Poling technique for domain engineering of lithium niobate for periodic poled lithium niobate fabrication

Lithium niobate ( \(\:LiNbO_3\) ) is one of the most important nonlinear optical materials due to its strong ferroelectric, electro-optic, and nonlinear properties. The ability to control its ferroelectric domains known as poling enables the fabrication of periodic domain structures required for quasi-phase matching, which provides an additional degree of freedom to design acoustic and optical devices with improved performance. Several methods have been developed to achieve precise domain inversion, each with its own advantages and limitations in terms of resolution, scalability, and compatibility with bulk and thin-film devices. This review highlights the major poling techniques, including defect diffusion, electric field poling (with patterned electrodes, atomic force microscopy, and electron/ion beam variations), and light-assisted approaches (light-assisted poling, poling inhibition, laser direct writing, and femtosecond laser writing). A comparative analysis is provided to clarify their operating principles, key advantages, and limitations, offering guidance for selecting suitable methods for the development of next-generation compact and scalable photonic integrated circuits as well as high-frequency acoustic devices.