Spectroscopic properties of Er 3+, Yb 3+ and Er 3+/Yb 3+ doped metaphosphate glasses

Abstract

The absorption and emission spectroscopies of Er 3+ doped and Er 3+/Yb 3+ codoped Ca(PO 3) 2, Sr(PO 3) 2 and Ba(PO 3) 2 glasses have been studied. From the Judd–Ofelt intensity parameters, the spontaneous emission probabilities of some relevant transitions and the radiative lifetimes of several excited states of Er 3+ have been calculated. The decay curves of the Er 3+ emission at 1.5 μm have been measured at different temperatures. The data have been fitted using a stretched exponential function and the obtained experimental lifetimes have been compared with the calculated radiative lifetimes. The difference between the experimental and calculated lifetimes is attributed to the presence of traces of OH groups in the host glasses. The absolute OH content in some glasses has been determined from the infrared spectra. The emission spectra at 1.5 μm of the Er 3+ ion in the codoped glasses have been measured at different temperatures. The integrated emission intensities decrease significantly on passing from room temperature to 13 K, suggesting a temperature dependence of the rate of the energy transfer process between Yb 3+ and Er 3+.