Tailor-made domain structures on the x- and y-face of lithium niobate crystals

Ferroelectric domains are engineered in lithium niobate crystals by scanning strongly absorbed UV laser light across the crystal surface. Focused UV laser light can not only write, but also erase previously written domains on the non-polar faces of lithium niobate, which allows tailoring of domain patterns. Such domain pattern was generated and afterward investigated by piezoresponse force microscopy and hydrofluoric acid etching. It was found that domains with dimensions down to 2 lm can be engineered, which was *30 % of the focus beam diameter (7 lm) used for writing the domains. Additionally, it was found that an unique domain depth profile can be formed, which is inclined to the crystallographic axes and can be described as 'half-crescent-shaped'.