Femtosecond laser pulse surface structuring methods and materials resulting therefrom

• US 8,685,185 B2
• Filed: 10/05/2011
• Issued: 04/01/2014
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: University of Rochester
• Original Assignee: University of Rochester
• Inventors: Guo, Chunlei, Vorobyev, Anatoliy Y.
• Primary Examiner(s): Zhu, Weiping
• Application Number:
  US13/253,173
• Publication Number:
  US 20120067855A1
• Time in Patent Office: 909 Days
• Field of Search: 219/121.69, 148/565
• US Class Current: 148/565
• CPC Class Codes: B23K 2103/05 Stainless steel
• CPC Class Codes: B23K 2103/08 Non-ferrous metals or alloys
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: B23K 2103/12 Copper or alloys thereof
• CPC Class Codes: B23K 2103/14 Titanium or alloys thereof
• CPC Class Codes: B23K 2103/16 Composite materials , e.g. fibre reinforced
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 2103/52 Ceramics
• CPC Class Codes: B23K 2103/54 Glass
• CPC Class Codes: B23K 2103/56 semiconducting
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/352 for surface treatment
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• CPC Class Codes: B23K 26/362 Laser etching
• CPC Class Codes: B44C 1/228 by laser radiation
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C21D 1/09 : by direct application of electrical or wave energy; by particle radiation
• CPC Class Codes: C21D 8/0294 : involving a localised treatment
• CPC Class Codes: C22F 3/00 : Changing the physical structure of non-ferrous metals or alloys by special physical methods, e.g. treatment with neutrons
• CPC Class Codes: Y10T 428/12201 : Width or thickness variation or marginal cuts repeating longitudinally
• CPC Class Codes: Y10T 428/12993 : Surface feature [e.g., rough, mirror]

Abstract

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.

Claims

1. 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.

2. The method of claim 1, wherein at least some of the nanoscale protrusions are each formed adjacent one of the nanoscale cavities.

3. The method of claim 1, wherein exposing the surface region of the metal or metal alloy to the one or more laser pulses of femtosecond duration to form the plurality of nanoscale structure shapes on the surface region additionally comprises forming a plurality of nanoscale rims, wherein at least some of the nanoscale rims are each around one of the nanoscale cavities.

4. The method of claim 1, wherein exposing the surface region of the metal or metal alloy to the one or more laser pulses of femtosecond duration to form the plurality of nanoscale structure shapes on the surface region additionally comprises forming nanoscale spherical structures on at least some of the nanoscale protrusions.

5. The method of claim 1, wherein forming the plurality of nanoscale structure shapes on the surface region increases the metal or metal alloy'"'"'s absorption of substantially all visible light wavelengths to give the metal or metal alloy a black or grey appearance.

6. The method of claim 1, wherein forming the plurality of nanoscale structure shapes on the surface region increases the metal or metal alloy'"'"'s absorption of some visible light wavelengths to give the metal or metal alloy a colored appearance.

7. The method of claim 1, wherein forming the plurality of nanoscale structure shapes on the surface region increases the metal or metal alloy'"'"'s absorption of some visible light wavelengths to give the metal or metal alloy a colored appearance that is the same at different viewing angles.

8. The method of claim 1, wherein exposing the surface region of the metal or metal alloy to the one or more laser pulses of femtosecond duration comprises exposing the metal or metal alloy to one or more laser pulses of the femtosecond duration at a fluence above an ablation threshold for the metal or metal alloy.

9. The method of claim 1, wherein exposing the surface region of the metal or metal alloy to the one or more laser pulses of femtosecond duration comprises subjecting the metal or metal alloy to one or more laser pulses of the femtosecond duration at a fluence at a near damage threshold for the metal or metal alloy.

10. A method of treating a metal or metal alloy, the method comprising:

exposing the metal or metal alloy to one or more laser pulses of a femtosecond duration to form a plurality of nanoscale structures on at least a portion of a surface of the metal or metal alloy, the nanoscale structures including nanoscale cavities extending into the surface, nanoscale protrusions extending out of the surface, and nanoscale rims extending out of the surface and around at least some of the nanoscale cavities.

11. The method of claim 10, wherein forming the plurality of nanoscale structures increases an absorption property of the metal or metal alloy of at least some visible electromagnetic wavelengths.

12. The method of claim 10, wherein forming the plurality of nanoscale structures increases an absorption property of the metal or metal alloy of at least some infrared electromagnetic wavelengths.

13. The method of claim 10, wherein forming the plurality of nanoscale structures increases an absorption property of the metal or metal alloy of at least some ultraviolet electromagnetic wavelengths.

14. 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 a plurality of femtosecond duration laser pulses sufficient to alter a surface structure of the metal or metal alloy to form a plurality of 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 structure shapes formed on the surface region include a periodic structure including a plurality of grooves and a plurality of ridges, wherein the plurality of structure shapes formed on the surface region further includes a plurality of nanoscale structure shapes extending from both the plurality of grooves and the plurality of ridges;

wherein the plurality of formed 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.

15. The method of claim 14, wherein the formed nanoscale structure shapes include nanoscale protrusions extending outwardly from the grooves and ridges.

16. The method of claim 15, wherein at least some of the formed nanoscale protrusions comprise nanoscale branches supporting nanoscale spherical structures.

17. The method of claim 14, wherein the formed nanoscale structure shapes include nanoscale protrusions covering both the grooves and ridges.

18. The method of claim 14, wherein the formed structure shapes are configured to increase the metal or metal alloy'"'"'s absorption of some visible light wavelengths to alter a colored appearance of the metal or metal alloy.

19. The method of claim 18, wherein the altered colored appearance is different at different viewing angles.

20. The method of claim 14, wherein the formed periodic structure has a period that is less than a wavelength of the laser pulses.

21. The method of claim 14, wherein exposing the surface region of the metal or metal alloy to one or more femtosecond duration laser pulses comprises exposing the surface region of the metal or metal alloy to one or more femtosecond duration laser pulses at a near damage threshold fluence for the metal or metal alloy.

22. A method of treating a metal or metal alloy, the method comprising:

exposing a surface region of the metal or metal alloy to a plurality of femtosecond duration laser pulses at a near damage fluence for the metal or metal alloy sufficient to alter a surface structure of the metal or metal alloy to form a plurality of structure shapes on the surface region;

wherein the plurality of formed structure shapes include a periodic structure including a plurality of grooves and a plurality of ridges, wherein the plurality of formed structure shapes further include a plurality of nanoscale structure shapes covering the plurality of grooves and the plurality of ridges.

23. The method of claim 22, wherein the formed nanoscale structure shapes include nanoscale protrusions extending from the grooves and ridges.