Tuning the structural and optical properties of gold/silver nanoalloys prepared by laser ablation in liquids for ultra-sensitive spectroscopy and optical trapping

E. Messina, L. D'Urso, C. Satriano, E. Fazio, M. G. Donato, B. Fazio, C. D'Andrea, O. M. Maragò, P. G. Gucciardi, G. Compagnini, F. Neri


The plasmon resonance of metallic Au/Ag alloys in the colloidal state was tuned from 400 nm to 500 nm using a laser irradiated technique, performed directly in the liquid state. Interesting optical nonlinearities, trapping effects and spectroscopic enhancements were detected as function of gold concentration in the nanoalloys. In particular a reduction of the limiting threshold was observed by increasing the gold amount. The SERS activity of the Au/Ag alloys was tested in liquid and in solid state in presence of linear carbon chains as probe molecules. The dependence of the increased Raman signals on the nanoparticle Au/Ag atomic ratio is presented and discussed. Finally preliminary studies and prospects for optical and Raman tweezers experiments are discussed.


Metal nanoparticles; Nonlinear photonics; Optical trapping

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DOI: http://dx.doi.org/10.1478/C1V89S1P064

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