Towards obtaining high-quality surfaces with nanometric finish by femtosecond laser ablation: A case study on coppers

•Surfaces with nanometric finish by femtosecond laser ablation on a copper workpiece have been realized.•A mathematical model of the ablation was established with different pulse overlap rates and scanning strategies.•Copper surface with surface roughness Sa of 0.056 μm was achieved with crossover scanning and pulse overlap rate of 60%.