Inversely Designed High-Efficiency Achromatic Slanted Metagratings for Augmented Reality Waveguide Displays

Waveguide displays are promising for augmented reality or mixed reality, but chromatic dispersion in conventional diffractive elements limits full-color display performance. Although promising, achromatic metagratings’ diffraction efficiency needs to be improved. We propose an inverse design method using a quantum genetic algorithm for achromatic slanted metagratings. Two designs with 20° and 40° fields of view exhibit diffraction efficiencies as high as 29% ± 1% for RGB wavelengths at normal incidence and excellent angular and spectral uniformity. The proposed single-layer manufacturable structures offer a promising route to future full-color waveguide displays.