Z-scan determination of the large third-order optical nonlinearity of Rh:BaTiO 3 thin films deposited on MgO substrates

Abstract

Highly c-axis oriented Rh-doped BaTiO 3 thin films were grown on MgO (1 0 0) substrates by pulsed laser deposition using a single-crystal Rh:BaTiO 3 target. The 150-nm thick films were deposited at 800 °C under the oxygen pressure of 7×10 −2 Pa. The structural properties of the samples were characterized by X-ray diffraction and atomic force microscopy. The full width at half maximum of the (0 0 2) Rh:BaTiO 3 rocking curve and the root-mean-square surface roughness within the 5×5 μm 2 area were 0.520° and 0.85 nm, respectively. The nonlinear optical properties of the films were determined by a single beam Z-scan at a wavelength of 532 nm with laser duration of 10 ns. The result shows that Rh:BaTiO 3 thin films exhibit a great nonlinear optical response with the real and imaginary parts of the third-order nonlinear optical susceptibility χ (3) being 3.59×10 −7 esu and 4.01×10 −8 esu, respectively.