Assessment of spectroscopic properties of erbium ions in silicate and phosphate glasses after silver exchange

We present a spectroscopic investigation of Er/Ag co-doped thin plates of silicate and phosphate glasses, with the aim of assessing the effective role of silver as a sensitizer for erbium. The composition of the rare-earth doped silicate glass is (wt%): 66.9 SiO2, 14.4 Na2O, 9.1 CaO, 1,9 Al2O3, 0.9 P2O5, 0.9 K2O, 1.9 Er2O3, 3,9 Yb2O3 and of the phosphate glass one (in mol%): 65 NaPO3, 20 Nb2O5, 15 Ga2O3 (7.5 wt% of Er2O3 was added to the glass). For each type of glass, two plates, with a thickness of 200 ?m, were cut and optically polished. One of these two plates was Ag- exchanged in its full thickness, while the other was kept as reference Additive heat treatments in air at different temperatures were performed on both the silver-exchanged and the silver-free plates. The optical and spectroscopic features of the samples were investigated by photoluminescence measurements in the region of the 4I13/2 --> 4I15/2 transition of the Er3+ ion. The results of excitation in the range from 350 to 750 nm, the decay curves from the 4I13/2 level, and the absorption measurements are reported and discussed.