The third-order optical nonlinearity of The pyrochlore phase 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 thin film on quartz

The xPb(Mg1/3Nb2/3)O3-(1−x)PbTiO3 (PMNT) (with x=0.7) thin film is prepared on quartz substrates prepared using a sol-gel process. The PMNT thin film has a well-crystallized pyrochlore phase structure. The sign and magnitude of both real and imaginary parts of third-order nonlinear susceptibility χ(3) of the thin film have been determined by the Z-scan technique performed at 800 nm with a femtosecond laser. The nonlinear refraction index coefficient γ, the nonlinear absorption coefficient β of the thin film are 1.37×10−12 cm2/W and −6.73×10−8 m/W, respectively. The real and imaginary part of the third-order nonlinear susceptibility of the film are 1.06×10−17 and −1.65×10−19 m2/V2, respectively. The results suggested that the nonlinearity is dominated by the refractive for the film.