Manipulation of LIPSS orientation on silicon surfaces using orthogonally polarized femtosecond laser double-pulse trains

Laser-induced periodic surface structures (LIPSS) provide an easy and cost-effective means of fabricating gratings and have been widely studied in recent decades. To overcome the challenge of orientation controllability, we developed a feasible and efficient method for manipulating the orientation of LIPSS in real time. Specifically, we used orthogonally polarized and equal-energy femtosecond laser (50 fs, 800 nm) double-pulse trains with time delay about 1ps, total peak laser fluence about 1.0 J/cm ² , laser repetition frequency at 100 Hz and scanning speed at 150 μm/s to manipulate the LIPSS orientation on silicon surfaces perpendicular to the scanning direction, regardless of the scanning paths. The underlying mechanism is attributed to the periodic energy deposition along the direction of surface plasmon polaritons (SPPs), which can be controlled oriented along the scanning direction in orthogonally polarized femtosecond laser double-pulse trains surface scan processing. An application of structural colors presents the functionality of our method.