Spectroscopic investigation and heat generation of Yb~(3+)/Ho ~(3+) codoped aluminosilicate glasses looking for the emission at 2 μm

摘要

Energy transfer (ET) and heat generation processes in Yb ~(3+)/Ho~(3+) -codoped low-silica calcium aluminosilicate glasses were investigated using thermal lens (TL) and photoluminescence measurements looking for the emission around 2.0 μm. Stepwise ET processes from Yb~(3+) to Ho~(3+), upon excitation at 0.976 μm, produced highly efficient emission in the mid-infrared range at around 2.0 μm, with high fluorescence quantum efficiency (η_1 ～ 0.85 and independent of Ho~(3+) concentration) and relatively very low thermal loading (<0.4) for concentration up to 1.5% of Ho_2O _3. An equation was deduced for the description of the TL results that provided the absolute value of η_1 and the number of emitted photons at 2.0 μm per absorbed pump photon by the Yb~(3+) ions, the latter reaching 60% for the highest Ho~(3+) concentration. These results suggest that the studied codoped system would be a promising candidate for the construction of photonic devices, especially for medical applications.