Collinear and isotropic diffraction of laser beam and incoherent light on periodically poled domain structures in lithium niobate

Possible variants of light diffraction from periodically poled domain structures in lithium niobate crystal are analyzed theoretically. It is shown that along with isotropic diffraction, elastic strains created by domain walls make it possible to observe the collinear interaction of ordinary and extraordinary waves propagating along X axis of the crystal. Diffraction of incoherent light in the collinear geometry on the PPLN with spatial period of 6.89 μm, developed on the basis of a Z-cut MgO:LiNbO3 crystal using electric-field poling, is investigated experimentally.