Femtosecond and picosecond near-field ablation of gold nanotriangles : nanostructuring and nanomelting

We report on recent insights into the interaction between ultra-fast laser pulses and plasmonic nanoparticles . We discuss femtosecond near-field ab lation as a simple but versatile too l for the nanoscale modification of surFaces and the high-resolution measurement of a nanostructure's near fi e ld . Two model systems are presented, illustrating the comp\t:Xily of near-field distributions. Furthermon::, finite difference time domain calculations in combination with absorption spectra provide a deeper insight into the factors influencing the near-field distribution. For the first time, an almost perfect agreement between the measured ablation pattern and experiment has been reached for gold triangles with a side length around 500 nm. Additionally, the results from picosecond laser irradiated plasmonic structures displaya new regime of nanoscale laser material processing. We present first resu lts showing nanometre confined melting induced by laser pulses.