CIOP   05384
CENTRO DE INVESTIGACIONES OPTICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Fragmentation of gold nanoparticles by femtosecond laser radiation
Autor/es:
F. VIDELA, G.A. TORCHIA , D. SCHINCA, L SCAFFARDI, P. MORENO, C. MÉNDEZ, L. GIOVANETTI , J. RAMALLO LOPEZ AND L. ROSO
Lugar:
San Diego, USA
Reunión:
Conferencia; Optics + Photonics SPIE 2009; 2009
Resumen:
Ultra short pulses from femtosecond IR laser has been considered to be an excellent tool to generate gold nanoparticles (Nps) in water as well as in vacuum However for generation followed by a fragmentation process, not only the IR pulses become important but also supercontinuum could be an additional source to perform the fragmentation in initial Nps solution. We have studied the fragmentation of golds NPs after generation by femtosecond laser ablation in deionised water. In order to investigate the fragmentation process, we have used direct ultra-fast IR pulses and super-continuum radiation focused in the colloidal solution to carry out experiments capable to elucidate the relative effect of each wavelength bands. . In this two step process, the second part has been performed as follow: it was applied in the solution IR pulses using both low and high fluences, and super-continuum generated by sapphire crystal and registered the respective spectra The fluences, were below the multiphotonic and breakdown thresholds For the purpose of assessing the effects of the different spectral bands present in the super-continuum for fragmentation, we have determined different efficiency regions characterized by means of the product of the its spectral response and the optical extinction spectrum corresponding to the initial Nps solution. From the analysis of the product function, we can conclude that the main mechanism correspond to the visible region The results obtained were contrasted using other techniques such as SAXS and TEM that allowed as to estimate the relative abundance and shape of particles respectively.