Spectroscopic characteristics of Sm3+-doped alkali fluorophosphate glasses

Optical absorption, luminescence and lifetime measurements of Sm3+-doped alkali fluorophosphate glasses with molar compositions of 50(NaPO3)6 + 10TeO2 + 20AlF3 + 19RF + 1Sm2O3 (R = Li, Na and K) are described. The variation of optical properties with glass composition plays a dominant role in the determination of efficient laser materials. From the experimental oscillator strengths of f–f electric dipole transitions, the phenomenological Judd–Ofelt parameters have been evaluated and are used to evaluate radiative parameters such as radiative transition probabilities (AR), branching ratios (βR), lifetimes (τR) and integrated absorption cross-section (σa) for various excited levels. The predicted values of τR and βR from the 4G5/2 excited level to its lower levels are compared with the experimentally measured values. Stimulated emission cross-sections (σe) were also determined for 4G5/2 → 6HJ (J = 5/2, 7/2, 9/2 and 11/2) emission transitions. From the emission transitions of Sm3+ in these alkali tellurofluorophosphate glasses certain potential laser transitions have been identified.