Highly-efficient full-color holographic movie based on silicon nitride metasurface.

Metasurface holograms offer various advantages, including wide viewing angle, small volume, and high resolution. However, full-color animation of high-resolution images has been a challenging issue. In this study, a full-color dielectric metasurface holographic movie with a resolution of 2322 × 2322 was achieved by spatiotemporally multiplexing 30 frames with blue, green, and red color channels at the wavelengths of 445 nm, 532 nm, and 633 nm at the maximum reconstruction speed of 55.9 frames per second. The high average transmittance and diffraction efficiency of 92.0 % and 72.7 %, respectively, in the visible range, were achieved by adopting polarization-independent silicon nitride waveguide meta-atoms, resulting in high color reproducibility. The superposition of three wavelengths was achieved by adjusting the resolutions and positions of target images for each wavelength while maintaining the meta-atom pitch constant. The improvement in diffraction efficiency was brought about by the optimization of etching conditions to form high-aspect vertical nanopillar structures.