Wavelength beam combining laser systems with micro-optics
In various embodiments, wavelength beam combining systems feature multiple beam emitters each emitting an individual beam, as well as multiple micro-optics arrangements each disposed optically downstream from a beam emitter to intercept the beam emitted thereby and direct the beam toward a dispersive element for combination into a multi-wavelength output beam.
1. A method of producing a multi-wavelength output beam, the method comprising:
emitting a plurality of individual beams from one or more emission points;
rotating each individual beam at a different angle to thereby direct the beams toward each other;
thereafter, focusing the rotated beams to overlap the beams at a common focal point;
wavelength-dispersing the focused beams;
propagating a first portion of the dispersed beams back to the one or more emission points; and
propagating a second portion of the dispersed beams as the multi-wavelength output beam.
2. The method of claim 1 , wherein, before focusing, the rotated beams are not converging toward the common focal point.
3. The method of claim 1 , further comprising splitting the dispersed beams into the first portion and the second portion.
4. The method of claim 3 , wherein the dispersed beams are split by a partially reflective output coupler, the output coupler reflecting the first portion back to the one or more emission points.
5. The method of claim 1 , wherein each beam is rotated by a different micro-optics arrangement.
6. The method of claim 5 , wherein each micro-optics arrangement comprises an optical twister.
7. The method of claim 6 , wherein the optical twister comprises two cylindrical lenses.
8. The method of claim 7 , wherein the cylindrical lenses are rotationally offset from each other.
9. The method of claim 5 , wherein each micro-optics arrangement comprises a fast-axis collimation lens, an optical twister, and a slow-axis collimation lens.
10. The method of claim 9 , wherein the optical twister is disposed (i) optically downstream from the fast-axis collimation lens and (ii) optically upstream from the slow-axis collimation lens.
11. The method of claim 1 , wherein the focused beams are wavelength-dispersed by a diffraction grating.
12. The method of claim 1 , wherein the plurality of beams are emitted by one or more diode bars.
13. The method of claim 1 , wherein the focused beams are wavelength-dispersed at the common focal point.
14. The method of claim 1 , wherein the rotated beams are focused by one or more spherical lenses.
15. The method of claim 1 , further comprising reducing or substantially eliminating cross-coupling between the individual beams.
16. The method of claim 15 , wherein cross-coupling is reduced or substantially eliminated via a plurality of spherical lenses.
17. The method of claim 15 , wherein the plurality of spherical lenses is positioned to intercept the dispersed beams.
18. The method of claim 15 , wherein cross-coupling is reduced or substantially eliminated via (i) a first lens having a first focal length, and (ii) a second lens, disposed optically downstream from the first lens, having a second focal length.
19. The method of claim 18 , wherein a ratio of the first focal length to the second focal length is two or greater.
20. The method of claim 18 , wherein an optical distance between the first and second lenses is approximately equal to a sum of the first and second focal lengths.
21. The method of claim 1 , wherein the rotated beams are focused by a lens having a focal length greater than an optical distance between the lens and the common focal point.