Impact of Bi₂O₃ on structural properties and lasing effects in Nd³⁺ doped bismuth phosphate glasses at 1.053μm...

Influence of addition of bismuth oxide (Bi₂O₃) on structural and optical properties of 0.5Nd³⁺doped different phosphate glasses prepared by melt quenching technique were reported. The structural properties were analysed by FT-IR and ³¹P MAS NMR techniques. ³¹P NMR results showed that, with the variation of Bi₂O₃ concentration in the prepared phosphate glass matrices there was no significant change in the structure. The optical properties have been analysed using Judd-Ofelt (J-O) theory. From absorption spectra, three phenomenological J-O intensity parameters (Ω_2, Ω_4, Ω₆) have been calculated and these parameters were used to estimate the radiative properties. The J-O intensity parameters increased with increase in the concentration of Bi₂O₃, which confirmed the higher covalency, asymmetry and rigidity. The branching ratios (β) and emission cross-sections (σ) were calculated from the emission spectra of Nd³⁺ doped bismuth phosphate (BiP) glasses. Among different glass matrices 15mol% of Bi₂O₃ glass matrix has higher β and σ values which are useful for the laser applications. The improved emission cross-section value with the addition of Bi₂O₃ content results low threshold and high gain applications. The decay curves of all these BiP glasses showed single exponential behaviour.