Photoluminescence properties of Er3+-doped alkaline earth titanium phosphate glasses

Er3+-doped alkaline earth titanium phosphate (RTP) glasses with molar composition of 24 (NaPO3)6 + 30 KH2PO4 + 25 TiO2 + 20 RCl2 + 1 Er2O3 were prepared by melt quenching technique. Judd-Ofelt intensity parameters (Ω2,4,6) were determined from the experimental oscillator strengths (fexp) of absorption bands. From these parameters spontaneous emission probabilities (AR), luminescence branching ratios (βR) and radiative lifetimes (τR) have been calculated. Visible and near infrared photoluminescence spectra has been recorded by exciting the samples at 380 and 970 nm respectively. An intense broad emission band at 1.53 μm was observed corresponding to 4I13/2 → 4I15/2 transition. McCumber theory has been applied to determine the emission cross-sections (σe) of the 4I13/2 → 4I15/2 transition using the absorption cross-sections (σa). The lifetimes of 4S3/2 level were measured for the glasses by exciting the samples at 540 nm wavelength and the quantum efficiencies were also determined.