Refractive index modulation in periodically poled MgO-doped congruent LiNbO3 crystal

An optical diffraction method is exploited to characterize periodically poled MgO-doped congruent LiNbO(3) crystal fabricated by electric induced technique. The optical diffraction patterns indicate that the refractive index changes occur in periodic domain structures. Light diffraction from this type of refractive index modulation is simulated, thus providing an effective and nondestructive technique to determine the refractive index changes and domain structures. From the normalized diffraction intensity, we estimate the refractive index change to be in the magnitude of 10(-5).