Linear and nonlinear optical properties of monodispersed gold clusters in silica glass by sol-gel method

摘要

Recently, we have successfully incorporated gold nanoclusters into silica matrix by a sol-gel technique, where the synthesis of gold clusters was conducted in presence of PVP. In this paper, we report linear and nonlinear optical properties of the polymer-blocked gold clusters in silica matrix. The Au/SiO$-2$/ glass were characterized by transverse electron microscopy (TEM), x-ray diffraction (XRD), and Mie-Drude analysis of linear absorption spectra. The hydrophilic polymer, exhibiting the strong metal-polymer interaction which stemmed from the lone pair from the nitrogen with the metal particles, prohibited the flocculation and growth of gold clusters in gel-glass transition. The degenerate four-wave mixing experiment was performed to obtain the nonlinear susceptibility $chi$+(3)$/, which was evaluated to be 1.7 $MUL 10$+$MIN@9$/ esu, in consistent with a theoretical value expected from hot electron contribution.