Optical nonlinearities of Au nanocluster composite fabricated by 300 keV ion implantation

Metal nanocluster-glass composite prepared by implantation of 300 keV Au ions into silica at a dose of 1×1017 ions/cm2 has been studied. The microstructural properties of the nanoclusters are characterized by optical absorption spectra and transmission electron microscopy (TEM). Third-order nonlinear optical properties of the nanoclusters are measured at 1064 and 532 nm excitations using Z-scan technique. The nonlinear refraction index, nonlinear absorption coefficient, and the real and imaginary parts of the third-order nonlinear susceptibility are deduced. Results of the investigation of nonlinear refraction using the off-axis Z-scan configuration are presented and the mechanisms responsible for the nonlinear response are discussed. Third-order nonlinear susceptibility χ(3) of this kind of sample was determined to be 1.3×10−7 esu at 532 nm and 4.3×10−8 esu at 1064 nm, respectively.