Broadband flat near-infrared emission from tellurite glass doped with Tm3+, Er3+ and Ag NPs

Abstract Tellurite glasses doped with trivalent Tm3+, Er3+ ions and metal Ag nanoparticles (NPs) were synthesized by single-step melt-quenching technique, and the near-infrared photoluminescence property was investigated. Differential scanning calorimeter (DSC) curve, X-ray diffraction (XRD) pattern, transmission electron microscopy (TEM) image, absorption spectrum, emission spectrum and fluorescence decay curve were measured. The good thermal stability and amorphous state nature of the as-prepared tellurite glasses were demonstrated by the DSC curve and XRD pattern, respectively. Absorption spectrum disclosed the electronic transitions in the ultraviolet to near-infrared spectral range and was further used to evaluate the potential in near-infrared band luminescence by the calculations of spontaneous radiative transition parameters and gain cross-sections of Tm3+(Er3+) ions. Under the excitation of 808 nm laser diode (LD), a broadband flat near-infrared emission with FWHM of approximately 160 nm was obtained in the Tm3+/Er3+ doped tellurite glass. This broadband flat near-infrared emission, originating from the spectral overlapping of Tm3+:3H4→3F4 transition (~1.47 µm) and Er3+:4I13/2 → 4I15/2 transition (~1.53 µm), was located in the 1350–1650 nm region and covered the E + S + C + L-bands simultaneously. With the precipitation of Ag NPs having diameter in the 10–20 nm range evidenced by TEM image in the Tm3+/Er3+ doped tellurite glass, the peak luminescent intensity increased by about 45%, which is attributed to the increased local electric field and the possible energy transfer from the Ag species to Tm3+(Er3+) ions. The obtained results demonstrate that Tm3+/Er3+/Ag NPs doped tellurite glass is prospective for broadband optical amplifiers, broadband lighting sources and so on.