Visible luminescence of Sm3+:K-Ca-Li fluorophosphate glasses

The Sm3+-doped fluorophosphate glasses have been prepared by conventional melt quenching technique and are characterized through structural and optical measurements. The refractive index, density, optical absorption, Judd-Ofelt parameters and spontaneous transition probabilities have been measured, calculated and analyzed. The emission spectra of Sm3+ ions in these glasses have been measured and an intense reddish-orange emission is observed. The luminescence decay curves exhibit single exponential at lower concentrations (<= 0.1 mol%) and turn into non-exponential at higher concentrations (>= 0.5 mol%). The lifetimes for the (4)G(5/2) level of Sm3+ ions are found to decrease (2.95-0.78 ms) with increasing concentration (0.01-3.0 mol%) due to energy transfer processes among Sm3+ ions. Inokuti-Hirayama model was applied in order to obtain information about interactions between the rare earth ions. The non-exponential decay curves are well-fitted to Inokuti-Hirayama model for S = 6 indicating that the nature of the energy transfer process is of dipole-dipole type. (c) 2014 Elsevier B.V. All rights reserved.