The optical superlattice structure derived from a periodic poling process endows ferroelectric crystals with tunable optical property regulation, which has become one of the most efficient strategies for fabricating high-efficiency optical devices. Achieving a precise superlattice structure has been the main barrier for preparation of specific optical applications due to the unclear dynamics of domain structure regulation. Herein, a real-time monitoring system for the in situ observation of periodic poling of lithium niobate is established to investigate ferroelectric domain reversal dynamics. The formation of reversed domain nuclei, growth, and expansion of the domain are monitored, which is highly related to domain growth dynamics. The nucleation and growth of domain are discussed combined with the monition of domain reversal and the variation of local electric field distribution along with finite element analysis. An electrode configuration with multiholes is proposed to use the local electric field more efficiently and controllably, which could achieve a higher domain nucleus density with high uniformity. Two-mm-thick periodically poled LiNbO₃ crystals with high quality are achieved. A nonlinear light conversion from 1064.2 to 3402.4 nm is realized by the single-resonance optical parameter oscillator with a nonlinear optical efficiency up to 26.2%.

中文翻译：

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用实时监测系统研究 LiNbO3 光学超晶格中的铁电畴反转动力学

源自周期性极化过程的光学超晶格结构赋予铁电晶体可调谐的光学性质调节，这已成为制造高效光学器件的最有效策略之一。由于畴结构调控的动力学不明确，实现精确的超晶格结构一直是制备特定光学应用的主要障碍。在此，建立了用于现场观察铌酸锂周期性极化的实时监测系统，以研究铁电畴反转动力学。监测反畴核的形成、生长和畴的扩展，这与畴生长动力学高度相关。结合畴反转的监测和局部电场分布的变化以及有限元分析，讨论了畴的形核和生长。提出了一种多孔电极配置，以更有效、更可控地利用局部电场，从而实现更高的畴核密度和高均匀性。两毫米厚的周期性极化 LiNbO_{获得了3 个}高质量的晶体。单谐振光学参数振荡器实现了1064.2到3402.4 nm的非线性光转换，非线性光学效率高达26.2%。