铌酸锂晶体中多畴层带区倍频光的研究

本文研究用声光调Q-YAG激光器作为基波光源,测量了LiNbO₃及BNN晶体中倍频光强-温度曲线。在生长层区,倍频曲线上往往出现双峰,同时有一一对应的NPM双光环出现。LiNbO₃的双峰之一在极化处理后消失,本文对此峰的产生进行了分析。LiNbO₃多畴层带区倍频光强比单畴区大10倍左右,实验表明此乃层带区180°畴的形成导致应力松弛的结果。 关键词：

THE STUDY OF SHG IN THE POLYDOMAIN STRIAE REGION OF LiNbO3 SINGLE CRYSTAL

Using acousto-optic Q-switched Nd³⁺: YAG laser as a source of fundamental beam, we measured the SHG scan vs temperature in LiNbO₃ and BNN single crystals. There are usually two peaks appearing on the SHG scan curves for the striae region, at the same time two NPM hollow cones of SHG light may be observed in one to one correspondence.One of the two peaks in the polydomain striae region of LiNbO₃ disappeared after the crystal was completely polarized. The occurrence of this peak was analyzed.The SHG power in the polydomain region of LiNbO₃ is usually several times larger than that of single domain region. We attributed the enhancement mechanism to the stress relaxation occurring with the formation of insular 180°domains.