Effect of ZnO on spectroscopic properties of Sm3+ doped zinc phosphate glasses

Spectroscopic properties of Sm3+ containing zinc oxide based phosphate glasses in the chemical composition (50−x)P2O5+20Na2HPO4+9AlF3+xZnO+1Sm2O3 (where x=5, 10, 15, 20 and 25) have been studied. Raman, optical absorption, emission spectra and luminescence decay profiles were recorded and systematically analyzed. Using Judd–Ofelt theory, Judd–Ofelt intensity parameters Ωλ (λ=2, 4 and 6), spontaneous radiative transition probabilities (Arad), radiative lifetimes (τR), branching ratios (β) were calculated and discussed. With 400 nm wavelength excitation, the emission spectra and decay lifetime of 4G52 level of Sm3+ doped zinc-phosphate glasses were studied. The branching ratios and emission cross-sections for the transition, 4G5/2→6H7/2 are found to be higher for x=25 mol% of zinc-phosphate glass matrix. The observed decay profiles were found to be exhibiting non-exponential behavior for all zinc-phosphate glasses, due to non-radiative energy transfer among the excited Sm3+ ions.