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Lead fluorosilicate (SKNPfLfDy) glasses doped with various Dy 3+ ion concentrations employed via melt-quenching method have been prepared and studied their thermal, optical and spectral properties for the spreading out of yellow laser applications. The emission spectra have prominent emission at 575 nm ( 4 F 9/2  →  6 H 13/2 ) transition. The stimulated emission cross-section (5.14 × 10 -21  cm 2 ) and branching ratio (62%) for the 4 F 9/2  →  6 H 13/2 transition were found to be relatively high. Lifetime is decreased from 1192 μs to 34 μs with increase in concentration due to concentration quenching as well cross-relaxation among the Dy 3+ ions. The quantum efficiency found to be 69%. The optical gain, figure of merit, yellow/blue (Y/B) intensity ratio and gain bandwidth for 1.0 mol% Dy 3+ :SKNPfLf glass is found to be 27.55 × 10 -25  cm 2  s, 19.01 × 10 -25  cm 2  s, 3.96 and 63.32 × 10 -28  cm 3 , respectively. The obtained results revealed that the SKNPfLfDy glasses possibly useful for yellow laser applications., (Copyright © 2019. Published by Elsevier B.V.)

Neodymium doped phosphate based glasses with composition of (P 2 O 5 +K 2 O+Al 2 O 3 +CaF 2 ) were prepared. The samples were analysed through differential thermal analysis (DTA), Fourier transform infrared (FTIR), absorption, emission and decay measurements. Judd-Ofelt parameters (Ω λ ) have been determined from the spectral intensities of absorption bands in order to calculate the radiative parameters like radiative transition probabilities (A R ), radiative lifetime (τ R ) and branching ratios (β R ) for the 4 F 3/2 → 4 I 11/2 laser transition of Nd 3+ ion. The effective emission bandwidths (Δλ eff ), experimental branching ratios (β exp ) and stimulated emission cross-sections (σ e ) have been determined from the emission spectrum. The decay curves of the 4 F 3/2 level exhibited almost single exponential nature for all the Nd 3+ ion concentrations., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Yttrium borate phosphors (KY(1-x)DyxBO3) doped with Dy(3+) ions were synthesized by the solid-state reaction method. The structural and morphological characteristics were studied by XRD, FTIR and SEM measurements. Luminescent properties of different concentrations of KY(1-x)DyxBO3 phosphors were investigated from the excitation, emission and decay analyses. The emission spectra exhibited characteristic blue (460-500nm) and yellow (555-610nm) bands of Dy(3+) ions which combines to give white light. The evaluated color co-ordinates (x, y) were found to lie within the white light region of CIE chromaticity diagram. All the decay curves of Dy(3+) ions exhibited non-exponential nature and the experimental lifetimes for the (4)F9/2 excited level were found to decrease from 0.87, 0.47, 0.35, 0.26 and 0.13ms with the increase of Dy(3+) ion concentrations from 0.05, 0.1, 0.15, 0.2 and 0.3mol%, respectively. In order to understand the energy transfer mechanism, the decay curves were fitted to Inokutti-Hirayama model and found that the energy transfer is of dipole-dipole type. From the results of these investigations, it is concluded that the KY(1-x)DyxBO3 phosphors are more useful for white light emitting diodes., (Copyright © 2016 Elsevier B.V. All rights reserved.)