Chromatic-aberration-free full-color augmented reality display via triple-stacked liquid crystal polarization volume grating waveguides

Liquid crystal polarization volume gratings (LC-PVGs) have attracted significant attention as optical combiners of diffractive optical waveguides in augmented reality (AR) displays due to intrinsic high diffraction efficiency, polarization-selectivity, and ultra-thin profile. However, conventional LC-PVGs based diffractive waveguide architectures face significant challenges in full-color imaging due to inherent chromatic aberration, which stems from the wavelength-dependent diffraction angles of waveguide coupling gratings, leading to unavoidable color separation as a critical barrier to practical full-color display implementation. To address this challenge, we propose an AR display system employing a triple-stacked waveguide structure with red, green, and blue liquid crystal polarization volume gratings (LC-PVGs). Through meticulous design and optimization of the horizontal grating periods in each color-specific waveguide layer, we achieve consistent diffraction angles for all three color channels during waveguide propagation. This angular synchronization enables subsequent chromatic recombination at the output grating, ultimately realizing achromatic imaging. The presented solution offers a promising approach to overcoming chromatic dispersion limitations in full-color diffractive waveguide AR displays, potentially advancing their applicability in high-fidelity augmented reality systems.