Effect of ingredient concentration on structure and optical properties of Cu nanoclusters

Metal nanocluster composite glass prepared by Cu ion implantation have been studied. The formation of nanocluster has been evidenced by optical absorption spectra and transmission electron microscopy (TEM). Fast nonlinear optical refraction and nonlinear optical absorption coefficients were measured at 790 nm of wavelength for Cu nanocluster composites by the Z-scan technique. With an increase in the implanted dose, nanoshells were formed and the optical nonlinearity shows a significant change from positive to negative values. The reason for the enhancement and sign reversal of the optical nonlinearities of Cu nanocluster in silica are discussed. It is suggested that by changing the ingredient percentage of metals in silica, different optical nonlinearities could be selectively obtained. (c) 2006 Elsevier B.V. All rights reserved.