Optical Properties and White-Light Emission in Dy3+-Doped Transparent Oxyfluoride Glass and Glass Ceramics Containing CaF2 Nanocrystals

Dysprosium-doped oxyfluoride glass and nano crystalline glass ceramics have been prepared and their luminescence properties have been studied. The thermal properties of the glass have been determined from the differential thermal analysis. X-ray diffraction spectra of the samples confirm the formation of a CaF2 nanocrystaline phase in the glass matrix. Both the glass and the glass-ceramic samples emit intense white light upon excitation with 451 nm laser light. The yellow-to-blue intensity ratios and the chromaticity color coordinates have been calculated from the emission spectra and their relative variation with respect to heat treatment conditions are discussed. The luminescence decay curves of the F-4(9/2) emitting level were measured and the variation of the lifetime with the heat treatment conditions is discussed.