Femtosecond laser near field ablation

The hi gh fi eld strength of fe mtosecond laser pulses leads to non I incar effects during the interacti on with condensed matter. One such e ffect is the ab latio n process, which can be initiated he low the threshold of common thermal ahlation if the excitation pul ses are suffic iently short . This effec t leads to structure formation, which is an isotropic because of the polari zation properties of the near fie ld and can result in pattern sizes below the resolu tion limit of light. These effects are explored by temporall y reso lved sca ttering methods and by post-mortem analys is to show the non-therma l and ani 'otropic nature of thi s proce~s. The nearfie ld distribution of plasmon modes can be tailored to a large ex tent in order to obtain contro l of the pattern format ion . 435 Ablat ion imract of a srherical rolystyrcnc parti cle on a s il icon surface (left) as visuali zed by atomic force microscopy and the change in the scattering pattern of a gold nanopa rti c le (right) bo th irradiated with s ingle femtosecond pul ses. The ani sotropy in hoth images is a result of the nearfi eld-enhanced sub-threshold ab lation process. Femtosecond laser near field ablation Anton Plech 1.2.* , Paul Leiderer 2 and lohannes Boneberg 2 I Institut flir Synchrotronstrahlung (TSS), Karl sruhe Tnstitute of Technology, Postfach 3640, 7602 1 Karlsruhe, Germany 2 Center fo r Applied Photonics , Universittit Konstanz, Universitatsstr. 10, 78457 Konstanz, Germany