In situ investigation of periodic poling in congruent LiNbO₃ by quantitative interference microscopy

The dynamic evolution of the periodic poling into resist patterned LiNbO₃ samples is investigated here by measuring the variation of the optical phase shift distribution across domain walls. In situ quantitative and high-contrast imaging is obtained through an interference microscope based on digital holography. Phase map movies of the evolving domains are presented and discussed. The method provides remarkable in situ information about the poling of ferroelectric crystals in the case of insulating constraints, under different voltage and resist conditions, providing a deeper understanding of the electric field periodic poling.