There are many different techniques to display 3D information. However, not many of them are able to provide sufficient depth cues to the observers to sense or feel the images as real three-dimensional objects. Volumetric three-dimensional displays generate images within a real 3D space, so they provide most of the depth cues automatically. This thesis discusses the basic notions required to understand three-dimensional displays. Also discussed are different techniques used to display 3D information and their advantages and disadvantages as well as their current limitations. Several rare-earth doped fluoride crystals that are excited to emit visible light by sequential two photon absorption have been investigated as display medium candidates for static volumetric three dimensional displays. A scalable display medium is suggested to enable large 3D displays. This medium is a dispersion of particles of the rare earth doped fluoride crystals in a refractive index-matched polymer matrix. Detailed experiments are described to prepare such a scalable display medium using a wide variety of polymers. The scattering problem in such a medium was greatly reduced by index-matching the polymer to the crystalline particles. An index-matching condition that optimizes the performance was identified and demonstrated. A potential near-future solution is demonstrated and improvements are suggested.