Laser system with staircased slow-axis collimators
In various embodiments, pointing errors in a non-wavelength-beam-combining dimension of a laser system are at least partially alleviated via staircased collimation lenses.
1. A laser system comprising:
a plurality of beam emitters each emitting one or more beams;
a dispersive element for receiving the beams and combining the beams, in a wavelength-beam-combining (WBC) dimension, into a multi-wavelength beam;
a plurality of collimators disposed optically downstream of the beam emitters and optically upstream of the dispersive element, wherein each collimator receives the one or more beams from a beam emitter and collimates the one or more beams in a non-WBC dimension; and
a partially reflective output coupler for receiving the multi-wavelength beam from the dispersive element, transmitting a first portion of the multi-wavelength beam as an output beam, and reflecting a second portion of the multi-wavelength beam back toward the dispersive element,
wherein optical axes of two or more of the collimators are displaced from each other in the non-WBC dimension.
2. The laser system of claim 1 , wherein the non-WBC dimension corresponds to a slow axis of the beams.
3. The laser system of claim 1 , wherein the non-WBC dimension corresponds to a fast axis of the beams.
4. The laser system of claim 1 , wherein the dispersive element comprises a diffraction grating.
5. The laser system of claim 4 , wherein the dispersive element further comprises one or more prisms.
6. The laser system of claim 1 , wherein at least one of the beam emitters comprises a diode bar configured to emit a plurality of discrete beams.
7. The laser system of claim 1 , wherein the collimators introduce beam smear in the non-WBC dimension at the dispersive element.
8. The laser system of claim 1 , further comprising, associated with each beam emitter, (i) a second collimator, and (ii) an optical rotator for rotating the one or more beams approximately 90°.
9. The laser system of claim 8 , wherein each collimator is a slow-axis collimator and each second collimator is a fast-axis collimator.
10. The laser system of claim 1 , wherein an optical distance between each of the collimators and the dispersive element is approximately equal.
11. The laser system of claim 1 , wherein heights of two or more of the collimators are different.
12. The laser system of claim 1 , wherein heights of two or more of the collimators are approximately equal.
13. The laser system of claim 1 , wherein heights of all of the collimators are approximately equal.
14. The laser system of claim 1 , further comprising one or more folding mirrors disposed optically downstream of the dispersive element and optically upstream of the output coupler.
15. The laser system of claim 1 , further comprising, disposed optically downstream of the beam emitters and optically upstream of the dispersive element, transform optics for converging chief rays of the beams toward the dispersive element.
16. The laser system of claim 1 , further comprising an optical fiber for receiving the output beam transmitted by the output coupler.
17. The laser system of claim 1 , wherein the dispersive element is oriented at a Littrow angle, in the WBC dimension, for at least one of the beams received by the dispersive element.
18. The laser system of claim 1 , wherein the dispersive element is oriented at an angle less than a Littrow angle, in the WBC dimension, of a center one of the beam emitters.
19. The laser system of claim 1 , wherein all of the collimators have approximately the same size and shape.
20. The laser system of claim 1 , further comprising a detection system for detecting beam smear and/or pointing errors of one or more of the beams.