Refractive-diffractive hybrid lens, in particular for beam shaping of high power diode lasers

• US 20050168837A1
• Filed: 11/18/2004
• Published: 08/04/2005
• Est. Priority Date: 11/21/2003
• Status: Active Grant

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Wolfing, Bernd, Luttmer, Jorg, Ebeling, Polina, Beier, Wolfram, Pawlowski, Edgar, Brinkmann, Matthias
• Granted Patent: US 7,345,828 B2
• Time in Patent Office: Days
• US Class Current: 359/710
• CPC Class Codes: G02B 19/0009 having refractive surfaces only
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0052 the light source comprising a laser diode coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/0966 Cylindrical lenses cylindrical lenses per se G02B3/06
• CPC Class Codes: G02B 27/4272 having plural diffractive elements positioned sequentially along the optical path
• CPC Class Codes: G02B 27/60 Systems using moiré fringes
• CPC Class Codes: G02B 5/1814 structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings G02B5/189 takes precedence
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence

Abstract

A cylindrical lens having a refractive optical element and a diffractive optical element is provided. The cylindrical lens can be fabricated cost effectively and precisely, and optical aberrations and defects in semiconductor diode laser arrangements can be corrected. The diffractive optical element can include various segments.

Claims

1. A cylindrical lens comprising:

a refractive optical element having a refractive surface; and

a diffractive optical element.

3. The cylindrical lens as claimed in claim 1, wherein the cylindrical lens has an optical axis, and wherein the refractive optical element and/or the diffractive optical element are not perpendicular to the optical axis.

4. The cylindrical lens as claimed in claim 1, wherein the diffractive optical element is arranged on a body of the refractive optical element or is defined by the body.

5. The cylindrical lens as claimed in claim 1, wherein the diffractive optical element is arranged in a plane opposite the refractive surface.

6. The cylindrical lens as claimed in claim 1, wherein the diffractive optical element is arranged on a body of the refractive optical element or is defined by the the body, and wherein the diffractive optical element is arranged in a plane opposite the refractive surface.

7. The cylindrical lens as claimed in claim 1, wherein the refractive surface and the diffractive optical element define an aspheric cylindrical lens.

8. The cylindrical lens as claimed in claim 1, wherein the cylindrical lens is a fast-axis collimator lens assigned to at least one semiconductor laser.

9. The cylindrical lens as claimed in claim 1, wherein the cylindrical lens is assigned to a linear array of semiconductor diode lasers.

10. The cylindrical lens as claimed in claim 1, wherein the cylindrical lens has at least one curvature in an optical and/or a physical longitudinal direction.

11. The cylindrical lens as claimed in claim 1, further comprising a further functional element.

12. The cylindrical lens as claimed in claim 11, wherein the further functional element directs a predefined portion of a light of a high power laser onto a monitor diode or a monitor camera.

13. The cylindrical lens as claimed in claim 11, wherein the further functional element directs a predefined portion of a light of a high power laser into one or more laser waveguides of a laser bar that serves only as a monitor diode.

14. The cylindrical lens as claimed in claim 11, wherein the further functional element produces an image that permits the cylindrical lens to be aligned relative to a light source and/or an external pattern.

15. The cylindrical lens as claimed in claim 11, wherein the further functional element is a second diffractive optical element for aiming light onto a detector as a function of a position of the cylindrical lens relative to a light source.

16. The cylindrical lens as claimed in claim 15, wherein the detector is a four quadrant detector.

17. The cylindrical lens as claimed in claim 11, wherein the further functional element images a structure by the adjustment or relative position of the cylindrical lens relative to a light source.

18. The cylindrical lens as claimed in claim 11, wherein the further functional element is a second diffractive optical element for imageing and/or reading out an identification.

19. The cylindrical lens as claimed in claim 1, further comprising a second diffractive optical element for producing a multilens imaging system.

20. The cylindrical lens as claimed in claim 19, wherein the second diffractive optical element is part of a multilens collimator system, and wherein the second diffractive optical element has a prefocusing effect.

21. The cylindrical lens as claimed in claim 19, wherein the second diffractive optical element defines a curved optical longitudinal axis.

22. The cylindrical lens as claimed in claim 19, wherein the second diffractive optical element defines a second cylindrical lens with an optical longitudinal axis that extends substantially transverse to an optical longitudinal axis of the cylindrical lens.

23. The cylindrical lens as claimed in claim 20, wherein the multilens system is at least a part of a slow-axis collimator lens system, and wherein the second diffractive optical element has a focusing or prefocusing effect.

24. The cylindrical lens as claimed in claim 19, wherein the second diffractive optical element is at least a part of a slow-axis collimator lens system, and wherein the second diffractive optical element has a focusing or prefocusing effect in a tilted fashion in a plurality of pairs relative to an optical longitudinal axis of the cylindrical lens.

25. The cylindrical lens as claimed in claim 24, wherein the second diffractive optical element is a refractive element.

26. The cylindrical lens as claimed in claim 24, wherein the diffractive optical element and/or the refractive optical element are segmented and tilted so that a plurality of partial beams bounded by a plurality of individual segments have a plurality of different angles.

27. The cylindrical lens as claimed in claim 9, further comprising an optical element assigned to one high power laser diode of the linear array of the semiconductor diode laser.

28. The cylindrical lens as claimed in claim 1, further comprising an antireflection layer.

29. The cylindrical lens as claimed in claim 28, wherein the antireflection layer is a moth eye antireflection layer that is a part of a diffractively acting layer.

30. The cylindrical lens as claimed in claim 15, wherein the cylindrical lens and/or the second diffractive optical element are produced by thermal shaping.

32. The cylindrical lens as claimed in claim 15, wherein the cylindrical lens and/or the second diffractive optical element are produced by pressing, embossing or fine embossing.

33. The cylindrical lens as claimed in claim 15, wherein the diffractive optical element and/or the second diffractive optical element are produced by lithographic techniques.

34. The cylindrical lens as claimed in claim 1, wherein the refractive optical element is produced by hot shaping so that a body with a plurality of rectangular elevations is heated and is cooled down.

39. The cylindrical lens as claimed in claim 1 wherein the refractive surface is a spherical surface.

40. The cylindrical lens as claimed in claim 15, wherein the cylindrical lens and/or the second diffractive optical element are produced by axial elongation in the heated state.

2. A cylindrical lens comprising:

a refractive optical element having an aspheric surface; and

a diffractive optical element.

31. (canceled)

35. (canceled)

36. A set of cylindrical lenses, comprising:

a plurality of cylindrical lenses, wherein each of the plurality of cylindrical lenses has a refractive optical element having a refractive surface, and a diffractive optical element, and wherein each of the plurality of cylindrical lenses has a different curvature in a longitudinal direction for compensating a tolerance range of curvatures of high power diode laser arrays.

37. A semiconductor laser system comprising:

a cylindrical lens having a refractive optical element with a refractive surface, and a diffractive optical element.

38. A material processing system comprising:

a cylindrical lens having a refractive optical element with a refractive surface; and

a diffractive optical element.