Structural and spectroscopic investigations of neodymium-doped strontium borophosphate glass

Neodymium-doped glass finds application in lasers with high energy and low pulse width. In the present study, a series of Nd³⁺ ions (0-2 mol%)-doped strontium borophosphate (SBP) glass samples was prepared through the conventional melt quench method. A broad peak in the X-ray diffraction spectrum confirmed the formation of a single-phase amorphous borophosphate glass. Fourier transform infrared spectra of the doped and undoped glass samples indicated the presence of borate and phosphate groups that form the anionic network. The thermal properties of the glass samples were determined from thermogravimetry/differential thermal analysis. Photoluminescence and ultraviolet-visible light techniques were used to investigate the optical properties of the as-prepared SBP:Nd glass. The Judd-Ofelt (JO) intensity parameters Ω_λ (2, 4, 6), stimulated emission cross-section, branching ratios, and transition probabilities of the Nd³⁺ -doped glass were obtained through the JO analysis. Characteristic Nd³⁺ emission peaks were observed at 1330, 1060, and 876 nm, corresponding to the ⁴ F_3/2 →⁴ I_S/2 (S = 13, 11, and 9) transitions, respectively. The suitability of SBP:Nd (0.5 mol%) glass for use in solid-state lasers was demonstrated by its intense luminescence, high transition probability, high emission cross-section, optical gain, and luminescence branching ratio.