Structural and optical investigations of Nd-doped fluorozirconate-based glass ceramics for enhanced upconverted fluorescence

We found enhanced upconverted fluorescence in Nd3+-doped fluorozirconate glasses which were additionally doped with chlorine ions. Upon annealing between 240 and 290 degrees C, hexagonal phase BaCl2 nanocrystals between 20 and 180 nm in diameter were formed in the glass. During the thermal processing, some of the Nd3+ ions enter the nanocrystals leading to additional splitting of the infrared fluorescence spectra and to increased upconverted fluorescence intensities. The optimum value was found for the 270 degrees C sample where the upconverted fluorescence intensity is approximately a factor of 60 stronger than the one found for the as-made glass. (c) 2008 American Institute of Physics.