Structural and spectroscopic studies on concentration dependent Er3+ doped boro-tellurite glasses

Er³⁺ doped boro-tellurite glasses have been prepared by the conventional melt quenching technique with the chemical composition (39?x) B₂O₃+30TeO₂+15MgO+15K₂O+xEr₂O₃ (where x=0.01, 0.1, 1, 2 and 3 wt%). The structural analysis of the glasses were made through XRD, FTIR spectral measurements and the optical absorption, luminescence measurements were made to analyze the optical behavior of the prepared glasses. The bonding parameters were determined from the optical absorption spectra and were found to be ionic in nature. The experimental oscillator strengths were determined from the absorption spectra have been used to determine the Judd–Ofelt parameters. The Judd?Ofelt parameters were used to explore the important radiative parameters such as transition probability (A), stimulated emission cross-section (σ_P^E) and branching ratios (β_R) of the emission transitions ²H_9/2→⁴I_15/2 and ²H_11/2 and ⁴S_3/2→⁴I_15/2 of the trivalent erbium ions. The optical band gap energy (E_opt) values corresponding to the direct and indirect allowed transitions and the Urbach energy values of the prepared Er³⁺ doped boro-tellurite glasses have been calculated and discussed with similar studies. The spectroscopic behavior of the Er³⁺ boro-tellurite glasses have been studied by varying the trivalent erbium ion content and the results were discussed and compared with similar studies.     

Judd–Ofelt analysis and improvement of thermal and optical properties of tellurite glasses by adding P2O5

Er³⁺ and Er³⁺/Yb³⁺ co-doped tellurite glasses, suitable for developing optical fiber laser and amplifier, have been elaborated from the conventional melt-quenching method. Results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of tellurite glasses. The DSC measurements show an improvement of thermal stability of glass hosts after adding P₂O₅. Absorption spectrum from near infrared to visible was obtained and the Judd–Ofelt (J–O) intensity parameters (Ω₂, Ω₄, and Ω₆) were determined. Spontaneous emission probabilities of some relevant transitions, branching ratio, and radiative lifetimes of several excited states of Er³⁺ have been predicted using intensity J–O parameters. Absorption cross-section and calculated emission cross-section, using the McCumber method, for the ⁴I_13/2→⁴I_15/2 transition, were determined and compared for the doped and co-doped glasses. Energy transfer (ET) and effect of changing concentration of P₂O₅ and Yb³⁺ ions on spectroscopic properties were investigated. It was found that the addition of P₂O₅ can increase the symmetry of the Er³⁺ ion. As a consequence, PL lifetime becomes more longer.The spectroscopic properties and the efficient infrared luminescence indicate that Er³⁺ doped TeO₂–ZnO–Na₂O–Er₂O₃(TZNE) is a promising laser and amplifier materials and may be a potentially useful material for developing upconversion fiber optical devices.     

Optical absorption and emission properties of Pr and Er in lithium cesium mixed alkali borate glasses

This article presents the optical absorption and emission properties of Pr³⁺ and Er³⁺ in mixed alkali borate glasses of the type 68B₂O₃·xLi₂O·(32-x)Cs₂O (where x=8, 12, 16, 20 and 24). The variation of Judd-Ofelt intensity parameters (Ω_λ), the peak wavelength of the hypersensitive transitions, radiative transition probabilities (A_rad) and peak emission cross-sections (σ_p) with x in the glass matrix have been discussed in detail. The changes in position of hypersensitive transition and intensity parameters with x are correlated to the structural changes in the host matrix. The estimated radiative lifetimes (τ_R) of certain excited states of both Pr³⁺ and Er³⁺ in lithium cesium mixed alkali borate glasses are reported. Branching ratios (β) and integrated absorption cross-sections (Σ) for certain important transitions are presented. Peak stimulated emission cross-sections (σ_p) are calculated for the observed emission peaks of Pr³⁺ and Er³⁺ ions in this glass matrix.     

Comparative investigation on spectroscopic properties of Er between Ce-doped and B2O3-added bismuth glasses

The comparative investigation on the spectroscopic properties of Er³⁺ in low phonon energy Bi₂O₃-GeO₂-Ga₂O₃-Na₂O glasses codoped with Ce³⁺ ion and added with B₂O₃ component, respectively, is presented. With increasing Ce₂O₃ content from 0 to 0.8 mol% or B₂O₃ content from 0 to 15 mol%, the lifetime of Er³⁺:⁴I_11/2 level decreases dramatically from 607 to 283 μs or to 197 μs, and the upconversion fluorescence is quenched in both glass samples. The nonradiative energy transfer from Er³⁺:⁴I_11/2→Ce³⁺:²F_5/2 or the enhanced multiphonon relaxation process together with the energy transfer between Er³⁺ and OH⁻ groups are, respectively, responsible for the results. Meanwhile, the lifetime of ⁴I_13/2 level remains almost unchanged in Er³⁺/Ce³⁺-codoped glasses whereas it decreases rapidly in B₂O₃-added cases. As a result, Er³⁺/Ce³⁺ codoping improves the 1.5 μm fluorescence emission intensity, however, B₂O₃ addition has a negative effect on it. The research results indicate that the Er³⁺/Ce³⁺-codoped bismuth glasses will be preferable for obtaining efficient 980 nm pumped EDFA.     

