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Ripple-like nanostructure patterns are known to occur in ultrafast laser ablation with linearly polarized radiation. The observation of similar features at the bottom of grooves produced during laser ablation of stainless-steel with circular polarization is reported here. A comprehensive morphological analysis of the machined surfaces, carried out by electron and scanning probe microscopes, reveals a marked dependence of feature shape on process parameters, in particular on the scanning velocity of the laser spot. Such a dependence is interpreted based on the occurrence of an inclined surface during the ablation and on the consequent differential absorption of s- and p-polarized components of the laser radiation by stainless-steel. The resulting anisotropy of the absorbed energy mimics irradiation with elliptical polarization that can drive formation of ripple-like, elongated nanostructures.

In this article we will present architecture, properties and application of a novel scanning probe microscopy (SPM) piezoresistive cantilever with thermal deflection actuator. This microprobe with an integrated planar microtip is utilized in shear-force microscopy (ShFM) in which the cantilever microtip vibrates parallel to the surface. We will describe the calibration procedure of sensitivity of cantilever piezoresistive deflection detection, thermal actuation and experimental setup of the developed measurement system. We will also present results of topography measurements of highly oriented pyrolytic graphite (HOPG) and Hafnia alvei bacteria culture surface using developed ShFM system.