Periodically poled lithium niobate structures grown by the off-center Czochralski technique for backward and forward second harmonic generation

We report on the characterization of periodically poled lithium niobate structures grown by the off-center Czochralski technique with periods ranging between 2 and 10 mm. The domains distribution along the crystal was inspected by a profilometer scan after etching the structures and carrying a suitable data processing. The second harmonic generation efficiency was predicted by numerically integrating the governing equations through to a recently proposed nonlinear bidirectional beam propagation method. The numerical analysis pointed out the feasibility of the backward second harmonic generation in the sample with the shortest domain period. The predicted second harmonic generation efficiency was finally corrected considering the phase shifts induced in the second harmonic wave by the presence of different sized domains.