Wide-Field-of-View Trans-Reflective RGB-Achromatic Metalens for Augmented Reality

Abstract

In recent years, various solutions for augmented reality (AR) head-mounted displays have been proposed. In order to achieve the dual functions of reflective focusing on virtual images and transparency to the real world, the optical design of AR eyepieces is particularly critical. Designs based on traditional optics still face the problems of huge volume and a limited field of view. Due to their extraordinary phase control ability, portability, easy integration, and other advantages, metalenses have triggered extensive research and found many applications, including providing an innovative solution for AR eyepieces. In this work, we propose a single-layer trans-reflective RGB-achromatic metalens with a large field of view of 90°. The metalens reflects the oblique incident virtual image while maintaining balanced transparency of real-world light. Through simulation, the ability of the metalens to focus light at the wavelengths of 488 nm, 532 nm, and 633 nm with the same focal length and balanced efficiency is validated. Moreover, the metalens is polarization-insensitive to the incident light, thus allowing the elimination of the polarization modulation components, which greatly simplifies the optical structure. Our work demonstrates the great potential of metalenses for AR eyepiece applications.