Development of a tip enhanced near-field laser ablation system for sub-micrometric analysis of solid samples

International audienceA near-field laser ablation system was developed for the analysis of inorganic solid samples in thenanometer resolution range. The instrument is based on the coupling of a nanosecond Nd:YAG laserwith an atomic force microscope. The technique uses a tip enhancement effect obtained by theinteraction of laser radiation with the conductive tip of the AFM maintained at a few nanometers abovethe sample surface. By applying this technique to conducting gold and semiconducting silicon samples,a lateral resolution of 100 nm was demonstrated. With a single laser pulse, craters of about 100 nm indiameter and a few nanometers in depth were obtained. A multi-parametric study was carried out inorder to understand the effect of different experimental parameters (laser fluence, tip-to-sampledistance, sample and tip nature) on the near-field laser ablation efficiency, crater dimensions andamount of ablated material. Numerical simulations of the localized heating with a home-made 3-D codepresented a good explanation for the nanometer-sized crater diameters obtained in our experiment