Figure 4.

AFM height images (2.5 × 2.5 µm² size) and cross-sections profiles along the corresponding white lines of PS films irradiated at 266 nm, 1 kHz of repetition rate, and at F = 0.6 m${\mathrm{J}/\mathrm{cm}}^2$, with number of pulses, N, (a) 50 × 10³, (b) 100 × 10³, and (c) 800 × 10³. The polarization direction of the laser beam is indicated by double arrows.