Effect of PbO on the spectral and thermo-optical properties of Nd3+-doped phosphate laser glass

Nd3+-doped P2O5-K2O–Al2O3–BaO-PbO phosphate glasses with various PbO/BaO ratios were synthesized using the melt quenching technique. Raman, absorption, and emission spectra were measured to investigate the effects of PbO/BaO ratios on the structures and spectroscopic properties of the glasses. The emission cross-sections of the Nd3+-doped phosphate glasses were calculated using the Judd–Ofelt theory, and were found to increase from 4.37 × 10−20 to 4.50 × 10−20 cm2 as the PbO/BaO ratio increased. In addition, thermo-optical properties were measured using an interferometric technique. The thermo-optical coefficients, which were −1.49 × 10−6, −1.65 × 10−6, and −1.64 × 10−6 K−1, respectively, were all largely negative values. The thermal expansion coefficients of the three glass samples varied within a small range. The results showed that increasing the PbO/BaO ratio of phosphate glasses can improve the laser properties while maintaining their good thermo-optical properties.