Spectroscopic investigation and heat generation of Yb3+/Ho3+ codoped aluminosilicate glasses looking for the emission at 2 μm

Energy transfer (ET) and heat generation processes in Yb3+Ho3+-codoped low-silica calcium aluminosilicate glasses were investigated using thermal lens (TL) and photoluminescence measurements looking for the emission around 2.0 mu m. Stepwise ET processes from Yb3+ to Ho3+, upon excitation at 0.976 mu m, produced highly efficient emission in the mid-infrared range at around 2.0 mu m, with high fluorescence quantum efficiency (eta(1) similar to 0.85 and independent of Ho3+ concentration) and relatively very low thermal loading (<0.4) for concentration up to 1.5% of Ho2O3. An equation was deduced for the description of the TL results that provided the absolute value of eta(1) and the number of emitted photons at 2.0 mu m per absorbed pump photon by the Yb3+ ions, the latter reaching 60% for the highest Ho3+ concentration. These results suggest that the studied codoped system would be a promising candidate for the construction of photonic devices, especially for medical applications. (C) 2013 Optical Society of America