Tm3+/Yb3+共掺碲酸盐玻璃的近红外发光及能量传递机理

采用高温熔融法制备了组分为TeO2-ZnO-Na2O的Tm3+离子单掺和Tm3+/Yb3+共掺碲酸盐玻璃,应用Judd-Ofelt理论计算分析了玻璃样品的强度参量Ωt(t=2,4,6),自发辐射跃迁几率A,荧光分支比β和荧光辐射寿命τrad等光谱参量,测量得到了不同Yb3+离子掺杂浓度下玻璃样品的Tm3+离子上转换发光谱.结果显示,在980nm泵浦光激励下玻璃样品发射出强烈的近红外上转换荧光.对Tm3+离子上转换发光分析表明,强烈的Tm3+离子近红外上转换发光主要来自于Yb3+/Yb3+离子间的共振能量传递以及基于单声子和双声子辅助的Yb3+/Tm3+离子间的非共振能量传递过程,并进一步计算得到了声子贡献比和能量传递系数.最后,计算分析了Tm3+∶3 F4→3 H6能级间跃迁的1.8μm波段吸收截面、受激发射截面和增益系数.研究表明,Yb3+/Tm3+共掺TeO2-ZnO-Na2O玻璃可以作为近红外波段固体激光器的潜在增益基质.

Near infrared Emission and Energy Transfer Mechanism of Tm3+/Yb3+ Codoped Tellurite Glasses

Tm3+ single doped and Tm3+/Yb3+ codoped tellurite glasses with the composition of TeO2 ZnO Na2O were prepared by melt quenching method. The intensity parameters Ωt(t=2, 4, 6), spontaneous radiative transition rates A, fluorescence branching ratios β and radiative lifetimes τrad of Tm3+ were calculated based on the Judd Ofelt theory, and the upconversion luminescence of Tm3+ for glass sample with different Yb3+ doping concentration was measured. The results show that the glass sample can emit strong near infrared upconversion emission under the excitation of 980nm pump light. The analysis of Tm3+ upconversion emission process reveals that the intense near infrared upconversion luminescence of Tm3+ ions is mainly ascribed to the result of energy transfers: first the resonant energy transfer from Yb3+ to Yb3+ ions, and then followed by one and two phonon assisted nonresonant energy transfer from Yb3+ to Tm3+ ions. The energy transfer coefficient and phonon contribution for the above energy transfer process were calculated. Furthermore, the 1.8μm band absorption, emission cross sections and gain coefficient of Tm3+∶3F4→3H6 transitions were calculated and analyzed. The research indicates that Yb3+/Tm3+ codoped TeO2 ZnO Na2O glass is a promising host material applied for near infrared band solid laser.