The resistance against optical damage of near-stoichiometric LiNbO3:Mg crystals prepared by vapor transport equilibration

Several near-stoichiometric lithium niobate crystals with the doping concentration of Mg near the second threshold were prepared by vapor transport equilibrium technique. All these samples show no laser beam distortion under a light intensity of 26 MW/cm2, that is three orders of magnitude higher than that of 5 mol% Mg doped congruent LiNbO3. And the light-induced refractive index (Δn) in one of them is as small as 4.6 × 10−7, which is two orders of magnitude lower than that of congruent crystals.