Broadband near-infrared luminescence in Erbium ions single-doping tellurite glass for optical amplification

This letter proposes a facile approach for the realization of a broadband near-infrared luminescence source in erbium-ion single-doping tellurite glass, which is bent on tailoring the network structure. Under the collective action of multiple broadening mechanisms and fluorescence capture, broadband fluorescence with a full width at half maximum (FWHM) of 132 nm (1500–1632 nm) was achieved. To the best of our knowledge, this is the largest FWHM reported for erbium single-doping tellurite glass materials. Meanwhile, this fiberglass exhibits excellent thermal stability and high visible to near-infrared transmittance. Furthermore, a novel equivalent 5-level Stark splitting model is proposed, which can effectively explain the spectrum broadening. This study is beneficial for the further development of broadband optical amplification.In this study, erbium-ion single-doping tellurite glass was synthesized using the conventional melt-quenching method for mol% compositions of 70TeO2-10ZnO- (20-x) WO3-xNb2O5 (x = 0, 1, 3, 5, 7, 10), referred to as Samples A0, A1, A2, A3, A4, and A5, respectively. Additionally, tellurite glass doped with a high concentration of RE ions was also prepared with elementary molar compositions of 70TeO2-10ZnO-15WO3-5Nb2O5-2Er2O3, which was denoted as Sample B. The chemical raw materials mentioned above were high-purity (99.99%) reagents. Batches of 20-gram mixtures were poured into an alumina crucible and then heated in an electronic furnace at a temperature of approximately 900 °C in an air atmosphere for 40 min. Subsequently, the melt was quickly transferred onto a preheated stainless plate and annealed at 400 °C in a muffle furnace for 6 h to remove thermal stress. Finally, the samples were polished into coincident shapes and thicknesses to measure their physical and optical properties.To determine the thermal behavior of the glass matrix, TG/DTA7300 was used to acquire the differential thermal analysis (DTA) curve at a heating rate of 10 K/min. The Raman spectra of the samples were obtained using a LabRAM HR Evolution Raman Spectrometer in the wavenumber range of 300 to 1200 excited by a 633 nm laser source. The transmission spectrum spectra were measured by the UV-VIS-NIR spectrophotometer of PerkinElmer LAMBDA 750 within the range of 250–2500 nm with a resolution of 1 nm. The NIR (1400–1700 nm) fluorescence spectra pumped with a commercial 980 nm LD and attenuation curve recording were collected using an FLSP980 spectrometer under liquid-nitrogen cooling conditions. All measurements mentioned in this study were performed at room temperature.