Modulating the thickness of the resist pattern for controlling size and depth of submicron reversed domains in lithium niobate

In this letter the electric field overpoling is used in combination with two-dimensional resist gratings exhibiting modulated topography and obtained by moiré interference lithography. The technique allows one to fabricate shallow submicron domains with lateral size and depth modulated according to the resist profile. Simulations of the electric field distribution in the crystal, in this specific poling configuration, are performed to interpret the mechanism leading to the formation of those surface domains. The results show that in principle complex domain structures could be designed for applications in the field of photonic crystals.