Initital research of three-dimensional volumetric display based on di-frequency upconversion

3D display may be one of the most wonderful techniques attracting scientists to research on. But most of current approaches are fictitious ones. On the CLEO'94, E. A. Downing and L. Hesselink et al. reported a virtual 3D volumetric display using Pr doped fluoride glass upconversion luminescence which is evaluated as a new excellent physics achievement in 1996. The ZBLAN:Pr glass is proved by L. Hesselink to be a interesting material for 3D volumetric display based on upconversion. In the processes of upconverting near-infrared radiation to visible, the 1 G 4 level of Pr 3+ locates at an important position. But the transition probability of 3 H 4 - 1 G 4 proved to be one or two order of magnitude smaller than other strong transitions. So to improve the population on 1 G 4 has an practical significance. In this paper, we report a simple 3D volumetric display experiment which has used the upconversion sensitization method. A bulk ZBLAN:Pr,Yb and ZBLAN:pr glasses were selected as display medium. Just as the sensitized action of Yb 3+ ion, the di-frequency upconversion luminescence intensity of Pr 3+ ion is enhanced more than thirty times. So, the brightness of 3D display is better than the work of E. A. Downing and L. Hesselink. Some technique consideration is discussed. In addition a conception of multilayer 3D display device is also presented, which are thought having several advantages.