Change in absorptance of metals following multi-pulse femtosecond laser ablation

Absorptance change of copper caused by surface modification following multi-pulse femtosecond laser ablation is studied as a function of number of applied laser pulses at various laser fluence. We show that laser-induced surface modification enhances the absorptance due to nano-, micro-, macro-structures and re-deposition of nanoparticles produced by the ablation. At sufficiently high fluence and with a large number of applied pulses, the absorptance of copper following ablation can reach a value of about 85%.