Light-induced order-of-magnitude decrease in the electric field for domain nucleation in MgO-doped lithium niobate crystals

We report an order-of-magnitude reduction in the electric field required for domain nucleation in 1 mol % MgO-doped near-stoichiometric and 5 mol % MgO-doped congruently grown lithium niobate crystals induced by illumination from a focused continuous wave laser beam at wavelengths of 514, 488, and 457 nm. A smaller decrease of 31% is also observed for undoped congruently grown crystals. The effect is independent of the visible wavelengths explored. Light-controlled domain patterning is also demonstrated.