外加电场法制备LiNbO3周期畴的工艺研究

研究了LiNbO₃单晶周期极化畴结构的制备工艺, 讨论了外电场的特性对周期极化过程的影响. 在对周期畴制备各工艺步骤进行实验研究的基础上, 提出解决LiNbO₃单晶周期畴制备中一直存在的边缘击穿问题, 必须选择合适的周期电极形式并对脉冲波形进行优化. 采用所提出的工艺, LiNbO₃周期极化畴的成品率提高到了90%. 为解决周期极化过程中反转畴的侧向扩展, 在对周期极化物理过程进行分析的基础上, 采取了对周期电极宽度进行优化设计和在样品上包覆聚酰亚胺绝缘胶的方法, 有效克服了这一问题, 制备了占空比符合预期的高质量的周期畴结构.

Technology of Periodic Poling Bulk LiNbO3 by Applying External Field

The preparation technics of periodically poled LiNbO₃ crystal (PPLN) was studied and the effects of external field characteristics including magnitude, duration of voltage pulse on periodic poling process were investigated. Improving magnitude of pulse could accelerate the poling process. After a detailed study of all technological steps, a resolution to overvcoming fringe breakdown is proposed, i.e. appropriate electrode figure and optimum waveform must be selected. By using the technics proposed, ratio of finished product reaches 90%. To eliminate the negative effects of reverse domain side expansion, a thin insulator layer is coated on the samples and the electrode width is optimized. By this method, high-quality periodically poled LiNbO₃, which meets the expected occupation ratio perfectly, is prepared successfully.