Three-dimensionally structured voxels for volumetric display.

A three-dimensional (3D) volumetric display has been the goal of the display research field for many years. However, volumetric displays capable of rendering multicolor and updatable graphics that users can view with the naked eye are still a challenge. Here, we show a new volumetric display using three-dimensionally structured fluorescent voxels. The fluorescent voxels were generated by two-photon excitation with a femtosecond laser. To realize colorization, volumetric graphics were spatially rendered on a fluorescent screen in which structured voxels having different luminescent colors were arranged in each layer. The color of the fluorescent voxels was changed by a holographic color switching method using computer-generated holograms displayed on a liquid-crystal spatial light modulator. Because this display employed RGB fluorescent voxels that are accessed optically, it has a number of advantages, such as being observable with the naked eye, and being capable of multicolor rendering and refreshable graphics. This technology will open up a wide range of applications in 3D displays, augmented reality, and computer graphics.