Optical properties of Au nanocluster embedded dielectric films

Composite films of Au and dielectric material (TiO2 and/or mixed ZnS-SiO2) with a wide range of Au fractions were fabricated through a co-sputtering m ethod utilizing a multi-target sputtering system. The optical absorption sp ectra of these composite films demonstrated an absorption peak due to surfa ce plasmon resonance of embedded Au nanoclusters. It was found that, depend ing on the dielectric matrix, Au concentration, and post-deposition anneali ng, the wavelength of the surface plasmon resonance of nanoclusters shifted by 130 nm: from 550 to 680 nm. The third-order non-linear susceptibility c hi ((3)) of these composite films, which also originates from field enhance ment due to the surface plasmon resonance, demonstrated a corresponding var iation. (C) 2000 Elsevier Science B.V. All rights reserved.