Broadband near-infrared luminescence at around 1.0 µm in Pr3+/Er3+ co-doped tellurite glass

In this work, the near-infrared band photoluminescence properties around 1.0 µm in Pr3+/Er3+ co-doped tellurite glass was investigated. The doped tellurite glass with composition TeO2-WO3-ZnO-La2O3 was synthesized using melt-quenching technique and characterized by UV/Vis/NIR absorption spectrum, near-infrared emission spectrum, X-ray diffraction (XRD) pattern and Raman spectrum. Under the excitation of 488 nm laser, a broad 1.0 µm band luminescence ranging from 950 to 1100 nm with a full width at half maximum (FWHM) up to 94 nm was observed, nearly two times compared to that in Pr3+ or Er3+ single-doped case. This broadband near-infrared luminescence was contributed by the Er3+:4I11/2 → 4I15/2 and Pr3+:1D2 → 3F4 radiative transitions which lead to two emissions located at 980 and 1040 nm, respectively. The structural analysis of XRD pattern and Raman spectrum proved the long-range structural disorder in synthesized glasses, and based on the absorption spectrum, some important spectroscopic parameters such as the Judd-Ofelt intensity parameter, spontaneous radiative transition probability, fluorescence branching ratio, absorption and emission cross-sections, and gain coefficient spectrum were calculated to reveal the radiative properties of doped tellurite glass. The obtained results indicate that Pr3+/Er3+ co-doped tellurite glass is a promising candidate to fabricate a broadband near-infrared luminescent source for telecommunication and other applications such as medical imaging system.