Intense orange emission in Pr 3+ and NIR emission at 1.53 μm in Er 3+ doped zinc phosphate glasses for potential broadband optical amplifier

Praseodymium (Pr3+) and Erbium (Er3+) doped zinc phosphate glasses with chemical compositions (60 − x) NH4H2PO4 + 20ZnO + 10BaF2 + 10NaF + xRE (where RE = Pr6O11 and Er2O3, x = 0.1, 0.5, 1.0, 1.5 and 2.0 mol%) have been prepared by melt quenching technique. Amorphous structure was ascertained by XRD analysis. The functional and vibrational bands have been assigned and clearly elucidated by FT-IR and Raman spectral profiles for all the glass samples. Judd–Ofelt (J–O) intensity parameters (Ω λ : λ = 2, 4, 6) have been obtained from the spectral intensities of different absorption bands of Pr3+ and Er3+ ions through optical absorption spectra. The radiative properties such as radiative transition probabilities (A R ), radiative lifetimes (τ R ) and branching ratios (β R ) for different excited states were calculated by using J–O intensity parameters. Visible photoluminescence spectra have exhibited six emission bands (3P1 → 3H5, 1D2 → 3H4, 3P0 → 3F2, 3P1 → 3F3, 3P0 → 3F3 and 3P0 → 3F4 states) for all the concentrations of Pr3+ ions. NIR photoluminescence spectra exhibited one emission band (4I15/2 → 4I13/2) of Er3+ ions. The energy transfer mechanism that leads to the quenching of lifetimes of 1D2 and 4I13/2 states have been discussed at higher concentrations of Pr3+ and Er3+ ions, respectively. These glasses were suggested as suitable hosts to produce intense orange emission at 608 nm for Pr3+ ion and efficient lasing action in NIR region at 1534 nm for Er3+ ion.