Luminescence spectral studies of Tm3+ ions doped Lead Tungsten Tellurite glasses for visible Red and NIR applications

Abstract

Lead Tungsten Tellurite (LTT) glasses doped with different concentrations of Tm3+ ions of composition (60−x) TeO2+25WO3+15PbF2+xTm2O3 (Here x=0.1, 0.5, 1.0, 1.5, 2.0, 2.5mol%) were prepared by using melt quenching technique and characterized through optical absorption, photoluminescence and decay spectral studies to know the feasibility of using these glasses as luminescent devices in visible Red and NIR regions. Judd–Ofelt (J–O) theory has been applied to the optical absorption spectral profiles to calculate the J–O intensity parameters Ωλ (λ=2, 4 and 6) and consecutively used to evaluate various radiative properties such as radiative transition probability (AR), radiative lifetimes (τR) and branching ratios (βR) for the prominent luminescent levels. The luminescence spectra for all the LTT glass samples have two intense peaks in bright red and near Infrared regions at 650nm (1G4→3F4) and 800nm (3H4→3H6) respectively for which effective band widths (ΔλP), experimental branching ratios (βexp) and stimulated emission cross-sections (σse) are evaluated. The decay profiles for all the glasses are recorded to measure the quantum efficiency by coupling the radiative with experimental lifetimes. From the measured emission cross-sections, quantum efficiency and CIE chromaticity co-ordinates, it was found that 0.5mol% of Tm3+ ions doped LTT glass is most suitable for generating bright visible Red and NIR lasers to operate at 650 and 800nm respectively.