One- and two-photon laser spectroscopy of silica gel-doped fluorescent nanoparticles

One- and two-photon laser spectroscopy of Rhodamine 6G (Rh6G) and Coumarin 153 (C153) dyes embedded in silica nanoparticles with and without TiO2 scatters was investigated. Silica gel samples with different dye-doped nanoparticle concentrations were prepared as homogeneous bulk disks by the sol–gel method. Fluorescence and lifetime measurements were performed in the bulk matrices as well as in the resulting ground powders under one- and two-photon excitation. The effect of nanoparticles and TiO2 scatters concentration on the lifetime quenching was evaluated. The results show a reduction of the fluorescence lifetime for increasing concentrations of both dye-doped nanoparticles and TiO2 scatters. The fluorescence degradation under infrared ultrashort laser pulses was also explored as a function of irradiation time.This research has been financially supported by the Spanish Government MEC under Projects No. MAT2004-03780, NAN2004-09317-C04-02, and Consolider Program “Science and Applications of ultrafast ultraintense lasers” CSD2007-00013. S.G.-R. acknowledges financial support from the Spanish MEC under the “Juan de la Cierva” program.Peer reviewe