Absorption and fluorescence properties of Sm3+ ions in fluoride containing phosphate glasses

Optical absorption, fluorescence and lifetime characteristics of Sm3+-doped fluoride containing phosphate glasses (PKFBASm) with molar composition of (56-x/2) P2O5 + 14 K2O + 6KF + (15-x/2) BaO + 9Al(2)O(3) + x Sm2O3, (x = 0.01, 0.05, 0.1, 1.0. 2.0, 4.0 and 6.0 mol%) were studied. From the measured energies of absorption bands, different free-ion energy level parameters along with calculated energies were determined using the free-ion Hamiltonian (H-FI) model. Judd-Ofelt (J-O) theory was applied to the experimental oscillator strengths to evaluate three phenomenological J-O intensity parameters Omega(lambda) (lambda = = 2, 4 and 6). Using these J-O parameters as well as from the emission and decay measurements, various radiative parameters such as transition probabilities (A(R)), radiative lifetimes (tau(R)), measured lifetimes (tau(mes)). calculated branching ratios (beta(R)), measured branching ratios (beta(mes)), effective bandwidths (Delta lambda(eff)) and stimulated emission cross-sections (sigma(lambda p)) have been calculated for the excited (4)G(5/2) luminescent level. The nature of decay curves of (4)G(5/2) level for different Sm3+ ion concentrations in all PKFBASm glasses has been analyzed using Inokuti-Hirayama (1-H) model and the lifetimes are noticed to decrease with increase of concentration. The cross-relaxation mechanism responsible for the quenching of measured lifetimes with concentration is also discussed. (C) 2009 Elsevier B.V. All rights reserved.