Nonlinear optical properties of calcium barium niobate epitaxial thin films

We investigate the potential of epitaxial calcium barium niobate (CBN) thin film grown by pulsed laser deposition for optical frequency conversion. Using second harmonic generation (SHG), we analyze the polarization response of the generated signal to determine the ratios d₁₅ / d₃₂ and d₃₃ / d₃₂ of the three independent components of the second-order nonlinear susceptibility tensor in CBN thin film. In addition, a detailed comparison to the signal intensity obtained in a y-cut quartz allows us to measure the absolute value of these components in CBN thin film: d₁₅ = 5 ± 2 pm / V, d₃₂ = 3.1 ± 0.6 pm / V and d₃₃ = 9 ± 2 pm / V.