Wavelength beam combining laser systems utilizing etalons
In various embodiments, wavelength beam combining laser systems incorporate etalons to establish external lasing cavities and/or to combine multiple input beams into a single output beam.
1. A laser system comprising:
an array of beam emitters each emitting a beam, the beams being emitted substantially parallel to each other in a propagation direction;
an etalon for receiving the beams and combining the beams into a multi-wavelength beam, the etalon having an optical axis, a front surface, and a back surface optically downstream of the front surface;
disposed optically downstream of the beam emitters and optically upstream of the etalon, focusing optics for focusing the beams toward the etalon; and
a partially reflective output coupler for receiving the multi-wavelength beam, reflecting a first portion thereof back through the etalon to the beam emitters, thereby stabilizing each beam to a different wavelength, and transmitting a second portion thereof as an output beam composed of multiple wavelengths.
2. The laser system of claim 1 , further comprising collimation optics disposed optically downstream of the etalon and optically upstream of the partially reflective output coupler.
3. The laser system of claim 1 , wherein the front surface of the etalon is substantially parallel to the back surface of the etalon.
4. The laser system of claim 1 , wherein the etalon comprises at least one of glass, sapphire, or fused silica.
5. The laser system of claim 1 , wherein the output coupler comprises at least one of a mirror, a volume Bragg grating, or a fiber Bragg grating.
6. The laser system of claim 1 , wherein the optical axis of the etalon is tilted at a non-zero angle with respect to the propagation direction.
7. The laser system of claim 1 , wherein the front surface of the etalon is partially reflective to the beams.
8. The laser system of claim 7 , wherein a reflectivity of the front surface of the etalon to the beams is greater than approximately 75% but less than 100%.
9. The laser system of claim 1 , wherein at least a portion of the back surface of the etalon is at least partially reflective to the beams.
10. The laser system of claim 9 , wherein the at least a portion of the back surface of the etalon has a reflectivity to the beams of approximately 100%.
11. The laser system of claim 1 , wherein the back surface of the etalon has (i) a reflective portion for reflecting the beams back toward the front surface, and (ii) an exit portion from which the multi-wavelength beam exits the etalon.
12. The laser system of claim 11 , wherein one or more of the beams is reflected by both the front surface and the reflective portion of the back surface prior to combination into the multi-wavelength beam.
13. The laser system of claim 11 , wherein the exit portion of the back surface of the etalon comprises an anti-reflective coating thereon.
14. The laser system of claim 11 , wherein the etalon is positioned to receive the beam from one of the beam emitters and propagate at least a portion thereof directly through the exit portion of the back surface without reflection from the reflective portion.
15. A laser system comprising:
an array of beam emitters each emitting a beam, the beams being emitted substantially parallel to each other in a propagation direction;
an etalon for (i) receiving the beams, (ii) reflecting a first portion of each beam from a surface of the etalon back to the array of beam emitters, thereby stabilizing each beam at a unique wavelength, and (iii) transmitting a second portion of each beam such that the second portions of the beams are transmitted through the etalon only once without reflection back to the etalon, the etalon having an optical axis, a front surface, and a back surface optically downstream of the front surface;
disposed optically downstream of the beam emitters and optically upstream of the etalon, focusing optics for focusing the beams toward the etalon; and
disposed optically downstream of the etalon, a dispersive element for receiving and dispersing the beams, thereby forming a multi-wavelength output beam.
16. The laser system of claim 15 , further comprising collimation optics disposed optically downstream of the etalon and optically upstream of the dispersive element.
17. The laser system of claim 15 , wherein the dispersive element comprises a diffraction grating.
18. The laser system of claim 15 , wherein the etalon comprises at least one of glass, sapphire, or fused silica.
19. The laser system of claim 15 , further comprising, disposed optically downstream of the etalon and optically upstream of the dispersive element, second focusing optics for focusing the beams onto the dispersive element.
20. The laser system of claim 15 , wherein the optical axis of the etalon is tilted at a non-zero angle with respect to the propagation direction.
21. The laser system of claim 15 , wherein the front surface of the etalon is substantially planar.
22. The laser system of claim 21 , wherein the back surface of the etalon is convexly curved.
23. The laser system of claim 15 , wherein the back surface of the etalon is convexly curved.
24. The laser system of claim 1 , wherein no dispersive element or diffraction grating is disposed optically between the array of beam emitters and the output beam transmitted by the partially reflective output coupler.
25. The laser system of claim 1 , wherein no dispersive element or diffraction grating is disposed optically between the etalon and the output beam transmitted by the partially reflective output coupler.
26. The laser system of claim 1 , wherein the etalon is positioned to receive each of the beams at a different point on the front surface of the etalon.
27. The laser system of claim 15 , wherein the etalon is configured to support multi-spatial modes.