掺Er3+碲酸盐玻璃的光谱性质与Judd-Ofelt理论分析

用高温熔融法制备了碲酸盐玻璃(70TeO₂-9B₂O₃-6Nb₂O₅-5Na₂O-10ZnO-1%(质量分数)Er₂O₃)样品。测试了玻璃样品的吸收光谱和荧光光谱。应用Judd-Ofelt理论计算了Er³⁺离子的谱线强度、自发辐射跃迁几率、荧光分支比、辐射寿命等光谱参数,并拟合了相应的强度参数Ω_t(t=2,4,6)(Ω₂=8.01×10^-20cm²,Ω₄=2.09×10^-20cm²,Ω₆=1.15×10^-20cm²)。结果发现该碲酸盐玻璃具有较大的Ω₂值,说明Er—O键的共价性强于它在硅酸盐、锗酸盐、氟化物、铋酸盐和磷酸盐玻璃中的共价性。Er³⁺在碲酸盐玻璃中⁴I_13/2→⁴I_15/2跃迁几率约为492s^-1,表明Er³⁺可能有较强的1.5μm发射。分析了Er³⁺在碲酸盐玻璃中能级⁴I_13/2→⁴I_15/2发射的荧光半峰全宽(FWHM=73nm),并应用McCumber理论计算了Er³⁺的受激发射截面(σ_e=1.08×10^-20cm²),发现其FWHM×σ_e远大于Er³⁺在铋酸盐、磷酸盐、锗酸盐和硅酸盐玻璃中的受激发射截面,说明碲酸盐玻璃是一种制备宽带光纤放大器的优良基质材料。

Spectroscopic Properties and Judd-Ofelt Theory Analysis of Er3+ Doped Tellurite Glass

The new Er³⁺ doped tellurite glass(70TeO₂-9B₂O₃-6Nb₂O₅-5Na₂O-10ZnO) was prepared by the technique of high-temperature melting.The spectral properties,such as absorption spectra and emission spectra of the glass sample have been measured and investigated.The Judd-Ofelt intensity parameters Ω_t(t=2,4,6)(Ω₂=8.01×10^-20 cm²,Ω₄=2.09×10^-20 cm²,Ω₆ =1.15×10^-20 cm²),transition probabilities,excited state lifetimes and the branching ratios have been predicted of several Er³⁺ ions transitions based on the Judd-Ofelt theory.Compared with the other glass hosts,it found that the Ω₂ is bigger of Er³⁺ in this tellurite glass,which shows that the covalency between the Er³⁺ and O^2- is stronger than silicate,germanate,fluorid,bismuthate,and phosphate glass.The transition probability of Er³⁺ in this tellurite glass is about 492 s^-1,indicating that Er³⁺ ions could have strong transition at 1.5 μm in tellurite glass.The broad 1.5 μm fluorescence was observed under 970 nm excitation,and its full width at half maximum(FWHM) is 73 nm.The emission cross-section was calculated according to the McCumber theory.The cross section was quite large due to a large refractive index of the host.The value of FWHM×σ_e for Er³⁺ in tellurite glass is more larger than that of the bismuth,phosphate,germinate and silicate glass.The results showed that the broad and flat ⁴I_13/2→⁴I_15/2 emission of Er³⁺ ions around 1.5 μm can be uses as an potential optical amplifier for the wavelength-division-multiplexing(WDM) network system.