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In this paper, the optical properties of Y 2 Te 4 O 11 microcrystalline powders doped with Dy 3+ 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 Ω λ ( λ =2, 4, 6) Judd-Ofelt parameters, radiative transition probabilities, branching ratios, the radiative lifetime of the 4 F 9/2 level as well as the stimulated emission cross-section for the 4 F 9/2 → 6 H 13/2 transition have been determined. The observed non-exponential decay nature and concentration quenching of the 4 F 9/2 emitting level of the Dy 3+ ion, have been attributed to cross-relaxation processes. The high value of the stimulated emission cross-section for the 4 F 9/2 → 6 H 13/2 transition at 576.6 nm, equal to 0.756×10 −20 cm 2 , indicates that Y 2 Te 4 O 11 activated by trivalent dysprosium ions is an attractive candidate for a solid-sate laser. [ABSTRACT FROM AUTHOR]

Among a wide variety of solid state materials, alkali lanthanide double phosphates are the subject of extensive spectroscopic investigations for their application as laser active materials. The edge of absorption in this compound is at rather high energies, which makes them suitable as efficient host for luminescent materials. Spectroscopic properties of Sm 3+ -doped K 3 Y(PO 4 ) 2 are reported basing on the high resolution absorption and emission spectra for various temperatures mainly at 4, 10, and 293 K from UV to IR range. The effects of concentration and temperature on intensities and shape of the observed bands were studied. Radiative transition probabilities were calculated from absorption spectra and Judd–Ofelt parameters evaluated. The excited state dynamics will be discussed based on the decay time measurement. [ABSTRACT FROM AUTHOR]

Spectroscopic properties of Sm 3+ -doped Y 2 Te 4 O 11 micro-crystals were studied in the 6000–18,500 cm −1 spectral range. Vibrational, electronic absorption, fluorescence and excitation spectra as well as fluorescence dynamics of the Sm 3+ -doped title micro-crystals are presented and analyzed in detail. A Judd–Ofelt intensity analysis of the absorption spectrum at 300 K has been applied for determination of Ω λ parameters which in turn have been used for calculations of the radiative transition probability factor ( A ), the fluorescence branching ratios ( β ), the natural (radiative) lifetime of the 4 G(4) 5/2 level of Sm 3+ and the emission cross-section ( σ em ). An analysis of the non-radiative decay was based on the cross-relaxation mechanisms. The achieved results indicate that the investigated samples are potentially applicable as a 605 and 652 nm laser host as well as an orange phosphor. [ABSTRACT FROM AUTHOR]