Regulation of Periodic Poling in KTP Crystals via Electrode Pattern and Connection Design

doi:10.15541/jim20250383

Regulation of Periodic Poling in KTP Crystals via Electrode Pattern and Connection Design

TAN Tingting¹, SONG Xudong^2,3,4, ZHAO Weidi^2,3,4, QIN Qi¹, HE Xiaoling^2,3,4, ZHANG Changlong^1,2,3,4

1. School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541000, China;
2. Guilin Bairay Photoelectric Technology Co., Ltd., Guilin 541000, China;
3. Guangxi Key Laboratory of Superhard Materials, Guilin 541000, China;
4. China Nonferrous Metal (Guilin) Geology and Mining Co., Ltd., Guilin 541000, China

Received:2025-09-29 Revised:2025-10-23
Contact: ZHANG Changlong, professor. E-mail: 573370768@qq.com; HE Xiaoling, professor. E-mail: hxlpl@hotmail.com
About author:TAN Tingting (2000-), male, Master candidate. E-mail: 1441232713@qq.com
Supported by:
Science and Technology Program of Guangxi Province (2023AB10008; 2023AB01273); Science Technology Project of China Nonferrous Metal Mining Group (2023KJZX007)

Abstract

Abstract: Periodically poled potassium titanyl phosphate (PPKTP) crystals, engineered based on the ferroelectric domain structure of KTP, have emerged as a core component for generating entangled quantum light sources in quantum optics. This is attributed to the entangled photon sources they produce, which exhibit superior performance such as low power consumption, compact size, and high entanglement quality. During the preparation of PPKTP crystals via the electric field poling method, inhomogeneous electric fields can lead to irregular domain structures, adversely affecting their nonlinear optical properties. Therefore, electric field uniformity is a critical control factor in the poling process. To improve the electric field homogeneity during the polarization of PPKTP crystals, this study systematically optimized both the electrode pattern and the electrode connection structure through simulation and experimental validation. Using finite element analysis, the spatial electric field distributions of different electrode patterns were simulated. A double-sided rounded electrode pattern was proposed to mitigate edge electric field concentration, while a parallel multi-contact electrode connection method was introduced to further enhance the uniformity of the electric field distribution. The domain structures of the poled crystals were characterized using metallographic microscopy. Experimental results from the ferroelectric domain morphology analysis confirmed that the double-sided rounded electrode pattern effectively alleviates the tip effect, and the parallel multi-contact connection method significantly improves electric field uniformity, thereby providing key conditions for high-quality domain inversion. Ultimately, hydrothermally grown PPKTP crystals were obtained with straight domain walls, a period of 46 μm, and a duty cycle of approximately (50±1)%. This work offers a simple, efficient, and structurally rational design solution for achieving uniform electric field distribution in the preparation of PPKTP crystals.

Key words: KTiOPO₄, PPKTP, finite element analysis, electric field spatial distribution

CLC Number:

TQ174

TAN Tingting, SONG Xudong, ZHAO Weidi, QIN Qi, HE Xiaoling, ZHANG Changlong. Regulation of Periodic Poling in KTP Crystals via Electrode Pattern and Connection Design[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20250383.

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