Investigation of the role of silver on spectroscopic features of Er(3)(+)--activated Ag--exchanged silicate and phosphate glasses

We present a spectroscopic investigation on Er/Ag co--doped platelets of silicate and phosphate glasses with the aim of assessing the effect of silver as a sensitizer for erbium. The silver was added by immersing the samples, at 663K for 67h, in a molten salt bath of molar concentration 0*5% AgNO3 and 99*5% NaNO3. Additive heat treatments in air at different temperatures, ranging from 673K to 773K for 30min and cooling in air after each anneal, 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 (4)I13/2-- > (4)I15/2 transition of the Er(3)(+)ion, excitation spectra in the range from 360 to 750nm, and absorption measurements. Increases of the Er(3)(+)luminescence at 1*5mum are demonstrated when the excitation is in an absorption band, located at 420nm, possibly originating from the surface plasmon resonance of silver particles.