Ionization and photomodification of Ag nanoparticles in soda-lime glass by 150 fs laser irradiation: a luminescence study

By studying luminescence and extinction spectra, combined with thermal treatment, novel information was obtained about the processes occurring during deformation of spherical Ag nanoparticles in soda-lime glass upon irradiation by intense fs laser pulses. The results give evidence that the nanoparticles are ionized by the laser pulses, and rather high local concentrations of Ag+ ions are created near to the clusters, apparently playing an important role for the processes of shape deformation. Annealing at temperatures between 100 deg. C and 400 deg. C leads first to the formation of small silver aggregates Ag2+, Ag3+, Ag32+, followed by reduction and aggregation to larger units. Corresponding changes in the extinction spectra indicate additionally changes in the cluster surroundings due to cluster ripening