

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 visions 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 to opposite propagation directions in the flat glass waveguide, subsequently extracted by the diffractive gratings 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 towards the implementation of high‐performance stereo displays with compact size, light weight, and multi‐color compatibility.