Self-organized micro/nano structures in metal surfaces by ultrafast laser irradiation

Ultrafast laser pulse interaction with matter, leading to formation of self-organized conical micro/nano structures in various metals like Ti. Al, Cu, and stainless steel have been observed Influence of laser parameters such as fluence, number of shots, and gaseous environments on micro/nano structure formation have been investigated The critical fluence required for well-developed structure formation is dependent on the optical and thermo-physical properties of the materials By changing the number of laser shots to generate micro/nano structures, surface reflectance of Ti surface could be tailored from their original value (over 50%) to near zero over the wavelength range of 500-1000 nm Also, we have demonstrated that arrays of micro/nano holes could be formed in thin Ti foils by direct laser treatment. (C) 2010 Elsevier Ltd All rights reserved