Patent ID: 8685185

Claim:
A method for treating a metal or metal alloy to modify optical properties of the metal or metal alloy, the method comprising: exposing a surface region of the metal or metal alloy to one or more femtosecond duration laser pulses sufficient to alter a surface structure of the metal or metal alloy to form a plurality of nanoscale structure shapes on the surface region; wherein the surface region has a pre-laser treatment surface profile, the metal or metal alloy having a first electromagnetic absorption for the pre-laser treatment surface profile; wherein the plurality of nanoscale structure shapes formed by the one or more femtosecond duration laser pulses include a plurality of nanoscale cavities extending inwardly into the pre-laser treatment surface profile and a plurality of nanoscale protrusions extending outwardly away from the pre-laser treatment surface profile; wherein the formed nanoscale structure shapes increase the absorption of at least some electromagnetic wavelengths of the metal or metal alloy so that the metal or metal alloy has a second electromagnetic absorption greater than the first electromagnetic absorption.