Characterization of Thin Layers of Metal Clusters Embedded in Silica Glass Formed by High Dose Ion Implantation

Thin layers of metal clusters in silica glass were formed by high dose ion implantation of Ag, Ni and Cu using a metal vapor vacuum arc (MEVVA) ion source. Characterization of the implanted layers was performed using Rutherford backscattering spectroscopy, transmission electron microscopy, x-ray diffraction, and optical measurements. The nonlinear optical properties of the implanted samples were studied by the z-scan method, using a self mode-locked Ti: sapphire laser delivering linearly polarized pulses of 130fs long at a wavelength of 790nm at 76MHz. The variation of the intensity-dependent refractive index n 2 with the ion species and the implantation conditions were studied. An n 2 value of about 0.6 cm 2 /GW was measured for one of the Cu and Ni co-implanted samples. The correlation between n 2 and the cluster size was also analyzed. Ellipsometry spectra of the samples were measured in the visible range from 0.4 to 0.7 [.proportional]m and in the near infrared range from 0.9 to 1.6 [.proportional]m. Preliminary results are reported on our attempt to deduce the effective complex refractive indices of the implanted layers by fitting of the ellipsometry spectra using a simple single uniform layer on substrate model and the Maxwell-Garnett effective medium approximation.