## 4 Conclusions  
In conclusion, we demonstrated the appearance of permanent and angle-dependent colors using femtosecond laser surface structuring of aluminum, copper, steel, and brass through the formation of laser-induced periodic surface structures and non-periodic nano/microstructing. We showed that both these groups of colored species can be either erased or re-colored using an additional step of laser processing. The process of material surface restructuring was attributed to the SPP excitation and its interference with the incident laser irradiation. This interference resulted in the laser intensity redistribution across the surface and its periodic patterning. The scanning speed was found to be a key factor in determining the resulted optical properties of the generated structures. There is an optimal scanning speed at which the pre-modified surface structure can serve as a feedback for each subsequent pulse, which enhances the accuracy of the produced LIPSS in a multipulse regime.  
The relation between the spectral reflective properties of different colored metals and the wettability of the processed metal surfaces was also studied. We demonstrated the possibility to simultaneously tailor the coloring as well as the wettability properties of metals by optimizing the set of laser parameters employed in the processing. Furthermore, vacuum storage of the laser-treated samples dramatically changed their wettability response from hydrophilic to superhydrophobic lasting permanently even after leaving the vacuum-stored sample in an ambient atmosphere. Vacuum ageing allows the surface energy of the sample to be changed via desorption of the oxide layer followed by adsorption of carbon species from the surrounding environment.  
All these manipulations of metal surfaces were carried out using the fiber femtosecond laser at 150 kHz repetition rate, which notably reduces the processing time to make this technique attractive for industrial applications. An 80 mm square stainless steel sample was processed in only 227 s to achieve LIPSS features on the surface.  
Conceptualization, A.S.A.; Data curation, V.K.; Formal analysis, M.I., V.I., G.B. and D.I.; Funding acquisition, A.S.A.; Investigation, M.I., V.K. and G.B.; Methodology, V.I.; Resources, B.R. and A.S.A.; Writing--original draft, D.I., R.A.G. and A.S.A.; Writing--review & editing, R.A.G. and A.S.A. All authors have read and agreed to the published version of the manuscript.  
This work was supported by FRG ASI801 grant and the Common Research Facility at the American University of Sharjah. The work in this paper was supported, in part, by the Open Access Program from the American University of Sharjah. This paper represents the opinions of the authors and does not intend to represent the position or opinions of the American University of Sharjah. DSI was supported by Deutsche Forschungsgemeinschaft projects RE 1141/14-2.  
The authors declare no conflict of interest.  
Figure 7: Images for the surface roughness using Atomic Force Microscope and Confocal Microscope. The images correspond to (**a**) black, (**b**) brown, (**c**) golden, (**d**) multicolor. The roughness histograms shown on the right side of the Figure were generated from the Confocal Microscope measurements.