Achromatic GP liquid crystal elements for near-eye displays

Geometry-phase liquid crystal (GP LC) elements have emerged as promising candidates as key optical elements for augmented reality (AR) and virtual reality (VR) near-eye displays due to their unique properties such as ultra-thin planar form factor, high diffraction efficiency, and polarization efficiency. However, the diffraction efficiency and focal length of GP LC lenses vary with wavelength, leading to chromatic aberrations that degrade imaging quality and limit their practical applications. To address these issues, we have developed a systematic optimization method that enables broadband diffraction efficiency across the entire visible spectrum by employing a multi-twist structure. We have experimentally demonstrated GP LC lenses with diffraction efficiencies > 95% from 450 to 750 nm. Additionally, we have proposed a method to suppress focal length variation in GP LC lenses for VR applications by designing sub-elements optimized for different color channels.