Graphical Direct-Writing of Macroscale Domain Structures with Nanoscale Spatial Resolution in Non-Polar-Cut Lithium Niobate on Insulators

TL;DR

This paper introduces a graphical technique for writing macroscale domain structures with nanoscale precision in lithium niobate thin films, enabling advanced device fabrication in optics and nanoelectronics.

Contribution

The authors developed a novel graphical domain engineering method using AFM to create large, nanoscale domain structures with arbitrary wall angles in lithium niobate on insulators.

Findings

Successfully fabricated periodic domain structures with 600 nm period.

Demonstrated nanoscale domain writing with millimeter-scale dimensions.

Revealed asymmetry in domain writing process relative to spontaneous polarization.

Abstract

We reported on a graphical domain engineering technique with the capability to fabricate macroscale domain structures with nanoscale spatial resolution in non-polar-cut lithium niobate thin film on insulators through the biased probe tip of scanning atomic force microscopy. It was found that the domain writing process is asymmetric with respect to the spontaneous polarization Ps even though the tip-induced poling field is mirror-symmetric. Various domain structures, with a dimension larger than millimeters while consisting of nanoscale domain elements and with arbitrary domain-wall inclination angle with respect to Ps, were designed graphically and then written directly into non-polar-cut lithium niobate crystals. As a proof of principle demonstration, periodically poled x-cut lithium niobate thin film on insulators with a period of 600 nm, a depth of 460 nm and a length of ~1 mm was fabricated. This technique could be useful for device applications in integrated optics and opto-electronics and domain-wall nanoelectronics based on lithium niobate on insulator.