A volumetric full-color display realized by frequency upconversion of a transparent composite incorporating dispersed nonlinear optical crystals

Abstract

Popular three-dimensional (3D) TV or film media primarily relies on misleading our visual system by presenting our two eyes with spatially offset two-dimensional (2D) images. In comparison, volumetric displays generate moving objects in three physical dimensions with unlimited viewing angles. In a static volumetric display, voxels instead of pixels are usually addressed by luminescence, scattering or deflection. Although various prototype volumetric display technologies have been developed, the generation of full-color moving objects remains a challenge. Herein, we demonstrate the generation of voxels by frequency upconversion based on second-harmonic generation (SHG) in nonlinear optical crystals that are dispersed in solid-state composite materials that serve as a transparent solid display. Notably, voxels that radiate all colors with near-monochromatic color purity can be created by pumping at different near-infrared wavelengths and thus enable a simple solution to realize a full-color display. A computer-controlled scanner allows the generation of moving 3D objects that are viewable from any direction in a prototype device at a 25 × 25 × 25 mm3 scale, and larger displays that are based on the colloidal dispersion of SHG crystals are envisioned. Our methodology may have important implications for the application of the transparent crystal-in-glass composites in both 3D and 2D display technologies.