Optimization of the static volumetric 3D display system based on two-step two-frequency upconversion of Er³⁺-doped tellurite glass

We demonstrate a high-brightness, high-contrast static volumetric three-dimensional (3D) display based on the two-step, two-frequency upconversion by optimizing the incidence angle and the number of two-dimensional graphical slices of the digital micromirror device (DMD). A homemade cubic volume of tellurite glass (22mm×22mm×22mm) doped with 0.7% erbium ions (Er 3+ ) is used as the display medium. The volumetric pixels (voxels) of 546 nm luminescence are activated by two lasers of 850 nm and 1550 nm, which are meticulously scanned by a DMD of 1280×800 resolution and a galvanometer scanner, respectively. The brightness and contrast of the resulting 3D imagery are investigated by adjusting the incidence angle of the DMD and optimizing the number of two-dimensional graphical slices. Experimentally, the optimal incidence angle of 55.76° and slices of 25 with nearly 26 million voxels are obtained. The resultant image display is remarkably steady, devoid of any flicker, while delivering exceptional luminance and contrast.