Figure 7
Schematics of the experimental setup used for fs laser surface structuring with VV beams generated by a q-plate. HWP = half-wave plate, P = polarizer, ES = electro-mechanical shutter; I = iris; L = lens. The silicon target is fixed on a computer controlled high precision 3-axis translation stage. The right panel shows images of the q-plates used in our experiments, e.g. q = 1, 3/2, 2, and 5/2, kept in between to cross-polarizing sheets. The image in the red dashed box corresponds to a q-plate with q = 1/2.
