Luminescence studies on Er3+ -doped zincfluorophosphate glasses for 1.53 μm laser applications

Abstract

The Er3+-doped zincfluorophosphate glasses have been prepared by conventional melt-quenching technique and characterized through X-ray diffraction, differential thermal analysis, Raman, visible and near-infrared (NIR) emission spectra and decay time measurements. Judd-Ofelt intensity parameters (Ωλ, λ = 2, 4 and 6) have been derived from the absorption spectrum and inturn used to calculate the radiative properties for the fluorescent levels of Er3+ ions. The studied glasses exhibit intense green and weak red emissions under 378 nm excitation and an intense NIR emission at 1.53 μm under 980 nm laser diode excitation. The wavelength dependence of gain cross-section for different values of population inversion (γ) has been derived from the McCumber theory. Lifetime for the 4I13/2 level of Er3+ ion is found to decrease from 7.17 to 1.42 ms whereas the gain bandwidth increases from 143.5 to 263.9 × 10−28 cm3 with increase of Er3+ concentration from 0.001 to 2.0 mol %. The results indicate that the glasses may be suitable for the development of optical amplifier in the 1.53 μm optical region.