Double-face and submicron two-dimensional domain patterning in congruent lithium niobate

We report on the simultaneous fabrication of two-dimensional submicron engineered domain patterns on both crystal faces, in congruent lithium niobate. The fabrication technique is based on interference photolithography, which allows short pitch over large areas, followed by electric field poling performed in overpoling regime. Experimental results for different domain pattern geometries, on the two crystal faces, are reported. These structures could be useful for short-wavelength frequency conversion and Bragg gratings applications. The moiré effect is used in the lithographic process to fabricate more complex structures which could find application in photonic bandgap devices.