Compact, thermally stable multi-laser engine

• US 7,903,706 B2
• Filed: 04/03/2009
• Issued: 03/08/2011
• Est. Priority Date: 04/04/2008
• Status: Active Grant

• Current Assignee: Melles Griot, Inc., Idex Health & Science LLC (RELX PLC)
• Original Assignee: CVI Laser LLC
• Inventors: Miller, Steven Lee, Lin, Mark, Hargis, David E., O'Shaughnessy, John
• Primary Examiner(s): Harvey; Minsun
• Assistant Examiner(s): Nguyen; Phillip
• Application Number:
  US12/418,537
• Publication Number:
  US 20090274176A1
• Time in Patent Office: 704 Days
• Field of Search: 372 22- 23, 372 34- 36, 372/38.01, 356/244, 356/246
• US Class Current: 372/34
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 21/0332 with temperature control control of temperature G05D23/00; cryostats F17C3/08
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/025 of solid state lasers, e.g. housings or mountings
• CPC Class Codes: H01S 3/027 comprising a special atmosphere inside the housing
• CPC Class Codes: H01S 3/2383 Parallel arrangements
• CPC Class Codes: H01S 3/2391 emitting at different wavelengths

Abstract

Various embodiments of a multi-laser system are disclosed. In some embodiments, the multi-laser system includes a plurality of lasers, a plurality of laser beams, a beam positioning system, beam focusing optics, a thermally stable enclosure and a temperature controller. The thermally stable enclosure is configured to thermally and mechanically couple to a flow cell. The thermally stable enclosure substantially comprises a material with high thermal conductivity. The thermally stable enclosure can have a relatively small volume.

Claims

1. A compact, thermally stable multi-laser system, comprising:

a plurality of lasers outputting a plurality of respective laser beams;

a beam positioning system configured to position the plurality of laser beams closer together;

beam focusing optics configured to focus the plurality of laser beams;

a thermally stable enclosure enclosing the plurality of lasers, the beam positioning system, and the beam focusing optics, and configured to thermally and mechanically couple to a flow cell, said thermally stable enclosure substantially comprising a material with high thermal conductivity of at least 5 W/(m K), and having a volume of 36 cubic inches or less; and

a temperature controller configured to control a temperature of said enclosure and flow cell and to align the focused laser beams to the flow cell over a range of ambient temperatures.

2. The system of claim 1, wherein the plurality of lasers comprises at least one diode laser.

3. The system of claim 1, wherein the plurality of lasers comprises at least one solid-state laser.

4. The system of claim 1, wherein the plurality of lasers comprises at least one frequency-doubled laser.

5. The system of claim 1, wherein the plurality of laser beams comprises at least a first laser beam at a first wavelength, a second laser beam at a second wavelength, and a third laser beam at a third wavelength, said first, second and third wavelengths being different from one another.

6. The system of claim 1, wherein the beam positioning system comprises a plurality of dichroic and trichroic mirrors.

7. The system of claim 6, further comprising a plurality of flexure mounts supporting the plurality of dichroic and trichroic mirrors.

8. The system of claim 6, wherein the dichroic and trichroic mirrors are configured with highly reflective and anti-reflective coatings in accordance with the respective wavelength of the plurality of laser beams.

9. The system of claim 6, wherein the dichroic and trichroic mirrors are configured to position at least two of the plurality of laser beams substantially coaxially, offset but parallel to each other or offset but not parallel to each other.

10. The system of claim 9, wherein the focused laser beams have centers separated by between about 110 μ

m and 140 μ

m of one another at the flow cell.

11. The system of claim 1, further comprising an automatic power control module for each laser of said plurality of lasers.

12. The system of claim 11, wherein the automatic power control module comprises a beam splitter and photodetector configured to sample light from the laser beam of each laser and to provide feedback to a laser controller to adjust each laser output power.

13. The system of claim 1, wherein the beam focusing optics includes an achromatic and anamorphic lens system to provide an output laser beam with an elliptical shape.

14. The system of claim 1, wherein the beam focusing optics includes an achromatic cylindrical lens to provide an output laser beam with an elliptical shape.

15. The system of claim 1, wherein the beam focusing optics includes an achromatic spherical lens to provide an output laser beam with an elliptical shape.

16. The system of claim 1 further comprising polarization rotators or waveplates which may be used to rotate the laser beam polarization to obtain a laser beam polarization orientation with respect to the laser beam geometry that enhances system performance.

17. The system of claim 1, wherein the beam focusing optics includes an anamorphic prism system to provide an output laser beam with an elliptical shape.

18. The system of claim 1, wherein the focused laser beams have respective spot sizes of between about 70 μ

m and 110 μ

m in one direction.

19. The system of claim 1, wherein the focused laser beams have respective spot sizes of between 6 μ

m and 14 μ

m in one direction.

20. The system of claim 1, wherein the material with high thermal conductivity comprises copper.

21. The system of claim 1, wherein the material with high thermal conductivity comprises copper tungsten material.

22. The system of claim 1, wherein the material with high thermal conductivity comprises aluminum material.

23. The system of claim 1, wherein the thermally stable enclosure comprises a top, a bottom and four sides.

24. The system of claim 1, wherein the thermally stable enclosure maintains a temporal temperature variation of less than about 1°

C. within the enclosure.

25. The system of claim 1, wherein the thermally stable enclosure has a width of about 3 inches or less.

26. The system of claim 1, wherein the thermally stable enclosure has a length of about 6 inches or less.

27. The system of claim 1, wherein the thermally stable enclosure has a height of about 2 inches or less.

28. The system of claim 1, wherein the thermally stable enclosure is hermetically sealed.

29. The system of claim 1, wherein the thermally stable enclosure matches the thermal expansion coefficient of the flow cell.

30. The system of claim 1, wherein the temperature controller comprises a thermal electric cooler, a temperature sensor and control electronics.

31. The system of claim 1, wherein the range of ambient temperatures is between about 10°

C. and 40°

C.

32. The system of claim 1, wherein the relative heights of the lasers in the enclosure assists in the relative positioning of the focused laser beams at the flow cell.

33. The system of claim 1, wherein the focused laser beams have centers separated by between about 110 μ

m and 140 μ

m of one another at the flow cell.