A new class of nanostructured RE-doped SiO.sub.2-base materials that display superior fluorescence properties is provided. In particular, high gain combined with a broad and flat spectral band width is observed in material composed of a high fraction of a nano-dispersed metastable silicate phase in a glassy SiO.sub.2 matrix, produced by partial devitrification (crystallization) of several glassy Al.sub.2O.sub.3/Er.sub.2O.sub.3- and Y.sub.2O.sub.3/Er.sub.2O.sub.3-doped SiO.sub.2 compositions. Also, a highly deconvoluted spectral emission, with several prominent peaks, is observed in completely devitrified material, consisting of a uniform nano-dispersion of an equilibrium silicate phase in a crystobalite SiO.sub.2 matrix. Such enhanced fluorescence properties were observed in heat treated nanopowders prepared by vapor-phase, solgel, rapid solidification, and spray-pyrolysis methods.