掺Bi的GeO_2-Al_2O_3-Na_2O玻璃的热学和光学性质

Thermal and optical properties of Bi ions doped GeO_2-Al_2O_3-Na_2O glasses

用高温熔融法制备了96GeO-(3-χ)Al2O3-χNa2O-1NaBiO3(将χ分别为0,0.5,1.5的玻璃命名为A1,A2,A3)和96GeO-(3.5-ψ)Al2O3-ψNa2O-0.5Bi2O3(将ψ分别为0,0.5,2的玻璃命名为B1,B2,B3)玻璃。观察到样品在1220 nm处(800 nm激光二极管激发)的超宽带发光特性(半高宽约250 nm)。结果表明,以NaBiO3形式引入Bi5+到玻璃原料中比以Bi2O3形式引入Bi3+到原料中得到的玻璃在1220 nm处的发光强度大4.6倍,且荧光寿命和荧光半高宽也分别从280μs和195 nm增加到了434μs和275 nm。从A3,A2和A1的吸收边带的红移可初步推断出A3,A2及A1玻璃中Bi5+的含量逐步增加。总结吸收光谱与发射光谱的变化规律,认为Bi离子近红外高发射强度和宽荧光半高宽是由Bi5+的发光引起的。在两组玻璃中,热稳定性以及荧光发射截面积与荧光寿命的乘积值和荧光发射截面积与荧光半高宽的乘积值随着Na2O含量的增加而增加。

The 96GeO-（3-χ）Al2O3-χNa2O-1NaBiO3 （molar fraction χ is 0,0.5,1.5, designated as A1, A2 and A3, respectively） and 96GEO-（3.5 -ψ） Al2O3-ψNa2O-0. 5Bi2O3 （molar fraction ψ is 0. 5,1,2, designated as B1, B2 and B3, respectively） glasses were prepared by conventional melting method. The near infrared superbroadband emission characteristics of the glasses were observed （peak at 1 220 nm） when pumped by an 800nm laser diode. The result indicated that doping of Bi^5＋ of NaBiO3 could increase the emission intensity of the glass in the infrared band by 4. 6 times than that of Bi^3＋ of Bi2O3. The emission life- time and the full width at half maximum（FWHM） at 1 220 nm increased from 280 μs, 195 nm to 434 μs, 275 nm, respectively. Meanwhile, the absorption edges of A3, A2, A1 were red-shifted. Thus, it could be concluded that the content of Bi^5＋ in A3, A2, A1 glasses increased gradually. It is suggested that the stronger emission intensity and longer FWHM of Bi ions in the near infrared region is due to the formation and fluorescence of Bi^5＋. In particular, with the increasing content of Na2O, the thermal stability and the value of emission cross-section by lifetime and the value of emission cross-section by FWHM of glasses increased.