Second harmonic generation and crystalline structure of corona poled BaTiO3 thin films

Second harmonic generation from a 1.064 μm fundamental was measured on BaTiO 3 thin films derived from metalorganic chemical vapor deposition. Significant enhancement of the second harmonic generation was observed upon poling of the film using corona discharge. The second harmonic intensity of the poled film was studied as a function of the incident fundamental polarization, showing that there was no in-plane symmetry in the poled films. The measured macroscopic second-order nonlinear optical coefficient of the poled film, d film 33 , is ∼ 7.5 pm/V. This value is comparable to that of the bulk BaTiO 3 along c -axis, d BaTiO 3 33 , suggesting that the majority of the crystalline c -axis of the poled film was aligned to the film normal.