Effect of concentration on spectral properties of lanthanide ions-doped fluorophosphate glasses

Abstract

Concentration dependent spectroscopic properties of Ln3+ (Ln= Nd, Sm, Dy and Yb) -doped fluorophosphate glasses have been investigated. From the absorption spectra, Judd-Ofelt (JO) intensity parameters have been evaluated which are in turn used to predict radiative properties for the fluorescent levels of the said Ln3+ ions. For example, three JO intensity parameters (Ω2, Ω4 and Ω6) for the Dy3+ ions in fluorophosphate glass are found to be Ω2 = 12.34 × 10-20 cm2, Ω4 = 2.67 × 10-20 cm2 and Ω6 = 2.30 × 10-20 cm2. Using FTIR spectra, OH- content in 1.0 mol% Nd2O3 -doped samples, responsible for quenching the lifetimes of Nd3+ ions, is found to be 2.01×1020 ions/cm3 which is very much less compared to other reported glass systems. The decay profiles for the 4G5/2 level of Sm3+ ions in the flurophosphate glasses are found to change from single exponential (0.1 mol%) to non-exponential (0.5, 1.0, 2.0, 4.0 and 6.0 mol%) with shortening of lifetimes. The Yb3+ -doped fluorophosphate glasses possess high absorption (2.55 cm2) and emission (3.44 cm2) cross-sections and high figure of merit (3.33). The analysis of the results confirm that the Ln3+ -doped fluorophosphate glasses could be useful for the development of photonic devices.