Synthesis and optical behavior of neodymium ion doped borophosphate glass for laser applications

Nd³⁺ ion doped lithium aluminum gadolinium borophosphate glasses were synthesized by melt quenching technique. The hypersensitive transitions were identified in the absorption spectra for ultraviolet (UV), visible (Vis) and near infrared (NIR) region, which the highest intensity is recorded at the transitions ⁴I_9/2→⁴D_5/2, ⁴I_9/2→⁴G_5/2 and ⁴I_9/2→⁴F_5/2 with wavelengths of 352, 582 and 804 nm, respectively. The spectroscopic properties of emission spectra in Nd³⁺ doped present glasses were investigated under 808 nm laser excitation and shows the strongest intensity at 1063 nm, which corresponding the transition ⁴F_3/2→⁴I_11/2. Furthermore, JO parameters (Ω₂, Ω₄ and Ω₆) are produced, which are then utilized to examine the radiative characteristics of Nd³⁺ doped glasses for example radiative transition probability (A_R), radiative lifetimes (τ_rad), branching ratios (β), gain bandwidth (Δλ_eff×σ_e), optical gain (σ_e×τ_rad) and emission cross-section (σ_e). The results demonstrated that the LBPNd0.5 glass might be used in laser applications around 1.058 µm region, which represent highest stimulated emission cross-section (53.49 ×10^–21 cm²), higher branching ratio (>0.5), highest quantum efficiency (84.58%), lower non-radiative decay rates (720 s⁻¹) compared with other glasses.