Light-induced superlow electric field for domain reversal in near-stoichiometric magnesium-doped lithium niobate

摘要

Light-induced domain reversal of near-stoichiometric Mg-doped LiNbO_3 crystal was investigated with a focused 532 nm continuous laser beam. The lowest electric field applied to accomplish domain nucleation is only 30 V/mm and 1/80 of the coercive field, which is safe and convenient for us to fabricate domain structures. Under this superlow applied field, the pinning effect of domain wall is so obvious that the inverted domain reveals a gear shape contrary to the hexagon in a higher applied field. Then two-dimensional domain patterns with the smallest domain size of 4 μm have been fabricated.