Inducing subwavelength periodic nanostructures on multilayer NiPd thin film by low-fluence femtosecond laser beam

Highlights: • Femtosecond laser beam was applied to multilayer Ni/Pd thin film. • The beam was applied in static and scanning regimes. • Spatial period dependence on the scanning direction is due to the phase difference increase between incoming and induced oscillations. • The structures formation has been caused by the surface plasmon polariton. - Abstract: During femtosecond interaction with surfaces, the processes of liquid and solid-state dewetting could be responsible for the generation and regrouping of nanoparticles and nanoparticle clusters. The occurrence of surface plasmon polariton most probably induces the LIPSS arrangement. We have used low-fluence scanning femtosecond beam to generate sub-wavelength periodic structures on multilayer Ni/Pd thin films on Si. The spatial period of LIPSS increases with the change of scanning directions in respect to the polarization direction due to the phase difference increase between the incoming and induced oscillations.