Impact of wavelength dependent thermo-elastic laser ablation mechanism on the generation of nanoparticles from thin gold films

This experimental study provides an insight into the wavelength dependence of femtosecond ablation mechanisms of thin gold films. A wavelength dependent, linear relationship was identified between the volume of the grain microstructure of 20 nm thick films and the volume of the nanoparticles generated during laser ablation. Laser ablation at 343 nm and 515 nm wavelengths resulted in the same linear relationship between the grain volume and the nanoparticle volume. However, no relationship at all was observed when ablated at 1030 nm. The wavelength dependence of these results was attributed to differing absorption mechanisms that ultimately lead to differing ablation mechanisms and nanoparticle formation. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773301]