Laser transition characteristics of Nd3+-doped fluorophosphate laser glasses

Fluorophosphate glasses of composition P2O5–K2O–MgO–Al2O3–AlF3 and P2O5–K2O–MgO–Al2O3–BaF2 were prepared with different Nd3+ ion concentrations. The absorption and emission spectra in the UV–VIS–NIR region were measured for these glasses. Judd–Ofelt analysis has been carried out using the absorption spectra of 1.0 mol% Nd3+-doped glasses to evaluate the radiative properties for some luminescent levels of the Nd3+ ion. The stimulated emission cross-sections of the 4F3/2 → 4I11/2 laser transition for the present glasses are found to be higher than for other Nd3+-doped glasses. Branching ratio calculations also revealed the potentiality of the 4F3/2 → 4I11/2 transition for laser action in these glasses. The observed concentration quenching of the lifetime of the 4F3/2 level is explained as a result of cross-relaxation process between the Nd3+ ions.