Q-switched microlaser apparatus and method for use

• US 7,649,920 B2
• Filed: 04/03/2007
• Issued: 01/19/2010
• Est. Priority Date: 04/03/2007
• Status: Active Grant

• Current Assignee: Topcon Positioning Systems Incorporated (Topcon Corporation)
• Original Assignee: Topcon Corporation, Voxis, Inc. (Topcon Corporation)
• Inventors: Welford, David
• Primary Examiner(s): Harvey; Minsun
• Assistant Examiner(s): Park; Kinam
• Application Number:
  US11/732,513
• Publication Number:
  US 20080247425A1
• Time in Patent Office: 1,022 Days
• Field of Search: 372/11, 372/10, 372/92
• US Class Current: 372/34
• 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 3/0627 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 3/1115 using intracavity saturable absorbers
• CPC Class Codes: H01S 3/113 using intracavity saturable absorbers

Abstract

A monolithic passively Q switched microlaser includes an optically transparent heat conductive element bonded to a gain medium, which is in turn bonded to a saturable absorber, which may also be bonded to a second optically transparent heat conductive element. Only the gain medium and saturable absorber are disposed within the laser resonator.

Claims

1. A microlaser arrangement comprising a monolithic body including:

a layer of optically pumped gain medium;

a layer of saturable absorber;

first and second reflectors arranged to enclose the gain medium and the saturable absorber in order to form a resonant cavity having an optical axis;

a pump beam at a pump laser wavelength applied through an input of the resonant cavity and absorbed by the gain medium to produce a laser beam at a microlaser wavelength from an output of the resonant cavity; and

a first heat spreader capable of selectively absorbing optical beams on the optic axis outside of the resonant cavity, the heat spreader coupled to the output of the resonant cavity and configured to substantially absorb the pump beam or the heat spreader coupled to the input of the resonant cavity and configured to substantially absorb the laser beam.

2. The microlaser of claim 1 wherein the gain medium active ion is Nd³⁺, Er³⁺, Ho³⁺, Tm³⁺, Yb³⁺, or a combination thereof.

3. The microlaser of claim 1 wherein the gain medium host material is a single crystal material that is a member of the garnet, fluoride, orthovanadate, tungstate, or oxyborate families.

4. The microlaser of claim 1 wherein the gain medium host material is a phosphate glass or a silicate glass.

5. The microlaser of claim 1 wherein the gain medium host material is an optical ceramic, such as ceramic YAG,

6. The microlaser of claim 1 wherein the gain medium is Nd:

YAG.

7. The microlaser of claim 1 wherein the gain medium is Yb,Er co-doped phosphate glass.

8. The microlaser of claim 1 wherein the saturable absorber active ion is Cr⁴⁺ or Co²⁺.

9. The microlaser of claim 1 wherein the saturable absorber host material is a single crystal material that is a member of the garnet, fluoride, orthovanadate, tungstate or oxyborate families.

10. The microlaser of claim 1 wherein the saturable absorber host material is a phosphate glass or a silicate glass.

11. The microlaser of claim 1 wherein the saturable absorber host material is an optical ceramic, such as ceramic YAG.

12. The microlaser of claim 1 wherein the saturable absorber is Cr:

YAG.

13. The microlaser of claim 1 wherein the saturable absorber is Co:

spinel.

14. The microlaser of claim 1 wherein the heat spreader is a single crystal host material that is a member of the garnet, fluoride, orthovanadate, tungstate or oxyborate families.

15. The microlaser of claim 1 wherein the gain medium, saturable absorber and heat spreader use a common host crystal.

16. The microlaser of claim 15 wherein the host crystal is a single crystal material that is a member of the garnet, fluoride, orthovanadate, tungstate or oxyborate families.

17. The microlaser of claim 1 wherein the heat spreader is transmitting at a pump laser wavelength and absorbing at a microlaser wavelength.

18. The microlaser of claim 17 wherein the heat spreader is Co:

spinel.

19. The microlaser of claim 1 wherein the first and second reflectors are dielectric coatings applied directly to the gain medium and saturable absorber, respectively.

20. The microlaser of claim 19 wherein the first reflector is highly transmitting at a pump laser wavelength and highly reflecting at a microlaser wavelength.

21. The microlaser of claim 19 wherein the second reflector comprises low transmission at pump laser wavelength and partial transmission at a microlaser wavelength.

22. The microlaser of claim 19 wherein the heat spreader is bonded to the first reflector and is transmitting at a pump laser wavelength and absorbing at a microlaser wavelength.

23. The microlaser of claim 1 wherein the heat spreader removes heat from an optically pumped surface.

24. The microlaser of claim 19 wherein the heat spreader is bonded to the second reflector, and comprises low transmission at a pump laser wavelength.

25. The microlaser of claim 1 wherein the first heat spreader is bonded to the first reflector, the heat spreader absorbing at a microlaser wavelength, and a second heat spreader is bonded to the second reflector, the second heat spreader absorbing at a pump laser wavelength.