Functional surface on periodical nanostructure self-organized by laser scanning at speed of 300 m/min

After CW lasers scanned a target at high speed of 300 m/min, periodical nanostructure self-organized on the target surface. Unlike fiber-like structure fabricated by femtosecond laser, the periodic structure showed trench structures with flat bottoms. A theoretical simulation of thermal distribution of the target indicated the target temperature exceeds its melting point, which was verified by micro-Raman spectroscopy. The time dependent thermal distribution indicated the existence of threshold melting period to form the trench nanostructure. The nanostructure showed well-regulated gratings, and the precise periodicity emerged structural color and modified water-repellent on the target surface.

► Nanostructure self-organized on the trace of scanning CW lasers. ► Self-organized nanostructure was literally trench structure unlike finer structure fabricated by femtosecond laser. ► Depending on laser power, the period of nanostructure was varied between wavelength of two lasers. ► Structural color and water repellent were shown as examples for structural functions.