Sensitizing effects in Ag-Er co-doped glasses for optical amplification

A set of samples co-doped with Er and Ag were prepared with a combined sol-gel and ion-exchange route. This multistep process synthesizes samples in which the silver atoms are dispersed in the matrix and/or aggregated in Ag multimers or nanoclusters. The samples exhibit a different photo- luminescence response depending on the sensitizing effect due to silver atoms. The spectroscopic properties were correlated with the structural properties investigated by extended x-ray absorp- tion fine structure (EXAFS) spectroscopy and x-ray diffraction. The Er3+ excitation via energy transfer, obtained in a wide range of wavelengths, has been clearly related to the presence in the sample of Ag multimers.