Spectroscopic Properties and Energy Transfer Analysis of Tm3+-Doped BaF2-Ga2O3-GeO2-La2O3 Glass

This paper reports on the spectroscopic properties and energy transfer analysis of Tm3+-doped BaF2-Ga2O3-GeO2-La2O3 glasses with different Tm2O3 doping concentrations (0.2, 0.5, 2.0, 2.5, 3.0, 3.5, 3.5, 4.0 wt%). Mid-IR fluorescence intensities in the range of 1,300 nm-2,200 nm have been measured when excited under an 808 nm LD for all the samples with the same pump power. Energy level structure and Judd-Ofelt parameters have been calculated based on the absorption spectra of Tm3+, cross-relaxation rates and multi-phonon relaxation rates have been estimated with different Tm2O3 doping concentrations. The maximum fluorescence intensity at around 1.8 mu m has been obtained in Tm2O3-3 wt% sample and the maximum value of calculated stimulated emission cross-section of Tm3+ in this sample is about 0.48 x 10(-20) cm(2) at 1,793 nm, and there is not any crystallization peak in the DSC curve of this sample, which indicate the potential utility of Tm3+-doped BaF2-Ga2O3-GeO2- La2O3 glass for 2.0-mu m optical fiber laser.