Figure 3. SEM images of the laser-textured samples prepared in ambient air. Blue arrows show the direction of scanning by laser beam. Direction of polarization is marked with white arrows in the case of linear polarization and with white circle in the case of circular polarization.
The morphology of the laser-textured surfaces prepared in ambient air is shown on Fig. 3. The direction of scanning is shown by blue arrows, and polarization direction is shown by white arrows. Changing scanning speed with saving single pulse fluence led to formation of the periodic submicron- and micron-sized ripples at low number of overlapped beams (Fig. 3, 300 mm/s) and microgrooves at intermediate number of overlapped beams (Fig. 3, 50 mm/s) and in principal can form the quasiperiodic arrays of microspikes at high number of pulses and linear polarization [19, 20]. In our case, at very low scanning speed, corresponding to optimal conditions for the microspikes formation, i.e. at high number of overlapped shots, the meshes started to deform due to accumulating heat and destruction of wires. Because of this we limited our experiments with 50 mm/s lowest speed.