Intense upconversion luminescence in ytterbium-sensitized thulium-doped novel oxychloride bismuth–germanium glass

Structural and up-conversion fluorescence properties in ytterbium-sensitized thulium-doped novel oxychloride bismuth–germanium glass have been studied. The structure of novel bismuth–germanium glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wave numbers. The Raman spectrum investigation indicates that PbCl2 plays an important role in the formation of glass network, and has an important influence on the up-conversion luminescence. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions 1G4→3H6 and 1G4→3H4, respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. This novel oxychloride bismuth–germanium glass with low maximum phonon energy (∼730 cm−1) can be used as potential host material for up-conversion lasers.