Femtosecond laser pulse surface structuring methods and materials resulting therefrom
Embodiments of the present invention are generally directed to materials processing methods using femtosecond duration laser pulses, and to the altered materials obtained by such methods. The resulting nanostructured (with or without macro- and micro-structuring) materials have a variety of applications, including, for example, aesthetic applications for jewelry or ornamentation; biomedical applications related to biocompatibility; catalysis applications; and modification of, for example, the optical and hydrophilic properties of materials including selective coloring.
1. An object comprising:
a metal or metal alloy having a surface with a femtosecond laser treated region;
the surface having a pre-laser treatment profile;
the metal or metal alloy having a first light absorption when profiled per the pre-laser treatment profile;
the femtosecond laser treated region of the surface comprising laser-induced periodic surface structures comprising:
periodic microscale structure shapes formed on the metal or metal alloy; and
a plurality of nanoscale structure shapes formed by the metal or metal alloy covering the periodic microscale structure shapes, the nanoscale structure shapes including a plurality of nanoscale protrusions extending outwardly away from the microscale structure shapes;
the laser-induced periodic surface structures increasing absorption of at least some light wavelengths of the metal or metal alloy within the femtosecond laser treated region so that the metal or metal alloy within the femtosecond laser treated region has a second light absorption greater than the first light absorption.
2. The object of claim 1 , wherein the microscale structure shapes comprise a plurality of at least one of micropores, microgrooves, and microchannels.
3. The object of claim 1 , wherein the laser-induced periodic surface structures have a period that is less than a wavelength of the femtosecond laser.
4. The object of claim 1 , wherein the laser-induced periodic surface structures form a grating.
5. The object of claim 1 , wherein the laser-induced periodic surface structures have a period on a sub-micron level.
6. The object of claim 1 , wherein the laser-induced periodic surface structures have a microroughness in a range of 1-15 micrometers.
7. The object of claim 1 , wherein the laser-induced periodic surface structures reflect less than 10% of light having a wavelength between 250-2500 nm.
8. The object of claim 1 , wherein the laser-induced periodic surface structures exhibit different colors depending on viewing angle due to a grating effect.