Tm3+/Yb3+共掺杂铋锗铅玻璃的上转换发光研究

设计并制备了一种组分为45Bi2O3-35GeO2-20PbO-0.02Tm2O3-xYb2O3(x=1.0,1.2,1.4,1.6和2.0 mol%)新型Tm3 /Yb3 共掺的铋锗铅玻璃材料,测量了玻璃的吸收光谱和上转换光谱,分析了玻璃中Tm3 的上转换发光机理.应用Judd-Ofelt理论计算了铋锗铅玻璃BGP1.0中Tm3 离子的三个强度参量Ωt(t=2,4,6)、振子强度、自发跃迁辐射几率和荧光分支比等光谱参数.通过975 nm的激光二极管激发,在室温下同时观察到强烈的上转换蓝光(476 nm)和微弱的红光(653 nm),分别是由于Tm3 离子1G4→3H6和1G4 →3F4跃迁.同时研究了蓝光和红光上转换发光强度随泵浦激发功率的变化,其曲线斜率分别为2.87和2.41,表明蓝光和红光都是三光子吸收过程.研究结果显示,Tm3 /Yb3 共掺铋锗铅玻璃是一种上转换蓝光激光器的潜在基质材料.

Study on the upconversion of Tm3+ and Yb3+ codoped in bismuth-germanium-lead glass

Novel Tm3+ and Yb3+ codoped bismuth-germanium-lead glass was fabricated and characterized;the glass sample components are 45Bi2O3-35GeO2-20PbO-0.02Tm2O3-xYb2O3(x= 1.0,1.2,1.4,1.6 and 2.0 mol%). The absorption and upconversion spectra of Tm3+ and Yb3+ codoped in bismuth-germanium-lead glass were investigated,and upconversion mechanisms of Tm3+ in the glass were analyzed. The Judd-Ofelt intensity parameters Ωt(t = 2,4,6),oscillator strengths,spontaneous transition probability and fluorescence branching ratio of each levels for Tm3+ were calculated by Judd-Ofelt theory. Intense blue and weak red emissions centered at 476 and 653 nm,correspongding to the transitions 1G4 →3H6 and 1G4→3F4,respectively,were simultaneously observed at room temperature under 975 nm diode laser excitation. The upconversion emission intensity varies with the power of infrared excitation intensity. A plot of log IUP VS log IIR yields a straight line with slope 2.87 and 2.41,corresponding to the 476 and 653 nm emission bands,respectively,which indicates a three-photon process for the blue and red emissions. The results suggest that Tm3+ and Yb3+ codoped bismuth-germanium-lead glass may be a potential host material for upconversion blue lasers.