Simultaneous Manipulation of the Optical and Wettability Properties of Metal Surfaces Using 150 kHz Femtosecond Fiber Laser

Abstract

We demonstrate the formation of permanent and iridescent colors on aluminum, copper, steel, and brass surfaces using femtosecond laser-induced periodic and non-periodic nanostructuring. We show that both the permanent and iridescent colors of the metal surfaces can be erased and re-colored using a second stage of laser processing. A correlation was found between the spectral reflective properties of the laser-processed surfaces and their wettability properties. Transition from superhydrophilic to superhydrophobic response is observed while tailoring the optical reflectance of the metal surfaces. We employ a high power femtosecond fiber laser at 150 kHz repetition rate, which notably reduces the processing time, making this technique attractive for practical applications.