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

Abstract

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 (⁴I_15/2 → ⁴I_13/2) of Er³⁺ ions. The energy transfer mechanism that leads to the quenching of lifetimes of ¹D₂ and ⁴I_13/2 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.

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