Breaking the in-coupling efficiency limit in waveguide-based AR displays with polarization volume gratings

Yuqiang Ding; Yuchen Gu; Qian Yang; Zhiyong Yang; Yuge Huang; Yishi Weng; Yuning Zhang; Shin-Tson Wu

doi:10.1038/s41377-024-01537-8

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Breaking the in-coupling efficiency limit in waveguide-based AR displays with polarization volume gratings

Original Articles

- Breaking the in-coupling efficiency limit in waveguide-based AR displays with polarization volume gratings
- Light: Science & Applications Vol. 13, Issue 9, Pages: 1919-1930(2024)
- Affiliations：
  
  1.College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA
  2.Joint International Research Laboratory of Information Display and Visualization, Southeast University, Nanjing 210096, China
  3.Meta Reality Labs Research, 9845 Willows Road NE, Redmond, WA 98052, USA
- Author bio：
  
  Yuning Zhang (zyn@seu.edu.cn)
  Shin-Tson Wu (swu@creol.ucf.edu)
- Funds：
- DOI：10.1038/s41377-024-01537-8
  CLC：
- Received：25 April 2024，
  
  Revised：16 July 2024，
  
  Accepted：2024-07-16，
  
  Published Online：12 August 2024，
  
  Published：30 September 2024
- Accepted：
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Ding, Y. Q. et al. Breaking the in-coupling efficiency limit in waveguide-based AR displays with polarization volume gratings. Light: Science & Applications, 13, 1919-1930 (2024).
DOI：

Ding, Y. Q. et al. Breaking the in-coupling efficiency limit in waveguide-based AR displays with polarization volume gratings. Light: Science & Applications, 13, 1919-1930 (2024). DOI： 10.1038/s41377-024-01537-8.

摘要

Abstract

Augmented reality (AR) displays

heralded as the next-generation platform for spatial computing

metaverse

and digital twins

empower users to perceive digital images overlaid with real-world environment

fostering a deeper level of human-digital interactions. With the rapid evolution of couplers

waveguide-based AR displays have streamlined the entire system

boasting a slim form factor and high optical performance. However

challenges persist in the waveguide combiner

including low optical efficiency and poor image uniformity

significantly hindering the long-term usage and user experience. In this paper

we first analyze the root causes of the low optical efficiency and poor uniformity in waveguide-based AR displays. We then discover and elucidate an anomalous polarization conversion phenomenon inherent to polarization volume gratings (PVGs) when the incident light direction does not satisfy the Bragg condition. This new property is effectively leveraged to circumvent the tradeoff between in-coupling efficiency and eyebox uniformity. Through feasibility demonstration experiments

we measure the light leakage in multiple PVGs with varying thicknesses using a laser source and a liquid-crystal-on-silicon light engine. The experiment corroborates the polarization conversion phenomenon

and the results align with simulation well. To explore the potential of such a polarization conversion phenomenon further

we design and simulate a waveguide display with a 50° field of view. Through achieving first-order polarization conversion in a PVG

the in-coupling efficiency and uniformity are improved by 2 times and 2.3 times

respectively

compared to conventional couplers. This groundbreaking discovery holds immense potential for revolutionizing next-generation waveguide-based AR displays

promising a higher efficiency and superior image uniformity.

关键词

Keywords

references

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