Fragmentation of the gold nanoparticles using femtosecond Ti:Sapphire laser and their structural evolution

This paper reports the production of gold nanoparticles (NPs) with controlled morphology in an aqueous solution of sodium dodecyl sulfate (SDS) by Ti:Sapphire laser. When nanostructures were exposed to an additional laser irradiation/exposure at a particular wavelength corresponding to resonant excitation of surface plasmons or to an interband transition, a considerable size reduction of NPs from 78 nm to 15 nm has been achieved. This can simply be defined as size refining of NPs by a two-step laser ablation. The relationship between supercontinuum (SC) emission and absorption spectrum of gold NPs has been explored. Additionally the transformation of gold NPs into fractal-like structures has been examined. At longer exposure periods, it is observed that there is a tendency of assembling of NPs into one-dimensional (1d) nanostructures.

► Two step laser assisted gold nanoparticle production in an SDS solution using a femtosecond laser.
► Gold nanoparticles with controlled size and morphology in liquid.
► Formation of micron size wire-like structures made up of SDS with gold nanoparticles in them.
► A broad spectral range supercontinuum emission during the second step with interesting plasmonic effects.