ZnO对碲铌基重金属氧化物玻璃的结构和光学性能的影响

The impact of ZnO on structure and optical performances for TeO_2-Nb_2O_5 glass

TeO2 Nb2O5系统重金属氧化物玻璃是一种新型的重金属氧化物玻璃材料,具有优良的非线性光学性能。本文研究了ZnO对碲铌基玻璃的结构、非线性光学性能和光学透过率的影响,研究表明:碲铌基玻璃的非线性光学效应源于电子云畸变效应,掺杂少量ZnO有利于玻璃非线性光学性能的提高,增加ZnO至2.5%(质量分数)时用四波混频法测得的玻璃三阶非线性极化率χ(3)可达9.2×10-13esu,然后随ZnO含量增至10%(质量分数)时χ(3)减至6.0×10-13esu。ZnO含量在10%～15%(质量分数)时χ(3)则无明显变化。同时,加入15%(质量分数)的ZnO有利于玻璃透过率的提高。Raman光谱研究表明,掺入过多的ZnO(>5%(质量分数))时,网络间隙中的Nb5+可被Zn2+取代而进入网络,同时提供更多的桥氧,从而使玻璃网络中的[TeO4]4-基团向[TeO3]2-转化。

TeO_2-Nb_2O_5 glass was a new kind of heavy metal oxide glass with excellent nonlinear optical performances. The optical transmittance, nonlinear optical performance and structure of the glass were investigated as function of ZnO content. The nonlinear optical performances of the glass, arising from electron cloud deformation, could be improved by adding few ZnO content. The third-order nonlinear optical susceptibility (_χ_^((3))) as measured by a degenerate four wave mixing (DFWM) method, initially increased with increasing ZnO content to about 9.2×10^(-13)esu for a glass containing 2.5wt% ZnO, and then down to 6.0×10^(-13)esu with increasing ZnO content up to 10wt%. The _χ_^((3)) value had no significantly changes in the ZnO content range from 10wt% to 15wt%. The transmittance of the glass could be improved by adding 15wt% ZnO. The structure of these glasses as analyzed by Raman spectroscopy, was affected by the addition of ZnO content up to 5wt%. It was believed that the Zn^(2+) ions would occupy the interstitial of the glass network by replacing the Nb^(5+) ions, and ZnO content provide with more free oxygen ions. Therefore, the exceed ZnO content could make ^(4-) transfer into ^(2-) group in the glass network.