Fig. 1. Schematic diagram of the experimental setup.

Fig. 2. SEM images of ablation Ti at a fluence of 0.1  J/cm2 and incident angles of 0°, 20°, and 30°: (a)–(c) p-polarized fs laser; (d)–(f) s-polarized fs laser.

Fig. 3. Dependence of LIPSS period on a variety of irradiating p- and s-polarized incident angles at a fluence of 0.1  J/cm2 on Ti.

Fig. 4. Dependence of ripple periodicity with p polarization on the incident laser angle at fluences of 0.6, 0.4, and 0.2  J/cm2 irradiating on Ti.

Fig. 5. Dependence of ripple periodicity with p polarization on the incident laser angle at fluences of 0.8, 0.6, and 0.4  J/cm2 on a W surface. Insets, ripples’ images of the selected data points.