Er3+/Yb3+共掺碲硼硅酸盐玻璃的光谱性质和热稳定性研究

制备了系列Er³⁺/Yb³⁺共掺碲硼硅酸盐玻璃样品(85-x)TeO₂-15B₂O₃-xSiO₂ (TBS x=0,5,10,15,20 mol%).测试和分析了样品的吸收光谱、荧光光谱、能级寿命、红外透射光谱及差热特性.并通过对Er³⁺离子⁴I_13/2→⁴I_15/2跃迁发射谱线的高斯拟合，设计了一个简单的四能级结构估算了Er³⁺离子⁴I_13/2和⁴I_15/2能级在碲硼硅酸盐中的Stark分裂情况.研究表明SiO₂的引入能有效地改善玻璃的热稳定性和光谱性能，玻璃析晶温度T_x与玻璃转变温度T_g之差(ΔT=T_x-T_g)可达178℃，说明碲硼硅酸盐是一种适合于光纤拉制的玻璃基质材料.比较了不同基质玻璃中Er³⁺离子的荧光半高宽和受激发射截面，结果表明TBS玻璃系统具有较好的带宽性能，是一种优良的宽带光纤放大器候选基质材料. 关键词： 碲硼硅酸盐 热稳定性 高斯拟合 -基')" href="#">OH^-基     

可紫外激光刻写的掺铒铋硅酸盐玻璃光谱性质研究

报道了可紫外激光刻写的掺铒Na₂O-Bi₂O₃-SiO₂和Na₂O-B₂O₃-Bi₂O₃-SiO₂玻璃的光谱特性. 测量和计算了玻璃的光谱参数，分析、讨论了Bi₂O₃和B₂O₃含量变化对光谱参数的影响.实验表明基质玻璃中Bi₂O₃和B₂O₃含量改变可有效调节掺铒铋硅酸盐玻璃光谱参数.Bi₂O₃和B₂O₃含量增加，玻璃的光吸收和荧光性质改善，但Er³⁺离子的⁴I_13/2能级寿命降低.在B₂O₃含量为40%(Bi₂O₃/SiO₂＝0.67)时，Er³⁺离子峰值发射截面、⁴I_13/2能级的荧光寿命和荧光半高宽分别为8.49×10^－21cm²，0.52ms和78nm.结果表明掺铒铋硅酸盐玻璃是有前途的紫外光敏有源玻璃材料之一.     

The microscopic interaction parameters for Er/Ho energy transfer in tellurite glasses

We investigate the energy transfer between Er³⁺/Ho³⁺ in tellurite glasses. The main channels of energy transfer between Er³⁺/Ho³⁺ are analyzed in detail. The microscopic interaction parameters of resonant and non-resonant (phonon-assisted) energy transfer parameters via Er³⁺→Ho³⁺ are calculated. The result shows that the resonant energy transfers Er³⁺(²H_11/2(⁴S_3/2))→Ho³⁺(⁵F₄(⁵S₂)) and Er³⁺(⁴F_9/2)→Ho³⁺(⁵F₅) are very efficient and non-resonant energy transfers Er³⁺(⁴I_13/2)→Ho³⁺(⁵I₇) and Er³⁺(⁴I_11/2)→Ho³⁺(⁵I₆), which are a phonon-assisted energy transfer process because of energy mismatch are also existed and cannot be neglected.     

