Enhancement of spectroscopic and luminescence properties of Er3+ doped tellurite glasses by adding P2O5 for lasing materials

Abstract Er 3+ -doped phosphor-tellurite glasses has been synthesized by conventional melting method. Results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of tellurite glasses. The DSC measurements show an improvement of thermal stability of glass hosts after adding P 2 O 5 . The structures of glasses were investigated by X-ray diffraction (XRD) and Raman spectroscopy to understand their dependence of structure on composition. Absorption spectrum from near infrared to visible was obtained and the Judd–Ofelt (J-O) intensity parameters (Ω 2 , Ω 4 , and Ω 6 ) were determined. Spontaneous emission probabilities of some relevant transitions, branching ratio, and radiative lifetimes of several excited states of Er 3+ have been predicted using intensity J-O parameters. Up-conversion luminescence characteristics, under 977 nm excitation wavelength, have been investigated at room and low temperature in these glasses. Intense green and red emissions from Er 3+ centered at 534 nm, 548 nm and 660 nm, corresponding to the transitions 2 H 11/2 → 4 I 15/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 , respectively, were simultaneously observed. The quadratic dependence of the up-conversion emission on the excitation power indicates that two-photon steps are involved for the three visible emission bands. The PL lifetimes is found to decrease in the temperature range 77–300 K. Using the Mc-Cumber method, emission cross-section (σ e ), Absorption cross-section (σ a ), and gain cross-section (G(λ)) for the 4 I 13/2 → 4 I 15/2 transition, were calculated. By analyzing obtained data based to all advantages after adding P 2 O 5 , the tellurite glasses can be used as potential host material for developing optical amplifiers applied for 1.53 µm band broad and high-gain erbium-doped fiber amplifiers (EDFA).