Application of RZ-scan technique for investigation of nonlinear refraction of sapphire doped with Ag, Cu, and Au nanoparticles

The results of investigation of the nonlinear refraction of sapphire doped by Ag, Cu, and Au nanoparticles using the reflection Z-scan technique are presented. The real parts of the third-order nonlinear susceptibility of Ag:Al2O3, Au:Al2O3, and Cu:Al2O3 were measured using the fundamental wavelength of Nd:YAG laser radiation (λ = 1064 nm, t = 55ps). It was shown that the Ag:Al2O3 possessed by self-focusing properties (n2 = 1.8 × 10−11 cm2 W−1), whereas the Au:Al2O3 and Cu:Al2O3 showed the self-defocusing properties (n2 = −1.46 × 10−10 and −1.7 × 10−11 cm2 W−1, respectively). The real part of third-order nonlinear susceptibility of Au:Al2O3 was measured to be 10−8 esu. The mechanisms of nonlinear refraction are discussed.