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This Letter, reports the focused-femtosecond-laser induced dissolution of gold nanoparticles in an Au+-doped glass. Gold nanoparticles, pre-precipitated in the glass either by thermal treatment or by irradiation of a focused femtosecond laser and successive thermal treatment, are broken to dissolve when they are reirradiated by a focused femtosecond laser. It is suggested that the dissolution of gold nanoparticles is due to dramatically increasing in the temperature of gold nanoparticles, resulting from the energy absorbing from the femtosecond laser. A repeatable process of precipitation and dissolution of gold nanoparticles is also realized anywhere selected inside the glass, so does the control of the size of gold nanoparticles. [Copyright &y& Elsevier]

Optical nonlinearities of Au nanoparticles precipitated inside glasses induced by irradiation of a focused femtosecond laser were investigated using Z-scan technique with 8 ns pulses at 532 nm. The transformation behaviors both from self-defocusing to self-focusing and from saturable absorption to reverse saturable absorption were observed in the glass samples, which depend drastically on the irradiation power density of the femtosecond laser used. The optical nonlinearities were analyzed in detail and proved numerically by the excited-state theory of conduction band electrons. [Copyright &y& Elsevier]

Abstract: We report a method for the selective introduction of fluorescent Ag nanoclusters in glass. Extinction and photoluminescence spectra show that a fraction of the Ag atoms are generated through femtosecond laser induced multiphoton reduction and then aggregate to form Ag nanoclusters after heat treatment. Red luminescence from the irradiated region is observed under blue or green laser excitation. The fluorescence can be attributed to interband transitions within Ag nanoclusters. This method provides a novel route to fabricate fluorescent nanomaterials in 3D transparent materials. [Copyright &y& Elsevier]