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arXiv · 2505.03162

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

Simin Yu·Mingyue Qi·Huizong Zhu·Bofu Zhao·Jingchun Qian·Qiushi Chen·Juanjuan Lu
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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 develop an ultralow-loss lithium tantalate integrated photonic platform and report the first functional second harmonic generator based on high-fidelity poling of z-cut TFLT. As a result, quasi-phase matching (QPM) is performed between telecom (1550 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. Such a second-harmonic generator exhibits stable temperature tunability (-0.44 nm/$^\circ C$) which is important for applications that require precise frequency alignment such as atomic clocks and quantum frequency conversion.

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Simin Yu, Mingyue Qi, Huizong Zhu, Bofu Zhao, Jingchun Qian, Qiushi Chen, Juanjuan Lu. 2025-05-06. Efficient and tunable frequency conversion using periodically poled thin-film lithium tantalate nanowaveguides. https://arxiv.org/abs/2505.03162

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