WO3对掺铒碲酸盐玻璃光谱性质的影响

制备了掺铒碲钨酸盐玻璃(80-x)TeO₂-(10+x)WO₃-8BaO-2Na₂O-0.5Er₂O₃(x=0,5,10,15,20)玻璃,研究了WO₃对掺铒碲钨酸盐玻璃的光谱性质. 研究发现：随着WO₃含量的增加,Ω₄,Ω₆先增加后减小,受 关键词： 碲钨酸盐玻璃 3+光谱性质')" href="#">Er³⁺光谱性质 Judd-Offelt理论     

Lead−barium fluoroborate glass ceramics doped with Nd<Superscript>3+</Superscript> or Er<Superscript>3+</Superscript>

Lead?barium fluoroborate glasses in the PbF₂–BaF₂–B₂O₃, PbF₂–BaO–B₂O₃, and PbO_– BaF₂–B₂O₃ systems doped with rare-earth ions (Nd³⁺ or Er³⁺) are synthesized and studied. It is shown that, based on these glasses, it is possible to produce transparent glass ceramics with fluoride crystalline phases, including ceramics with one crystalline phase of the fluorite structure. The spectral and luminescent properties of the doped glasses, glass ceramics, and polycrystalline complex fluorides containing Pb, Ba, and rare ions are studied.     

Optical Analysis of Er3+:Boro-Fluoro-Phosphate Glasses

This paper deals with the preparation and optical analysis of Er³⁺ (0.2 mol%) boro-fluoro-phosphate glasses in the following glass compositions:

• Series A: 69.8 B₂O₃–10 P₂O₅–10(ZnO/CdO/TeO₂)–10 AlF₃

• Series B: 69.8 B₂O₃–10 P₂O₅–10(ZnO/CdO/TeO₂)–10 LiF

Measured Vis-NIR absorption spectra of Er³⁺:boro-fluoro-phosphate glasses have revealed nine absorption bands at 377 nm, 405 nm, 450 nm, 486 nm, 519 nm, 543 nm, 649 nm, 973 nm and 1529 nm, which correspond with the transitions of ⁴I_15/2 → ⁴G_11/2, (²G_9/2,⁴H_9/2), ⁴F_5/2, ⁴F_7/2, ²H_11/2, ⁴S_3/2, ⁴F_9/2, ⁴I_11/2, and ⁴I_13/2, respectively. With an excitation at λ _exci = 375 nm, a bright green emission (⁴S_3/2 → ⁴I_15/2) at 547 nm has been observed from these erbium glasses. Judd–Ofelt characteristic intensity Ω_λ (λ = 2, 4, 6) parameters are obtained from the absorption spectra, and these results were used to compute the radiative properties of Er³⁺:boro-fluoro-phosphate glasses. The NIR emission (⁴I_13/2 → ⁴I_15/2) at 1547 nm from these glasses was measured with an Ar⁺ laser (514.5 nm) as an excitation source.     

混合形成体对掺铒碲酸盐玻璃的热力学稳定性和发光性能的影响

研究了混合形成体效应对掺铒碲酸盐玻璃热力学稳定性、1.53 μm发光特性和上转换发光强度的影响.通过拉曼光谱测试,分析了WO₃,Nb₂O₅,GeO₂等氧化物对Er³⁺离子配位场结构,以及对发光谱的非均匀展宽机理的作用.结果表明,通过掺杂适当声子能量的网络形成体氧化物,不但可获得热力学稳定性较好的玻璃,还可有效降低Er³⁺离子⁴I_11/2能级的寿命,在抑制Er³⁺离子在可见光波段的上转换发光的同时不致劣化其在1.53 μm的发光特性.本文制得的碲酸盐玻璃具有较大的受激发射截面((9.64—10.96)×10^-21cm²)和荧光半高宽(FWHM)(50—67 nm),热力学稳定性良好,是一种理想的掺Er³⁺宽带有源光纤用基质玻璃. 关键词： 掺铒碲酸盐玻璃 混合形成体 1.53 μm发光 声子能量     

Luminescence enhancement in (Nd+Ce) doped SiO2 : Al2O3 sol–gel glasses

An enhancement in NIR luminescence from Nd³⁺-doped Ce³⁺ co-doped SiO₂+Al₂O₃ sol–gel glasses has been observed. The lasing transition (⁴F_3/2→⁴I_11/2) at 1072 nm from the dual rare-earth Nd³⁺+Ce³⁺-doped glasses has shown an emission strength of about five times that of the single rare-earth ion Nd³⁺-doped glass. From the measurement of lifetimes of the transition at 1072 nm, the transfer rate (W_tr), critical distance (R₀) and energy transfer efficiency (η) of the neodymium glasses have been calculated.     

