Surface domain engineering in congruent lithium niobate single crystals: A route to submicron periodic poling

TL;DR

This paper introduces a surface domain engineering technique in lithium niobate crystals that enables submicron periodic poling, enhancing the fabrication of nonlinear optical devices with precise domain structures.

Contribution

A novel surface domain engineering method using overpoling in lithium niobate that achieves submicron periodic poling compatible with integrated optical devices.

Findings

Achieved domain periods as small as 1 μm

Demonstrated good domain uniformity

Compatible with waveguide-based nonlinear optical devices

Abstract

We describe a technique for surface domain engineering in congruent lithium niobate single crystals. The method is based on conventional electric-field poling, but involves an intentional overpoling step that inverts all the material apart from a thin surface region directly below the patterned photoresist. The surface poled structures show good domain uniformity, and the technique has so far been applied to produce domain periods as small as 1 \mu m. The technique is fully compatible with nonlinear optical integrated devices based on waveguide structures.