Tunable two-dimensional hexagonal phase array in domain-engineered Z-cut lithium niobate crystal

An optical phase array with tunable phase step is demonstrated. The phase array consists of a twodimensionalhexagonal lattice of inverted ferroelectric domains fabricated on a Z-cut lithium niobate substrate.The electro-optically tunable phase step is obtained by the application of an external electric fieldalong the z axis of the crystal via transparent electrodes. Theoretical analysis and experimental results arepresented, showing that a tunable and flexible adaptive optical illuminator device can be realized by combiningthe electro-optic tunability with the Talbot effect. Generation of a multiplicity of light patterns isshown.