Ce3+对Er3+/Yb3+共掺TeO2-WO3-ZnO玻璃发光性能的影响

在Er³⁺/Yb³⁺共掺TeO₂-WO₃-ZnO玻璃中引入Ce³⁺，研究了Ce³⁺对Er³⁺1.5μm发射性能及其上转换发光性能的影响。结果表明，随Ce³⁺浓度的增加Er³⁺1.5μm波段的荧光强度先增强后降低，优化的Ce³⁺掺杂浓度在2.07×10²⁰/cm³左右；1.5μm波段的荧光寿命则随Ce³⁺浓度的增加有轻微降低，从3.4ms降到3.0ms，但Ce³⁺浓度的增加对1.5μm波段的荧光半高宽基本无影响；Er³⁺/Ce³⁺间的交叉弛豫Er³⁺(⁴I_11/2)+Ce³⁺(²F_5/2)→Er³⁺(⁴I_13/2)+Ce³⁺(²F_7/2)使玻璃的上转换发光强度大大降低，但在过高的Ce³⁺浓度下，Er³⁺/Ce³⁺间的另一交叉弛豫Er³⁺(⁴I_13/2)+Ce³⁺(²F_5/2)→Er³⁺(⁴I_15/2)+Ce³⁺(²F_7/2)则使Er³⁺⁴I_13/2能级粒子数减少，导致1.5μm波段荧光强度和荧光寿命降低. 关键词： 碲钨酸盐玻璃 发光性能 3+离子')" href="#">Er³⁺离子 3+离子')" href="#">Ce³⁺离子 交叉弛豫     

Broadband 1.5-μm emission of high erbium-doped Bi2O3–B2O3–Ga2O3 glasses

High Erbium-doped glass showing the wider 1.5-μm emission band is reported in the Bi₂O₃–B₂O₃–Ga₂O₃ system and its thermal stability and optical properties such as absorption, emission spectra, absorption and stimulated emission cross-sections and fluorescence lifetime are investigated. Compared with other glass hosts, the gain bandwidth properties of high Er³⁺ content in BBG glass are better than those of tellurite, germanate, silicate and phosphate glasses. The broad and flat ⁴I_13/2→⁴I_15/2 emission and the larger stimulated emission cross-section of Er³⁺ ions around 1.5 μm enable it to be used as a host material for potential broadband optical amplifiers at C and L bands in the microchip configuration.     

Spectroscopic investigations on Tb3+ doped lead fluoroborate glasses

This article presents the optical properties of Tb³⁺ in lead fluoroborate glasses of the type X PbF₂·(89–X)B₂O₃·10 Al₂O₃·1Tb₂O₃ (where X=8, 12, 16, 20, 24, 28, 34 and 36). The standard Judd–Ofelt model was applied to the room temperature absorption intensities of Tb³⁺ (4 f⁸) to determine the phenomenological intensity parameters Ω₂, Ω₄ and Ω₆. These parameters have been used to calculate radiative transition probabilities (A_rad), lifetimes (τ_R) and branching ratios (β_R) for the excited level ⁵D₄. The predicted values of τ_R are compared with the measured values for ⁵D₄ level for eight glass compositions (Glass (A–H)). Among the eight-terbium glasses Glass A with 8 mol% of PbF₂ (as the optimum content) has revealed an intense green emission with maximum life time and higher quantum efficiency. The stimulated emission cross section σ(λ_P) is also evaluated for the ⁵D₄→⁷F_J (J=6, 5, 4 and 3) transitions.     

Er3+-doped sol–gel SnO2 for optical laser and amplifier applications

Erbium-doped tin dioxide (SnO₂:Er³⁺) was obtained by the sol–gel method. Spectroscopic properties of the SnO₂:Er³⁺ are analyzed from the Judd–Ofelt (JO) theory. The JO model has been applied to absorption intensities of Er³⁺ (4f¹¹) transitions to establish the so-called Judd–Ofelt intensity parameters: Ω₂, Ω₄, and Ω₆. With the weak spectroscopic quality factors Ω₄/Ω₆, we expect a relatively prominent infrared laser emission. The intensity parameters are used to determine the spontaneous emission probabilities of some relevant transitions, the branching ratios, and the radiative lifetimes of several excited states of Er³⁺. The emission cross section (1.31×10^-20 cm²) is evaluated at 1.54 μm and was found to be relatively high compared to that of erbium in other systems. Efficient green and red up-conversion luminescence were observed, at room temperature, using a 798-nm excitation wavelength. The green up-conversion emission is mainly due to the excited state absorption from ⁴ I _11/2, which populates the ⁴ F _3/2,5/2 states. The red up-conversion emission is due to the energy transfer process described by Er³⁺ (⁴I_13/2)+Er³⁺(⁴I_11/2)→Er³⁺(⁴F_9/2)+Er³⁺ (⁴ I _15/2) and the cross-relaxation process. The efficient visible up-conversion and infrared luminescence indicate that Er³⁺-doped sol–gel SnO₂ is a promising laser and amplifier material. PACS 71.20.Eh; 74.25.Gz; 78.55.-m     

Dysprosium doped alkali fluoroborate glasses—Thermal, structural and optical investigations

