Ferroelectric domain micro-engineering is performed on Lithium Niobate (LiNbO₃) by high-voltage external circuit. Periodic reversed domain structures are fabricated by selective polarization reversal achieved by electric field poling applied to resist patterned samples. Periods down to 500 nm have been achieved by novel technique called overpoling. Ordered relief structures are fabricated in LN by selective chemical etching of domain engineered samples. Such structures find interesting application in the field of optoelectronic and photonic band-gap devices.

A Mach-Zehnder type interference set-up is used for in-situ electro-optic characterization of LN samples during poling. High-fidelity domain patterned samples are hard to get due the spreading of reversed domains under the insulating layer. Amplitude and phase reconstruction of reversing samples by digital holography is a novel method to monitor on-line the poling process.