Nonlinear optical properties of copper nanoparticles synthesized in indium tin oxide matrix by ion implantation

Copper nanoparticles were elaborated in an indium tin oxide matrix by ion implantation. The nonlinear refraction and absorption coefficients of the composite materials obtained were measured using the z-scan method with nanosecond pulses (τ=7 ns) at the wavelength of 532 nm. In addition to the conventional on-axis z-scan configuration, measurements were carried out in the off-axis scheme to get a better sensitivity. The mechanisms responsible for nonlinear refraction and absorption in these nanocomposite materials are discussed. By using the temporal trace of the signal in the off-axis configuration, we show the thermal lensing effect to be negligible as compared with pure electronic ones.