双掺杂铌酸锂晶体中铟杂质含量对光致折射率变化的影响

研究了铟杂质含量不同的双掺杂铌酸锂(In∶Fe∶LiNbO3)晶体的光致折射率变化规律,采用切片干涉法对铟杂质含量为1mol%、2mol%和3mol%的In∶Fe∶LiNbO3晶体光辐照导致的折射率变化进行了实验观测。实验结果表明,不同含铟量的In∶Fe∶LiNbO3晶体光致折射率变化趋势相近,随着铟杂质浓度的升高,折射率变化量△n逐渐减小,△n大小依次为:1mol%<2mol%<3mol%。从建立的光伏迁移机制简化模型出发,对不同浓度的铟杂质在In∶Fe∶LiNbO3晶体中导致的折射率变化分布进行了理论分析,数值模拟的结果同△n实测结果相吻合,结果表明理论分析采用的简化模型是可靠的。

Effects of Indium Impurity Content on Light Induced Refractive Index Change of Double Doping In:Fe:LiNbO3 Crystals

The distributions of the refractive index changes in In∶Fe∶LiNbO3 crystals were measured using the interferometric method,when the concentration of indium impurity was respectively 1mol%,2mol% and 3mol% in crystal.The experimental results indicate that the refractive index and the changing behaviour in three In∶Fe∶LiNbO3 crystals were similar,a variation of the refractive index changes(△n) decreased progressively as the concentration of indium was increased,the △n values in a lower to higher order were 3mol%,2mol% and 1mol% respectively.According to the simplified model based on the photovoltaic charge carriers transport mechanism,the distributions of the refractive index changes in In∶Fe∶LiNbO3 crystals are theoretically analyzed at different concentration of indium impurity the numerically simulated results was coincide with the △n measured results.The results show that the simplified model used on the theoretical analysis is reliable.