Thermal, structural and optical properties of Dy³⁺-doped alkali fluoroborate glasses with composition (in mol%), 49B₂O₃+25XO+25NaF+1Dy₂O₃ (where X=Li₂, Na₂, K₂, Mg and Ca), have been investigated. Thermal analysis revealed the homogeneous formation of the glasses. The FTIR spectra reveal that the glasses contain BO₃, BO₄ non-bridging oxygen atoms and strong OH⁻ bonds. From the optical absorption spectra, Judd-Ofelt intensity parameters (Ω_λ, λ=2, 4 and 6) have been evaluated and are in turn used to predict radiative properties such as radiative transition probability (A), stimulated emission cross-section () and branching ratios (β_R) for the excited levels of Dy³⁺ ions in alkali fluoroborate glasses. The dependence of the spectral characteristics of Dy³⁺ ions due to compositional changes has been examined and reported.     

Improvement of thermal and spectroscopic behavior of Er<Superscript>3+</Superscript>/Ce<Superscript>3+</Superscript> co-doped tellurite glass for lasing materials

Tellurite glasses (TeO₂–ZnO–Nb₂O₅) mono-doped Er³⁺ and co-doped Er³⁺/Ce³⁺ have been prepared using the melt-quenching technique. To evaluate the effect of Ce³⁺ on the structural, thermal stability of glass hosts and fluorescence properties of Er³⁺, X-ray diffraction patterns, Ftir spectra, differential scanning calorimeter curves, absorption spectra, fluorescence emission spectra, fluorescence lifetimes, up-conversion emission spectra of glass samples were measured and investigated. Using Judd–Ofelt theory, we calculated intensity parameters (Ω₂, Ω₄ and Ω₆), spontaneous emission probabilities, the radiative lifetime, luminescence branching factors and the quantum yield of luminescence for ⁴I_13/2 → ⁴I_15/2 transition. The co-doping with Ce³⁺ was effective on the suppression of up-conversion emission of Er³⁺ owing to the phonon-assisted energy transfer: Er³⁺:⁴I_11/2 + Ce³⁺:²F_5/2 → Er³⁺:⁴I_13/2 + Ce³⁺:²F_7/2 which contributed the effective enhancement of 1.53 µm fluorescence emission. The change in optical properties with the addition of Ce³⁺ ions have been discussed and compared with other glasses. Using the Mc Cumber method for the ⁴I_13/2 → ⁴I_15/2 transition, absorption cross-section, calculated emission cross-section, and gain cross-section values support that TZNEr1Ce1 glass is a potential material for developing broad-band and high-gain erbium-doped fiber amplifiers applied for 1.53 µm.     

Er3+，Tm3+共掺的NaY(WO4)2晶体的光谱分析和上转换发光

在室温下，测量了Er:Tm:NaY(WO₄)₂晶体的吸收光谱、激发光谱、发射光谱以及上转换发光，并运用J-O理论对测量的结果进行了计算，得出了Er:Tm:NaY(WO₄)₂晶体的强度参数.报道了Tm，Er离子间特殊的能量传递和相关上转换，解释了离子间的能级跃迁过程.同时，对于Er增强Tm离子近红外发光的特性也作了充分研究. 关键词： 4)₂晶体')" href="#">Er:Tm:NaY(WO₄)₂晶体 吸收光谱 发射光谱 激发光谱 上转换     

Effects of Nb2O5 on thermal stability and optical properties of Er3+-doped tellurite glasses

Er³⁺-doped tellurite glasses with molar compositions of xNb₂O₅-(14.7-x)Na₂O--10ZnO--5K₂O--10GeO₂-- 60TeO₂--0.3Er₂O₃ (x=0, 3, 5, 7 and 9) have been investigated for developing 1.5~μm fibre and planar amplifiers. The effects of Nb₂O₅ on the thermal stability and optical properties of Er³⁺-doped tellurite glasses have been discussed. It is noted that the incorporation of Nb₂O₅ (x=5) increases the thermal stability of tellurite glasses significantly. Er³⁺-doped niobium tellurite glasses exhibit a large stimulated emission cross-section (7.2\times 10^-21- 10.7×10^-21~cm² and the gain bandwidth, FWHM×\sigma_e^{\rm peak} (274\times 10^-28 - 480×10^-28~cm³), which are significantly higher than that of silicate and phosphate glasses. In addition, the intensity of upconversion luminescence of the Er³⁺-doped niobium tellurite glasses decreases rapidly with increasing Nb₂O₅ content. As a result, Er³⁺-doped niobium tellurite glasses might be a potential candidate for developing laser or optical amplifier devices.