Efficient and tunable frequency conversion using periodically poled thin‐film lithium tantalate nanowaveguides

作者：Simin Yu, Mingyue Qi, Huizong Zhu, Bofu Zhao, J. J. Qian, Yiqun Wu, Qiushi Chen, Juanjuan Lu · 发表于：Nanophotonics · 年份：2025 · DOI：10.1515/nanoph-2025-0201 · 被引用次数：6 · 研究领域：Advanced Fiber Laser Technologies、Photorefractive and Nonlinear Optics、Photonic and Optical Devices

Abstract Thin‐film lithium tantalate (TFLT) has recently emerged as a promising photonic platform for chip‐scale nonlinear optics due to its weaker photorefraction, higher optical damage threshold, broader transparency window, and lower birefringence compared to that of thin‐film lithium niobate. Here we report the first functional second harmonic generator achieved through high‐fidelity poling of z‐cut TFLT waveguides, based on a low‐loss lithium tantalate integrated photonic platform. As a result, quasi‐phase matching is performed between telecom (1,550 nm) and near‐visible (775 nm) wavelengths in a straight waveguide and prompts strong second‐harmonic generation with a normalized efficiency of 229 %/(W·cm 2 ). An absolute conversion efficiency of 5.5 % is achieved with a pump power of 700 mW in the waveguide. Such a second‐harmonic generator exhibits stable temperature tunability (−0.44 nm/°C), which is important for applications that require precise frequency alignment such as atomic clocks and quantum frequency conversion.