High non-resonant third-order optical nonlinearity of Ag–glass nanocomposite fabricated by two-step ion exchange

Abstract We observe high third-order optical nonlinearity of Ag–glass nanocomposite fabricated by a two-step ion exchange method. The nonlinear refractive index and absorption are studied using the well-known Z-scan technique. In our experiments, we use a femtosecond Ti–Sapphire laser source operating at 800 nm, which is far from the plasmon resonance of the Ag nanoparticles. Our nanoparticles possess a high positive nonlinear refractive index and also a very high saturable absorption. We estimate the nonlinear refractive index to be on the order of 10 −10  cm 2 /W and the saturable absorption to be on the order of 10 −5  cm/W.