2D Pupil Expansion Full-Color Volume Holographic Waveguide AR Display

In this study, we developed and optimized a dual-layer 2D pupil expansion full-color volume holographic waveguide (2D-FVHW) for use in an augmented reality (AR) near-eye display (NED) system. We designed a dual-layer structure: one layer features a mixed red-green grating for the 639 and 532 nm channels, while the other layer is dedicated to the 457 nm blue channel. A novel exposure method utilizing monotonic progressive diffractive efficiency is proposed to address issues related to brightness uniformity and color uniformity. This approach not only enhances brightness and color uniformity but also significantly reduces both preparation time and costs. The fabricated 2D-FVHW exhibits a horizontal field of view of (FOV) 19 (Formula presented.), a vertical FOV of 21 (Formula presented.), and a diagonal FOV of 28 (Formula presented.), with an eyebox size of 14 (Formula presented.) 16 mm and an eye relief of 15 mm. The system demonstrates excellent performance in terms of brightness and color uniformity, achieving a full FOV white light brightness uniformity of 53.9%. Additionally, its color gamut encompasses nearly 100% of the sRGB color gamut, making it a promising solution for high-performance AR displays. Meanwhile, we provides a detailed analysis of the stray light phenomenon in the 2D-FVHW, with experimental results showing strong alignment with simulations.