Co^(2+)掺杂ZnO-MgO-Al_(2)O_(3)-SiO_(2)系微晶玻璃的制备及光学性能

Preparation and Optical Properties of Co^(2+)-Doped ZnO-MgO-Al_(2)O_(3)-SiO_(2) System Glass-Ceramics

本文采用熔融法和热处理制备了Co^(2+)掺杂的ZnO-MgO-Al_(2)O_(3)-SiO_(2)(ZMAS)系透明微晶玻璃,基于X射线衍射的结果确定了微晶玻璃的主要晶相为ZnAl_(2)O_(4)/MgAl_(2)O_(4),并且随着晶化处理时间的增加,微晶玻璃的物相构成没有发生明显变化,尖晶石相的结晶度和平均晶粒尺寸呈现先增大后减小的趋势。吸收光谱和发射光谱的结果表明Co^(2+)进入了尖晶石相ZnAl_(2)O_(4)/MgAl_(2)O_(4)中,并取代了四面体位置(T_(d))的Zn^(2+)或Mg^(2+)。随着晶化处理时间的增加,样品的吸收光谱强度和发射光谱强度均呈现先升高后降低的趋势,这与X射线衍射结果的变化趋势一致,说明可以通过控制微晶玻璃的结晶度来调控光学性能,这对制备性能优良的微晶玻璃材料具有一定的指导意义。对比了采用不同价态Co的氧化物原料制备的微晶玻璃,结果表明无论是掺杂CoO还是Co_(2)O_(3),微晶玻璃尖晶石相中的Co元素均以Co^(2+)形式存在。此外,将所制备的微晶玻璃材料在1540 nm处的基态吸收截面(σ_(gas))同Co掺杂的其他基体材料进行了对比,发现它有望作为可饱和吸收体应用于调Q激光器中。

In this paper,transparent glass-ceramics of the Co^(2+)-doped ZnO-MgO-Al_(2)O_(3)-SiO_(2)(ZMAS)system were prepared via melting method and heat-treatment.Based on the X-ray diffraction results,it determine that the main crystalline phase of glass-ceramics is ZnAl_(2)O_(4)/MgAl_(2)O_(4),and the composition of the glass-ceramics don’t change significantly with the increase of the crystallization treatment time.The crystallinity and the average grain size of spinel increase first and then decrease.It shows that the broad absorption band of 4T 1(4F)→4A 2(4F)transitions and the emission peak of 4T 1(4P)→4A 2(4F)transitions of tetracoordinated Co^(2+)do not appear in both the absorption spectra and emission spectra of glass-ceramics.This indicates that Co^(2+)enter the spinel phase ZnAl_(2)O_(4)/MgAl_(2)O_(4) and replace Zn^(2+)or Mg^(2+)in the tetrahedral(T_(d))sites.With the increase of crystallization treatment time,the absorption spectral intensity and emission spectral intensity of the samples increase first and then decrease.This is consistent with the changing trend of X-ray diffraction results.It shows that the optical properties can be controlled by controlling the crystallinity of glass-ceramics,which has certain guiding significance for the preparation of glass-ceramics with good properties.Comparing the glass-ceramics prepared by using raw materials with different valence states of Co oxides the result shows that the element Co exists as divalent Co^(2+)in the spinel phase of the final glass-ceramics,whether it is doped with CoO or Co_(2)O_(3).Moreover,the prepared glass-ceramics material was compared with other Co-doped matrix materials in terms of the ground state absorption cross section(σ_(gas))at 1540 nm,showing that it can be used as a saturable absorber in Q-switch lasers.