The 1.2 and 2.0 μm Emission from Ho3+ in Glass Ceramics Containing BaF2 Nanocrystals.

Ho31 and/or Yb31 doped glass ceramics containing spherical BaF2 nanocrystals sized 10-20 nm were prepared by melt quenching and subsequent thermal treatment. Radiative properties such as transition probabilities (A), radiative lifetimes (τ), branching ratios (β) along with absorption and emission cross sections have been calculated from the absorption spectra. Upon 637 nm excitation, Ho31-doped glass ceramics yield an intense infrared emission at 1191 nm with a full-width at half-maximum of 80 nm and weaker emissions at 980 and 1473 nm. Efficient 1.2 and 2.0 μm infrared emissions have been achieved in Ho31/ Yb31 co-doped glass ceramics under 980 nm excitation, demonstrating the occurrence of energy transfer ( ET) from Yb31 to Ho31. The microscopic parameters of the ET processes between Yb31 and Ho31 have been evaluated, revealing that the forward ET Yb31 → Ho31 is more efficient than the backward one and both the processes are mainly assisted by one-phonon emission (annihilation). [ABSTRACT FROM AUTHOR]