Expansion matched thin disk laser and method for cooling

• US 7,027,477 B2
• Filed: 08/30/2002
• Issued: 04/11/2006
• Est. Priority Date: 08/30/2002
• Status: Expired due to Fees

• Current Assignee: Newport Corporation (MKS Instruments Incorporated)
• Original Assignee: Spectra-Physics Incorporated (MKS Instruments Incorporated)
• Inventors: Kafka, James D., Sutter, Dirk
• Primary Examiner(s): Harvey, Min
• Assistant Examiner(s): Nguyen, Dung T.
• Application Number:
  US10/232,885
• Publication Number:
  US 20040052283A1
• Time in Patent Office: 1,320 Days
• Field of Search: 372/34, 372/36, 372/71, 372/70
• US Class Current: 372/70
• CPC Class Codes: H01S 3/0405 Conductive cooling, e.g. by heat sinks or thermo-electric elements
• CPC Class Codes: H01S 3/042 for solid state lasers H01S3/0401 takes precedence
• CPC Class Codes: H01S 3/0604 in the form of a plate or disc
• CPC Class Codes: H01S 3/0606 with polygonal cross-section, e.g. slab, prism H01S3/0604 takes precedence
• CPC Class Codes: H01S 3/0627 the resonator being monolithic, e.g. microlaser
• CPC Class Codes: H01S 3/08072 Thermal lensing or thermally induced birefringence; Compensation thereof
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/1618 ytterbium

Abstract

An optical system includes a diode pump source and a thin disk gain media. The thin disk gain media has first and second surfaces and is made of a material with an anisotropic thermal expansion. At least one of the first and second surfaces is a cooling surface. The thin disk gain media is cut at an angle to provide substantially the same thermal expansion coefficient in all directions lying in a plane that is parallel to the cooling surface. An optical coupler is positioned between the diode pump source and the thin disk gain media to direct an output from the diode pump source to the thin disk gain media.

Claims

1. An optical system, comprising:

a diode pump source;

a thin disk gain media with first and second surfaces with at least one of the first and second surfaces being a cooling surface, the thin disk gain media being made of a material with an anisotropic thermal expansion and cut at an angle to provide substantially the same thermal expansion coefficient in all directions lying in a plane that is parallel to the cooling surface; and

an optical coupler positioned between the diode pump source and the thin disk gain media to direct an output from the diode pump source to the thin disk gain media.

2. The system of claim 1, wherein the thin disk gain media is made of a double-tungstate gain material.

3. The system of claim 1, wherein the thin disk gain media is made of an Yb³⁺ doped material.

4. The system of claim 2, wherein the thin disk gain media is made of Yb³⁺:

KYW.

5. The system of claim 2, wherein the thin disk gain media is made of Yb³⁺:

KGW.

6. The system of claim 1, wherein the thin disk gain media is made of a stoichiometric gain material.

7. The system of claim 6, wherein the thin disk gain media is made of KYbW.

8. The system of claim 1, wherein the thin disk is coated for high reflectance for laser light emitted by the system on one of the first and second surfaces, and with an anti-reflection coating for the laser light emitted by the system on the other of the first and second surface.

9. The system of claim 8, where the coating material is selected to provide a low thermal tension.

10. The system of claim 8, where the high reflectance coating is selected to provide a high reflectance for pump light over a range of incidence angles from 10 to 70 degrees, and the anti-reflection coating is selected to provide a low reflectance for the pump light over a range of incidence angles from 10 to 70 degrees.

11. The system of claim 1, wherein the thin disk is cooled by at least one cooling device coupled to at least one of the first and second surfaces.

12. The system of claim 11, wherein the cooling device has substantially the same thermal expansion coefficient as the cooling surface of the thin disk.

13. The system of claim 11, further comprising:

a bonding layer that couples the cooling device to the cooling surface, the bonding layer having substantially the same thermal expansion coefficient as the cooling surface of the thin disk.

14. The system of claim 1, wherein the diode pump source is fiber-coupled.

15. The system of claim 1, wherein the diode pump source is a stack of diode bars.

16. The system of claim 1, wherein the optical system is a laser system.

17. The system of claim 1, wherein the optical system is an amplifier system.

18. A method of producing an output beam from an optical device,

comprising:

providing an optical system with a diode pump source and a thin disk gain media made of a material with an anisotropic thermal expansion; and

cutting a cooling surface of the thin disk gain media at an angle to provide substantially a same thermal expansion coefficient in all directions in a plane of the cooling surface.

19. The method of claim 18, further comprising:

coupling a cooling device to the cooling surface.

20. The method of claim 18, further comprising:

coating a surface of the thin disk gain media with a high reflectance coating.

21. The method of claim 18, further comprising:

coating a surface of the thin disk gain media with an anti-reflection coating.

22. A method of treating an article, comprising:

providing an optical system with a diode pump source and a thin disk gain media made of a material with an anisotropic thermal expansion, the thin disk gain media being cut at an angle to provide substantially a same thermal expansion coefficient in all directions in a plane of a cooling surface;

producing an output from the optical system; and

directing the output to the article.

23. The method of claim 22, wherein the article is selected from a metal, a dielectric, a ceramic and a polymer.

24. The method of claim 22, wherein the output is directed to the article to ablate a surface of the article, drill a hole in the article or cut the article.