Judd-Ofelt analysis and NIR spectroscopy properties of Nd³⁺-doped Na₂O/ NaF-Al₂O₃-Y₂O₃-P₂ O₅ glass and transparent glass-ceramics containing NaYP₂O₇ crystals

In the present work, the Nd3+-doped Na2O/NaF-Al2O3-Y2O3-P2O5 glass and transparent glass-ceramics were fabricated by conventional melting-quenching and subsequent heat treatment. The glass structure was studied by XRD, DSC, and FTIR spectrum, the fluorophosphate glass exhibits a more compact cross-link network. The UV-Vis-NIR absorption spectra, Judd-Ofelt theory, and photoluminescence spectra were used to explore the absorption and NIR spectroscopic features of the Nd3+-doped phosphate and fluorophosphate glasses. Under the excitation of 582 nm, the intense NIR emission in the Nd3+-doped glasses originating from the internal transition F-4(3/2) -> I-4(J/2) (J = 13, 11 and 9) was observed, and the transition F-4(3/2) -> I-4(11/2) (1053 nm) is the most dominate. The transparent glass-ceramics (GC) was fabricated via heat treating on the precursor glass (PG) at T-g+100 degrees C, and the precipitation of NaYP2O7 crystals in GC was confirmed by XRD and SEM. With the benefit of the existence of the NaYP2O7 crystals, the Nd3+-doped GC exhibits higher NIR emission intensity, higher quantum efficiency (72.85% and 84.11%), larger sigma(lambda(p)) values of 4.24x10(-20) cm(2) and 4.86x10(-20) cm(2), larger sigma x Delta lambda(eff) values of 10.22x10(-26) cm(3) and 11.67x10(-26) cm(3) than that of PG. These results indicate that the Nd3+-doped phosphate and fluorophosphate glasses and glass-ceramics may be used as a gain medium for 1053 nm laser emission.