Lithium niobate thin film (LNTF) is a promising platform for ultra‐low loss nonlinear integrated photonics. Here, the simultaneous generation of second harmonic wave (SHW) and dispersive wave (DW) are demonstrated in a single LNTF under the pump of a femtosecond pulse laser, with a conversion efficiency exceeding 25%. The second harmonic generation (SHG) uses the modal phase matching mechanism based on the second‐order nonlinear effect, while the DW generation is based on the perturbations of soliton dynamics caused by self‐phase modulation and higher‐order dispersion. Notably, significant and symmetrical SHW and DW patterns are observed, which exhibit strong spatial dispersion properties. A comprehensive analysis of the phase‐matching conditions are conducted for SHG and DW generation and provide a clear elucidation of the spectral properties of different regions of the emitted light patterns. Additionally, the evolution of the pump light in LNTF is thoroughly investigated, and the solutions of the generalized Schrödinger equation are in good agreement with these experimental results. This work sheds new light on the rich physics of nonlinear optical interactions on LNTF, and by utilizing the synergistic effect of second‐order and third‐order nonlinear effects, this study anticipates achieving efficient and high energy on‐chip broadband frequency conversion and supercontinuum generation across octaves.

中文翻译：

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在铌酸锂薄膜中高效同步产生二次谐波和产生色散波


铌酸锂薄膜 （LNTF） 是一个很有前途的超低损耗非线性集成光子学平台。在这里，在飞秒脉冲激光器的泵浦下，在单个 LNTF 中同时产生二次谐波 （SHW） 和色散波 （DW），转换效率超过 25%。二次谐波产生 （SHG） 使用基于二阶非线性效应的模态相位匹配机制，而 DW 产生基于自相位调制和高阶色散引起的孤子动力学扰动。值得注意的是，观察到显著且对称的 SHW 和 DW 模式，它们表现出很强的空间色散特性。对 SHG 和 DW 生成的相位匹配条件进行了全面分析，并清楚地阐明了发射光图案不同区域的光谱特性。此外，对 LNTF 中泵浦光的演变进行了深入研究，广义薛定谔方程的解与这些实验结果非常吻合。这项工作为非线性光学相互作用对 LNTF 的丰富物理学提供了新的思路，通过利用二阶和三阶非线性效应的协同效应，本研究有望实现高效和高能量的片上宽带频率转换和跨倍频程的超连续谱生成。