Nd3+-doped B2O3-SiO2-AlF3-NaF-CaF2 glass ceramics for 1.06 μm emission

Trivalent neodymium (Nd³⁺) doped transparent oxyfluoroborosilicate glass and glass ceramics (GCs) comprising CaF₂ nanoparticles (NPs) were fabricated via melt quench route followed by two step heat treatment process. The X-ray diffraction and scanning electron microscopic studies confirm the presence of CaF₂ NPs. The GC environment for efficient luminescence was obtained at a heat treatment of 450 °C/1 h. The wavelength of pumping laser source was optimized as 808 nm by studying the luminescence properties at different excitations. The Nd³⁺ ions exhibit their characteristic emission transitions with peak maxima at around 0.89 μm (⁴F_3/2 → ⁴I_9/2), 1.06 μm (⁴F_3/2 → ⁴I_11/2) and 1.32 μm (⁴F_3/2 → ⁴I_13/2). The Nd³⁺ concentration was also optimized as 1.0 mol% for strong emission up on 808 nm pumping. Various spectroscopic, radiative and laser characteristic parameters were determined using Judd–Ofelt theory. The luminescence decay of ⁴F_3/2 state was studied controlling the excitation and emission wavelengths at 808 and 1060 nm, respectively. The reasons for quenching in luminescence were discussed with suitable illustrations. The experimentally observed results confirm that the GC sample obtained at 450 °C/1 h heat treatment was highly appropriate to design 1.06 μm fiber lasers and optical amplifiers.