Tm3+/Ho3+共掺碲酸盐玻璃的2.0μm发光特性及能量传递

研究了Tm³⁺/Ho³⁺共掺TeO₂-WO₃-ZnO玻璃在808 nm激光二极管抽运下的2.0μm发光特性及Tm³+与Ho³⁺之间的能量传递.应用Judd-Ofelt理论计算了Ho³⁺在碲酸盐玻璃中的谱线强度参量Ω_t (t=2,4,6)、自发辐射概率A_r、辐射寿命τ_r等.计算了Ho³⁺的吸收截面σ_a(λ)和受激发射截面σ_e(λ).结果表明：碲酸盐玻璃中Tm³⁺→Ho³⁺正向能量传递系数大约是Tm³⁺←Ho³⁺反向能量传递系数的18倍.Ho³⁺离子的⁵I₇能级的寿命为3.9ms，2.0μm处的最大发射截面为9.15×10^-21cm².在0.5mol% Tm₂O₃和0.15mol% Ho₂O₃共掺的碲酸盐玻璃中能获得2.0μm的最大增益.通过比较氟化物、碲酸盐和镓铋酸盐重金属氧化物等玻璃中Ho³⁺的量子效率η，σ_e×τ_m值和增益系数G(λ)等，发现Tm³⁺/Ho³⁺共掺碲酸盐玻璃是一种理想的2.0μm激光器用基质玻璃. 关键词： 2.0μm发光 能量传递 增益 碲酸盐玻璃

2.0 μm emission properties and energy transfer of Tm3+/Ho3+-codoped tellurite glass

This paper reports on spectroscopic properties and energy transfer of Tm³⁺/Ho³⁺-codoped ZnO-WO₃-TeO₂ glass upon excitation of 808nm diode laser. The J-O strength parameters， spontaneous emission probability and radiative lifetime of Ho³⁺ were calculated using Judd-Ofelt theory. The absorption cross-section and stimulated emission cross-section were also investigated. Our result indicates that the highest gain of 2.0 μm emission, which comes from ⁵I₇ to ⁵I₈ transition of Ho³⁺, might be achieved from the glass at the rare-earth ion concentration of 0.5 mol% of Tm₂O₃ and 0.15 mol% of Ho₂O₃. It is found that coefficients of the forward Tm³⁺→Ho³⁺ energy transfer is about 18 times that for the backward Tm³⁺←Ho³⁺ energy transfer. The calculated fluorescence lifetime of the ⁵I₇ level of Ho³⁺ is 3.9 ms and the emission cross section of the ⁵I₇→⁵I₈ transition of Ho³⁺ exhibits a maximum of 9.15×10^-21 cm² at 2027 nm. We also found that Tm³⁺/Ho³⁺-codoped tellurite glass is a promising host material for potential 2.0 μm laser by comparing the quantum efficiencies, the values of σ_e×τ_m and gain coefficients of fluoride and heavy metal oxide glasses respectively.