Spectroscopic properties of heavily Ho^(3+) -doped barium yttrium fluoride crystals

The 30 at.% Ho： BaY2F8 crystals were grown by the Czochralski method, and their spectroscopic properties are analyzed systematically by standard Judd–Ofelt theory. The Judd–Ofelt intensity parameters are estimated to be Ω2 =6.74 × 10^-20cm^2,Ω4 = 1.20 × 10^-20cm^2, and Ω6= 0.66 × 10^-20cm^2, and the fluorescence branching ratios and radiative lifetimes for a series of excited state manifolds are also determined. The emission cross sections with our measured infrared luminescence spectra, especially important for 4.1 μm, are calculated to be about 4.37 × 10^-21cm^2. The crystal quality is preliminarily tested through a mid-infrared laser emission experiment.

Effect of chloride introduction on the optical properties in Eu^(3+)-doped fluorozirconate glasses

Fluorozirconate glass containing Euions and chloride ions are prepared by a meltquenching method. The luminescence behavior of Euaffected by Cl ions is investigated. With increasing Cl ion concentration, the luminous intensity of Euis significantly enhanced and the quantum efficiency of fluorozirconate glass is improved. Meanwhile, the intensity parameter ?increases according to the Judd–Ofelt calculation, which indicates the decrease of local symmetry. The average lifetime of Euincreases by introducing the Cl ions. Moreover, we find two kinds of sites for Euions in a glass network by analyzing the fluorescence decay. The distribution of Euions changes with increasing Cl ion concentration.In addition, the excessive Cl ions lead to the separation of the glass phase and the formation of the crystal phase, thus reducing the transmittance dramatically.

Spectral Parameter Study on Tm^(3+) in Na_5Tm(WO_4)_4 Crystal

On the basis of the obtained intensity parameters Ω λ(λ =2,4,6) of Tm 3+ in the Na 5Tm(WO 4) 4 crystal, we performed calculations on the radiative transition probability, radiative lifetime, branching ratios and stimulated emission integrated cross sections between the two excited J manifolds of Tm 3+ , and discussed potentiality for the usage of this crystal as a laser material.

Spectroscopic properties in Er^(3+)/Yb^(3+) Co-doped fluorophosphate glass

Using the technique of high-temperature melting, a new Er3＋/Yb3＋ co-doped fluorophosphate glass was prepared. The absorption and fluorescence spectra were investigated in depth. The effect of Er3＋ and Yb3＋ concentration on the spectroscopic properties of the glass sample was also discussed. According to the Judd Ofelt theory, the oscillator strength was computed. The lifetime of 4113/2 level （t-m） of Er3＋ ions was 8.23 ms, and the full width at half maximum of the dominating emission peak was 68 nm at 1.53 μm. The large stimulated emission cross section of the Er3＋ was calculated by the McCumher theory. The spectroscopic properties of Er3＋ ion were compared with those in different glasses. The full width at half maximum and σe are larger than those of other glass hosts, indicating this studied glass may be a potentially useful candidate for high-gain erbium-doped fiber amplifier.

Er^(3+)-doped fluorogallate glass for mid-infrared applications

We report an Er3＋-doped fluorogallate glass with good thermal and chemical stability. The low maximum phonon energy and high mid-infrared （IR） transmittance of the glass are confirmed by Raman and IR spectra, respectively. Based on Judd-Ofelt theory, intensity parameters and radiative properties are determined from the absorption and emission spectra. The proposed glass possesses a large fluorescence branching ratio β （21.71%） and a maximum stimulated emission cross-section σem of Er3＋：4 I11/2 → 4 I13/2 transition at 2.71 μm （1.04 × 10^-20 cm2）. The results indicate that it can be potentially applied in high-power 2.7 μm fiber lasers.

Spectroscopic properties and energy transfer processes in Er^(3+)/Nd^(3+) co-doped tellurite glass for 2.7-μm laser materials

Intense 2.7-μm emissions are obtained from Er3＋/Nd3＋ co-doped tellurite glass samples under the 808-nm laser diode excitation. According to the absorption spectra, Judd-Ofelt parameters and radiative transition probabilities are calculated and analyzed using the Judd-Ofelt theory. The spectroscopic properties and energy transfer mechanism between Er3＋ and Nd3＋ are analyzed. The effects of OH- content on the spectroscopic properties of Er3＋/Nd3＋ co-doped samples are discussed. The obtained results indicate that Er3＋/Nd3＋ co-doped tellurite glass can significantly develop optical properties of 2.7-μm emission, if OH- groups can be effectivelv eliminated.