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我们从紫外到红外范围测量了掺入MgO和ZnO的LiNbO3 单晶的光学透射系数。计算了与波长有关的光学吸收系数α和它的根α1/2 (也相应得到了α对hν和α1/2 对hν的曲线图 ) ,并对吸收边的性质进行了分析。计算了该晶体的直接跃迁能隙Eg、间接跃迁能隙E′g 和参与间接跃迁的声子能量 ,讨论了杂质Mg和Zn对光学吸收边性质的影响。我们发现 ,双掺杂MgO和ZnO的样品的间接跃迁能隙E′g 较纯LiNbO3 晶体的间接跃迁能隙E′g 为小 ,从而导致了该样品的间接跃迁吸收边出现紫移
We measured the optical transmission coefficients of LiNbO3 single crystals doped with MgO and ZnO from the UV to the IR range. The wavelength-dependent optical absorption coefficient α and its root α1 / 2 (corresponding to the graph of α vs. hν and α1 / 2 vs. hν) were calculated and the properties of the absorbing edge were analyzed. The direct transition energy gap Eg, the indirect transition energy gap E’g and the phonon energy involved in indirect transition were calculated. The influence of impurities Mg and Zn on the optical absorption edge properties was discussed. We found that the indirect transition energy gap E’g of double-doped MgO and ZnO samples is smaller than the indirect transition energy gap E’g of pure LiNbO3 crystal, resulting in a purple shift in the indirect transition absorption of the sample