Structural, spectroscopic and optical gain of Nd3+ doped fluorophosphate glasses for solid state laser application

Nd3+ doped fluorophosphate glasses (PANCaFN) with chemical composition of (50-x) P2O5–12Na2O–8Al2O3–10CaO–10KF–10CaF2-xNd2O3 (where x = 0, 0.5, 1.0, 1.5 and 2.0 mol%) have been successfully prepared by melt-quenching method and characterized by several techniques. The optical absorption measurements exhibited signature of Nd3+ absorption bands in fluorophosphate glasses showed. The spectroscopic analysis have been carried out using Judd-Ofelt parameters and oscillator strength to determine radiative properties such as radiative transition probability (AR), branching ratio (βr), lifetime (τ), emission cross-section (σe) and quantum efficiency (η). The highest emission intensity was found at 1060 nm for transition 4F3/2 → 4I13/2 under excitation wavelength of 582 nm for PANCaFN2. The emission cross section, branching ratio and lifetime were evaluated and showed 4.92 × 10−20 cm2, 0.7 and 200 μs, respectively. More importantly, the outstanding quantum efficiency of PANCaFN2 could reach to 98.92%. The addition of Nd3+ ion into fluorophosphate glass could enhance the spectroscopic properties which could play as a potential candidate for solid state applications. Theoretical optical gain evaluation and experimental calculation confirmed that PANCaFN2 had the higher gain than other samples.