Optical and structural investigation of dysprosium doped-Y2Te4O11

In this paper, the optical properties of Y2Te4O11 microcrystalline powders doped with Dy3+ ions, ranging between 0.01 and 5.0 at%, are reported. The powders were successfully synthesized by the solid state reaction method. Absorption (300 K), excitation (300 K) and fluorescence spectra (at 11.6 and 300 K) as well as fluorescence decay curves recorded at room temperature are presented and analyzed in details. Oscillator strengths, phenomenological Ωλ (λ=2, 4, 6) Judd-Ofelt parameters, radiative transition probabilities, branching ratios, the radiative lifetime of the 4F9/2 level as well as the stimulated emission cross-section for the 4F9/2→ 6H13/2 transition have been determined. The observed non-exponential decay nature and concentration quenching of the 4F9/2 emitting level of the Dy3+ ion, have been attributed to cross-relaxation processes. The high value of the stimulated emission cross-section for the 4F9/2→ 6H13/2 transition at 576.6 nm, equal to 0.756×10−20 cm2, indicates that Y2Te4O11 activated by trivalent dysprosium ions is an attractive candidate for a solid-sate laser.